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Laying Out for Boiler Makers 
 
 and 
 
 Sheet Metal Workers 
 
 A Practical Treatise on the La^^ottt of 
 Boilers^ Stacks^ Tanks, Pipes, Elbol^s, and Miscellaneous 
 
 Sheet Metal Work 
 
 SECOND EDITION 
 
 OVER 600 ILLUSTRATIONS 
 
 Copyright 1 91 3, by Aldrich Publishing Company 
 
 NEW YORK 
 
 ALDRICH PUBLISHING COMPANY 
 
 17 Battery Place 
 
 I9I3 
 
n I?) 
 
 PREFACE TO FIRST EDITION 
 
 This book has been compiled for the purpose of giving the practical boilermaker the 
 information necessary to enable him to lay out in detail different types of boilers, tanks, stacks 
 and irregular sheet metal work. While the work of laying out, as it is carried on in the boiler 
 shop, requires considerable technical knowledge in addition to that gained by a practical 
 mechanic in the course of his experience in the shop, yet a complete mastery of such subjects 
 as geometry, mechanics and similar branches of elementary mathematics is not essential 
 for doing the work. For this reason no attempt has been made to present these subjects 
 separately from a theoretical standpoint. The practical application of certain of the principles 
 involved in these subjects is, however, very important, and this has been explained in a prac- 
 tical way in connection with different jobs of laying out which form a part of the every-day 
 work in every boiler shop. Only those layouts which are of immediate material use to boiler- 
 makers are described, and as far as possible the minor details are given so as to make each 
 problem complete. 
 
 The first two chapters explain the methods of laying out by orthographic projection 
 and triangulation, since these are the two principal methods used in solving any problem in 
 laying out. A few simple problems are given in each case from which the application of the 
 methods to more complicated problems may be learned. The chapters which take up the 
 detailed layout of different types of boilers give not only the methods for laying out the actual 
 boiler but also the rules for determining the size, shape and strength of the different parts. 
 These computations are given more in detail in the case of the plain tubular boiler, since the 
 problems involved in this case are general and may be applied to almost any other type of 
 boiler. 
 
 PREFACE TO SECOND EDITION 
 
 The second edition of this book contains all of the material published in the first edition, 
 together with one hundred and thirteen additional pages, fully illustrated, comprising forty- 
 four new laying out problems and chapters on miscellaneous calculations and tools for boiler 
 makers. The new laying out problems form a part of Chapter VIII, bringing the total number 
 of problems in this chapter up to fifty-four. They cover a wide range of work, showing the 
 layout and construction of regular and irregular elbows, pipe connections, transition and 
 offset pieces, taper courses, spiral pipe, hemispherical water tanks, firebox wrapper sheets 
 for locomotive boilers and smokestack collars, hoods, uptakes and smokeboxes for Scotch 
 boilers. The chapter on miscellaneous calculations shows how to figure the strength and 
 efficiency of riveted joints, the area of circular segments and the cost of boiler construction. 
 In the chapter on tools for boiler makers and their uses, no attempt is made to describe all 
 of the various types and makes of tools used in a boiler shop, but the tools are classified accord- 
 ing to their various uses and the general principles governing their construction and operation 
 are given, together with many practical hints as to the proper way to use the tools. 
 
 /3-/^ 
 
 ?- 
 
 /jp^ 
 
TABLE OF CONTENTS 
 
 CHAPTER 1. 
 
 PAGE 
 
 THE SUBJECT OF LAYING OUT. Squaring up a Plate— Plane Surfaces— Cylindrical Surfaces- 
 Cylindrical Tank — Open Tank — Intersection of Cylinders — A Cylindrical Coal Chute 
 — Angle Iron Rings — Conical Surfaces — Intersection of Cone and Cylinder at an Angle 
 of 60 Degrees — Conical Surfaces Where the Taper is Small — 90-Degree Tapering Elbow 7 
 
 CHAPTER II. 
 
 TRIANQULATION. Definitions— Truncated Oblique Cone— Circular Hood for Stack— A "Y" 
 
 Connection 25 
 
 CHAPTER III. 
 
 HOW TO LAY OUT A TUBULAR BOILER. Factor of Safety— Riveted Joints— Treble Riveted 
 Lap Joint— How to Ascertain the Lap — Circumferential Seams — Butt Joint with Inside 
 and Outside Straps — Thickness of Butt Straps — Welded Joints — Effect of Punching 
 Steel Plate — Size of Shell Plates — Size of Heads — Specifications for Boiler Steel — 
 Layout of Tubes — Holding Qualities of Flues — Collapsing Pressure of Flues — Direct 
 Bracing — Methods of Fastening Braces — Strength of Braces — Area of a Segment — 
 Indirect Bracing — Size and Number of Rivets in a Brace — Size of Brace Palm — Forms 
 of Braces — Brace Pins — Steam Domes — Dome Braces — Dished Heads — Manholes — 
 Suspension of Boiler — Layout of Sheets of Completed Boiler — Details of Longitudinal 
 Seams — Piping and Fittings — Main Steam Outlet — Safety Valve — Dry Pipe^-Blow-off 
 Pipe— The Injector— The Check Valve— The Feed Pipe— The Feed Water Pump — 
 Water Gage and Test Cocks — Steam Gage— High and Low Water Alarms — Damper 
 Regulator 31 
 
 CHAPTER IV. 
 
 HOW TO LAY OUT A LOCOMOTIVE BOILER. Steam Domes — Dome Liner— Front Tube Sheet 
 — Shell Plates — Gusset Sheet — Firebox Back Sheet — Firebox Tube Sheet — Firebox 
 Side Sheet — Firebox Crown Sheet — Mud-Ring — Water Space Corners — Fire Doors — 
 Outside Firebox Sheets — Throat Sheet — Top Throat Sheet — Back Head — Belpaire 
 Firebox Crown Sheet — Smokebox Liner — Smokebox Connection — Smokebox Exten- 
 sion — Smokebox Front Door — Deflecting Plates — Netting Door— Stack — Lagging — 
 Boiler Mountings — Tubes and Piping 65 
 
TABLE OF CONTENTS — Con^maec/ 
 
 CHAPTER V 
 
 PAGE 
 
 HOW TO LAY OUT A SCOTCH BOILER. Arrangement of Furnaces—Side Elevation— Arrange- 
 ment of Tubes — Back Connections — Stay Tubes and Plain Tubes — Shell Plates — Butt 
 Straps — Circumferential Seams — Manholes — Locating Butt Straps — Through Stays — 
 Boiler Saddles — Ordering Material — Laying Out Shell Plates — Front and Back Heads 
 — Tube Sheet — Back Heads of Combustion Chambers — Wrapper Plates — Furnace 
 Fittings — Uptakes — Boiler Mountings — Specifications for a Typical Three-Furnace 
 Boiler 105 
 
 CHAPTER VL 
 
 REPAIRING LOCOMOTIVE AND OTHER TYPES OF BOILERS. Renewing a Set of Half-Side 
 Sheets, Half-Door Sheets, Front Flue Sheet and Smokebox Bottom — Applying Back 
 Corner Patches, Back Flue Sheet, Backing Out Rivets and Repairing Cracked Mud- 
 Ring — Renewing a Set of Radial Stays, Broken Staybolts and Flues — Applying a 
 Patch on Back Flue Sheet, a New Stack, Bushings Between Staybolt Holes and Straight- 
 ening a Bulge in the Firebox — Stationary Boilers — ^Two-Flue Cylindrical Boiler — 
 Vertical Fire Engine Boiler — Water Tube Boilers — Babcock- Wilcox, Stirling, Yarrow, 
 Nest Coil Semi-Flash Boilers 139 
 
 CHAPTER Vn. 
 
 THE LAYOUT AND CONSTRUCTION OF STEEL STACKS. Size of Stack— Guyed vStack— Self- 
 Supporting Stack — Base Plate — Anchor Bolts — Lining — Fancy Top — Stability — Thick- 
 ness of Shell Plate— Calculations for Stack 191 Feet High by 10 Feet Diameter— Bell- 
 Shaped Base i57 
 
 CHAPTER VIII. 
 
 MISCELLANEOUS PROBLEMS. A "Y" Breeching--A Tank 85 Feet in Diameter by 30 Feet 
 High — Offset from a Round to an Oblong Pipe — A Four-Piece 90-Degree Elbow with 
 Large and Small Ends on Each Course — Bottom Course of Stack — A Simple Method 
 of Laying Out Ship Ventilating Cowls — Intersection of a Cylinder and Elbow by Pro- 
 jection — A Copper Converter Hood — A Hopper for a Coal Chute by Triangulation — 
 A 90-Degree Elbow — A Flue and Return Tubular Boiler with Drop Leg Furnaces — 
 A Lobster Back Boiler — A Dog House Boiler — Layout of an Exhaust Elbow — To 
 Develop Regular and Irregular " Y" Pipe Connections — Layout of a Horizontal Return 
 Tubular Boiler 18 Feet Long by 72 Inches Diameter — Construction of a 90-Degree 
 Elbow — Development of an Irregular Elbow — Layout of Gusset Plates — Layout of a 
 Conical Elbow — Unusual Layout of an Irregular Elbow — Pipe with a Compound 
 Curve — Development of a 90-Degree Elbow, Running frcm a Round into a Rectangular 
 Section — Development for a Y-Pipe Connection — Layout of an Irregular Pipe Inter- 
 secting a Large Cylinder at Right Angles — Development of an Irregular Pipe Con- 
 nection — Layout of Intersecting Cones — Layout of a Rectangular Pipe Intersecting 
 a Cylinder Obliquely — Layout of the Intersection of Two Right Cones — Layout of a 
 Hopper for a Concrete Mixer — Layout of a Transition Piece — Layout of Special Transi- 
 tion Piece — Pattern for a Hood for a Semi-Portable Forge — Layout of a Spout Interr 
 secting a Conical Body — Layout of Tapered Transition Piece — Triangulation Applied 
 
TABLE OF CONTENTS — Continued 
 
 PAGE 
 
 to the Layout of a Transition Piece — Layout of an Irregular Offset Piece — Layout of 
 a Tapered Course — Method of Laying Out the True Camber of a Tapered Course — 
 The Development of an Irregular Connection by Triangulation — Layout of a Taper 
 Course with a Flat Side — Layout of a Granet or Hood for an Oval Smokestack — 
 Layout of a Double Angle Pipe from the Same Mitre Line — Layout of an Irregular 
 Spiral Piece — A Spiral Pipe — Laying Out a Wrapper Sheet for a Locomotive Firebox — 
 Layout of a Smokestack Collar — Layout of an Intersection Between a Dome and Slope 
 Sheet for a Locomotive Boiler — Approximate Method of Developing a Sloping Firebox 
 Wrapper Sheet — The Layout of an Arched Smoke-Box — Layout of an Uptake for a 
 Scotch Boiler — Layout for a Hemispherical Head for Tank — Layout of a Breeching 
 for a Scotch Boiler — A Simple, Accurate and Positive Method for Securing the Template 
 for a Segment of a Sphere — Calculations for Determining the Size of Plates for a Self- 
 Supporting Steel Stack Base — Layout of a Hemispherical Tank Head — Layout and 
 Construction of a Large Water Tank 165 
 
 CHAPTER IX. 
 
 M ISCELLANEOUS CALCULATIONS. Lap Joints— Diagram for Finding the Efficiency of Riveted 
 Joints — The Area of Circular Segments — Estimating the Cost of a Small Scotch Boiler — 
 Estimating the Cost of a Return Tubular Boiler 266 
 
 CHAPTER X. 
 
 TOOLS FOR BOILER MAKERS AND THEIR USES. Staybolt Taps— Pipe Taps— The Hammer- 
 Calking Tools — Beading Tools — Tube Expanders — Tool Steel — High Speed Steel- 
 Annealing Steel — Chisels — Chipping — Center Punch — Ratchets — Ratchet Drills — The 
 "Old Man"— Operation of a Ratchet Drill— Other Ratchet Drills— The Sledge— Uses 
 of the Drift Pin — Patch Bolts and Patch Bolt Taps — Erecting Bolts — Heavy Machine 
 Tools — Punches — Operation of Punching Machines — Machine Tool Drive — Shears — 
 Rotary Bevel Shears — Hydraulic Shears — Hydraulic Flanging Presses — Machine Tool 
 Accessories — Bending Rolls — Cranes and Hoists — Compressed Air and Its Uses — 
 Power Required for Compressing Air — Air Compressors — Air or Pneumatic Tools — 
 The Unbalanced Area System — The No-Valve System — Other Forms of Air Tools. . . . 281 
 
FLUE AND RETURN TUBULAR BOILER INSTALLED ON THE UNITED STATES REVENUE CUTTER "PERRY." II FEET 
 6 INCHES DIAMETER BY 1/ FEET LONG, STEAM PRESSURE 6o POUNDS PER SQUARE INCH. 
 
THE SUBJECT OF LAYING OUT 
 
 The work of laying out in a boiler shop consists of first 
 determining from blue prints or drawings the true size and 
 shape of the plates, bars, etc., of which an object is to be 
 constructed, and of then marking out on the material itself to 
 these dimensions the lines on which it is to be cut and shaped. 
 This necessitates on the part of the layer out a knowledge of 
 some of the more common problems in plane geometry, such 
 as are ordinarily used in drafting; a knowlefdge of that part 
 of descriptive geometry which deals with the development of 
 the surfaces of solids of all kinds ; and an intimate knowledge 
 of the behavior of the material which is used in the construc- 
 tion, when it is being punched, roMed, flanged, etc. 
 
 The work of a layer out is similar in many respects to that 
 of a draftsman, except that it is done to a much larger scale, 
 with coarser instruments, and upon iron and steel instead of 
 paper. While some of it is merely copying what the drafts- 
 
 FIG. I. — TRAMMELS. 
 
 man has already worked out, yet the layer out must know how 
 to construct accurately the common geometrical figures and 
 figure out their dimensions, as he often has to work out in de- 
 tail what the draftsman indicates only in a general way. He 
 must know how to find the development of the surfaces of all 
 kinds of solids, because most of the drawings of the various 
 objects made in a boiler shop give only the dimensions of the 
 completed article, showing the plates, angles, etc., after they 
 have been bent or forged to the required shapes. From these 
 dimensions the layer out must find the exact size and shape 
 of every piece of material when laid out flat, so that after it 
 has been cut out and shaped by these lines it will be of ex- 
 actly the required size and shape and fit accurately in its 
 proper place. To get this result, the layer out must not only 
 understand how to find the development of diflferent surfaces, 
 but he must also know how the material will behave when it 
 is being bent, flanged, forged, etc., for in some instances the 
 metal will be drawn out, or "gain" in length, while in others 
 it will be upset, or "lose" in length. Allowances must be made 
 for these "losses" and "gains" when the plate is laid out, and 
 
 while, in certain cases, rules can be given for this, the most 
 successful man will have to depend upon his experience 
 for this knowledge. For this reason every layer out should 
 be a practical boiler maker, and have a thorough understand- 
 ing of the boiler maker's trade, as he will then more readily 
 
 J 
 
 riG. 2. — ME.VSURINC WHEEL. 
 
 understand when such allowances should be made and how 
 much they should be. 
 
 Most of the tools and instruments used by a layer out in 
 his work are well known to a boiler maker and need little ex- 
 planation. The lines are drawn in with chalk or soapstone 
 pencils. Long, straight lines are snapped in with a chalk line. 
 Short ones are drawn in with a steel straight edge. Circles 
 are drawn with trammels, or, as they are more commonly 
 called "trams," a sketch of which is given in Fig. i. 
 
 FIG. 3. 
 
 This instrument consists of two steel points fastened to 
 metal blocks which slide upon a rod or stick of sufficient 
 thickness to resist bending. The blocks can be clamped at 
 any point on the rod by screws. Circles of small diameter 
 are drawn in with dividers. A more common use of the 
 dividers, however, is that of spacing off a succession of equal 
 distances, as in spacing rivet holes. 
 
LAYIXG OUT FOR BOILER MAKERS 
 
 Lines are drawn at right angles to each other, or "squared 
 up" by means of a steel square, although this cannot be de- 
 pended upon where great accuracy is required, as the sides of 
 the square are too short to determine the direction of a long 
 line. The method of "squaring up" lines by a geometrical 
 construction will be explained later. All measurements along 
 straight lines are made with an ordinary 2-foot rule or steel 
 tape. For measuring along curved lines, the tape may be 
 used by holding it to the curve at short intervals, but a better 
 device is the measuring wheel, as shown in the illustration. 
 
 at the point on the wheel indicating the fractional part of a 
 revolution remaining. 
 
 The use of these tools, as well as the construction of the 
 ordinary geometrical problems, will be apparent from the 
 problems in laying out which are to be taken up and fully ex- 
 plained. Also such rules as can be given for the allowances 
 to be made due to bending, flanging, etc., will be explained in 
 connection with these layouts. 
 
 In general, there are four kinds of surfaces which must be 
 dealt with in boiler work, and of which the layer out must be 
 
 FIG. 4. — PLAN AND ELEVATION. 
 
 This wheel is made of a thin piece of metal, beveled to a 
 sharp edge, and having a circumference of a certain exact 
 length, as 2 or 3 feet, with the divisions in inches and frac- 
 tions of an inch marked upon it. The wheel is pivoted to a 
 handle and can be run over the line, measuring its length 
 exactly. If it is impossible to get one of these graduated 
 wheels, a blank wheel of any diameter may be used by first 
 running it over a straight line on which the distance to be 
 layed off has been marked, and noting the number of com- 
 plete revolutions of the wheel and placing a mark upon it at 
 the fractional part of a turn left over. Then the wheel can 
 be run over the curved line until it has made the same num- 
 ber of complete revolutions and the end of the curve marked 
 
 able to find the development. These are plane surfaces, cylin- 
 drical surfaces, conical surfaces and irregular curved surfaces. 
 A plane surface is one in which all the lines lie in the same 
 plane, that is, an ordinary flat surface. A cylindrical surface 
 is one which is formed by a line moving parallel to itself in a 
 curved path. The most common form of the cylinder is 
 that in which this path is a circle. A conical surface is in a 
 similar manner generated by a straight line and has a circular 
 or elliptical cross section ; but the surface tapers to a point 
 instead of being formed of parallel lines, as in the cylinder. 
 All surfaces which do not come under the above types may 
 be included in the last division, that of irregular curved sur- 
 faces, and must be developed by special methods. 
 
THE SUBJECT OF LAYING OUT 
 
 PLANE SURFACES. 
 
 Plane surfaces are very simple to lay out, as usually their 
 true dimensions are given on the blue print or drawing, so 
 that it is only a matter of drawing out the outline of the sur- 
 face to these dimensions. There is always one operation, how- 
 ever, which must be performed upon every plate that is layed 
 
 The trams can now be reset to very nearly one-half AB, and . 
 arcs struck as before. The arcs will practically intersect the 
 line at the same point this time, and a center punch mark can 
 be put in at exactly the middle point of the line. Now with 
 A and B as centers and a radius greater than AC strike arcs 
 intersecting at some point D above the line. Then a line 
 
 -JT^ 
 
 -32 Spaces © I.9S = 72^ 
 
 FIG. 5. — TOP PATTERN. 
 
 out, and that is squaring it up. Squaring up a plate means, 
 practically, drawing upon it two lines at right angles to each 
 other so that all dimensions of length can be laid off along 
 or parallel to one of these lines, and all dimensions of breadth 
 can be laid off along or parallel to the other line. 
 
 A plate is squared up as follows : Consider the plate shown 
 in Fig. 3, which is to be laid out rectangular in shape with a 
 length of S feet between the center lines of the rivet holes at 
 each end of the plate, and a width of 3 feet between the 
 upper and lower rows of rivets. Assume the lap or distance 
 
 drawn through C and D will be at right angles to, or "squared 
 up" with, AB. 
 
 The lines for the other rows of rivets can now be drawn in 
 as follows: Draw EF at a distance of 3 feet from AB, cut- 
 ting the center line CD at j\I. Then with the trams set to the 
 distance AC and with M as a center strike arcs cutting EF at 
 E and F. Join A and E, B and F, and then you have the 
 center lines of the rows of rivets squared up and drawn in 
 according to the dimensions called for. If the plate has been 
 ordered to size and sheared with the corners square, a l^^-inch 
 
 I 
 
 4-5 spc 
 
 1.37 = 36; 
 
 1 
 
 5- 
 
 .i 
 
 -I- i^ 
 
 AB 
 
 FIG. 6. — SIDE PATTERN. 
 
 from center of rivet to edge of plate to be Ij^ inches. Then 
 draw a line for the lower row of rivets, as AB, lYs inches 
 from one edge of the plate. Locate the point A 1% inches 
 from one end of the plate and B at a distance of S feet from 
 A. Put in center punch marks at A and B, and then locate 
 the middle point C of the line AB. This may be done by 
 measurement, or with the trams as follows : Set the trams by 
 guess at about half the length of AB, and with A and B as 
 centers strike arcs intersecting AB. These arcs will probably 
 be only a short distance apart, and of course the center of 
 the line is at the center of the distance between the arcs. 
 
 lap should remain all around the plate outside the rivet lines. 
 It is never safe to assume that the edges of a plate, as it 
 comes from the mill, have been sheared out square with each 
 other, and so lay out the plate from them. They may be very 
 nearly square, but the rivet lines must be laid out exactly 
 square or the plate will not fit when put in place. 
 
 After the plate has been squared up and the rivet lines 
 drawn in, the rivet holes must be spaced in. This is most 
 easily done with the dividers, stepping the spaces otT on the 
 lines which have been drawn on the metal ; but where the same 
 spacing is to be used again, it may be done on a thin strip of 
 
lO 
 
 LAYING OUT FOR BOILER MAKERS 
 
 wood, called a regulator or gage, and then the spaces marked 
 from this upon the metal. In either case, set the dividers 
 roughly to the pitch or distance between the centers of the 
 rivet holes called for by the drawing, and, starting with one 
 point of the dividers at one end of the line, step off the spaces 
 until the other end of the line is reached. If this setting of 
 the dividers leaves a fraction of a space at the end of the 
 line, reset the dividers and go over it again until the last 
 space is exactly equal to the others. Mark these points with 
 a deep center punch mark, to aid in centering the punch or 
 drill when the holes are put in the plate. 
 
 The plate should now be marked with white paint, showing 
 the number of the job or contract for which it is to be used, 
 the size of the rivet holes, and any other information neces- 
 sary to tell what operations should be performed upon it in 
 
 fore space them about I'/i inches or 1 54 inches between centers. 
 
 The plan which has been layed down full size will serve 
 as a pattern for the top and bottom plates. Make the joints 
 at the lines AC and BD, so that a plate will not have to be 
 cut out with a reentrant angle, as that would mean a loss of 
 material. Strike in the rivet lines, leaving a ^<-inch lap all 
 around the plate, and space in the rivet holes at about lyi 
 inches or i^ inches. 
 
 Patterns showing the angles to which the angle bars are to 
 be bent must be made for the blacksmith. Unless the layer 
 out feels sure of the amount to be allowed for the bends in 
 tlie bars, the rivet holes should not be spaced in until after 
 they are bent. Care should be taken not to bring a joint in 
 the angles at the same place as a joint in the plates. 
 
 While this is a very simple layout, and one which is easily 
 
 il I I I I 1 1 I 1 1 I. 
 1315,7 S II 111 II? 117 i» l;ilUy 
 
 II )a li n 19 Zl 23 £5 £3 21 19 17 IF 13 II 
 
 •^12 46 8 10 12 /-T 16 18 2BZ2Z*) '^ 
 FIG. 7. 
 
 B 
 
 2 4 6 8 /O /Z H /6 IS io Z2 Z4 ai £< 22 20 le /6 /< /2 /O 8 6 4 a 
 FIG. S. 
 
 the shop or how it should be assembled in the finished article. 
 
 Fig. 4 shows a portion of a rectangular flue leading from 
 the uptakes of a battery of boilers to the stack. This is made 
 up entirely of flat surfaces fastened together with inside 
 angles. As the top and bottom plates are alike, it is necessary 
 to get the layout of only one of the plates, which may then 
 be used as a pattern for the other. Similarly, one pattern will 
 do for the two sides. 
 
 First lay out the plan full size according to the dimensions 
 of the drawing. Then the lengths of the plates can be meas- 
 ured directly from this plan. Since the plates are only y^ inch 
 thick, no allowance will have to be made for the bends at A 
 and B. Consider that there will be a joint in the side plates 
 I foot from each bend. Then lay out the side pattern as fol- 
 lows: Lay off the width of the plate from edge to edge as 
 3 feet. Strike in the rivet lines, leaving ^<-inch lap. Square 
 up the rivet line at one end of the plate, leaving a '/2-inch lap. 
 Then measure i foot from the edge of the plate and square 
 up a line on which the plate is to be bent. Then lay off from 
 this the distance AB, measuring it from the full-size plan 
 already laid out. Square up another line for the bend at B, 
 and measure i foot beyond that for the edge of the plate. 
 Strike in the rivet line l/i inch back from this edge. Now 
 space off the rivet holes; j4-inch rivets will be useo, there- 
 
 understood from the drawing, the apprentice will find little 
 difficulty with any other problem involving only plane or flat 
 surfaces, as the size and shape of the plates can easily be 
 found, and few allowances must be made. As nearly all 
 problems involve cylindrical or other curved surfaces, we will 
 next take up the method of developing such surfaces. 
 
 CYLINDRICAL SURFACES. 
 
 Cylindrical surfaces are laid out by a method of parallel 
 lines ; for instance, in developing the surface of the cylinder 
 shown in Fig. 7, proceed as follows : Draw a half view of the 
 plan and divide the semi-circumference into any number of 
 equal parts, in this case twelve. Project lines down from these 
 points of division upon the cylinder. Lay out the line AB, Fig. 
 8, equal to the length of the circumference of the base of the 
 cylinder and divide it into the same number of equal parts 
 into which the base was divided ; in this case twenty-four as 
 the semi-circumference was divided into twelve equal parts. 
 Draw lines at right angles to AB at these points and lay off 
 along them the lengths of the corresponding lines in Fig. 7. 
 When each base of the cylinder is at right angles with the 
 axis as in Fig. 7, all of these lines are equal so the developed 
 surface will be a rectangle. If the base MN had been inclined 
 as MN', then the length of each of the parallel lines would 
 
THE SUBJECT OF LAYING OUT 
 
 II 
 
 have been different and it would have been necessary to meas- 
 ure each line separately and lay it out on the corresponding 
 line in the development. Then the bottom edge of the de- 
 veloped surface would have the form shown by the dotted line 
 in Fig 8, the numbers showing the corresponding lines on the 
 cylinder and development. 
 
 FIG. 9. 
 
 Before taking up the actual layout of a cylindrical boiler 
 or tank shell, the apprentice must first be able to find the 
 circumference of a circle in order to get the length of the 
 plate corresponding to the distance AB in Fig. 8, as this line 
 was made equal to the length of the circumference of the base 
 
 times its radius squared. The use of such tables will greatly 
 reduce the labor of computation and the chances of making 
 mistakes. 
 
 As the material used in boiler construction has considerable 
 thickness, it will be apparent that when a plate is rolled up 
 in the form of a cylinder, the diameter at the inside of the 
 plate is less than the diameter at the outside by twice the 
 thickness of the plate; therefore, the circumference corre- 
 sponding to the inside diameter will be considerable less than 
 that corresponding to the outside diameter. When laying out 
 the plate it will be seen that neither of these values for the 
 circumference should be used for the length of the plate, as 
 one would be too short and the other too long; but the cir- 
 cumference of a circle, whose diameter may be called the 
 neutral diameter or the diameter to the middle of the thick- 
 ness of the plate will be the correct one to use. Thus, in Fig. 
 9, if a half-inch plate is to be rolled to a cylinder whose in- 
 side diameter is 48 inches, the plate must be laid out with a 
 length between the center lines of the rivet holes equal to 
 the circumference of a circle whose diameter is 4814 inches, 
 or referring to Fig. 9, it will be seen that if t =: the thickness of 
 the material and D the inside diameter, then the neutral di- 
 ameter is D -|- 2 X H t or D -|- t. Therefore the circumfer- 
 ence corresponding to this diameter is 3.1416 X (D -(- t) or 
 3.1416 D -|- 3.1416 t. That is, it is equal to the circumference 
 corresponding to the inside diameter plus 3.1416 times the 
 thickness of the plate. For ordinary work three times the 
 thickness of the plate is generally used. The circumference 
 ■corresponding to the outside diameter might have been found, 
 in which case three times the thickness of the plate should 
 have been subtracted from it. When two rings or courses of 
 plates are to be joined together, one of which is an inside 
 and the other an outside ring, the circumference correspond- 
 ing to the neutral diameter of the inside ring may be found. 
 
 f" 
 
 CO 
 
 to 
 
 4__: 
 
 -s- 
 
 Plate a 
 
 -48- 
 
 12' 
 
 Plate B 
 
 48 
 
 Plate A 
 
 4 8"- 
 
 of the cylinder. The circumference of a circle is equal to 
 3.1416 times its diameter. If the apprentice is not familiar 
 ■with the use of decimals, the same result may be obtained by 
 multiplying the circumference by 22 and dividing by 7. In 
 nearly all engineers' and boiler makers' hand-books, tables 
 are given, in one column of which are values of diameters, and 
 in another column the corresponding values of the circum- 
 ferences of the circles, and in a third column the values of 
 the areas of the circles. The area of a circle is equal to 3.1416 
 
 and then for the length of the outside plate six times the 
 thickness of the material should be added to this. This will 
 make a close fit between the rings, as the exact amount to be 
 added is 2 times 3.1416 or about 6^4 times the thickness of 
 the material. For an easy fit, add a little more to this. 
 This amount can best be determined from the experience of 
 the layer out for the particular job in hand. In the case of a 
 straight stack, with in and out rings, where there is no pres- 
 sure upon the shell and the work is not to be water-tight, 
 
LAYING OUT FOR BOILER MAKERS 
 
 seven times the thickness of material can be added to the 
 length of the inside ring for the length of the outside ring. 
 
 Bearing in mind the foregoing manner of determining the 
 length of the rings of a cylindrical shell and the allowances 
 to be made due to rolling the material, let us consider the lay- 
 out of the shell of the pressure tank shown in Fig. lo. This 
 tank is 36 inches diameter and 12 feet long, excluding the 
 heads. It is to be made of three rings of S-i6-inch plate with 
 double-riveted lap joints for the longitudinal seams and single- 
 
 Ca 
 
 v.^' 
 
 
 
 
 ' • • /\ 
 
 ' 
 
 
 
 
 
 
 
 
 
 
 
 Plate 
 
 A 
 
 
 
 
 
 
 A.- 
 
 . . . • . t 
 
 
 , J 
 
 Sl^ 
 
 ^ 3 8 SPACES ® 3 = //•+- 
 
 draw in the rivet lines for the longitudinal seams. Space in 
 the rivet holes about 3 inches between centers. As the length 
 of the circular seam is 114 inches, a 3-inch pitch will give just 
 thirty-eight spaces in the circular seam. 
 
 The length of the longitudinal seam is 48 inches, so there 
 will be sixteen equal spaces using the 3-inch pitch. As this 
 seam is double riveted, the rivet holes should be staggered as 
 shown in the detail Fig. 13. Care should be taken to see 
 which end of the plate will come outside when the plate is 
 
 FIG. II. 
 
 riveted lap joints for the circumferential seams, all rivets to 
 be J4 of an inch in diameter. The width of each ring as 
 shown on the drawing is 4 feet between the center lines of the 
 rows of rivets. Lay out the plates to dimensions taken 
 through the center lines of the rivet holes, and afterward 
 add the necessary amount for laps. 
 
 First, lay out one of the end or outside plates. As each ring 
 forms a cylinder whose bases are at right angles with its axis 
 the development will be a rectangle similar to the first develop- 
 ment in Fig. 8. Therefore it will not be necessary to draw th;; 
 parallel lines. The width of this plate between the centers of 
 rows of rivets is 48 inches. The length must be computed 
 from the diameter of the ring. The drawing indicates that 
 the inside diameter of this ring is 36 inches. The circum- 
 ference corresponding to a diameter of 36 inches is 113 1-16 
 inches. 
 
 3-1416 
 36 
 
 188496 
 94248 
 
 113.0976 or 113 1-16 inches. 
 
 .'^dd three times the thickness of the plate or three times 5-16, 
 which equals 15-16. Therefore, the length of the plate between 
 the centers of the rivet lines is 114 inches. Having found 
 these dimensions lay out the plate as follows. 
 
 First, draw the line AB for the lower row of rivets lyi 
 inches from the edge of the plate. Then measure from one 
 end of the plate along the line AB 1% inches for tlie lap. 
 From this point measure I 13-16 inches for the second row of 
 rivets. Now, lay off from this point along AB 114 inches as 
 shown by the dimensions on Fig. II. Measure back from this 
 point I 15-16 inches for the second row of rivets at this end of 
 the plate. Draw the line CD 48 inches from AB. Now, 
 square up the plate by the method previously explained and 
 
 rolled up so that the outer row of rivets at this end of the 
 plate can be spaced equally. The rivet holes in the other row 
 may be conveniently located by setting the dividers to the 
 diagonal pitch, and then with the centers of the holes, which 
 have been equally spaced as centers, strike intersecting arcs as 
 shown in Fig. 13. When the end of the plate comes between 
 two other plates at the corners the plate should be drawn 
 out thin or scarfed. As this plate is an outside ring, the 
 
 FIG. 13. 
 
 corners of the end which comes inside at the lap should be 
 scarfed as indicated by the dotted lines in Fig. 11. 
 
 The layout of the inside ring is similar to that of the out- 
 side, except that the length between the centers of the rivet 
 holes is less than that of the outside plate by six times the 
 thickness of the material. As the plate is 5-16 inch thick, six 
 times the thickness will be 1% inches; therefore, the length of 
 this plate should be 114 inches minus 1% of 1121^ inches. The 
 pitch of the rivets in the circular seam will not be the same as 
 in the outside plate, since the number of spaces must be the 
 
THE SUBJECT OF LAYLNG OUT 
 
 13 
 
 same. As this is an inside ring, the corners of that end of the 
 plate, which comes outside at the lap when the plate is rolled 
 up, should be scarfed as indicated by the dotted lines in 
 Fig. 12. 
 
 The layout of the heads has not been given in this article, 
 neither have the nozzles in plates A and A' been located, as 
 this layout was given simply to show the method of getting 
 the sizes of the plates which form a cylindrical surface. 
 
 LAYOUT OF AN OPEN TANK. 
 
 Fig. 14 shows an open tank 6 feet wide by 4 feet deep (in- 
 side dimensions) and 15 feet long between the center lines of 
 
 I2J4 inches. Therefore, the length of one-quarter of the cir- 
 cumference corresponding to this diameter will be 
 3.1416 
 
 62832 
 31416 
 ■7854 
 
 38.4846 
 
 = 9.6215 
 
 38.4846 
 or gs/s". 
 
 J5 
 
 -60 
 
 60" 
 
 FIG. 14. 
 
 the rivet holes in the heads. This tank is to be made of three 
 courses of J-<J-inch plate joined together by single-riveted lap 
 seams, the rivets being i/s inch in diameter. The radius of 
 the curve at the corners of the tank is 6 inches. The heads are 
 to be flanged. 
 
 First lay out one of the end or outside plates, a sectional 
 view of which is shown in Fig. 15. It will be seen that the 
 length of this plate is equal to zVi feet (the length of the flat 
 part of the plate at the side), plus one-quarter of the circum- 
 ference of a circle of 6)4, inches radius, plus 5 feet (the length 
 of the flat portion of the plate at the bottom) plus one-quarter 
 
 I 
 
 6g- RAD. 
 6" RAD.- 
 
 ,'vK\\\\\V\\\V\V\T\\V^^'yV\\\\\V'v\\'v\V^\\VV\\V\V^ 
 
 Now, lay out the plate as shown in Fig. 16. As the rivets 
 are to be 5^ inch, the lap, which is usually 1Y2 times the 
 diameter of the rivet, will be about I inch. Therefore, draw in 
 a line i inch from the longest edge of the plate. Lay ofif 354 
 feet or 42 inches from one end of the plate for the side; then 
 gYs inches for the curved portion ; then 5 feet or 60 inches for 
 the bottom, and then g% inches for the other corner, and then 
 2V2 feet or 42 inches for the other side. Lay out the width 
 of the plate 60 inches. Square up the ends and the flange 
 lines to which the corners are to be rolled. The rivet holes 
 should be spaced in at about V/z inches between centers. Put 
 in the first rivet hole i inch from the end of the plate, and then 
 step off the spaces at about this pitch to the flange line at the 
 
 f^ 1634: >i 
 
 
 
 OUTSIDE PIPJE 
 
 
 
 
 
 
 
 , 1 
 
 J 
 
 ^,Z\SPi.=4t '><)->X QOsps.= 60"— ^^Zisps-'^Z-^ 
 
 ffS«=9| 
 
 nc. 15 
 
 FIG. 16. 
 
 of the circumference of a circle of 6% inches radius, plus 3^^ 
 feet (the length of the straight portion of the other side). The 
 length of the curved or cylindrical part must be computed as 
 follows. 
 
 Since the inside radius at the corner is 6 inches and the 
 thickness of the plate Y^ of an inch, the neutral diameter of the 
 cylinder, of which this forms one-quarter of the surface, will be 
 
 corner. The same spacing may be used on the other side. 
 Then step off an even number of spaces in the curved part, 
 changing the pitch if necessary, also step off the spaces on the 
 bottom at as near the same pitch as possible. 
 
 For the inside plate, the only difference in the dimensions 
 will be in the length of the curved part at the comer. The 
 neutral diameter for this plate will be Ii54 inches, or the 
 
14 
 
 LAYING OUT FOR BOILER MAKERS 
 
 ntutral diameter of the outside plate minus twice the thick- moved. After the plate is flanged the rivet line can be drawn 
 
 ness of the material. One-quarter of the circumference of a - and the holes spaced to correspond with the holes in the ad- 
 circlc liJi inches in diameter will be joining plate. 
 
 3.1416 
 
 31416 
 31416 
 23562 
 
 36.9138 
 
 36-9138 
 
 = 9.2285" or 9 7-32". 
 
 FIG. 17. 
 
 This gives us then 97-32 inches as the length of this part of 
 the plate. The spacing of rivets in the flat portions of the plate 
 will be the same as in the outside plate. In the curved portion 
 the number of spaces must be the same, although the pitch will 
 be different. As there were five spaces in this part of the out- 
 side plate there, must be five spaces in this part of the inside 
 plate, but the pitch will be about 1.85 inches instead of 1.92 
 inches. 
 
 To lay out the hoads, first draw the flange line, making the 
 head 6 feet wide and 4 feet deep, with a 6-inch radius at the 
 
 This tank will need angle-bars along the top edges to stiffen 
 it. As these are simply straight bars, it will not be necessary 
 to show how they are laid out. 
 
 While the foregoing problems are in themselves simple, they 
 
 FIG. 19. 
 
 comers. We will assume that the flange is to be 3 inches 
 deep. As the metal will be drawn down at the curved part of 
 the flange, it will not be necessary to leave 3 inches to make 
 this flange. Subtract from the depth of the flange twice the 
 thickness of the plate, giving us 3 inches minus Vi inch, or 2V2 
 inches as the distance from the flai ge line to the edge of the 
 plate. At the corners the plate should be sheared off in some 
 such manner as indicated by the dotted lines, Fig. 17. as there 
 will be too much material in the corner when it is flanged over, 
 and by cutting the plate, as shown, some of this will be re- 
 
 rcpresent some of the common everyday work which an ap- 
 prentice must learn to do accurately before attempting to lay 
 out more complicated surfaces, where it will be necessary 
 to make use of the principles of orthographic projection. 
 Having mastered these elementary principles for finding the 
 sizes of plate which are to be rolled to form cylindrical sur- 
 faces, he will then more readily understand the more compli- 
 cated layouts which are to follow. 
 
 Problems frequently come up in both boiler and sheet-metal 
 work in which it is necessary to find tlie development of the 
 
THE SUBJECT OF LAYING OUT 
 
 15 
 
 surfaces of cylinders which intersect each otiier or are cut by 
 plane or curved surfaces. One of the simplest of these prob- 
 lems is that in which two cylinders of the same or different 
 diameters intersect at right angles, as shown in Fig. 18. 
 
 The development of the small cylinder, which is shown in 
 Fig. 19, may be found in the following manner : Draw a plan 
 or half-plan view of the cylinder and divide it into any con- 
 venient number of equal parts. In this case the half-plan is 
 shown dotted just above the cylinder, with the semi-circum- 
 ference divided into eight equal parts. Project these points 
 of division down to the elevation and draw the parallel lines 
 
 the edge of the plate should be located at a distance below it 
 sufficient to give the desired width of flange after flanging, or 
 appro.ximately the width of flange minus two times the thick- 
 ness of the plate. 
 
 To get the development of the opening in the large cylinder 
 at the line of intersection it would be necessary to draw a 
 side elevation of Fig. 18; draw the parallel lines on the small 
 cylinder, and then project the points I, 2, 3, 4, etc., from thf 
 large cylinder across to the respective lines i-i, 2-2, 3-3, 4-4, 
 etc., in the side elevation. The lines which were used in pro- 
 jecting the points from one elevation to the other would of 
 
 i-i, 2-2, 3-3, etc. Then lay out the line l-l, Fig. 19, equal 
 to the circumference of the cylinder. Divide i-i into six- 
 teen equal parts to correspond with the divisions in the plan. 
 Draw the parallel lines i-l, 2-2, 3-3, 4-4, etc., at right angles 
 to I-I at these points of division and lay off upon each its 
 proper length as measured from the top of the cylinder in 
 the elevation, Fig. 18, to the surface of the large cylinder at 
 the line of intersection. A smooth curve drawn through these 
 points defines that edge of the development. 
 
 If the small cylinder were to be made of a plate rolled to 
 the proper diameter and flanged at the lower edge for a riveted 
 joint to the large cylinder, it would be necessary to make the 
 line I-I equal to the circumference corresponding to the 
 mean diameter of the cylinder measured to the center of the 
 plate. This would give the distance between the rivet lines 
 and the laps, equal to l^ times the diameter of the rivets 
 should be added outside this. The lower edge of the develop- 
 ment as shown in Fig. 19 would then be the flange line, and 
 
 course be parallel and might be used as the parallel lines in 
 the development. These will not, however, be spaced equally 
 on the circumference of the large cylinder, for as can be seen 
 in Fig. 18, the spaces 1-2, 2-3, 3-4, etc., are unequal. There- 
 fore care should be used in spacing them in a corresponding 
 manner in the development. 
 
 In Fig. 20 is shown a cylindrical coal chute leading from a 
 floor forward at an angle through a wall. Here we have two 
 cylinders of the same diameter, intersecting at an angle and 
 also one of the cylinders cut by a plane surface at an angle. 
 In this problem it will'be seen that the line of intersection of 
 the two cylinders must be determined before the lengths of 
 the parallel lines on the surfaces of the cylinders can be ob- 
 tained. Furthermore, since the inclined section of the chute 
 appears foreshortened in both the plan and elevation, the true 
 lengths of parallel lines drawn upon its surface will not be 
 shown in either plan or elevation. 
 
 The projection of the cylinders upon a vertical plane par- 
 
r6 
 
 LAYIXC, OUT I'OR i'.OILER ^[AKERS 
 
 allcl to the axis of the inclined section will show the true 
 lengths of all lines parallel to the axis of cither cylinder. 
 Such a view is shown in Fig. 21. The plan, Fig. 21, is ex- 
 actly like the plan, Fig. 20, except that the axis of the in- 
 clined section has been taken parallel to the plane of the paper. 
 Therefore, the distances A B, C D, E P, etc., Fig. 21, are 
 equal, respectively, to the distances A B, C D,E F, etc.. Fig. 
 20. In order to draw the elevation, Fig. 21, project the point 
 B down from the plan to the line A' X, locating one end of 
 the axis of the cylinder. The other end of the axis may be 
 projected over to the line Y Y from Fig. 20. Then t'.ie out- 
 line of the cylinder will be drawn parallel to this line. 
 
 The lower end of the inclined section will appear as a curve 
 and must be determined as follows : Divide any cross-section 
 of the cylinders, as the plan view of the vertical section, into 
 a convenient number of equal parts, and from these points of 
 division, draw lines parallel to the axis of the cylinder in 
 both plan and elevation, lettering or numbering the corre- 
 sponding lines to avoid confusion. Then to locate any point, 
 as 2, in the elevation, project the point 2 from the plan down 
 to the line 1-2 in the elevation. Do the same for each point 
 at the lower end of the inclined section and then draw a 
 smooth curve through these points, completing the elevation. 
 
 Since the true length of each of the parallel lines is shown 
 
 in the elevation, Fig. 21, the development of the two sections 
 forming the chute may now be laid out in the usual manner. 
 Assume that the outside diameter of the vertical section is 
 20 inches, and that the thickness of the plate is J4 inch. Then 
 th.e mean diameter of the vertical section will be 62 1-32 
 inches. 
 
 3.1416 
 I9-7S 
 
 i5;dSo 
 219912 
 282734 
 31416 
 
 62.045600" or 62 1-32" 
 
 Lay out the line M N, Fig. 22, for the top edge of the plate, 
 62 1-32 inches long, and divide it into 16 equal parts to cor- 
 respond with the divisions in Fig. 21. Draw parallel lines at 
 right angles to M N from these points; then on each of these 
 lines lay out its length as shown in the elevation. Fig. 21. 
 This will locate the flange line and the necessary amount for 
 the flange must be added below this. In Fig. 22, both laps 
 and flange have been omitted. 
 
 Since the vertical section fits inside the inclined section, the 
 
 mean diameter of the inclined section will be 20j4 inches. 
 The length of the plate will therefore be 635-^ inches. 
 3-1416 
 
 20.25 
 
 157080 
 62832 
 62832 
 
 63.617400" or 635'8" 
 
 As it is not necessary to have a close fit in this case, make 
 this length 63^4 inches. 
 
 As there is an irregular cut at each end of the plate, take 
 a cross-section at any point in the cylinder as the section 5 T, 
 and measure the length of each of the parallel lines from this 
 section in both directions. Lay out the line S T, Fig. 23, 63}4 
 inches long; divide it into sixteen equal parts, drawing lines 
 at right angles to S T at these points; and lay off the lengths 
 of these lines as measured from the elevation. Fig. 21. This 
 gives the development of this plate to the rivet and flange 
 lines. 
 
 Without giving further examples it will be seen that the 
 development of any cylindrical surface can be obtained in 
 the manner above described if a projection of the solid on a 
 plane parallel to its axis can be drawn. If the axes of two or 
 
 FIG. 23. 
 
 more intersecting cylinders lie in the same or parallel planes, 
 such a projection may be obtained. If their axes do not lie in 
 the same or parallel planes, it will be necessary to find the 
 true lengths of the parallel lines on each solid separately. 
 
 THE L..\Y0UT OF ANGLE-IRON RINGS. 
 
 Where it is necessary to bend bars of angle-iron into the 
 form of a circle or ring in order to fit around a circular tank 
 or pipe, it is a much easier and quicker job to lay out the bars 
 and punch the rivet holes before the iron is bent. This can be 
 done very accurately, and is by no means a difficult job of 
 laying out. It is necessary, however, to know some rule by 
 which the exact length of the bar may be obtained, so that 
 when it is bent either the inside or the outside diameter of the 
 ring, depending upon whether it is an inside or outside angle, 
 will be the required amount. 
 
 There are two good working rules which may be used and 
 
THE SUBJECT OF LAYING OL'T 
 
 "will apply equally well whether the bar is bent cold or hot. 
 For an outside angle, that is, with the heel of the angle toward 
 the center of the circle, the diameter to be used in computing 
 the length of the bar will be as follows : Using the figures in- 
 dicated in Fig. 24, and calling the inside diameter of the ring 
 D, then tiie proper diameter to use will be 
 
 D + 1/3 IV + T. 
 That is, it is the inside diameter of the ring plus one-third the 
 
 FIG. 24. 
 
 width of the angle plus the thickness of the angle measured 
 at the line of rivet holes. The length of the bar will, of course, 
 be this diameter multiplied by 3.1416. For an inside angle, if 
 
 FIG. 25. 
 
 D equals the outside diameter of the ring, the diameter to be 
 used for computing the length should be 
 D - (1/3 W + T). 
 The length will, therefore, be 3.1416 times this amount. 
 
 Another good working rule is as follows: For outside angles 
 the diameter to be used in computing the length should be D 
 + zA where D is the inside diameter of the ring and A is the 
 thickness of the root of the angle measured diagonally as indi- 
 cated in Fig. 24. For inside angles, if D is the outside diameter 
 
 of the ring, then the diameter to be used in computing the 
 length should be D — 2A. 
 
 Some small allowances are frequently made, due to the 
 stretch in the bar caused by punching the holes, but this is 
 
 nc. 26. 
 
 best determined by observation, as no definite allowance can be 
 stated. It would be small at most. The bars may be bent 
 to a comparatively short radius after the holes have been 
 punched without tearing the metal from the rivet holes to the 
 edge of the bar, or destroying the shape of the holes, by in- 
 serting in the holes the small pieces which have been punched 
 
 FIG. 27. 
 
 out. These will tend to keep the holes perfectly round, and the 
 small pieces may easily be knocked out after the bar is bent. 
 
 CONICAL SURFACES. 
 
 Conical surfaces may be developed by a method some- 
 what similar to that used Avith cylindrical surfaces. A cross 
 section of the cone is divided into a number of equal parts, 
 and lines are drawn on the surface of the cone from tliese 
 
1 8 
 
 LAYING OUT FOR BOILER iMAKERS 
 
 points to the vertex. For instance, in Fig. 25 the circumfer- 
 ence of the base of the cone is divided into sixteen equal parts, 
 and lines are projected from these points of division to the 
 base of the cone in the elevation. These points are then con- 
 nected with the vertex of the cone A. It may then be seen that 
 the surface is divided into a number of triangles, the sides of 
 which are elements of the cone, and therefore equal to the dis- 
 tance Ai, and the bases equal to the length of the equal divis- 
 ions shown in the plan, that is, the distances 1-2, 2-3, 3-4, 4-5, 
 etc. This side of the triangle is, of course, the arc of a circle 
 since each point in the circumference of the base is equidistant 
 from the vertex of the cone A. The circumference of the base 
 of the cone, when laid out in the development, will then be the 
 arc of a circle drawn with radius Ai. This development is 
 shown in Fig. 26. 
 If the base of the cone had been inclined, as shown by line 
 
 bV- ' 
 
 connecting piece and the section of 4-foot pipe which it in- 
 tersects. 
 
 The construction, by means of which this is done, is shown 
 in Fig. 28. This is shown at a larger scale for the sake of 
 clearness. Produce the sides 4c in the end elevation until they 
 intersect at the vertex of the cone A. Project this point over 
 to the side elevation and the point where the horizontal line 
 A A intersects the axis of the branch pipe will be the side 
 elevation of the vertex. Take a cross-section of the. cone 
 through the line 4-4 in the side elevation. The diameter of 
 this section is the distance 4-4. Draw S C in the side eleva- 
 tion perpendicular to A-4 through the point 4, making it ei|ual 
 to the length of the diameter 4-4. Connecting B and C with 
 A gives the outline of the side elevation of the cone. 
 
 On 5 C" as the diameter draw a half view of the cross- 
 section of the cone, and divide it into six equal parts. A 
 
 FIG. 28. — SIDE ELEV..\TION .XND DEVELOPMENT OF CONE. 
 
 END ELEV.'\TION. 
 
 iB in the elevation of Fig 25, it would be necessary to lay out 
 the development as shown by the outline in Fig. 26, and then 
 measure the length of each of the elements which have been 
 drawn on the surface of the cone from the point A to the base 
 l5. It will be noted that in the elevation. Fig. 25, the true 
 length of only two of these elements is shown, that is, the 
 elements Ai and AB. The length of the remaining elements 
 may be found by projecting the points at which the line iB cuts 
 the lines A-2. A-3, A-4. etc., over to either the line A-l or A-g, 
 and then measuring the distances A2', A3', A4', etc. These dis- 
 tances have been laid off on the corresponding lines in Fig. 26, 
 locating the dotted line i-p'-i, which is the development of the 
 circumference of the inclined base of the cone iB. 
 
 THE INTERSECTION OF A CONE AND CYLINDER AT AN ANGLE OF 
 60 DEGREES. 
 
 In Fig. 27 is shown a cone connecting a 2-foot with a 4- 
 foot pipe. The 2-foot pipe branches from the larger one at an 
 angle of 60 degrees. The end elevation shows that the sides 
 of the connection are tangent to the cross-section of the large 
 pipe. The problem is to find the development of the conical 
 
 greater number of divisions should be taken in actual prac- 
 tice, but only six were used in this problem to avoid confus- 
 ing the figure. Project these points of division to the line 
 B C and connect the latter points with the vertex A. Since 
 the axis of the cone in the end elevation is inclined downward 
 and backward, in order to draw the equally spaced elements 
 in this view, it will be necessary to revolve the cone about the 
 vertex A until the axis is vertical or in the position indicated 
 by the dotted lines A M N in the side elevation. The cross- 
 section of the cone through 4-4 will then be represented in the 
 end elevation by the line 5 T, which may be divided in a sim- 
 ilar manner to the line B C. The points of division should 
 then be projected upward until they intersect horizontal lines 
 drawn from the corresponding points on the line B C in the 
 side elevation. This will give the end elevation of the cross- 
 section of the cone in the inclined position. This is shown 
 by the dotted ellipse. Join the points thus found in the 
 cross-section with the vertex A. In Fig. 28 the elements .on 
 the front of the cone are shown to the left of the center lii.c 
 and those on the back are shown to the right in order to avoid 
 confusion in tlic figure. 
 
THE SUBJECT OF LAYING OUT 
 
 19 
 
 Number the points where these lines intersect the circum- 
 ference of the 4-foot pipe in the end elevation I, 2, 3, 4, 5, 6 
 and 7; then project these points to the corresponding ele- 
 ments drawn on the surface of the cone in the side elevation, 
 thus locating the line of intersection between the cone and the 
 large pipe. 
 
 Having obtained this line of intersection, the cone may be 
 developed in the usual way. The half pattern of the cone is 
 shown just at one side of the side elevation. The arc B' C is 
 made equal in length to half the circumference of the cross- 
 section B C. B' C is then divided into the same number of 
 equal parts as the semi-circumference of the cross-section, 
 and these points are connected with the vertex A. The top 
 edge of the connection is the arc of a circle, whose radius is 
 A a. The bottoin edge of the connection is found by project- 
 ing the points 2, 3, 4. 5 and 6 to the line A B and then by 
 
 height of the cone is very large. In the case of Fig. 31 it 
 would be about si.xty. 
 
 The layout of such a plate where the slant height is not too 
 great to be used as a radius, is shown in Fig. 30. Of course, 
 the upper and lower edges of the plate are arcs of circles 
 drawn from the same center with a radius equal to the dis- 
 tance of the respective bases from the apex of the cone. The 
 curved lines ATB and CD are, of course, equal in length to 
 the respective circumferences of the two bases. Now, it will 
 be seen that where the distance ^0 is too great to be used in 
 the shop when laying out the plate full size; that is, if it were 
 30 or 40 feet, the plate might be laid out by drawing the Fig. 
 ACDB, if the distance ST, commonly known as the rise or 
 camber of the sheet, can be found. 
 
 The distance ST is often called by boiler makers the versed 
 sine, without much knowledge of what this function is. In 
 
 laying off along the corresponding lines in the development 
 the distances measured from A to these points. 
 
 The development of the section of large pipe intersected by 
 the cone is shown in Fig. 29. The width of the plate R H 
 corresponds to the line R H in Fig. 28. The length of the 
 plate R O is made equal to the circumference of the pipe, 
 i. c, of a circle 4 feet in diameter. Square up the plate and 
 locate the center line 8-1 ; then on either side of 8, the dis- 
 tances 8-9, 8-10, 8-1 1, 8-12 and 8-13 are laid off equal to the 
 distances 1-7, 1-2, 1-6, 1-3, 1-5 and 1-4 in the end elevation. 
 Fig. 28. The distance 8-7 measured from the side elevation, 
 Fig. 28, is then laid off along the line 8-1. Similarly the dis- 
 tances 9-6, 1 1-5, 13-4. I--3. 10-2, 8-1, measured from the side ele- 
 vation, are laid off on their respective lines as indicated by the 
 numbers. A smooth curve through these points is then the 
 developed line of intersection. The proper amount for laps 
 and flanges should of course be added on both patterns, the 
 amount depending on the thickness of material, size of 
 rivets, etc. 
 
 CONICAL SURFACES WHERE THE TAPER IS SMALL. 
 
 There are many cases in boiler making where it is necesary 
 to lay out a plate which, when it is rolled up, will have the 
 form of the frustum of a right circular cone, the taper of which 
 is very slight. An example of this is shown in Fig. 31, where 
 there is little difference between the diameters of the upper 
 and lower bases of the frustum. This means that the slant 
 
 reality the versed sine is a trigomoraetric function of an angle, 
 
 ST 
 
 and in the case of Fig. 30 the ratio is the versed sine 
 
 OB 
 of the angle SOB. The distance ST itself should not be called 
 a versed sine, and the versed sine of the angle SOB will never 
 equal the distance ST except when the radius OB is unity. 
 If the length of the radius OB is known the distance ST may 
 be found by multiplying OB by the versed sine of the angle 
 SOB. 
 
 This distance, however, may be found graphically as well 
 as by calculation, thus enabling one to lay out the sheet with- 
 out striking in the curves CD and AB from the apex of the 
 cone. There are many different methods for laying out this 
 form of sheet, and most of them are absolutely correct. Some 
 few are only approximately correct, but since the taper of the 
 ring is always small, the camber or distance ST is always 
 small, and, therefore, the approximate method will be suf- 
 ficiently accurate for ordinary purposes. 
 
 Two methods in common use for this layout are given 
 herewith. Consider the frustum shown in Fig. 31, whose 
 height is 12, the diameter at the top being 8 and that at the 
 bottom being 10. The length of the sheet along the top edge 
 will be the circumference of a circle whose diameter is 8, or 
 3.1416 X 8 = 23.14. The length of the bottom edge of the 
 sheet is the circumference of a circle whose diameter is 10, or 
 3.1416 X 10 = 31.416. The width of the sheet must be com- 
 
LAV[\G OUT FOR BOILER MAKERS 
 
 puted, since tlie height of the frustum between bases is given. 
 The width of the sheet or the slant height of the frustum is 
 the hypotenuse of a right triangle, one leg of which is 12 and 
 the other one-half the difference between the diameters of the 
 lower and upper bases, or ;j (10 — • 8) = i. Therefore, the 
 width of the plate equals Vu" -7- i" = V145 = 12.04. 
 
 Referring to Fig. 32, it will be seen that we now have the 
 following dimensions : 
 
 tlie distance OE or tlic camber of the plate. To do this, with 
 a straight edge and square, square up from O the center of 
 the line CD, the line OS to the line AC. With O as a center 
 set the trams tn tlie line OS and draw an arc from S to the 
 line CD. Find the middle point of this arc and draw the line 
 OT through it. Then the distance TC is equal to the required 
 camber of the plate, and may be laid off from O to E. Care 
 should be taken to use the distance TC and not the distance 
 57", since the two are unequal, especially when the camber is 
 
 10-^ 
 
 fk;. 31. 
 
 The length of the top edge of the plate = 25.14 large. The distance ST varies by an appreciable amount from 
 
 The length of the lower edge of the plate =: 31.416 the true camber. 
 
 The width of the plate = 12.04 Having found the point E, we now have three points on the 
 
 In order to lay out Fig. 22 we must know the distance be- curve, viz. : C, D and E. To get additional points on the 
 
 '.tween the upper and lower edges. This will be found from the curve divide the distance OE by 16, and multiply the result 
 
 2 5.14 
 
 FIG. 2^ 
 
 right triangle shown dotted at the left of the figure, or it is 
 equal to the V 12.04" — 3.138' = 11.62. 
 
 Having found these dimensions the diagram ABDC, Fig. 22< 
 may be laid out according to them. It is then necessary to 
 construct on the lines AB and CD, as chords, the arcs of the 
 circles, which are the true development of the upper and lower 
 •edges of the plate. It, therefore, becomes necessary to find 
 
 by 7, 12 and 15. respectively Then divide the lines CD and 
 A3 into eight equal parts, and draw dotted radial lines to these 
 points. Then along these lines, below the line CD, lay off 
 the three distances just computed. Through these points a 
 smooth curve can be drawn, and then the true length of this 
 edge of the plate, which was found to be 31.416, may be 
 measured off along it. This will bring the ends of the pl.ite in 
 
THE SUBJECT OF LAYING OUT 
 
 towards the center £ a slight amount, since the length of the 
 curve measured from C to D is slightly longer than 31.416. 
 
 The development of the upper edge of the plate may be found 
 by setting the trams to the width of the sheet 12.04, and laying 
 off this distance along the dotted radial lines from the lower 
 edge of the plate. Draw a smooth curve through these points 
 
 lines .-IB and CD into eight equal parts, and through the points 
 of division draw radial lines. Only those to the left of LP 
 have been shown in Fig, 34. Then in the manner previously 
 described for finding the point i, determine the points 2, 3, 4 
 and S, each of which is equidistant from the two sides of the 
 respective figure in which it is located. Then, beginning with 
 
 and make its length equal to the length of the top edge of 
 the plate 25.14. 
 
 .In Fig. 34 a second method of laying out a tapered sheet is 
 shown. The Fig, ABDC corresponds to the diagram ABDC, 
 Fig. 33. Square up the line EF at the middle point of the 
 line CD. Then locate any point as the point I, equidistant from, 
 the lines EF and BD. This may be done by drawing a line 
 parallel to EF at a distance from EF less than half ED, and 
 then by drawmg a line pnrallcl to BD at the same distance 
 
 the point 5, set the trams to the distance 5C, and with 5 as a 
 center strike an arc intersecting the first dotted line; also set 
 the trams to the distance $A, and with 5 as a center, strike 
 an arc intersecting the dotted line for the upper edge. Then 
 with 4 as a center, setting the trams to the distance from 4 
 to the intersection of the arcs just drawn with the first dotted 
 line, strike the arcs intersecting the second dotted line, and re- 
 peat this process for the points 3 and 2. Then the curve, which 
 is the true development of the edge of the plate, may be drawn 
 
 FTC. 34. 
 
 from BD. The point where these two lines intersect is, of 
 course, equi'Hstant from the lines EF and BD. This is shown 
 by the circle which has been drawn from i as a center, and 
 which is tangent to both of these lines. With i as a center, 
 set the trams to the distance iD, and strike an arc intersecting 
 the line EF at E; also with i as a center, set the trams to the 
 distance iB and strike an arc intersecting EF at the point F. 
 The point E is one point in the curve of the lower edge of the 
 plate, and similarly the point F is one point in the curve of 
 the upper edge of the plate. 
 
 It will be necessary to locate several other points in the 
 curve in order to determine it exactly. To do this, divide the 
 
 through these points. The points 2, 3, 4 and 5 may be taken 
 anywhere within their respective figures so long as they are 
 equidistant from the sides of the figure. 
 
 With the second method just described, it is unnecessary 
 to compute the dimensions shown in Fig. 32 and draw the 
 diagram ABDC, Fig. 34, since the curve may just as well be 
 drawn on Fig. 31 at once. In this case the side elevation, 
 F'g. 31, should be considered in the same way as the diagram 
 ABDC. Fig. 34. The curves, which are constructed to repLice 
 the upper and lower edges, will, however, be too short for the 
 entire development of the plate. The curves may be continued 
 l>:yond the side elevation. Fig. 31, by constructing on either 
 
LAYING OUT FOR BOILER MAKERS 
 
 side other figures exactly like the side elevation of the 
 frustum. If one such figure is constructed on each side, the 
 curve will then be increased just three times, which is nearly 
 the required length, since the length of the curve is 3.1416 
 times the diameter of the base of the cone. 
 
 A NINETY-DEGREE TAPERING ELBOW. 
 
 The problems on the preceding pages showed several different 
 methods for laying out conical surfaces where the taper of 
 the cone was so small that the surface could not be developed 
 full size by the usual method of using the slant height of the 
 cone as a radius. These methods may often be applied with 
 slight variation to the development of regular conic surfaces 
 where triangulation is usually employed, thus saving both time 
 
 will then be tangent to the quarter circle and will be the 
 center line of the middle section of the elbow. At B square 
 up the line BP at right angles to AD, and similarly at F, 
 square up the line FI at right angles to DG. The lines BP, PI 
 and IF are then the center lines of the three sections of the 
 elbow. 
 
 To draw the outline of the sections it is necessary to know 
 the diameter of the sections at the points P and /, which are 
 the intersections of their center lines. Since the taper is reg- 
 ular, and the center section has twice the length of the end 
 sections, the diameter of the cone at the point P would be the 
 diameter CE -\- J4 the difference between AC and GE. With 
 P as a center and with this diameter as just computed, draw 
 the arcs aa. Similarly the diameter of a cross-section of the 
 
 H 
 
 FIG. 35. 
 
 and unnecessary labor. A case of this kind is that of the go- 
 degree elbow shown in Fig. 35, where it is desired to con- 
 struct an elbow which shall have a regular taper from a sec- 
 tion whose diameter is /4C to a section whose diameter is CE. 
 It is first necessary to draw a side elevation of this elbow 
 in such a way that the sections will have a regular taper, 
 that is, so that if the separate sections were turned about and 
 placed one on the other, the center lines BP, PI and IF form- 
 ing one continuous straight line, the resulting figure would be 
 the frustum of a cone. To do this draw the line AD and at 
 D square up the line DG at right angles to AD. With D as 
 a center, and the trams set to a radius DB, strike the arc BLF, 
 which curve the elbow is to follow. Divide the quarter circle 
 BLF into two equal parts at the point L, then draw the line 
 DL, and at L square up the line PI at right angles to LD. PI 
 
 cone at the point / would be the diameter GE -f >i of 
 the difference between AC and GE. With / as center, 
 and with this diameter draw the arcs bb. Then draw 
 the lines .4N and CO from A and C, respectively, tan- 
 gent to the arcs aa; also draw the lines NH and 01 tan- 
 gent to the arcs aa and bb' and the lines GH and EI from G 
 and E, respectively, tangent to the arcs bb. Draw NO from 
 the intersection of the sides AN and NH to the intersection 
 of the sides CO and 01; likewise draw HI from the inter- 
 section of the lines NH and GH to the intersection of the 
 lines 01 and EI. HI and NO are then the miter lines of the 
 sections. This completes the side elevation of the elbow. 
 
 The elbov/ is now made up of four similar sections (the 
 center section may be divided into two parts at the line MK 
 and each part developed separately). Since the layout of all 
 
THE SUBJECT OF LAYING OUT 
 
 23 
 
 of these sections is accomplished in a similar manner, using, 
 of course, the proper dimensions for each as determined from 
 the side elevation, we will take up in detail the patterns for 
 only one section ; as, for instance, the section ANOC. This 
 
 tances as measured from the cross-section BE to the miter 
 line FE in the side elevation. Since this is the side elevation 
 of a cone, the points at which these lines intersect the miter 
 line should be projected across to the line AF in order that 
 
 section is shown at AFEC, Fig. 37. Divide the section into 
 two parts by means of the line BE, which is parallel to the 
 base AC. The section ABEC is then the frustum of a right 
 circular cone and may be laid out in the usual manner. Hav- 
 ing found the development of the section ABEC, the portion 
 BFE can be easily added to it. The procedure is as follows : 
 
 To lay out the section ABEC, Fig. 37, find the circumfer- 
 ences corresponding to the diameters AC and BE. It will be 
 necessary to lay out only one-half of the pattern, since the two 
 halves are exactly alike. Therefore, in Fig. 36, draw the line 
 CD equal to one-half the circumference of the base AC, Fig. 
 37. Also draw the line AB equal to one-half the circumfer- 
 ence of the base BE at a distance from CD equ;J to AB, Fig. 
 37, the slant height of the frustrum. Draw the lines AC and 
 BD and then from 0, the center of CD, square up the line OP 
 at right angles to AC. Bisect the angle COP with the line 
 05". Then the distance SC measured along the line AC is 
 the camber of the sheet. Lay off OX equal to SC. Divide the 
 lines CD and AB each into 8 equal parts and draw the dotted 
 lines, as shown, through the corresponding points in each base. 
 Divide the distance OX by 16 and multiply the quotient by 7, 
 12 and IS, respectively, giving the camber to be laid out on each 
 of these dotted lines. Having determined the curve CXD at 
 the lower edge of the plate, set the trams to the distance AC, 
 the width of the plate, and lay off this distance along each of 
 the dotted lines from the curve CD, locating the upper edge 
 of the plate .44B. Make the length of the curves CXD and 
 Ai^B correspond exactly to the semi-circumferences of the 
 bases AC and BE, respectively. Fig. 27- 
 
 Reiurning to Fig. 37, draw a half-plan view of the bases AC 
 and BE. Divide the semi-circumference of each into the same 
 number of equal parts into which the lines CD and AB, Fig. 
 36 were divided. Project these points of division to the lines 
 AC and BE and through the corresponding points on these 
 two lines draw the dotted lines as indicated, producing them 
 to intersect the line FE. It will be seen that we now have 
 drawn on the side elevation of the section the equally spaced 
 lines which have been drawn in the pattern and it is onlv 
 necessary to lay off along these lines in the pattern the dis- 
 
 X 
 
 their true lengths may be measured. Then lay off i l', 
 ~ -') 3 3', etc., in the pattern equal, respectively, to the dis- 
 tances Bi, S2, B3, etc., as measured from Fig. 27- Draw a 
 
 FIG. 27. 
 
 smooth curve through the points E, 1 , 2', 3', 4', 5', 6', 7', 
 B and the half pattern for the section is complete. 
 
 The sections MKON, MKJH and GEIH may be laid out 
 in the same manner. Care should be taken to make the proper 
 allowances in the length of the plates which form inside and 
 outside rings. The laps must also be added to the pattern 
 shown in Fig. 36. 
 
24 
 
 LAYING OUT FOR BOILER MAKERS 
 
TRIANGULATION 
 
 In the preceding articles the methnds used in laying nut or will be readily nnderstood. Once tlic boiler maker lias these 
 expanding parallel and tapering forms were fully illustrated principles thoroughly mastered he should experience little or 
 and described. The surfaces that the boiler maker encounters no' difficulty in applying them to any problem that may arise 
 
 cannot always be expanded by the use of the two methods 
 mentioned above. This is due to the fact that these surfaces do 
 
 in the practice of his profession. 
 
 The definition of the word triangulation is simply the 
 measurement by triangles. In surveying, it is the series of 
 triangles with which the face of a country is covered in a 
 trigonometrical survey and the operation of measuring the 
 elements necessary to determine the triangles into which the 
 country to be surveyed is supposed to be divided. In boiler 
 making, triangulation simply means the division of the sur- 
 
 DlAC,RAn OF 
 
 DOTTED Limes 
 
 '234-5^ 
 
 Solid lines 
 
 not conform to any particular law, that is, they are not cylin- 
 drical in form or conical, etc. Consequently some method 
 must be devised whereby those forms can be laid out accu- 
 rately and quickly. The method most commonly used is 
 that of triangulation. !Most young layersout seem to experi- 
 ence difficulty in grasping the principles involved in this 
 method and in consequence are always experiencing diffic-.ilty 
 in laying out forms by triangulation. This trouble is largely 
 caused by the fact that the layerout has failed to grasp the 
 elementary or underlying principles involved. We shall un- 
 dertake to present these principles in such a manner that they 
 
 face of any irregular object into triangles, determining the 
 lengths of their sides from the drawing and transforming 
 them in regi.ilar order in the pattern. In constructing these 
 triangles the lengths of three sides are known, and as it is 
 obvious that from any three given dimensions only one tri- 
 ajigle can be formed, this method furnishes an absolutely 
 correct method of measurement. In all articles whose sides 
 do not lie in a vertical plane, the length of a li:-e running 
 parallel with the form cannot be determined from the elevation 
 above nor from the plan. The elevation gives us the distance 
 from one end of the line vertically to the other as it appears 
 
26 
 
 LAYIXG OUT FOR BOILER IMAKERS 
 
 to the eye. To get the distance forward or back from one end 
 of the line to the other we must go to the plan. From the 
 foregoing we can readily see that the true length of a straight 
 line lying in the surface of an irregular form can be found 
 only by constructing a right-angled triangle whose base is 
 the horizontal distance between the points and whose alti- 
 tude is the vertical distance of one point above the other. 
 The hypothenuse of this triangle is the true distance between 
 the points, or the required length of the line. To illustrate 
 this, let C D E F, Fig. I, be the elevation of a conical article, 
 and L its corresponding plan view. It is required to find the 
 true length of the line AB. It is evident that the distance 
 AB in the elevation is the actual vertical height of the line, 
 and that the distance AB in the plan is the actual horizontal 
 length of the line. We will consequently proceed to con- 
 struct a right-angle triangle whose height A'B' corresponds 
 to the height AB in the elevation, and whose base B'C cor- 
 responds to the distance AB in the plan view. Draw A'C 
 and it is evident that the distance A'C is the true length of 
 the line AB. This is the principle upon which triangulation 
 is based. 
 
 In Fig. 2, A B C D is the side elevation of a truncated 
 scalene or oblique cone. We will assume that this truncated 
 cone is a transition piece connecting two round pipes. It is 
 also somewhat similar, though greatly exaggerated, to the 
 throat sheet of a locomotive boiler. The idea of the article 
 is simply to explain the method of triangubtion, any other 
 irregular piece would serve our purpose as well. E f C U 
 is the corresponding plan view of the truncated cone. We 
 will simply expand one-half of the article, the other half being 
 the exact duplicate of it. Divide the large half circle EHG 
 into any number of equal parts. Eight parts were taken in 
 this case, though as a rule, the larger number of parts taken 
 the more accurate will be the work. Divide the small semi- 
 circle into the same number of parts ; number the divisions on 
 the large semi-circle to 8, and on the small semi-circle o'-8'. 
 Join the points o-o', I-l', 2-2', 3-3', etc., with full lines ; also 
 join the points o'-i, i'-2, 2'-3, 3'-4, etc., with dotted lines. 
 
 We are now ready to construct our triangles to find the 
 true lengths of the lines 0-0', i-i', etc., and the lines o'-i, i'-2, 
 etc. Erect the vertical line 07? and at right angles to OR 
 draw a horizontal line. The line 07? is equal to the vertical 
 height from the line BC to the line AD or the actual vertical 
 height of the cone. This line is evidently one leg of our 
 triangles. The other legs are the distances 0-0', i-i', 2-2', etc., as 
 explained in Fig. I. Transfer the distance 0-0' to 7?-o, the 
 distance i-i' to 7?-i, the distance 2-2', to 7?-2 on our diagram 
 for triangles. Join O-o, O-l, O-2, O-3, etc., these lines give 
 us the true lengths of the solid lines. In a similar way we 
 find the true lengths of the dotted lines, laying the distances 
 out to the left of 7? and joining these points with 0. We now 
 have the true lengths of all the solid and dotted lines and 
 are ready to proceed with the actual expansion. 
 
 In Fig. 3 lay out the horizontal line 0-0' equal in length to 
 the full line O-o in Fig. 2. Set a pair of dividers to the spac- 
 ing o'-l', l'-2', etc., on the small semi-circle and set another 
 pair of dividers to suit the spacing of the large semi-circle. 
 
 The setting of these dividers should be very carefully done 
 as any little inaccuracy here will throw the whole work out. 
 Now, with o as a center, with the dividers set to the large spac- 
 ing, strike an arc. With 0' as a center, and the distance o-i'. 
 Fig. 2, as a radius, strike an arc cutting the previous arc at i. 
 With I as a center, and the distance o-i, Fig. 2, as a radius, 
 strike an arc. Now, with o' as a center, with the dividers set 
 to the small spacing, strike an arc cutting the previous arc at 
 i'. Continue this operation until the points 8 and 8' are 
 reached. Join the points o, I, 2, 3, 4, S, 6, 7 and 8 with a 
 
 FIG. 3. 
 
 smooth curve, and similarly with the points o', i', 2', 3', 4', 
 5', 6', 7' and 8'. This then is the true expansion of half of 
 the truncated cone shown in Fig. 2. 
 
 The above illustrates in a simple manner the method of de- 
 veloping irregular surfaces by triangulation. It will be readily 
 seen that it is not an absolutely accurate method of laying 
 out, due to the fact that a curved surface is divided into a 
 small number of parts and these parts are assumed to be 
 straight lines. However, with a sufficient sub-division and 
 with great care on the part of the layerout, no great inac- 
 curacy will result. It is not advisable to lay out surfaces by 
 triangulation, except as a source of last resort, that is, if 
 there is any other feasible method for expanding the article, 
 use it. However, there are a great many irregular-shaped 
 forms that can only be expanded by adopting this method, 
 and every layerout should understand it thoroughly. The 
 frustrum of an oblique cone, which we have just expanded, 
 can be laid out by applying the principles of laying out taper- 
 ing forms. It w-as chosen as an easy example, illustrating the 
 fundamental principles of triangulation. In a later chapter 
 we will apply the principles of triangulation to more intri- 
 cate forms. 
 
TRI ANGULATION 
 
 27 
 
 LAYING OUT A CIRCULAR HOOD FOR A SMOKESTACK. 
 
 In this article we will consider the development by triangu- 
 lation of a circular hood for a stack which projects through 
 an inclined roof. In Fig. 4 is shown the elevation of the 
 stack; ABCD is the elevation of the circular hood. A'B' is 
 the plan view of the stack and the circle CD' the plan view 
 of the outer edge of the flange. This shows as a circle in the 
 plan view, as it is required that the flange be equal on all 
 sides. 
 
 Fig. 6 shows an elevation ABCD of the hood similar to 
 ABCD, Fig. 4. Above this elevation is a half plan of the top 
 AEB. This half plan is divided into ten equal parts. From 
 
 the points on the larger semi-circle EHG from o to 10. Con- 
 nect the points 0-0', i-i', 2-2', 3-3', etc., with full lines, and 
 the points o'-i, i'-2, 2'-3, 3'-4, etc., with dotted lines. These 
 solid and dotted lines form the bases of a series of right- 
 angled triangles, whose altitudes are obtained from the eleva- 
 tion. Fig. 6. The hypothenuse of these triangles will give us 
 the correct lengths of the lines on the pattern. 
 
 Returning to Fig. 6, connect the points on AB with the 
 correspondingly numbered points on the line CD. Also ex- 
 tend the lines AB and DS indefinitely to the right. Do the 
 same with the points on the line CD. At .S" erect a perpen- 
 dicular line between the lines BR and DS. At ^ set off the 
 
 these points drop perpendiculars to AB. We must now ob- 
 tain the actual shape of the section as it passes through the 
 roof. To do this, construct the half plan of the base GHK 
 and divide this semi-circle into the same number of equal 
 parts as the semi-circle AEB. From these points erect per- 
 pendiculars cutting the line GK. Extend these lines to cut 
 the line CD. From these points drop lines perpendicular to 
 CD. On these lines lay out distances equal to the similarly 
 numbered perpendicular lines on the half plan view GHK. 
 Through these points draw a smooth curve. This gives us 
 the true shape of the section as it passes through the roof and 
 furnishes us with the stretchout of the base used in obtain- 
 ing the pattern. 
 
 We are now ready to prepare for constructing the triangles 
 for developing the pattern. In Fig. 5 construct a plan view of 
 the hood similar to that shown in Fig. 4. Divide these semi- 
 circles similarly to the semi-circles in Fig. 6 and number the 
 ooints on the smaller semi-circle, E'H'G'. from o' to 10' and 
 
 distance SQ equal to the distances o'-l, l'-2, 2'-3, etc., Fig. 5. 
 At Q erect a perpendicular cutting the line BR at P. Join P 
 with the points, o, i, 2, 3, etc., on the line RS. This gives us 
 the true lengths of the dotted lines on the pattern. Now at 
 O on line DS erect a perpendicular line cutting the line BR 
 at A''. Now set off the distance OM equal to the lengths 01 
 the full lines in Fig. 5, 0-0', i-i', 2-2', etc., which are all equal. 
 Erect the perpendicular ML and join L with the various points 
 on the line NO. This gives us the lengths of the solid lines 
 on the pattern. 
 
 We are now ready to lay out our pattern. The stretch- 
 out of top end of tlje flange is obtained from the semi-circle 
 AEB, Fig. 6, and that of the lower part, or where the flange 
 strikes the roof, is obtained from the section CFD, Fig. 6. 
 Draw the line A'C, Fig. 9, equal in length to AC, Fig. 6. Set 
 a pair of dividers to the distance o-i on CFD and another 
 pair to the distances o'-i', i'-2', etc., on AED. These dis- 
 tances are all equal. With as a center and o-i on CFD as a 
 
28 
 
 LAYIXC OUT FOR BOILER :MAKERS 
 
 radius strike the arc o-i. With o' as a center and tlie distance 
 P-i, Fig. 8, as a radius, strike an arc catting the previously 
 constructed arc at i. With T as a center and the distance L-i, 
 Fig. 7, as a radius, strike an arc, and with o' as a center and 
 
 5, and 7, and on the small pipe 8, g, lO, n, 12, u and 14. 
 Now divide the surface of the connection into triangles by 
 connecting points 1-8, 2-9, .3-10, etc., by solid lines and the 
 points 2-8, 3-9, 4-10, etc., by dotted lines, as shown in Fig. 10. 
 
 JLe- 
 
 the distance o'-i', Fig. 6, as a radius, strike an arc cutting this 
 arc at i'. Continue this process until the points 10 and 10' 
 are reached. Draw a smooth curve through these points and 
 join 10 and 10'. The resulting surface A'B'C'D' gives us the 
 development of one half of the hood. The other half is ex- 
 actly similar. 
 
 the; l.wout of .\ "y" connection. 
 The plan and elevation of a "Y" connection, such as it is fre- 
 quently necessary to construct for the uptakes of boilers or in 
 branch pipe work, is shown in Fig. 10. The main pipe is circu- 
 lar and the two branch pipes are oval in shape, the diameter of 
 the large pipe and major diameter of the small pipes being the 
 same. It will be seen that not only would the connection from 
 the large pipe to one of the rmaller ones be an irregular and 
 difficult piece to lay out, but that the int'cresectiou of two of 
 these irregular pieces make the problem still more complicated. 
 The fact that the connections to each of the branch pipes are 
 exactly similar brings their intersection in a vertical plane. 
 as shown by the line .14. Divide the half plans of the large 
 pipe and one of the small pipes into the same number of 
 equal spaces. Number the points on the large pipe i, 2, 3, 4, 
 
 Fjq.9. 
 
 It is necessary to find the true length of each of these lines of 
 which we have just drawn the plan and elevation, in order 
 to obtain the shape of the connection when stretched out 
 flat. 
 
 Draw the line BA, Fig. II, and at any point, as Y, square up 
 the line .VI'. It will be seen from the elevation. Fig. 10, that 
 the vertical distance between the upper and lower ends of 
 each of the lines of which we wish to get the true length is 
 the same; that is, it is the perpendicular distance between the 
 lines 1-7 and 8-14. Therefore, lay ofif this distance in Fig. 11 
 from y to X and then set the trams to the distance 1-8 in the 
 
TRIANGULATION 
 
 29 
 
 ■plan, Fig. 10, with V as a center, Fig. II, lay off the distance K8 
 to the right of the hne YX. Again, set the trams to the dis- 
 tance J-8 in the plan, Fig. 10, and with Y as a center lay off the 
 distance Y8, Fig. 11, to the left of the line XY. Draw the solid 
 
 on the half plan of the branch pipe), strike an arc intersecting 
 the arc previously drawn at point 13. Again set the trams to 
 the solid line X-13. Fig. 11, and with 13, Fig. 12, as a center, 
 strike an arc at point 6. With 7 as a center and with dividers 
 
 line A'8, and also the dotted line, X8. These lines will then be set to the distance 7-6, Fig. 10 (the length of the equal spaces 
 
 -the true lengths of the solid line 1-8 and the dotted line 2-8, 
 •shown in Fig. 10. 
 
 Perform the same operation for each of the solid and dotted 
 lines in Fig. 10, obtaining the lines Xg, Xio, X12, .Y13 and 
 A'14, Fig. II. In order to avoid confusing the figure, since all 
 of the lines are of nearly the same length, draw the solid lines 
 .at the right of the figure, and the dotted lines at the left. 
 
 in the half plan of the large pipe) . strike an arc intersecting 
 the arc previously drawn at point 6. Proceed in a similar man- 
 ner, locating the points S, 4, 3, 2 and I on the long edge of 
 the sheet, and the points 12, 11, 10, 9 and 8 on the short edge 
 of the sheet. 
 
 Having obtained the pattern for the entire connection from 
 the large pipe to one of the small ones, it is now an easy mat- 
 
 Having obtained the true length of all the lines which form 
 the triangles into which the connection is divided, we are 
 now ready to lay out the sheet as it will be before it is rolled 
 up. Draw the line 7-14, Fig. 12. equal in length to the line 7-14, 
 shown in the elevation. Fig. 10. Now set the trams to the 
 •dotted line .Y-13, Fig. 11. and with 7, Fig. 12, as a center draw 
 an arc at the point 13. With 14 as a center and the dividers 
 .set to the distance 14-13 (the length of one of the equal spaces 
 
 ter to locate the line of intersection between the two intersect- 
 ing connections. Set the trams to the distance 7B in the plan, 
 Fig. 10 and with ]', Fig. 11, as a center lay off the distance YB. 
 At the point B square up the line B B' until it intersects the 
 line ^13 ; then set the trams to the distance X B' and with the 
 point 7. Fig. 12. as a center, lay off the distance 7B along the 
 line 7-13. Again set the trams to the distance 6C on the plan, 
 Fig. 10, and with Y, Fig. 11, as a center lay off the distance 
 
30 
 
 LAYING OUT FOR BOILER MAKERS 
 
 y C; at C square up the line C C until it intersects the line A'13 
 at the point C ; then set the trams to the distance X C ; and 
 with point 6, Fig. 12, as a center lay off the distance 6C along the 
 line 6-13. In a similar manner locate the point D on the line 
 6-12; E on the line 5-12, and F on the line 5-1 1. Draw a 
 smooth curve through these points, and then the figure A, 4, i, 
 8, 14 represents a half pattern of the connecting pipe. 
 
 This problem shows how the principles of triangulation 
 make possible the solution of problems which require the de- 
 velopment of surfaces of which there is no regular form or 
 taper. The only inaccuracies or errors which creep into this, 
 as well as any other problem which is solved by triangulation, 
 are those due to the fact that the lines forming the triangles 
 into which the surfaces are divided are considered as straight 
 lines when, as a matter of fact, they are slightly curved. Un- 
 less there is a very great curvature to the surface, however, 
 this error is very small and the patterns developed by this 
 method will be found to fit nicely into the required positions. 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 In this layout of an ordinary tubular boiler, one which is 
 generally rated as an 80-H. P. boiler has been selected, as being 
 a standard size. It is 60 inches in diameter by 14 feet long. 
 It is desired to give as complete a description as possible of 
 the design and laj'out of this boiler, using several different 
 formulEE to show how each point is found. The object of 
 this is to give some idea of the necessity of having all boilers 
 constructed under some law or authoritj'. Under present con- 
 ditions boilers can be constructed from mere ideas, and this 
 results in some parts of the boiler being unnecessarily strong, 
 while other parts are too weak. Many of the mysterious boiler 
 explosions result from this class of construction. 
 
 In computing the allowable working pressure of the boiler, 
 we will first have to find out what pressure is required to suit 
 the needs of the particular plant where the boiler is to be in- 
 stalled. Let us assume that our customer has placed an order 
 with us for a boiler to be constructed for a working pressure 
 of 150 pounds per square inch, but expressly states that at 
 times he will need a pressure of 175 pounds per square inch. 
 He figures that in time he may need this additional 25 pounds 
 pressure, so he orders his boiler accordingly. The object in 
 bringing this out is to show purchasers of boilers that it is a 
 wise idea when installing new boilers to have them constructed 
 for a greater pressure than they need at the time of purchas- 
 ing, as there is always a tendency to use more pressure rather 
 than less. It is not to be expected that the majority of plant 
 owners know- how to figure out whether these boilers are safe 
 for the pressure they are carrying. Consequently, advantage is 
 taken of their ignorance in this respect. Instances are known 
 where it was desired to increase the pressure of a boiler, and a 
 boiler maker was called in to see if the boiler could stand an 
 mcreased pressure. x\fter he had made a general survey, or 
 bird's-eye view of the boiler, he advised the owners that it 
 would be safe to do so, and they acted accordingly. The 
 majority of parties who authorize this increased pressure do 
 not know one item about figuring out the safe working pres- 
 sure of a boiler. 
 
 An idea seems to prevail that the more rivets there are in 
 a seam the stronger the joint will be. We will see how this 
 works out in specific cases a little further along. Another fea- 
 ture to be considered is the factor of safety. Some use 4, 
 others 5. A set factor is all right providing it specifies in 
 detail how the work is to be done using that factor, but the 
 grade of work should be taken into consideration in deciding 
 the factor. Therefore, to encourage good vork we should have 
 different percentages, that we can add, covering each opera- 
 tion where work may be slighted. The very best of construc- 
 tion consists of drilling all holes and having longitudinal seams 
 made with double-butt strapped jiints. If the holes are not 
 drilled in place, the next best construction is punching the 
 holes small and reaming out from % inch to 3/16 inch after 
 the sheets are in place. 
 
 HoTjj to Ascertain the Factor of Safety. 
 When cylindrical shells of boilers are made of the best 
 material (either iron or steel), with all holes drilled in place, 
 the plates afterwards taken apart and the burrs removed, and 
 all longitudinal seams fitted with double-butt straps, each at 
 least (5^) five-eighths the thickness of the plates they cover, 
 the seams being double riveted, v;ith rivets 75 percent over 
 single shear and having the circumferential seams constructed 
 so the percentage is at least one-half that of the longitudinal 
 seams, and provided that the boiler has been open for inspec- 
 tion to the government inspector during the whole period of 
 construction; then 4 may be used as a factor of safety. But 
 when the above conditions have not been complied with, the 
 conditions in the following scale must be added to the factor 
 4, according to the circumstances of each case : 
 A = .1 — To be added when all holes are fair and good in 
 longitudinal seams, but drilled out of place after 
 bending. 
 Tj = .2 — To be added when all holes are fair in longitudinal 
 
 seams, but drilled before bending. 
 C = .2 — To be added when all holes arc fair and good in 
 longitudinal seams, but punched after bending. 
 D = .3 — To be added when all holes are fair and good in 
 longitudinal seams, but punched before bending. 
 *E = .7 — To be added when all holes are not fair and good 
 in longitudinal seams. 
 F = .07 — To be added if the holes are all fair and good in 
 the circumferential seams, but drilled out of 
 place after bending. 
 G = .1 — To be added if all holes are all fair and good in 
 the circumferential seams, but drilled before 
 bending. 
 H =: .1 — To be added if the holes are all fair and good in 
 the circumferential seams, but punched after 
 bending. 
 I r= .15 — To be added if the holes are all fair and good in 
 the circumferential seams, but punched before 
 bending. 
 *J ^.15 — To be added if the holes are not fair and good in 
 the circumferential seams. 
 K = .2 — To be added if double butt straps are not fitted to 
 the longitudinal seams, and said seams are lap 
 and double riveted. 
 L = .07 — To be added if double butt straps are not fitted 
 to the longitudinal seams, and said seams are 
 lap and treble riveted. 
 !M = .3 — To be added if only single butt straps are fitted to 
 the longitudinal seams, and said seams are 
 double riveted. 
 N = .15— To be added if only single butt straps are fitted 
 to the longitudinal seams, and said seams are 
 treble riveted. 
 
LAYING UL"T FOR TOILER M.\K[:RS 
 
 O — I. — To be added when any description of joint in the 
 longitudinal scam is single riveted. 
 
 P z= .J — To be added if all holes arc punched small and 
 reamed afterwards, or drilled out in place. 
 
 O = .4 — To be added if the longitudinal seams are not prop- 
 erly crossed. 
 *R =: .4 — To be added when material or workmanship is in 
 any way doubtful, and the inspector is not satis- 
 fied that it is of best quality. 
 
 S =: I. — To be added if boiler has not been open for inspec- 
 tion during the whole period of construction. 
 
 XoTE. — When marked with an (*) the factor may be in- 
 creased still further if the workmanship or material is such 'm 
 in the inspector's judgment renders such increase necessary. 
 
 XoTn. — Steam Boiler Inspection Act. 1901. for British Co- 
 lumbia. Canada. 
 
 The following examples will serve to show how the factor 
 may be determined for any given case : 
 
 Lap. treble riveted, holes punched full size before bending: 
 4.00 
 .JO = D 
 
 .T5 = : 
 
 .07 = L 
 
 4.52 = Combined factor. 
 
 To this is every possible chance of having to add £ = .7 and 
 / = .15, this then would make the factor 5.37. 
 
 Lap. treble riveted, holes punched small, being drilled or 
 reamed out in place : 
 
 4.00 
 .20 = P 
 .07 = L 
 
 4.J7 = Combined factor. 
 
 In this method we are able to drop both D and / and bring 
 in P, making a difference of .25 in percentages. It also cuts 
 out any chance of E or / being added in, and it is the best 
 method that can be exercised with a lap treble riveted joint, 
 having holes punched before bending. From yi inch to 3/16 
 inch should be drilled out of each hole. 
 
 Treble-riveted butt joint, with holes punched full size: 
 4.00 
 ■30 = D 
 .13 = / 
 
 4.45 = Combined factor. 
 
 To this there is every possible chance of having to add 
 E = .7 and / = .15. This would then make the factor 5.30. 
 
 Treble-riveted butt joint, with holes punched sm:dl, being 
 drilled or reamed out in place : 
 4.00 
 .20 = P 
 
 4.20 = Combined factor. 
 
 In this method we arc able to drop both D and 1 and bring 
 in /', making a difference of .25 in percentage. It also cuts 
 out any chance of iZ or / being added in, and it is the best 
 method that can be exercised other than holes drilled in place. 
 The reaming should be not less than Ys inch in diameter. 
 
 It will be noted that with holes drilled in place we can use 
 a factor 4. providing we have double butt straps at the longi- 
 tudinal seams, but with the same joint with holes punched 
 .•^mall and reamed out. the combined factor is 4.27. The latter 
 will be generally used on account of the punching being so 
 r.nich cheaper, even though heavier plates might be required. 
 
 In order to calculate the allowable working pressure of a 
 boiler it is necessary to know not only the factor of safety 
 but also the efficiency of the riveted joints, since a riveted joint 
 is always weaker than a solid plate, and therefore the pressure 
 allow-ed a boiler must be less than would be the cr.se if the 
 shell were one solid plate with no joints. The efficiency of 
 the joint is the ratio of the strength of the joint to the strength 
 of tlie solid, plate. The strength of the net section of the 
 plate after the rivet holes arc cut out is figured, and also the 
 shearing strength of the rivets is figured. Then the smaller 
 of these values is used as the strength of the joint to be used 
 in the ratio. Dififerent laws have given various formulae of 
 slightly different form for figuring the efficiency of a joint, as 
 will be seen from the examples given below. These do not 
 give exactly the same results, as different conditions and as- 
 sumptions were used in deducing them. 
 
 According to the practice of the Hartford Steam Boiler In- 
 spection & Insurance Company, the efficiency of a riveted joint 
 would be found as follows : 
 
 Treble Riveted Lap Joint. 
 Steel plate, tensile strength per square inch of section 60,000 
 pounds. 
 
 Thickness of plate, 7/16 = .4375 
 Diameter rivet holes, 15/16 = .9375 
 Area of one rivet hole = .69029 
 Pitch of rivets, 3 15/16 = 3.gi7= 
 
 Shearing resistance of steel rivets per square inch 42,000 
 jiounds. 
 
 3-9375 X -UTS X Coooo = 103,359 pounds = strength of solid 
 plate, 
 
 5-9373 — -9375 = 3-oo. 
 3 X -4375 X 60000^ 78.750 pounds, strength of net section of 
 plate. 
 
 3 X .69029 X' -;2000 = 86,976.54 pounds, strength of three 
 rivets in single shear, 
 
 100 X 78750 H- 103.359 = 76 percent 
 efficiency of joint. See Eig. i. 
 The British Columbia formula gives the following results : 
 P = Pitch of rivets in inches. 
 D = Diameter of rivets in inches. 
 A = Area of one rivet in square inches. 
 A' = Number of rivets in one pitch (greatest pitch). 
 y = 23 for steel rivets and plate. 
 5" = 28 for steel rivets and plate. 
 T = Thickness of plate 'n inches. 
 C =: I for lap. 
 
C = 1.75 for double butt strap joint. 
 F s^ Factor of safety. 
 % =: Percentage of plate between greatest pitch of rivets. 
 %* := Percentage of rivet section as compared with solid 
 plate. 
 100 X {P — D) 
 — = % for iron or steel plates. 
 
 HOW TO LAY OUT A TUBULAR BOILER 
 
 (Pitch — diameter of rivet hole) X 100 
 
 33 
 
 Pitch 
 
 ^ % of strength of 
 plate, at joint, 
 compared with 
 solid plate. 
 
 (Area of rivets X number rows of rivets) X 100 
 
 Pitch X thickness of plate 
 % of strength of rivets as compared with solid plate. 
 
 Fig. 3 
 
 100 x A X N X y X C X P 
 
 %' for steel plates 
 
 4X y X T X P 
 
 rivets. 
 ;oo (P— D) = (3.937s — -9375) 100 =-- 3 X 100 = 300. 
 300 -f- 3.9375 = 76 % net section plate between rivets. 
 100 X .69029 X3X23X 4-20 
 = 104% := percentage of strength 
 
 4 X 28 X 3-9375 X -4375 of rivets compared 
 
 to plate. 
 
 Note. — P in this example is factor on longitudinal seam 
 only. 
 
 The computation, according to the Canadian marine law, is 
 jjiven below : 
 
 Fig. 6 
 
 Taking the same example, when we obtain 104 percent with 
 B. C. formula, we find as follows : 
 
 .69029 X 3 X 100 
 
 3-9375 X .4375 
 
 120 percent. 
 
 Note. — It will be noticed that the Canadian marine law does 
 not take into consideration the factor of safety as is done in the 
 British Columbia law. Also in the formula for the percentage 
 of strength of the rivets as compared with the solid plate, no 
 account is taken of the fact that the shearing strength of the 
 rivets is different from the tensile strength of the plate. As- 
 suming that the shearing strength of the rivets is 42,000 pounds 
 
34 
 
 LAYING OUT FOR BOILER MAKERS 
 
 ler square inch, and the tensile strength of the plate 60, 00 
 pounds per square inch, then tlie percentage strength of the 
 rivets, compared to the soHd plate, is 84 instead of 120, as given 
 by the formula. In the British Columbia law this has been 
 taken care of by the conitant factors in the formula. Tims 
 our percentage with 7/16 plate, treble-riveted lap joint ^s 
 rivets, 15/16 holes is 76 percent in each instance, as the net 
 section of the plate was found to be weaker than the strengtli 
 of the rivets. 
 
 To get the allowable working pressure for a given thickness 
 of plate for this joint we figure as follows : 
 T S X R X 2T 
 
 = B 
 
 D XF 
 TS ^ Tensile strength. 
 T = Thickness. 
 D =r Inside diameter of boiler. 
 F = Factor of safety. 
 R = Percentage of joint. 
 B = Working pressure per square inch. 
 60000 X 76 X -^73 665.0 
 
 = = 156 pounds allowed with holes 
 
 60 X 427 4.27 punched small and reamed 
 
 out in place. 
 60000 X •"6 X -875 16,625 
 
 = = 147 pounds allowed with holes 
 
 1. 13 punched full size before 
 
 bending. All holes being 
 perfectly fair. 
 
 = 163 pounds allowed with all holes drilled 
 
 60 X 4.07 in place. 
 
 Note. — F is the combined factor in these examples. 
 
 Just to give some idea of the pressure allowed on the same 
 boiler, with the same joint and pitch of rivets, but having the 
 holes punched full size and more or less of them in the cir- 
 cumferential and longitudinal seams, not fair or good, the fol- 
 lowing is given: As the extent to which they are blind, will 
 have the effect of deciding just what should be added to the 
 factor, this is left to the inspector. The British Columbia 
 laws would bring the factor up to 5.37, or even greater, if the 
 inspector considered the work such as to warrant it. Assum- 
 ing 5-37 3s a factor we figure as follows: 
 60000 X 76 X .875 
 
 = 124 pounds. 
 
 60 X 5-37 
 Thus we see just what effect the workmanship has on the 
 factor and amount of pressure that cr.n be allowed. It is pos- 
 sible with a treble-riveted lap joint to get 76 percent efficiency 
 and build boilers good for 163 pounds pressure. Yet another 
 boiler constructed with the defects which have been pointed 
 out will, when completed, look as well and get just as high a 
 pressure. Thus we see the great importance of government 
 inspection and laws covering construction of boilers. Let us 
 also figure this same style of joint with ^ rivets instead of ]4, 
 and we will see what effect it has in the efficiency of the joint. 
 
 60 X 4- 52 
 
 60000 X -"6 X .875 
 
 Trcblc-Rii'ctcd Laf Joint. 
 Steel plate, tensile strength per square inch of section, oo.coo 
 pounds. 
 
 Thickness of plate, 7/16 = .4375 
 Diameter rivet hole, 13/16 = .C125 
 Area of one rivet hole = .51S5 
 Pitch of rivets = 3 inches. 
 
 Shearing resistance of steel rivets per square inch = 42,000 
 pounds. 
 
 3 X -4375 X 60,000 = 78,750 pounds, strength of solid plate. 
 (3 — .8125) X .4375 X 60,000 = 57,421.875 pounds, strength 
 of net section of plate. 
 
 ■5185 X 3 X -P,ooo ^ 65,331 pounds, strength of 3 rivets ih 
 single shear. 
 
 57,421.875 -^ 78,750 = 72 percent, efficiency of joint. See 
 Fig. 2. 
 
 It might be asked how the pitch of rivets is decided. No 
 set pitches can be stated for every joint, but a maximum pitch 
 can be stated. While it is true the greater the pitch the greater 
 will be the percentage of the net section of plate, but at the 
 same time the percentage strength of the rivets, compared to 
 the solid plate, is decreasing. It is this weakness that makes 
 the single and double-riveted lap joint longitudinal scams low 
 in efficiency, and makes them unsuitable for boilers of large 
 diameters and pressure. It will be seen the efficiency of a 
 joint with 54 rivets, 3-inch pitch is 3 percent weaker than a 
 joint with Ji rivets, 3 15/16-inch pitch. 
 
 By the Canadian marine law and British Columbia formula 
 the pitch may be ascertained as follows : 
 
 (C XT) + i./s = PM 
 T ^= Thickness of plates in inches. 
 PM = Maximum pitch of rivets in inches not to exceed 
 
 10 inches. 
 C =^ Constant applicable from the following table : : 
 No. of Rivets Constant for Constant for Double 
 
 in One Pitch. Lap Joint. Butt Strap Joint. 
 
 One 1.31 1.75 
 
 Two 2.62 3.50 
 
 Three 3.47 463 
 
 Four 4.14 5-55 
 
 Five 6.00 
 
 For a treble-riveted lap joint with 7/16-inch plate, 3^-inch 
 rivets, and 13/16-inch rivet holes, the pitch will be found as 
 follows : 
 
 (3-47 X -4375) + 1-625 = i-5i8 -t- 1.625 = 3.143-inch pitch. 
 Therefore, the percentage of the net section of the plate to tlie 
 solid plate will be 
 
 loox (3143 — -8125) 
 = 74 percent. 
 
 3143 
 
 Note. — See Fig. 3. 
 
 It will be seen with these formulas we do not get the same 
 percentage in net section with -)4 rivets as we did with % 
 rivets. The maximum pitch, 3.14 inches, was used. If we use 
 3-inch pitch, as was done with the preceding example, the 
 percentage of the net section of the plate will be a fraction 
 less, but the percentage of the rivet area will be greater. > 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 35. 
 
 It might be asked whether it is possible to design a se:im for 
 a double-riveted lap joint, with any size rivets, that will 
 permit the same working pressure as in the preceding prob- 
 lems. Let us see if this is possible. First, we know our rivet 
 area will be less, so we will use a larger rivet, with a view of 
 getting the necessary rivet area. We will use a is/i6 rivet in 
 our example. 
 
 Steel plate, tensile strength per square inch of section, 60,000 
 pounds. 
 
 Thickness of plate, 7/16 =: .4375 
 Diameter of rivet holes == i inch. 
 Area of rivet holes = .7854 
 Pitch of rivets, 3 s/i6 = 3.3124 
 
 Shearing resistance of steel rivets per square inch, 42,000. 
 3,3124 X -4375 X 60,000 =^ 86,887 pounds, strength of solid 
 
 plate. 
 3-3I24 — I = 2.3124 
 2.3124 X -4375 X 60,000 = 60,700 pounds, strength net section 
 
 of plate. 
 7854 X 2 X 42,000 = 65,973.6 pounds, strength of two rivets 
 
 in single shear. \ 
 
 60,700 -=- 86,887 = 70 percent efficiency. 
 
 Acsume that the holes are punched small, as in the treble- 
 riveted lap joint, and see just what pressure we can allow. 
 4.00 
 .20 = P. 
 .20 = K. 
 
 Rule- 
 
 6P + 4D 
 
 r= PD. 
 
 60000 X 7 X -875 
 
 4,40 := Combined factor of safety. 
 
 := 139 pounds allowable working pressure. 
 
 60 X 440 
 
 156 pounds treble-riveted lap joint, with ^-inch rivets. 
 139 pounds double-riveted lap joint, with 15/16-inch rivets. 
 
 17 pounds difference under same conditions. 
 
 Thus we see what efficiency and allowable pressure can be 
 obtained with a treble-riveted lap joint, and also the decrease 
 in these which will occur ia a boiler with only a double-riveted 
 lap joint. We also ascertain how important it is for the factor 
 of safety to be set according to the actual conditions of holes, 
 etc. We further see the value of all holes being reamed, so 
 that the factor of safety is not allowed to increase. A high 
 factor is not necessary with good work, 
 
 A question most liable to be asked is, what distance should 
 there be between the rows of rivets, as well as the amount of 
 lap from center of rivet hole to calking edge. The distance 
 between the rows of rivets is not very important, as it will have 
 no bearing on the efficiency of the joint. It is well not to have 
 too great a distance, because of the trouble in keeping the seam 
 tight. Again, it must not be too small, so that one rivet head 
 laps upon another, A good idea is to make the diagonal pitch 
 about equal to the pitch of a single riveted lap seam. This 
 permits the rivet sets or dies to perform their work without 
 cutting the head of an adjoining rivet, and also brings the 
 sheets close together, making a tight joint with a slight amount 
 of calking. 
 
 P =: Pitch of rivets in inclies. 
 D =^ Diameter of rivets in inches. 
 PD = Diagonal pitch i ■ inches. 
 
 If the pitch is 3 inches, with J4-'"ch rivets, t'..e diagonal pitch 
 will be found as follows : 
 
 (3X6) + (4X?4) 
 
 = 2.1-inches diagonal pitch. Sec Fig 4- 
 
 10 
 Our readers will understand that PD, which in this example 
 is 2,10 inches, is the minimum pitch, and they are privileged to 
 increase it, and cause no decrease in the efficiency of the seam. 
 Too great a pitch (PD) will, as explained, make trouble in 
 having a steam-tight job. Many of our readers have, no doubt, 
 frequently seen seams made tight and then break out in 
 spots a little later on. These leaks are caught only to break out 
 in another place. The diagonal pitch in a case of this kind 
 is generally too great. 
 
 To Ascertain the Lap. 
 The amount of lap 's varied according to the ideas of those 
 who handle the work. A short lap is desired, when the seam 
 is exposed to flames or heat, so as to prevent the sheets crack- 
 ing from the rivpt holes to the calking edge. The water being 
 unable to reach the sheet and rivet head directly, causes the 
 material at this point to get hotter, resulting in cracks. There- 
 fore, as short a lap as possible is used when the seam is 
 directly exposed to the fire and heat. Some boiler makers have 
 resorted to counter-sinking the rivet holes, and aie driving an 
 oval counter-sunk rivet, as shown in Fig. 6. The rule generally 
 used is to make the lap 1I/2 times the diameter of the rivet 
 hole. This is sometimes varied by taking i'/2 times the diam- 
 eter of the rivet, which, of course, gives a slightly smaller 
 lap, as the diameter of the rivet is 1/16 inch less than the 
 diameter of the hole. 
 
 Circumferential Scams. 
 The question will arise as to why the circumferential seams 
 can go single riveted. In our boiler the flues extend from 
 head to head, and therefore brace the greater portion of the 
 head. Also the braces extending from shell to head help sup- 
 port the head. Thus the rivets are not subjected to any great 
 strain. If it were a tank with dished heads and no flues or 
 braces to assist the rivets, it will be seen that the stress on the 
 rivets holding the head is not excessive. First, we must find 
 the area of the head which will be the outside diameter of the 
 
 3.1416 
 
 head squared, times 
 
 59 9/16 X 59 9/16 X .7854 = 2786.12 square inches, area. 
 
 2786.12 X 17s (pounds pressure) = 487,571 pounds, pres- 
 sure on head. Suppose the head is riveted to the shell with a 
 single row of 34-inch rivets which are 13/16 inch when driven. 
 
 Area of 13/16 rivets = .5185 square inch. Figuring on 
 
36 
 
 LAYIXG OUT FOR BOILER MAKERS 
 
 4.-2,0(Xi pounds shearing strength of rivets per square inch, we 
 find one rivet good for : 
 
 42000 X -5185 = 21777 pounds. 
 487571 -f- 21777 =: 22.4 number of rivets. 
 
 Therefore. 23 rivets, 13/16 diameter, will represent the mini- 
 mum number of rivets in the circumferential seams. The pitch 
 will be determined as follows : 
 
 60 X 3-l4l6 = 188.5 inches, circumference. 
 188.5 -^ 23 = 8.19 inches, pitch of rivets. 
 
 area, providing we use a 2-inch pitch for 94 rivets, in the cir- 
 cumferential seam to stand 2,047,038 pounds. We find the 
 head is subjected to 487,571 pounds pressure with net section 
 of plate good for 2,954,796 pounds. Therefore, 
 
 2,954,796 -=- 487,571 =^ 6.1 factor of safety. 
 
 2,047,038 -H 487,571 := 4.2 factor of safety. 
 These examples will throw some light on the reasons for 
 single-riveted circumferential seams. Later on, it will be 
 shown how the plates suffer from other causes. 
 
 If J-i instead of ^ rivets were used in the circumferential 
 
 'ISS^h^ 
 
 DOUBLE AND TREBLE 
 
 This, as will be seen, is out of all reason, or about 3>< times 
 too great a pitch. Therefore, if we use a 2-inch pitch the 
 rivet area creeps up more than three times. The next point 
 is to find whether a 2-inch pitch leaves a sufficient net section 
 of plate. 
 
 2 — 13/16 = I 3/16 inches net section of plate. 
 
 I 3/16 X 7/16 — .5195 area of net section. 
 
 188.5 -f- 2 ^ 94 spaces. 
 
 94 X .5195 = 48.833 square inches, total area of net section. 
 
 48.833 X 60,000 = 2,929,980 pounds, total strength of net sec- 
 tion of plate. 
 
 21.777 X 94 = 2,047,038 pounds, total strength of rivets. 
 We find we have on the head 487,571 pounds and sufficient rivet 
 
 RIVETED BUTT JOINTS. 
 
 seams, the area to be supported being the same, the pitch 
 should be increased to about 25's inches : 
 
 188.5 -i- 2.375 ^= 79-4 number of rivets. 
 As a }i rivet equals lS/16 when driven the corresponding 
 area will be .69029 square inch. 
 
 42000 X .69029 ^= 28992.18 pounds, shearing strength of one 
 rivet. 
 
 28992.18x80^2,319,374.4 pounds, total strength. 
 
 23193744 -^ 487571 — 4-75 factor of safety. 
 Therefore, we gain the difference between 4.75 and 4.2, or .55 ; 
 thus 7-^ rivets at this pitch give more strength than 54 rivets 
 at 2 inches. As the strength of the net section of plate is in 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 37 
 
 excess of the strength of the rivet area, we have only to figure 
 on the rivets in this example. 
 
 Butt Joint With Inside and Outside Straps. 
 Fig. I showTS a double-riveted butt strap joint, a construc- 
 tion which is far superior to any lap joint. Fig. 2 shows a 
 treble-riveted butt joint with which a very high efficiency can 
 be obtained. Our boiler must stand 175 pounds pressure. 
 With a treble-riveted lap joint we could not get any better 
 than 163 pounds pressure, so that is out of consideration. Let 
 us see if a double-riveted joint, as shown in Fig. i, will do. 
 We will consider that all our holes are punched small and 
 reamed out. Thus we get a factor of safety of 4 plus {P = 2) 
 or 4.20. 
 
 Having decided this, our next move is to find the efficiency 
 of joint necessary. 
 Rule: 
 
 A = Radius of boiler. 
 
 B = Working pressure. 
 
 C = Constant = 100. 
 
 D = Thickness of plate in inches. 
 
 T. S. = Tensile strength. 
 
 F = Factor. 
 
 E := Efficiency. 
 
 F X A X B X C 
 
 — = E 
 
 D X TS 
 
 60000 X -83 X .875 
 
 173 pounds, allowaoie pressure. 
 
 4.2 X 29.78 X 1.7s X 100 
 
 834% 
 
 ■4375 X 60000 
 We must now find out whether a double-riveted butt joint 
 will give us 83.4 percent efficiency or not. First, we will 
 have to ascertain the greatest pitch so we can get the strongest 
 net section of plate, as the efficiency will be figured from the 
 net section of plate at the outer row of rivets. This pitch 
 wil be twice that of the inner row. In Part I we found from 
 the table for the inner row the constant 1.75. Hence by the 
 formula the maximum pitch will be 
 
 (7/16 X i-7S) + 15^ = 2.39> or about 2^ inches. 
 Therefore the pitch for the outer row will be 2f^ X 2 == 
 4.7s inches. 
 
 475 — .9375 = 3-8125 
 
 3.8125 — 4.75 = 80 percent of net section compared to 
 solid plate. 
 
 Having taken the limit in pitch of rivets, we cannot reach 
 the proper efficiency with a double-riveted butt joint with in- 
 side and outside straps. Hence this joint will not do for our 
 boiler, as the following computation shows that only a pres- 
 sure of 166.6 pounds per square inch would be allowed. 
 60000 X .80 X .875 
 
 = 166.6 pounds, allowable pressure. 
 
 60 X 4-2 
 
 With 54 rivets, 13/16 holes, the efficiency will be as follows: 
 4.7s. — .8125 =: 3.9375 net section of plate. 
 3-9375 -^ 4-75 -^ 83 percent efficiency. 
 
 60 X 4-2 
 
 Here, however, another feature presents itself. The net 
 section of plate might be strong enough, but the rivet area 
 would very likely be too small. 
 
 Steel plate, tensile strength per square inch of section 
 60,000 pounds. 
 
 Thickness of plate 7/16 = .4375. 
 
 Diameter of rivet holes 13/16 = .8125. 
 
 Area of rivet hole = .5185. 
 
 Pitch of inner row = 2js inches. 
 
 Pitch of outer row = 4^^ inches. 
 
 Resistance of rivets in single shear = 42000 pounds. 
 
 Resistance of rivets in double shear = 85 percent excess 
 over single shear, or 77700 pounds. 
 
 4-75 X -4375 X 60000 = 124687.5 pounds, strength of solid 
 plate. 
 
 4.75 -f- .8125 = 3.937s net section of plate. 
 
 3-9375 X -4375 X 60000 = 103359.375 pounds, strength of net 
 section of plate. 
 
 •5185 X 2 X 77700 = 80574.9 pounds, strength of two rivets 
 in double shear. 
 
 -5185 X 42000 = 21777 pounds, strength of one rivet in 
 single shear. 
 
 80574.9 + 21777 = 102351.9 pounds, total strength of rivets. 
 
 Therefore the rivet strength is the weaker. 
 
 10235 1. 9 -i- 124687.5 = 82 percent, efficiency of rivets. 
 
 103359-375 -^ 124687.5 = 83 percent, efficiency of plate. 
 
 Again, if ^ rivets were used, and the rivet efficiency in- 
 creased, the efficiency of the net section of the plate would be 
 decreased. 
 
 4-75 — -9375 =; 3-7125 inches. 
 
 3.8125 X -4375 X 60000 = 100078.125 pounds, strength net 
 section of plate. 
 
 100078.125 -=-124687.5 = 80 percent efficiency with Ji rivets. 
 
 Another rule which the author believes is quite simple is as 
 follows ; 
 
 A ^= Area of one rivet. 
 
 B = 1.85 constant for rivets in double shear. 
 
 B' ^ I constant for rivets in single shear. 
 
 P =; Pitch for outer row of rivets. 
 
 F" = Pitch for inner row of rivets. 
 
 C =^ Shearing strength of rivets. 
 
 C = Tensile strength of plate. 
 
 T = Thickness of plate in inches. 
 
 % = Percent of rivet strength compared to solid plate. 
 
 E = Number of rivets in one pitch in inner row. 
 
 E' = Number of rivets in one pitch in outer row. 
 .4XB'XCX.E' ^XBXCX-E 
 + 7o 
 
 P X T X C 
 .5185 X 42000 X I 
 
 4-75 X -4375 X 60000 
 
 P' X T X C 
 
 = 17.5 percent 
 
38 
 
 LAYING OUT FOR BOILER MAKERS 
 
 .5185 X 1.85 X 42000 
 
 64.5 percent 
 
 2.375 X •4375 X 60000 
 
 64.5 + 17.5 = 82 percent, efficiency of rivets. 
 
 Our readers will see that the net section of plate with 13/16 
 holes, 434-inch pitch, gives an efficiency of 83 percent, but the 
 rivets only give 82 percent. It is necessary for the rivet per- 
 cent to be in excess of the percent of the net section of plate. 
 There are three places where the joint can fail when the 
 rivets and the net section of the plate are nearly alike, 
 
 1. It can break through net section of plate at outer row of 
 rivets. (This we found had an efficiency of 82 percent.) 
 
 2. It can shear the rivets (which we found had an efficiency 
 of 82 percent). 
 
 3. It can break the net section of the plate at the inner 
 row of rivets and shear the outer row of rivets ; which are in 
 single shear. (The following computation will show that this 
 hns an efficiency of 83 percent.) 
 
 2-375 — .8125 = 1.5625. 
 
 1.5625 -=- 2.37s = 65.8 percent, efficiency of net section of 
 plate at inner row. 
 
 65.8 + 17.4 = 83.2 percent. 
 Therefore the strength of rivets is the weaker. 
 
 Let us figure the joint first with 7/s rivets. On page 4 
 the constant for obtaining the pitch is 3.5. Therefore 
 (7/16 X 3.5) + 15^ ^ 3.15 inches, maximum pitch for inner 
 row of rivets. 
 
 3.15 X 2 = 6.30 inches, pitch for outer row. 
 
 A X B' X C X E' A X B X C X E 
 
 . + = % 
 
 P X T X C P' X T X C' 
 .69 X I X 42000 X I 
 = 17.5 percent 
 
 6.30 X .4375 X 60000 
 .69 X 1.85 X 42000 X 2 
 
 130 percent 
 
 3.15 X .4375 X 600CO 
 
 130 -f 17.5 = 147.5 percent, strength of rivets compared to 
 plate. 
 
 6.30 — .9375 = 5.3625. 
 
 5.3625 H- 6.30 = 85 percent, efficiency of net section of plate 
 at outer row of rivets. 
 
 3.15 — .9375 = 2.2125. 
 
 2.2125 -^ 3.15 = 70 percent, efficiency of net section of plates 
 at inner row of rivets. 
 
 70 + 17.S = 87.5 percent, strength of net section of plate at 
 inner row and shearing of outer row of rivets. Therefore, net 
 section of plate at outer row is the weakest point. 
 
 As our rivet area is far in excess of plate, we can use a 
 larger pitch for the rivets. By doing so we can increase the 
 efficiency of the net section of the plate. As the pitch of rivets 
 increases so does the net section of plate, and this increases 
 the efficiency of plate, but the increased pitch cuts down the 
 percentage strength of rivets. 
 
 If 34 rivets, 13/16 holes had been used instead of }i rivets, 
 15/16 holes, the result would have been as follows: 
 
 .5185 X 1.85 X 42000 X 2 
 
 3.15 X .4375 X 60000 
 .5185 X I X 42000 
 
 97 percent 
 
 = 13.2 percent 
 
 6.30 X .4375 X 60000 
 
 97 -\- 13.2 = 1 10.2 percent, strength of rivets compared to 
 plate. We find a large cut in rivet percentage, yet it is above 
 the plate. 
 
 6.30 — .8125 = S.4875. 
 
 5.4875 -^ 6.30 = 87 percent, efficiency of net section of plate 
 at outer row. 
 
 3.15 — .8125 = 2.3375. 
 
 2.3375 -J- 3.15 = 74 percent, efficiency of net section of plate 
 at inner row. To this we add the percent of rivet strength of 
 one rivet in single shear at the outer row. Thus 74 -\- 13.2 -= 
 87.2, or about 87 percent. Therefore, the breakage will occur 
 at net section of plate at outer row of rivets as this is the 
 weakest point. 
 
 Fig. 2 shows the layout of rivet holes when 13/16 inch in 
 diameter. 
 
 A = Rivet in single shear with a 13.2 percent value. 
 
 B and C = Rivets in double shear with a 97 percent value. 
 
 A, B and C = Combined strength (13.2 + 97 percent == 
 1 10.2 percent). 
 
 E =^ Net section of plate at outer row with 87 percent. 
 
 D = Net section of plate at inner row with 74 percent, 
 
 A and D together equal 87.2 percent. It is the assistance 
 derived from the rivet A that prevents D from being the 
 weakest point. If the inner strap did not extend out, taking 
 in the row of rivets A in single shear, the net section at D 
 would be the efficiency of the joint, or 74 percent. 
 
 The following computation will show what pressure may be 
 allowed on the boiler with this joint; 
 60000 X .87 X .875 
 
 = 181 pounds, pressure allowed with 
 
 60 X 4.2 J4"i"ch rivets. 
 
 60000 X .85 X .875 
 
 177 pounds, allowed with Js-inch 
 rivets. 
 
 60 X 4.2 
 
 In the preceding articles the efficiencies of both lap and bun- 
 joint seams have been found for diflferent sizes of rivets. With 
 the treble-riveted butt joint with inside and outside straps, 
 .54-inch rivets, a factor of safety of 4.2, tensile strength of the 
 plate 60,000 pounds per square inch, and thickness of phite 
 7/16 inch, the boiler under consideration was found good for 
 181 pounds per square inch steam pressure. The strength of a 
 section of plate, the length of one pitch of rivets, is equal to 
 60,000 X 5.4875 X 1-4375 =^ 144.047 pounds. The stress on 
 a similar section of the boiler shell, due to a steam pressure of 
 60 X 6.3 X 181 
 
 181 pounds, is equal to = 34,209 pounds. 
 
 2 
 Thus we have a stress of 34,209 pounds upon a section capable 
 by the former gives, of course, the factor of safety, 144,047 --■ 
 34,209 =: 4.2 factor of safety. This, as will be seen, checks the 
 other calculations. 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 39 
 
 Thickness of Butt Straps. 
 To ascertain the thickness of butt straps, the area of a 
 section of the strap at its weakest point for one pitch may be 
 made equal to the area of the section of the plate at its weakest 
 point for one pitch. The weakest point in the butt straps is 
 along the line of holes nearest to where the plates butt, since 
 
 as nearly equal strength as possible, it would not be good prac- 
 tice to use a joint whose strength is uncertain. 
 
 In the preceding articles we have found by means of dif- 
 ferent formula; and different methods of doing work, the pres- 
 sure which would be allowed on the boiler under different 
 conditions. Actual conditions will upset these calculations to a 
 
 ML 
 
 <r^'-}{ 
 
 ^ 
 
 H3?rK- 
 
 FIG. 9. — SECTION SHOWING OUTLINE OF BOILER SHELL AND HEADS. 
 
 this section receives no assistance from the shearing strength 
 of the rivets. The weakest point in the plate is at the outer 
 row of rivets. 
 
 If /i = net section of plate at outer row. 
 B = thickness of plate. 
 C = net section of plate at inner row. 
 D = thickness of straps. 
 
 A X B 
 Then D = 
 
 certain extent, as it will be found impossible in general work 
 to calculate the distances such that the rivet holes can be 
 stepped off exactly to the pitch as found by the formula. It 
 may be a fraction one way or the other, r.nd this will effect 
 the percentage of strength to a slight extent; thus it will be 
 seen that both a scientific and practical education are of 
 great importance for the layer out, in order that he may know 
 what the effect on the efficiency of the joint will be when he 
 finds it necessary to increase or decrease the pitch of rivet 
 
 •^— A- 
 
 FIG. 10. — EFFECT OF PUNCHING HOLES 
 IN LIGHT PLATE. 
 
 5-4873 X -4373 
 
 = .514 inch, thickness of both straps. 
 
 2-3373 X 2 
 .514 -^ 2 ^ .257 inch, thickness of one strap. 
 This is a fraction over % inch thickness. As it is the minimum 
 thickness, it would be better to make the straps at least ^ 
 inch thick. Frequently the thickness of the strap is made §^ 
 the thickness of the plate. 
 
 Welded Joints. 
 It has been generally proved in actual tests that welded 
 joints are unreliable, due to the uncertainty of the weld. Even 
 where perfect welds have been made, the strength of the joints 
 has not proved equal to the strength of the plate. Since the 
 main idea in boiler construction should be to make all parts of 
 
 K — e-- 
 
 FIG, II. — EFFECT OF PUNCHING HOLES 
 l.^f HEAVY PLATE. 
 
 holes to cover a certain distance. It is quite impossible to 
 make laws or rules defining the exact pitch for the strength of 
 all the joints, for the reason that the pitch in nine cases out 
 of ten cannot be stepped off in equal spaces. Only the maxi- 
 mum pitch allowable for a certain size of plate can be fixed 
 exactly. 
 
 Preceding examples have shown the effect on the percent- 
 ages produced by punching holes full size, by punching small 
 and reaming out, and also by drilling in place. Another fea- 
 ture must be taken into consideration, and that is the damage 
 done by punching. On light plates the damage is not great, 
 but it increases as the plates increase in thickness. It is 
 estimated that holes punched full size damage the strength of 
 plates from about 8 percent in 54-inch plates to 33 percent 
 
40 
 
 LAYING OUT FOR BOILER MAKERS 
 
 in j4-inch plates. In plates Iiaving the holes punclied 
 small and reamed out, this damage is obviated to a large 
 extent. Actual experiments show that the punched holes make 
 the plate between the rivet holes less in tensile resistance ac- 
 cording to the thickness of the plates frora 6 to 20 percent. 
 
 It is utterly impossible for each and every hole to be fair 
 regardless of the care exercised in laying out. This is due 
 partly to the great variation in the thickness of plates. The 
 thickness of every plate is greater at the center than at the 
 edge, and the wider and thinner the plate the greater is this 
 variation. This variation will certsir.'.y have its effect when 
 the sheet is rolled up ; also the punching may cause the hole 
 to vary slightly, so that when the sheet is connected some of 
 the holes may be slightly unfair. 
 
 In Fig. 10 is shown the section of a rivet hole punched full 
 size in a light plate. In light plates, with good punches and 
 
 FIG. 12. — SECTION SHOWING DIMENSIONS OF SHELL PLATE. 
 
 dies, the holes will be slightly tapered. In heavy plates the 
 
 metal is so compressed that it will tear the sheet in the center 
 
 of the thickness of the plate, causing the diameter of the holes 
 
 to vary according to the thickness of the plate. A section of 
 
 holes punched full size in heavy plates is shown in Fig. 11. C 
 
 is % inch greater in diameter than A, and is also larger than 
 
 B. It will readily be seen how difficult it is to upset rivets so 
 
 as to fill the entire hole. Rivets driven in holes of this shape 
 
 will leak, since the holes are not properly filled. It is almost 
 
 impossible to remove or knock out one of these rivets after its 
 
 head has been cut off. The effect of all such conditions upon 
 
 the factor of safety has been clearly shown by the preceding 
 
 examples. 
 
 Sice of Shell Plates. 
 
 Since the boiler under consideration is 60 inches in diameter 
 and 14 feet long, the shell can be made in two equal courses. 
 The circumference to be used for the length of the plates may 
 be found by multiplying the inside diameter of the boiler by 
 3.1416, and adding to the result three times the thickness of 
 the plate, by multiplying the outside diameter of the boiler by 
 3.1416 and subtracting three times the thickness of the plate, 
 or by multiplying the mean diameter of the boiler measured to 
 
 the center of the thickness of the plate by 3.1416. The latter 
 method is the correct one to use. Since the inside diameter is 
 60 inches, and the thickness of plate 7/16 inch, the mean diame- 
 ter will be 607/16 inches. The circumference corresponding to 
 this diameter is 189.87 inches. If the circumference corre- 
 sponding to the inside diameter had been found and three 
 times the thickness of the plate added, tlie result would have 
 been 189.81 inches. If the circumference corresponding to the 
 outside diameter had been found and three times the thickness 
 of the plate subtracted, the result would have been 189.93 
 inches. 
 
 The circumference, 189.87 inches, will be the length of the 
 plate for a butt joint. For a treble-riveted lap joint the dis- 
 
 -*;2r' 
 
 56 
 
 *ii: 
 
 
 
 
 
 1 
 
 i.;B.d.''| 
 
 \] '^^~~ .urColn by g^lhsr 
 
 
 
 FIG. 13. — PLAN AND ELEVATION OF HEAD. 
 
 tance between the rivet holes and the laps must be added. As- 
 suming a distance between rivet holes of i->^ inches and a lap 
 of i}i inches, the length of the plate would be 
 
 189.87 + 2Xiys + 2XiH = 189.87 + 6= 195.87 inches. 
 This would be the length for the large course. INIake the small 
 course six times the thickness of the plate shorter. It is a 
 good idea to allow ^ inch more for squaring up the sheet, 
 making the total length about 196J4 inches. 
 
 In determining the length of the boiler we will figure on using 
 14-foot flues. It will be necessary to make allowance for the 
 beading of the flues, which would require, roughly, 54 inch at 
 each end, making l4 inch in the total length ; therefore, the 
 length of the boiler from outside to outside of the heads will 
 be 13 feet li;'2 inches. 
 
 We will assume that the heads are to be flanged to a 2-inch 
 outside radius. It has been previously decided to make the 
 laps I'yi inches; therefore, to prevent the calking edge of the 
 plate extending onto the curved part of the flange, the gage 
 line for the rivets on the head should be 2 -|- i}i = 3^ 
 inches from the outside of the head. Therefore, for both 
 heads, the total distance will be 2 X 3H = ^ii inches. Sub- 
 tracting 654 inches from 13 feet ilj^ inches for the distance 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 41 
 
 between the rivet lines in the heads leaves 13 feet 4^ inches, 
 or i6o->4 inches. Dividing l6o54 by 2 we get 8o}i inches as 
 the width of each shell plate from center to center of the 
 circumferential seams. For the total width of these plates add 
 the laps. 
 
 ^H X 2 = 2^4 inches. 
 80H + 234 = 8314. 
 
 Add an allowance, say J| inch, making the total width of the 
 plate 83$^ inches. Some do not make such a great allowance. 
 
 Size of Heads. 
 Some authorities have certain stated thicknesses of heads for 
 certain diameters of boilers. The heads should be at least as 
 heavy as the shell, and in most cases slightly heavier. Let us 
 make the heads Vz inch thick in the boiler under considera- 
 tion. The pressure this plate will stand will be figured out 
 
 £■ Test Pieces to be of same thickness as Plate 
 
 
 -< 1- 
 
 -4 
 
 f^abont-3-"-^ J}^^-l^-lijetc. ^^ , 
 • t<- - -Parallel-Section-not-less-than 9" - >J 
 L alinutJal: 
 
 FIG. 14. — STANDARD TEST PIECE FOR BOILER PLATE. 
 
 when laying out the braces and flue pitches. The majority of 
 shops order boiler heads equal in diameter to the length of a 
 cross-section of the flanged head measured at the center of 
 the thickness of the plate. This is not bad practice, but it 
 allows a fraction more than is necessary. 
 
 Ji A ^ outside diameter of the head. 
 
 B = outside radious of the flange. 
 
 C = yi circumference of the flange at the center of 
 the thickness of the plate. 
 
 D = Vioi A —B. 
 
 E = F — B. 
 
 F = depth of flange. 
 
 16 := constant. 
 Then, as seen from Fig. 13, the length of a cross-section of 
 the flanged head measured at the center of the thickness of 
 the plate will be 2D -{- 2C -\- 2E. 
 
 36 -1- 2 X 2.7s -1- 2 X 2.75 = 67 inches. 
 This, according to the above rule, would be the diameter of 
 the head before flanging. The writer has originated the fol- 
 lowing rule for determining the amount which would be 
 gained in this length in the operation of flanging: 
 
 E + C 
 
 — ■ X 16 
 
 ■ = gain in flanging. 
 
 F X V2A 
 2-75 + 2.7s 
 
 X 16 
 
 475 X 30 285 
 
 Therefore, .31 equals the amount to be taken off all around, 
 due to the gain caused by the gather of the material when 
 
 flanged. Thus 67 — .31 = 665^ inches diameter. This is for 
 the large head. Since the small head is Jg inch less ii? 
 diameter a similar calculation should be made for it. 
 
 Having figured out the shell sheets and heads we will make 
 up the bill of material as follows : 
 
 Material required for one 60-inch by 14-foot tubular boiler 
 with butt joints : 
 
 One sheet, 7/16 inch by 8314 inches by 190J4 inches, for 
 large course. 
 
 One sheet, 7/16 inch by 83;^ inches by 18753 inches, for 
 small course. 
 
 One sheet, J^ inch by 665^ inches diameter, for large head. 
 
 One sheet, V2 inch by 6s*/2 inches diameter, for small head. 
 
 In recent years steel has supplanted iron in boiler construc- 
 tion. Its use has become universal, because it can be manu- 
 
 1 
 
 style 1 
 
 Style ; 
 
 FIG. 15. — TWO METHODS OF FASTENING STAY-TUBES. 
 
 factured more cheaply than iron, and thinner sheets may be 
 used, since its tensile strength exceeds that of iron. It is as 
 ductile and more homogenous than iron. 
 
 The following standard specifications for open-hearth plates 
 were adopted by the Association of American Steel Manufac- 
 turers : 
 
 Special Open-Hearth Plate and Rivet Steel. 
 
 Steel shall be of three grades : extra soft, fire-box and 
 flange or boiler. 
 
 Extra Soft Steel. 
 Ultimate strength, 45,000 to 55,000 pounds per square inch; 
 elastic limit, not less than one-half the ultimate strength; 
 elongation, 26 percent ; cold and quench tests, 180 degrees flat 
 on itself, without fracture on outside of bent portion : maxi- 
 mum phosphorus, .04 percent; maximum sulphur, .04 percent. 
 
 Fire-Box Steel. 
 Ultimate strength, 52,000 to 62,000 pounds per square inch; 
 elastic limit, not less than one-half the ultimate strength ; 
 elongation, 26 percent; cold and quench bends, iSo degrees flat 
 on itself, without fracture on outside of bent portion ; maxi- 
 mum phosphorus, .04 percent; maximum sulphur, .04 percent. 
 
 Flange or Boiler Steel. 
 
 Ultimate strength, 55,000 to 65,000 pounds per square inch; 
 elastic limit, not less than one-half the ultimate strength; 
 elongation, 25 percent; cold and quench bends, 180 degrees 
 flat on itself, without fracture on outside of bent portion; 
 maximum phosphorus, .06 percent; maximum sulphur, .04 per- 
 cent. 
 
 Steel for boiler rivets shall be made of the extra soft grade 
 
42 
 
 LAYIXG OL'T FOR BOILER MAKERS 
 
 as specified above. All tests and inspections shall be made at 
 place of manufacture prior to shipment. The tensile strength, 
 limit of elasticity and ductility shall be determined from a 
 standard test piece, cut from the finished material, the stand- 
 ard shape of this test piece for sheared plates to be as shown 
 in cut. Fig. 14. Test coupons cut from other material than 
 plates may be the same as those for the plates, or they may 
 be planed or turned parallel throughout their entire length. 
 The elongation shall be measured en an original length of 8 
 inches, except in rounds of ^ inch or less in diameter, in 
 
 Having fully decided about the plates, and sent the order to 
 the mills to be tilled, we will now direct our attention to the 
 flues. Tubular boilers derive their heating surface mostly from 
 the flues. The smaller the flues the more that can be put in, 
 and this naturally makes more heating surface. Locomotive 
 boilers have small flues for this reason, as the ratio of heating 
 surface to grate area in a locomotive boiler is greater than in 
 tubular boilers. Tubes of tubular boilers are laid out in 
 vertical and horizontal rows. It is customary in some dis- 
 tricts to have a manhole in the front head. This is a splendid 
 
 7.1-3 lubes, 4!4 Centers 
 
 nc. 16. 
 
 61-3« Tubes, iX Centers 
 
 FIG. 17. 
 
 62.4"Tube.'i,'5>i Centers 
 FIG. 18. 
 
 which case the elongation shall be measured in the length 
 equal to eight times the diameter of section tested. Four 
 coupon pieces shall be taken from each melt of finished ma- 
 terial, two for tension and two for bending. 
 
 JIaterial, which is to be used without annealing or further 
 treatment, is to be tested in the condition in which it comes 
 from the rolls. When material is to be annealed, or otherwise 
 treated, before use, the specimen representing such material 
 is to be similarly treated before testing. Every finished piece 
 of steel shall be stamped with the melt number. All plates 
 shall be free from surface defects, and to have a workman- 
 like finish. 
 
 Each boiler inspection and insurance company has its own 
 specifications for the material which is used in boilers built 
 according to its rules. These are all of the same general 
 character as the set already quoted. 
 
 FIG. 19. 
 
 feature, as it permits of inside inspection as well as permitting 
 the boiler to be thoroughly cleaned, and, furthermore, in case 
 of repairs to the bottom of the shell the work can be done 
 without removing the tubes, except in large repairs, when only 
 a portion will have to be removed. 
 
 Layout of Tubes. 
 In Fig. 16 is shown the layout of 3-inch tubes, seventy-four 
 in number. It will be noticed that there is a large space in 
 the center. Manj' desire this, as they believe this space causes 
 a better circulation of the water. Fig. 17 shows the layout of 
 3^-inch tubes, sixty-one in number. This layout, as will be 
 noted, has one row in the center. Fig. 18 is the layout of 4-inch 
 tubes, fifty-two in number. They are laid out with the same 
 r.mount of space in the center as there is between the other 
 rows of tubes. It will be noted in Figs. 16, 17 and 18 that on 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 43 
 
 one side of the manhole the location of an end to end stay is 
 shown, while on the other side is a flue shown dotted. The 
 flue used in place of the end to end stay is a poor construc- 
 tion, as will be seen later on. When a manhole is not located 
 in the front head, a greater number of flues can be placed in 
 the boiler. For instance, if the manhole were omitted in 
 Fig. i6 an additional row of flues could be put in, giving ten 
 more flues; likewise in Fig. 17, two additional rows could be 
 put in, giving thirteen more flues. In Fig. 18, one more row, 
 making ten additional flues, could be used in place of the 
 manhole. 
 
 Holding Qualities of Flues. 
 
 Experiments show that the holding qualities of flues ex- 
 panded in the flue sheets vary very greatly. As the thick- 
 ness of the head will have a bearing on this, no set rule can 
 be made governing same. Much depends on the grade of 
 workmanship performed. Ordinarily the flue expanded into 
 the flue sheet will be perfectly safe. Experiments show that 
 the mere beading of the flues increases the factor from 200 
 to 400 percent. This being the case, it is needless to say that 
 this should be done when so much can be gained by so little 
 trouble and work. If the flue could be fastened at the ends, 
 so as to make the flue body the weakest point, it would be 
 quite easy to figure out the strength of the flue and the stress 
 to which it could be subjected. This could be figured in the 
 same manner as the braces. 
 
 The holding qualities of flues has been proven as safe for 
 boilers of small diameters, but large boilers should be stayed 
 with stay-tubes. Fig. 19 shows two views of stay-tubes, with 
 two modes of fastening them to the flue sheet. On the right- 
 hand side, Fig. 19, view B, is the layout, showing the area that a 
 stay-tube will support. The stay-tubes are shown with nuts, 
 but can be applied as in view A by screwing into the sheet 
 and beading over. There are two different values allowed, 
 according to the method used. It will be seen that when the 
 stay-tubes are laid out as in view B they form a much better 
 support for the boundary rows of flues than in view A. Fig. 15 
 is an enlarged view, showing how the flues are fastened to the 
 flue sheets. 
 
 The British marine rules for stay-tubes are as follows : 
 T = The thickness of plate is sixteenth of an inch. 
 P = The horizontal pitch, center to center of boundary 
 
 rows. 
 C = Constant. 
 
 The formula is as follows : 
 
 C X T X T 
 
 = working pressure. 
 
 P X P 
 C = 120 when the stay-tubes are pitched with two plain 
 tubes between them and not fitted with nuts on 
 the outside of plates. 
 C ^ 130 when they have nuts on the outside of plate. 
 C = 1.^0 if each alternate tube is a stay-tube not fitted 
 
 with nuts. 
 C = 150 when they are fitted v/ith nuts, outside the 
 
 plates. 
 C = 35o if every tube is a stay-tube, and not fitted with 
 nuts. 
 
 C = 170 if every tube in these rows is a stay-tube and 
 each alternate stay-tube is fitted with nuts, out- 
 side the plates. 
 Assuming that the boiler had 3!^-inch tubes, laid out as in 
 Fig. 17, with J-^-inch flue sheet and tubes fitted with nuts as in 
 view B, every other tube being a plain tube, the working pres- 
 sure would be found as follows. The constant in this case 
 is 140: 
 
 140 X 81 11,340 
 
 = = 132. s pounds. 
 
 3s.6 85.6 
 
 Note. — Boilers of 60 inches diameter do not require stay- 
 tubes. 
 
 What pressure is the stay-tube subjected to, laying aside any 
 assistance derived from the plain tubes? As the centers of 
 our tubes are 45-^ inches, the stay-tube centers would be twice 
 as great, or g% inches. Thus g}/^ inches by gl4 inches =^ 85.6 
 square inches. This would not be the actual area exposed to 
 pressure, as there are some deductions to make, consisting of 
 one 3j4-inch hole, four half holes 3^2 inches diameter, and 
 four quarter holes, yA inches diameter. Adding these resu'its 
 together we have four 3^-inch holes. To find the area we 
 multiply 3I/2 inches by yA inches by .7854=; 9.621 square inches. 
 
 The area of one tube being g.621, the area of four tubes 
 would be 4 X 9.621 =: 38.484 square inches. Therefore, 85.6 — 
 38.484 = 47.116 square inches. 
 
 Total pressure to each stay-tube is 47.116 X 175 pounds = 
 8245.3 pounds per stay-tube. Assuming that the metal of the 
 stay-tube has 60.000 pounds tensile strength per square inch, 
 let us see if a tube ys inch thick is thick enough. 
 
 Three-inch flue, % inch thick, equals 3^4 inches inside 
 diameter and 3H inches neutral diameter. Thus, 60,000 X 
 14 inch X 2H inches X 3-i4i6 = 79>50O. 
 
 79,500 
 ^= 9.64 factor. 
 
 8245.3 
 Thus we see that stay-tubes ]4 inch thick are thick enougW. 
 Since tubes are in a measure braces they should have a factor 
 as high as braces, which is figured as 7 or 8. 
 
 Heating Surface. 
 The heating surface of a boiler includes the tubes and the 
 parts of the shell and heads which are exposed to the flames 
 and gases. The following general rule for calculating the 
 amount of heating surface covers all parts exposed to thK 
 flames and gases : 
 
 Multiply two-thirds of the circumference of the shell in 
 inches by its length in inches. Multiply the number of tubes 
 by the length in inches. Multiply this product by the inside 
 diameter X 3.1416. Add to these products two-thirds of the 
 area of the tube sheets or heads. Then subtract from this 
 sum twice the area of the tubes. This product gives the num- 
 ber of square inches. To find the number of square feet divide 
 by 144. Take as an example, the boiler with the layout of 
 tubes 3 inches diameter, seventy-four in number : 
 A = Circumference of shell in inches. 
 B = Length of shell in inches. 
 C = Heating surface of shell in square inciiea. 
 
44 
 
 LAYrXG OUT FOR 1 '.OILER MAKERS 
 
 D = Circumference of tube in inches. 
 
 E = Heating surface of tubes in square inches. 
 
 F = Area of one head in square inches. 
 
 G = Two-thirds of the area of both Iieads in square 
 
 inclics. 
 H = Area of all tubes in square inches. 
 / = Total heating surface. 
 
 Some mechanical engineers figure that the area of the head 
 should be figured from the outside diameter of the boiler, 
 while others the outside diameter of the head, which is the 
 inside diameter of the boiler. This, however, does not have a 
 great bearing on the final number of square feet. 
 
 Working out the boiler to the letters A, B, C, D, E, F, G, 
 H and I we will have the following : 
 
 A =• 6o7s inches X 3-i4i6 ^ 191.25 inches. 
 
 5 ^ 14 feet X 12 inches = 168 inches. 
 
 C ;= 191.25 X 168 X 2/3 = 21,420 square inches. 
 
 D = 2i/4 inches X 3-i4i6 = 8.64 inches. 
 
 £ = 74 X 168 X 8-64 inches = 107412.48 square inches. 
 
 F = 6oJ^ X 60^ X .7854 = 2910.5 square inches. 
 
 G = 2/3 X 2 X 2910.S square inches = 3880.66 square 
 
 inches. 
 H =: 23/4 inches X 234 inches X 74 X 7854 = 439-52 
 square inches. 
 Thus our formula will read as follows : 
 
 C+E+G-2XH 
 
 = / 
 
 144 
 
 Substituting values, we have 
 21,420 + 107,412.48 + 3880.66 — 2 X 43952 
 
 144 
 
 = 915-55 sq. ft. 
 
 EXPLANATION OF BURSTING AND COLLAPSING PRESSURE. 
 
 Flues are subjected to external pressure, while the boiler 
 shell is subjected to internal pressure. There is considerable 
 difiference between them. Excess pressure on a boiler shell will 
 result in bursting the shell, while on a flue it will cause a 
 collapse. The shell of a boiler may be out of round but the 
 pressure will tend to round it out to its true shape unless the 
 shell is braced to resist such a stress. 
 
 The pressure on a flue being equal on all sides, it would 
 appear reasonable to presume that the pressure on one side 
 would offset the pressure on the other side. This is not 
 actually the case, however, as the working of the boiler causes 
 shocks, and once the flue assumes any shape other than that of 
 a perfectly true cylinder, it is easy prey to the pressure and 
 will result in a collapse. 
 
 This explanation will show the prime necessity of having all 
 flues and furnaces that are subjected to external pressure made 
 perfectly true in diameter. The United States allows 225 
 pounds pressure on all lap-welded flues up to 6 inches diameter, 
 if the material conforms to the following table: 
 
 O. Dia. Thickness. O. Dia, 
 
 Ins. Ins. Ids. 
 
 I .072 3% 
 
 1% .072 3I/2 .120 10 ,203 
 
 1V2 .083 3^4 .120 II .220 
 
 iH -095 4 .134 12 .229 
 
 hickness. 
 
 0. Dia, 
 
 Thickness. 
 
 Irs. 
 
 In.s. 
 
 Ins. 
 
 .120 
 
 9 
 
 .180 
 
 O. Dia. Thickness. O. Dia. Thickness. O. Dia. Thickness. 
 
 Ins. Ins. Ins. Ins. Ins. Ins. 
 
 2 .095 4'/2 .134 13 -238 
 
 2}i .095 5 -148 14 -248 
 
 214 .109 6 .165 15 .259 
 
 254 .109 7 -165 16 .270 
 
 3 .109 S .165 
 
 Flues above 6 inches diameter are allowed other values. 
 
 COLLAPSING PRESSURES OF FLUES. 
 
 Prof. Reid T. Stewart, of Allegheny, Pa., has conducted ex- 
 tensive experiments to ascertain the collapsing pressures of 
 flues, and has deduced several formulas, which tend to show 
 that all previous formula are more or less incorrect. The 
 general practice has been to take into consideration the length 
 of the flue or furnace from end to end, ring to ring or joint 
 to joint. Figuring on the total length has been found as incor- 
 rect, as flues and furnaces do not collapse their entire length. 
 
 Experiments conducted by Prof. Stewart demonstrate that 
 long flues will collapse at one point and the balance of flue 
 be perfectly true. The extent that the rigid ends will support 
 the flue cannot be fully determined. It is true that when the 
 flue or furnace is of great length it derives no assistance from 
 the rigid ends. The assistance derived from the rigid ends 
 cannot be taken into consideration, as it does not extend far 
 enough to be accepted as any value. 
 
 After a great many tests Prof. Stewart has advanced the fol- 
 lowing formula B : 
 
 r 
 
 P = 86,670 1,386. (B) 
 
 D 
 P = Collapsing pressure in pounds per square inch. 
 D = Outside diameter of tube in inches. 
 T = Thickness of wall in inches. 
 Formula A : 
 
 {'-^ x-i6oo^] 
 
 (A) 
 
 Formula A is for values less than 581 pounds, or for values 
 T 
 
 of less than 0.023. Formula B is for values greater than 
 
 D 
 these. 
 
 Prof. A. P. Carman, of the University of Illinois, has con- 
 ducted experiments vipon the collapsing of flues, and has ad- 
 vanced the following formulae: 
 
 P = 50,200,000 for thin, cold-drawn seamless tubes. 
 
 D 
 
 95.520 
 
 2,090 for seamless cold-drawn tubes 
 
 having a ratio of greater than .03. 
 
 D 
 
 A formula advocated is to add to the length of the furnace 
 expressed in feet the unit I. Taking the British Columbia 
 Rule, we have 
 
 C X T' 
 
 ■ = B 
 
 iL + I) X D 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 45 
 
 C = Constant. 
 
 T = Thickness of plate in inches. 
 L = Length of furnace in feet. 
 
 B = Working pressure per square inch, which must 
 
 1,000 X T 
 
 not exceed the value 
 
 D 
 11,250 is allowed for the constant (C) when the longitudinal 
 seam is welded or fitted with double butt straps, single riveted. 
 
 FORMUL/E. 
 
 Diameter 
 of Flue. 
 
 Thickness 
 of Flue. 
 
 Collapsing 
 Press. 
 
 Style of Flue 
 
 86670 T 
 
 3" 
 
 .109 
 
 1763 
 
 
 3i« 
 
 .120 
 
 1585 
 
 Lap weld Bessemer stee 1 
 
 D 
 
 4" 
 
 .134 
 
 1517 
 
 
 95520 T 
 
 3" 
 
 .109 
 
 1348 
 
 
 3i" 
 
 .120 
 
 1176 
 
 Seamless cold drawn 
 steel. 
 
 D 
 
 4" 
 
 .134 
 
 1100 
 
 It will be seen that the length represented by (L) has added 
 to it the unit (l). The adding of the unit (i) is not correct, 
 as it will readily be seen that if the length of the furnace is 
 3 feet an increase of 33 1/3 percent has been added, or if the 
 furnace is 4 feet long and the unit (i) is added, the increase is 
 25 percent. It is quite apparent that the further the center of 
 the furnace or tube is from the rigid ends the less support they 
 receive from this source. The first foot of flue or furnace is 
 naturally more benefited than the next foot. This continues 
 this way until the flue or furnace receives no benefit from the 
 rigid ends. In furnaces this is taken care of by rings and 
 joints of several different forms. In boiler flues the rigid ends 
 are not taken into consideration, for the reason that boiler 
 tubes will collapse at one place and the balance of tube be 
 in its true shape. 
 
 BRACING. 
 
 Above the tubes of tubular boilers is a space in the form of 
 the segment of a circle, and this space has to be supported so 
 that it will be safe for the pressure sought. To support this 
 space braces are placed in the boiler. There are several dif- 
 ferent styles of braces, and among the several styles are a 
 number of patent braces. Braces may be classified into two 
 kinds, direct and indirect. 
 
 DIRECT BRACES. 
 
 Direct braces are recommended wherever possible, as the 
 brace is allowed its full value per square inch of area. Direct 
 braces are generally called end to end stays or braces. The 
 pressure allowed per square inch of area depends upon the 
 material and manner of making the braces. Braces with welds 
 are not allowed as great a value as braces without welds. Steel 
 braces are allowed a larger stress per square inch than iron 
 braces, as the tensile strength is greater. Different authorities 
 allow different values, so for this reason no set allowance can 
 be stated that will answer for all cases. Iron braces with welds 
 are generally allowed 6,000 pounds per square inch and steel 
 braces without welds 9,000 pounds per square inch. These 
 values will be assumed in onr calculations. 
 
 The factor of safety of braces is figured higher than the 
 shell, and this runs from 6 to 8, according to different authori- 
 ties. Some difficulty is experienced in placing the braces so as 
 to support the segment, with as near an equal tension on each 
 brace as possible. It is quite impossible to so arrange the 
 braces that each one will have the same load. Therefore, we 
 must arrange them so that the pressure will be figured on those 
 which carry the greatest pressure. 
 
 RELATIONS OF BRACE TO PLATE. 
 
 It is an easy matter to figure the pressure a brace will carry 
 when the area that it will have to support is known. 
 
 Rule. — Divide the value for the strength of the brace (ex- 
 pressed in pounds) by the area to be supported and the allow- 
 able pressure is found. 
 
 While the brace may be good for any stated amount the mode 
 of attaching the brace to the plate will have a bearing on the 
 pressure allowable on the plate, as well as having a bearing 
 on the pitch of the stays. Therefore, we must in placing in 
 stays consider the mode of attaching the braces to the plate. 
 It would be possible to have a few large stays whose area was 
 great enough to stand the pressure, but the pitch of the stays 
 might be so great that the pressure could not be allowed on 
 account of the weakness of the plate. 
 
 In Figs. 20 and 21 are shown views of a stay which has been 
 threaded and riveted over in the plate. This is regular stay- 
 bolt practice, and may be found in use in the smaller tubular 
 boilers. The United States rule has two constants — 112 for 
 plates lighter than 7/16 inch and 120 for plates heavier than 
 7/16 inch. As our head is J^ inch we use the constant 120. 
 We desire to find the area that !^2-inch plate with screwed stays 
 riveted over will be good for ; that is the maximum pitch which 
 can be used for the stays. 
 
 Formula : 
 
 A = Constant (United States rule 120 for ;'2-inch plate). 
 
 B =: Pressure per square inch. 
 
 C = Maximum pitch of stays. 
 
 D = Thickness of plate in sixteenths of an inch. 
 
 f^- 
 
 ■4 X rf- 
 
 B 
 
 = C 
 
 Substituting values we have : 
 
 j/ 120 X 64 
 
 ^ ^^ = 6.63" pitch, or 6.63 X 6.63 = 43.9" area. 
 
 175 
 
 Having found the pitch of the stays and the area that the stay 
 will have to carry we must now determine the size of the 
 stay. Area X pressure per square inch = total stress upon the 
 stay. Thus 43.9 X I7S = 7.683 pounds pressure on the 
 plate. Value of stay 6,000 pounds. Thus 7,683 divided by 
 6,000 = 1.2805 area of stay. We will have to have an area 
 of 1.2805 to support this plate, assuming that the strength of 
 the stay is 6,000 pounds per square inch. This is equal to a 
 fraction less than i 5/16 inches diameter. These calculations 
 apply to measurements taken at the root of the tlirtad, there- 
 fore I S/i6 inches must not be taken as the diameter of the 
 bolt. Adding on the threads we would for practical purposes 
 use a iH-inch bolt. 
 
 Other rules : 
 
46 
 
 LAYING OUT FOR BOILER MAKERS 
 
 Other authorities allow different values for the strength of a 
 stay-bolt as the constant is increased, and also the unit one 
 is added to the thickness of the plate. 
 Formula : 
 
 A X (D + jy 
 = c 
 
 B 
 Just to show the difference between the two rules let us assume 
 that the stays are 6-inch pitch. 
 United States Rule : 
 120 X 64 
 
 = 213 pounds pressure. 
 
 36 
 
 Figs. 24 and 25 show a brace with nuts inside and outside, but 
 no thread in the sheet. There is also a washer used on the 
 outside. Stays of this character are generally used where there 
 is difficulty in putting them in or in removing them. The 
 hole in the sheet is made large enough to permit the brace to 
 slide through, the inside nut merely acting to keep the 
 joint. The nut and washer on the outside is a substitute 
 for the nut and thread in the sheet as in Figs. 23 and 24. 
 
 In large boilers of high pressure it is found necessary when 
 using large braces to increase the thickness of the plate where 
 the braces are attached. It may not be necessary for the entire 
 head to be heavier, as the part held by the flues vv'ould be thick 
 enough. Therefore, the part to be increased in thickness would 
 
 Fig. 25 
 
 Fig. 23 
 
 Kg. 22 
 
 METHODS OF F-^STENING DIRECT STAYS. 
 
 British Columbia rule: 
 125 X 81 
 
 281 pounds pressure. 
 
 36 
 
 It will be understood that while there is a difference in the 
 pressure it only applies to the plate. However, the Bntish 
 Columbia rule would permit of a larger stay, and this would 
 then allow greater pressure, while the United States rule will 
 not allow a larger stay, as the plate is the weaker, and nothing 
 would be gained by increasing the size of the stay. 
 
 Figs. 20 to 27 inclusive, show four different ways of fastening 
 the braces to the plate. Fig. 21 shows screwed stays riveted 
 over as just worked out in the preceding examples. 
 
 Figs. 22 and 23 show the stay screwed into the plate with a 
 nut on the outside. This nut assists in supporting the plate, 
 so a different constant may be used than with Fig. 21. 
 
 be that part where the stays are spaced with the greatest pitch. 
 In order for the plates to withstand the pressure a doubling 
 plate is applied, which increases the thickness of the heads at 
 that portion. 
 Constants : 
 
 Figs. 20 and 21 — 120. 
 Figs. 22 and 23 — '140. 
 Figs. 24 and 25 — 140. 
 Figs. 26 and 27 — 200. 
 
 With the constant 140, using the United States rule, the pitch 
 of stays would be as follows: 
 
 / 
 
 140 X 64 
 ITS 
 
 = 7.15" pitch. 
 
 When a doubling plate is used it is not the practice to figure 
 the entire thickness, including the doubling plate, but to use 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 47 
 
 about So percent of this. Thus with ^-inch plate and a ^-inch 
 doubling plate .8, or about 13/16 inch would be used in the 
 United States rule as the thickness of the plate. 
 
 Assuming 13/16 inch as the thickness we would have for the 
 pitch 
 
 = 1,425 square inches. 
 
 . 200 X K9 „ .. , 
 
 1/ . = 13.9 pitch. 
 
 ' 17s 
 
 These calculations are based upon the fact that all stays 
 have an equal pitch, but this is not always a feasible arrange- 
 ment in bracing with end to end stays. Some authorities figure 
 on the maximum pitch regardless of the minimum pitch ; thus 
 if the stays were 10 by 12-inch pitch they would figure the area 
 at 12 X 12 inches = 144 square inches. Others square the pitch 
 of stays and square the distance between rows of braces, add 
 the two results together, and then divide this sum by two. 
 A = Pitch of stays in inches. 
 B = Distance between rows of stays in inches. 
 C = Area. 
 A'- + B' 
 
 = C 
 
 2 
 
 After the size and strength of the braces have been found, 
 and the proper thickness of plate and pitch of stays have been 
 decided, there is still another matter to consider. It is general 
 practice for the ends of end to end stays to be larger where 
 they are screwed into the sheet. As the smallest diameter must 
 be used as the diameter of the brace, we must be sure to have 
 the diameter at the root of the threads on the upset ends as 
 large or larger than the diameter of the body of the brace. 
 Therefore, the diameter of the upset end depends upon the 
 number of threads per inch. 
 
 If United States standard, five threads to the inch are used, 
 the diameter at root of thread would be 1.4902 inches. This 
 is a fraction smaller than the ij'2-inch body. Assuming that 
 the brace is good for 9,000 pounds per square inch its total 
 strength would be 13,411.8 pounds. 
 
 If twelve threads per inch are used the diameter at the root 
 of the thread would be 1.641 inches and the brace would be 
 good for 14,769 pounds. 
 
 Thus, the more threads per inch that are cut the stronger the 
 brace is at the threaded part, since the threads are not as 
 deep. 
 
 TO FIND THE AREA OF A SEGMENT. 
 
 In this also authorities differ and different results are ob- 
 tained by using different rules. 
 Rule i: 
 
 H = Height of the segment in inches. 
 C = Length of the chord of the segment in inches. 
 A = Area of the segment in square inches. 
 Formula : 
 
 IT- 2C X H 
 
 + = A 
 
 2C 3 
 
 Assuming that the segment is one-half the head we will 
 figure this rule out. Substituting values we have 
 
 120 3 
 
 In order to ascertain just how correct this rule is we will 
 find the area by squaring the diameter and multiplying this 
 product by the constapt .7854, which will equal the area for the 
 whole circle. Dividing by 2 vill then give the area of the 
 segment. 
 
 Example : 
 
 60 X 60 X .7854 
 
 = 1413.72 square inches. 
 
 2 
 We find that the two rules are nearly alike, and as the seg- 
 
 no. 28. — SKETCH SKOWINC THE EQUIVALENT AREA BRACED 
 BY THE UPPER ROWS OF TUBES. 
 
 ment to be braced is usually only a small part of the semi- 
 circle the difference is yet smaller. 
 
 Another rule is to find the area of the semi-circle and to sub- 
 tract from it the equilateral space. This does not give the 
 exact result, but nearly all rules are sufficiently accurate for the 
 purpose. 
 
 Special Note: — The examples given are taken as if the 
 whole segment were being braced. This is done merely to 
 explain the rules clearly. 
 
 indirect braces. 
 
 Indirect or diagonal braces of different kinds, either of iron 
 or steel, are being extensively used in tubular boiler construc- 
 tion. The iron braces are usually welded, while the steel 
 braces are without welds. The latter have, from practical and 
 scientific tests, proven themselves from 30 to 50 percent 
 stronger than iron-welded braces, due to the lower tensile 
 strength and uncertainty of the weld in iron braces. Steel 
 braces may thus be made lighter and the factor of safety does 
 not need to be so great as with iron braces. Many authorities 
 are allowing on weldless steel braces 9,000 pounds per square 
 inch sectional area. 
 
 Diagonal braces are not allowed the full value of the 
 strength of the brace, due to the fact that they do not strike 
 
48 
 
 LAYIXG OUT FOR BOILER AFAKERS 
 
 the head at right angles. Thus, if a brace is allowed 9,000 
 pounds in direct pull, it would be allowed less if set at 10 
 degrrees, and still less if set at 15 degrees. 
 If /4 = Area of brace in square inches. 
 
 B = Stress per square inch, net section of brace. 
 
 C = Length of line at right angles from the surface to 
 
 be supported to the end of diagonal brace. 
 D = Length of diagonal brace. 
 E = Surface to be supported in square inches. 
 A X S X C 
 
 Then = pressure allowed per square inch. 
 
 D X E 
 Assuming that the brace is allowed 9,000 pounds per square inch 
 in direct pull, and the length of (C) is 49 inches, with (D) 
 
 FIG. 29. — BOILER HEAD BR.\CED WITH DI.'\GON.\L BRACES. 
 
 50 inches and the surface to be supported 49 square inches, 
 the pressure allowed would be found by substituting these 
 values in the above equation. 
 
 9000 X I X 49 
 
 = 180 pounds. 
 
 49 X SO 
 
 The photograph. Fig. 29, and the sectional view. Fig. 30 
 show the manner of fastening diagonal braces, B and D, Fig. 
 30, representing the distance C in the formula. From the dis- 
 tances A and C and B and D in Fig. 30, the length of the 
 brace is determined. 
 
 In Fig. 31 is shown a layout of diagonal braces for a 60-inch 
 boiler head, in which there are sixty-one 3j4-inch tubes. Au- 
 thorities differ in regard to the area to be supported, but 
 nearly all admit that a certain distance from the flange of 
 the head is self-supporting. It is necessary, then, to determine 
 how far from the flange the head may be considered to be self- 
 supporting. First, however, let us determine the amount that 
 will be supported by the top row of flues. 
 
 In Fig. 31 we find that the flues are 75^ inches above the 
 center line, and the diameter of the flues is 3P2 inches. One- 
 half of 3;-^ is 154, which, added to 7%, makes from the center 
 
 line to the top of the flue, gJ's inches. The allowance that the 
 flue will support be3-ond the flue itself is, as explained in 
 previous chapters, a question depending upon the manner and 
 grade of work. It is quite reasonable not to make this al- 
 lowance too great, as this will cause a much greater stress on 
 the upper row than upon the rest of the flues. Therefore, if 
 we have i^-inch bridge between the flues, we know that each 
 flue is supporting beyond its edge 9-16 inch. From personal 
 observation the writer thinks that the majority are inclined to 
 allow too great a self-supporting distance from the flues. 
 One-half the bridge is, no doubt, a very small allowance, yet 
 it is better to cut the allowance rather than have too much. 
 
 The following consideration may throw some light on the 
 reason why that part of the head nearest the flange may go 
 unsupported. The sections of plate between the rivet holes 
 in the flange of the head act practically as a series of braces. 
 With eighty rivets in the circumferential seams we would have 
 
 FIG. 30. 
 
 about 2.35 inches pitch. This, minus the diameter of the rivet 
 hole (15-16 inch), makes 1.41 inches, giving the net section of 
 plate an area of 1.41 X V2 inch =: .705 square inches. As this 
 is subjected to a direct pull, allowing 9,000 pounds stress per 
 square inch, we would have for each section 6,345 pounds. 
 Thus, we see that the net section of plate of the head is act.i- 
 ally a very strong brace. 
 
 Assuming that the mode of fastening the braces to the 
 head entitles us to use the constant 120, we will find that the 
 maximum allowance for J^-inch plate is 
 
 4 
 
 120 X 64 
 ^5~ 
 
 = 6.63 inches, maximum pitch. 
 
 The inside diameter of the boiler being 60 inches, the 
 radius will be 30 inches. In order to find the actual distance 
 or height of the segment that we wish to support we will have 
 to make some deductions as follows : 
 
 7.625 distance from center line to center of flues. 
 1.75 distance from center of flue to top of flue. 
 .56 supported by upper row of flues. 
 .50 thickness of head. 
 
 10.43S inches. 
 30 — 10.43s = 19.565 inches. Referring to Fig. 31 we find 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 49 
 
 that we will have three rows of braces. In figuring stays 
 or braces it is assumed that the brace will carry an equal 
 amount on each side. As pointed out, the net section of plate 
 of the head was equal to a brace, so we will assume that the 
 net section of plate will support the head for a distance half 
 way between itself and the next row of braces, but not to ex- 
 ceed the limit as found by the formula. The formula gave 
 6.63 inches, but to this we add yk inch, the thickness of the 
 head, and we have 7.13 inches. Thus, we find that from the 
 outside of the head to the nearest row of braces the maximum 
 distance is 7.13 inches. 
 
 We then have 19.565 inches, which is to be divided into three 
 and one-half spaces, giving 5.59 inches as the distance be- 
 tween the rows of braces. This is less than the maximum 
 pitch. Distributing the braces in the three rows with a pitch 
 of 8^ inches we have each brace supporting an area of 
 8.7s X 5-6 = 49 square inches. 49 X 175 pounds = 8,575 
 pounds total stress per brace. 
 
 Some authorities will not allow diagonal braces to have less 
 than I square inch sectional area. In order to get the full 
 benefit of their strength very short braces should not be used, 
 since the brace should be as nearly square with the head as 
 possible in order to be allowed the full value of its strength. 
 The less value allowed the brace the greater the net sectional 
 area will have to be. In this case if the braces are not too 
 short they will be large enough if they have I square inch 
 sectional area. 
 
 FACTOR OF SAFETY. 
 
 With 60,000 pounds tensile strength and each brace carryingf 
 
 8,575 pounds, we have 60,000 divided by 8,575 or 7. as the 
 factor of safety, for the braces. 
 
 RIVETS IN THE BRACES. 
 
 In dealing with the rivets we have to consider them under 
 two conditions as the rivets in the head will be in tension and 
 the rivets in the shell in shear. Since the strength of these 
 is different it will be necessary to figure both. The practice in 
 some places is to figure only the rivets in shear and make the 
 rivets in tension the same size, paying no attention to their 
 greater strength. Assuming the shearing strength as 42,000 
 and the tensile strength as 50,000 we will readily see that 
 there is a ratio of 25 to 21. Some allow more for the tensile 
 strength of rivets, but as explained in previous chapters the 
 maximum is considered at 55,000 pounds. 
 
 Strength of rivets in shear assuming the shearing strength 
 per square inch as 42,000 pounds : 
 
 Diameter, Inches. Area. Strength, Pounds. 
 
 '/i ' .601 25,242 
 
 15/16 .69 28,980 
 
 I .7854 32,986.6 
 
 Strength of rivets in tension, assuming the tensile strength 
 
 per square inch as 50,000 pounds : 
 
 Diameter, Inches. Area. Strength, Pounds. 
 
 li -601 30.030 
 
 15/16 .69 34,500 
 
 In Fig. 31 we find that brace rivets are spaced 454 inches by 
 
 5.6 inches, thus making 4.75 X 5-6 = 26.6 square inches, as the 
 
 area supported by each rivet 26.6 X I75 = 4,655 pounds, stress 
 per rivet. 
 
 With %-inch rivets, tensile strength 30,050, the factor of 
 safety will be 30,050 divided by 4,655 = 6.45. It will be noted 
 that the area alloted to two rivets will exceed the area that 
 the brace will have to carry. In this connection it might be 
 stated that some authorities figure the area from the maximum 
 pitch of rivets or stays, paying no attention to the minimum 
 pitch. Others square both the maximum and minimum pitch, 
 add them togeher and divide the product by two. This, of 
 course, does not give the actual area, but it does serve as a 
 check on unreliable w'ork. 
 
 The rivets in the palm of the brace where the brace is at- 
 tached to the shell will be in single shear. The brace being 
 subjected to 8,575 pounds, the rivets should likewise be figured 
 for this load. Since the factor 7 was used in figuring the 
 brace, it should also be used in figuring the rivets so they will 
 
 FIG. 31. 
 
 not be weaker than the stay. 8,575 X 7 = 60,025. Our table 
 shows that this would require us to use two l-inch rivets. 
 Using the factor 6.45 required for the rivets in tension we find 
 8,575 X 6.45 = 55,315.9. This would require two is/i6-inch 
 rivets. 
 
 SIZ2 OF PALM. 
 
 The width of the palm will depend upon its thickness. As- 
 suming that we make the braces out of 5^-inch steel we will 
 have I square inch (the sectional area) divided by .375 = 2.66 
 inches. To this we must add the diameter of the rivet hole. 
 If made of J/^-inch steel we would have i square inch divided 
 by .50 := 2 inches, to which we must add the diameter of the 
 rivet hole. 
 
 FORMS OF DI.\GONAL BRACES. 
 
 In Fig. 32 is shown a diagonal brace fastened to the head 
 with inside and outside nuts. It will be seen that this brace 
 strikes the sheet at an angle and to have the hole a proper 
 fit it would be necessary to drill the hole small and then en- 
 large it at the angle at which the brace is set. Practical men 
 know that this is a very costly operation and that it does not 
 paj'. The general practice is to drill a hole large enough to 
 permit the brace being set at the necessary angle. This makes 
 the hole too large on the sides, and the part of the hole that 
 is not filled with the brace is packed. Bevel washers are 
 
5° 
 
 LAYING OUT FOR BOILER MAKERS 
 
 placed on both sides of the head to permit the nuts to be 
 tightened up. This style of brace is generally considered the 
 poorest of bracing. 
 
 In Fig. 33 is shown the brace attached to a crowfoot. The 
 crowfoot should be set as indicated by the dotted lines as this 
 gives the brace a proper pull, and not as shown by the solid 
 lines where there is an eccentric loading. 
 
 In the use of steel braces the length of the distance A, Fig. 
 
 palm of the brace should be as shown in Fig. 34, but the gen- 
 eral satisfaction given by the brace shown in Fig. 35 indicates 
 that the prying-off strain on the first rivet is not of great con- 
 sideration. The one main feature is not to have the distance 
 ^, Fig. 35, too great. 
 
 Fig. 36 is a view of an eye-brace as used between two angles. 
 To figure out the proper area for both the round and square 
 parts of the brace we must consider the area of the body of 
 
 ^f 
 
 .\'\ ,-■ 
 
 \ /' ' ' 
 
 ''i \ '-; 
 
 .>' / 
 
 
 -kS^-' 
 
 ' y ^ 
 
 ^ 1 ' ' ". ^ 
 
 FIG. 32. 
 
 35, should not be too great as the braces will have a tendency 
 to straighten out, as shown by the dotted lines. In Fig. 34 
 we have the palm wider where the rivet holes are placed. 
 There are many who think that the first rivet in Fig. 35 car- 
 
 ^ I ^ 
 
 \ 
 
 FIG. 34. 
 
 ries more t'lan its share. It is very reasonable to consider 
 that the first rivet is subjected to a prying-off strain, and many 
 contend that both rivets should be subjected to the same con- 
 ditions. In the case of Fig, 35 we will consider that the rivet 
 is subjected to a prying-off strain. Rivets are either subjected 
 to shear or tension and if the prying-off strain is tension, we 
 find that the strength is increased, because the tensile strength 
 is greater than the shearing strength. Many claim that the 
 
 FIG. 33. 
 
 the brace. Thus if the body of the brace were 2 inches in 
 diameter, the area would be 3.1416 square inches. To find 
 the size of (/4) take the square root of 3.1416, which gives 
 1.79 inches for (/4). Having found the proportions of A and 
 B, and assuming that the material of the angles is of the same 
 quality as that of the brace, we must find the values of F and 
 £. Assuming that £ is ^ inch, in order to make (F) strong 
 enough, we must multiply £ by 2 and divide 3.1416 by that 
 product. 2 X M = 1^2 inches. 3.1416 divided by i.S ^ 2.094 
 inches, value of F. C should be a fraction greater than B to 
 permit the brace to go in and have a little clearance. The 
 proportions of Fig. 36 are figured out for no particular stress 
 per square inch, but merely to show the manner of finding the 
 proper proportions. 
 
 BRACE PINS. 
 
 There are several different kinds of brace pins. Three, 
 which are in common use, are show-n in Fig. 3'/. The pin 
 shown at /4 is a rough, round bolt, split and bent over. It is 
 a very cheap pin, but hard to put in as well as to remove. At 
 B is shown a pin something on the order of the pin A, but it 
 has a separate split key. This is not a very satisfactory pin. 
 C is a turned pin with nut and cotter key. There is also a 
 recess on the pin so that the threads will not come upon the 
 body of the pin. It is customary in some shops to have the 
 diameter of the threaded part smaller than the body A. This 
 pin has much to commend its usage. Many concerns, how- 
 ever, apply simply the rough machine bolt. 
 
 STRENGTH OF BRACE PINS. 
 
 The strength of brace pins is an unsettled matter. It is 
 assumed that the pin can be treated in the same manner as 
 rivets, that is, they can be so placed as to be in single shear 
 or in double shear. Some authorities do not allow any value 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 51 
 
 for the pin in double shear and require the area of the pin 
 to be equal to the area of the brace. 
 
 The British Cokimbia rules allow the area of the pin to be 
 25 percent less than the area of the brace, but at the same time 
 they allow different values on braces. Thus, if a brace made 
 
 of work. Welded braces are not allowed as great a stress 
 per square inch as braces that are weldless. Assuming the 
 tensile strength as 54,000 and allowing 9,000 pounds stress 
 per inch with a weldless brace, the factor of safety is 6, but 
 with a welded brace, allowing only 6,000 pounds stress per inch. 
 
 hH 
 
 t£ r^i 
 
 ^.-^ 
 
 FIG. 36. 
 
 of iron were allowed 6,000 pounds per square inch, it would 
 be satisfactory for the pin to be 25 percent less in area. Should 
 the same style and size of brace be made of steel and not 
 worked in the fire, the brace would be allowed 9,000 pounds 
 per square inch of area. It will be seen that the mere fact 
 that the body of the brace is made of two different metals and 
 by two different methods will give different stresses. Thus 
 they require the same size pin for a stress of 6,000 pounds as 
 they do for 9,000 pounds. This does not seem very consistent. 
 
 When the brace pin is in double shear it may be' considered 
 as a rivet. Assuming that the shearing strength of the pin is 
 42,000 pounds per square inch in single shear, the strength in 
 double shear is generally considered as 85 percent more than 
 this, or 42,000 X i-8s ^ 77,700 pounds. 
 
 What size pin would be needed for a 2-inch diameter brace, 
 allowing 60,000 pounds tensile per square inch for the brace? 
 2 inches, diameter ^= 3.1416 square inches, area. 3.1416 X 
 60,600 =^ 188,496 pounds, stress. 188,496 divided by 77,700 = 
 2.43 inches, diameter of pin. It will be seen that in this case 
 the diameter of the pin is larger than the diameter of the 
 brace. If the tensile strength of the brace is less than 60,000, 
 the diameter of the brace pin would, of course, be less. 
 
 Taking the same proportions as to strength, let us figure out 
 the pin with a smaller brace, say, lyi inches diameter. 
 
 If/2 inches, diameter ^ 1.767 area. 1.767 X 60,000 ^ 106,029 
 pounds. 
 
 106,029 divided by 77,700 = 1.365 inches, diameter of pin. 
 It will be seen that with 2 inches diameter of brace, 60,000 
 pounds tensile strength, 77,700 pounds shearing strength, the 
 diameter of the pin is larger than the diameter of the brace. 
 In the other example, with lyi inches diameter of brace, but 
 with the same tensile and shearing strength, the diameter of 
 the pin is less than the diameter of the brace. 
 
 Braces are allowed different stresses according to the mode 
 
 the factor is 9. The increased factor is on account of the 
 weld. It will be readily seen that the pin does not lose, 
 whether the brace is welded or not. Therefore, the pin 
 should have a factor of safety regardless of the factor of 
 
 ■JV^ 
 
 FIG. 37. 
 
 safety of the brace or material in the brace. A factor of 6 
 should be ample for brace pins. 
 
 With a factor of 6, and allowing 9,000 pounds stress per 
 square inch, what size pin will be needed for a brace 1 3/2 inches 
 diameter, 60,000 pounds tensile strength? 
 
 42,000 X 1-85 
 
 1.5 X 1-5 X .7854 X 9.000 H- = 1.23 square 
 
 6 
 inches, area of pin. 
 
 / I 2*^ 
 
 i/ — '- = 1,25 inches, diameter of pin. 
 
 ' 3-1416 
 
 While 6 was used as the factor of safety of the pin, it will 
 
 be seen that the factor for the brace is 60,000 -^ 9.000 = 6.666. 
 
 STEAM DOMES. 
 
 The use of steam domes on boilers is fast becoming obso- 
 lete, especially where high pressures are used, but their wide 
 use in the earlier days of boiler making makes some con- 
 sideration of their construction necessary. 
 
 Several things must be considered with the dome, viz., 
 
52 
 
 LAYING OUT FOR BOILER ^L\KERS 
 
 how it is fastened to tlie boiler, the style of the vertical seam, 
 the dome head, the bracing, etc. There are in use two gen- 
 eral methods of attaching the dome to the shell, one by flang- 
 ing the dome and the other by having a separate dome base 
 or collar. The latter is generally used in locomotive boiler 
 
 FIG. 38. 
 
 construction, mainly on account of the size of hole that has 
 to be cut in the shell sheet in order to put in the dry pipe and 
 fittings. The general practice with most boiler manufac- 
 turers is to dish the head so that it will be self-supporting. 
 There is no set rule to govern the diameter or length of 
 
 vv 
 
 FIG. 40. 
 
 the dome, as large and small domes are used indiscriminately, 
 and frequently the same size dome is placed upon several dif- 
 ferent sized boilers. 
 
 NEUTRAL SHEET UNDER DOMR 
 
 The neutral sheet under the dome derives its name from 
 the fact that it is subjected to pressure from both sides. 
 There are several methods of providing for the passage of 
 steam through the neutral sheet into the dome. Some punch 
 out a hole in the center one and a half times the diameter of 
 the steam outlet, while others perforate the neutral sheet with 
 
 a great number of small holes. The latter method is used in 
 order not to weaken the sheet to such an extent as when a 
 large hole is punched. Some claim that placing a dome on a 
 boiler brings an unequal strain upon the shell sheets, due to 
 the fact that the pressure on the dome is borne by the shell 
 
 FIG. 39. 
 
 sheet where the dome is attached. Authorities differ on this 
 point however. The use of a liner inside underneath the 
 dome is advocated for strength to cover any weakness that 
 
 FIG. 41. 
 
 might exist from attaching the dome. In Fig. 38 is shown the 
 neutral sheet with a large hole in the center to permit the 
 steam to enter the dome. Fig. 39 shows the neutral sheet per- 
 forated. 
 
 BR,\CING THE DOME. 
 
 Steam domes may be braced in two ways : First, as shown 
 in Fig. 40 by diagonal braces from the dome head to the dome 
 shell ; and, second, as in Fig. 41 by through stays from the 
 dome head to the boiler shell. The diagonal stays in Fig. 40 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 53 
 
 serve the purpose of bracing the dome head, but do not take 
 any of the load from the joint where the dome is riveted to 
 the boiler shell. On the other hand, the direct braces, as 
 shown in Fig. 41, carry a part of the load which would other- 
 wise come upon the joint between the dome and shell. As- 
 suming the inside diameter of the dome as 26 inches, the 
 area of the dome head will be 530.93 square inches. At 175 
 pounds steam pressure, there is a stress tending to tear the 
 dome from the shell of 530.39 X I75 = 92,819 pounds. As- 
 suming that the dome sheet is ^ inch thick, and that the joint 
 between the dome and boiler shell is double riveted, so that 70 
 
 FIG. 42. — DOME COLL.KR. 
 
 percent efficiency will be obtained, the total stress which the 
 joint will stand will be 60,000 X -375 X 26.375 X 3-i4i6 X 
 .7 =^ 1,305.040 pounds. 
 I 1,305,040 
 
 =: 14, the factor of safety. 
 
 92,819 
 A large factor of safety should always be used when comput- 
 ing the strength of this part of the dome, since the sheet is 
 almost aUvays thinned out in the process of flanging; also 
 unknown strains may be set up in the plate due to unequal 
 heating and cooling of the metal, or a weakness may be de- 
 veloped through careless hammering or workmanship. In 
 Fig. 41 the dome head is dished, and therefore does not re- 
 quire bracing. In this case the braces merely protect any 
 weakness at the joints A, B and C. 
 
 Fig. 42 shows a dome base or collar. If the base is made out 
 of heavy material there is no danger of any weakness at A, 
 B or C, and the dished head can be used without stays. 
 
 DISHED HEADS. 
 
 The dishing of the head makes it able to resist pressure, 
 the greater the dish the more the pressure allowed, until the 
 head is hemispherical and then it reaches its limit. It is 
 customary to make the radius of the dished head equal to 
 the diameter of the dome or shell to which it is attached. 
 
 The United States rule for convexed heads, as amended 
 January, 1907, is 
 
 SXT 
 = P 
 
 Where . ^ 
 
 P = Pressure allowable per square inch in pounds, 
 
 T = Thickness of head in inches, 
 
 6" = One sixth of the tensile strength, 
 
 R = One-half the radius to which the head is bumped. 
 Add 20 percent when heads are double riveted to the shell 
 and all holes fairly drilled. 
 
 Substituting values we have for the head under considera- 
 10,000 X -375 
 
 tion = 288.5 pounds. Adding 20 percent for 
 
 13 
 double riveting we have 288.5 X 1-20 = 346.2 pounds, pressure 
 allowed. 
 
 According to a different rule, if 
 T = Tensile strength, 
 7" ^Thickness of plate in inches, 
 R = Radius to which the head is dished, 
 F= Factor of safety, 
 P= Pressure allowed, 
 
 then P = 
 
 RXF 
 Referring to previous work we find that our factor with 
 
 FIG. 43. — MANHOLE, WITH CAST IRON REINFORCING RING. 
 
 holes reamed was 4.2. We will therefore use this factor in 
 
 60,000 X -375 
 
 our example = 206 pounds. 
 
 26 X 4-2 
 
 It will be seen that neither of these rules figure on the net 
 section of plate at the rivet joint where the head is attached 
 to the shell. The United States rule allows different values 
 for single or double riveting, but does not mention what 
 efficiency is required. We will assume that it is expected 
 that the net section of plate and rivets compare favorably. 
 
 Assuming that the head is dished so the weakness is at the 
 net section of plate, we will figure this out to ascertain what 
 factor we will have. Using the constant 1.31 as in previous 
 w-ork, we have 1.31 X -375 + 1.625 = 2.12 inches, approximate 
 
 FIG. 44. — MANHOLE REINFORCED WITH STEEL LINER PL.\TE. 
 
 pitch. The circumference corresponding to the mean diameter 
 of the dome (26^^ inches) is 82.86 inches. Divide this by the 
 approximate pitch for the number of rivets. 82.86 -^ 2.12 := 
 39.1, say 40 (number of rivets). 82.86 -f- 40 = 2.0715 inches, 
 exact pitch. 
 
 Using 54-inch rivets with 13-16 inch holes we have 2.0715 — 
 
54 
 
 LAYING OUT FOR BOILER MAKERS 
 
 .8125 = I.2S9 inches. 1.259 X 60,000 X 40 X -375 = 1, 134.000 
 pounds, strength of net section of plate for single-riveted joint. 
 1.134.000 
 
 = 12.2 factor of safety. 
 
 92,912-75 
 The strength of the rivets to resist shearing is 40 X -5185 X 
 42,000 = 871.080 pounds. 
 
 Thus, 871.080 -=- 92,912.7s = 9.4 factor for the rivets. Thus, 
 a single-riveted joint with a properly dished head will give a 
 large margin of safety for a 26-inch diameter dome. 
 
 M.\NH0LES. 
 
 Manholes are placed in boilers of the larger sizes in order 
 to give an entrance to the boiler. The manhole should be 
 
 -6- -<^ -9- 
 
 run lengthwise of the boiler, therefore we must replace a sec- 
 tion of plate II inches wide and of the same thickness as the 
 boiler shell. As the boiler shell is 7-16, or .4375 inch thick, 
 this area is 11 X -4375 = 4-8125 square inches. Either the 
 width or thickness of the liner must be decided in order to de- 
 termine the other dimension. Assume that the liner is 9-16 
 
 4-8125 
 
 inch thick, its width will then be = 8.59 inches. One- 
 
 ■5C2 
 half of this will be on each side of the hole, and for the total 
 width the diametei of the rivet holes must be added to this, 
 making, if j4-inch rivets are used, 10^ inches for the total 
 width. 
 
 Having determined the size of the manhole liner we must 
 now direct our attention to the size and number of rivets 
 necessary in the liner. We found the sectional area of the 
 plate to be 4.8125 and as the steel has a tensile strength of 
 60,000 pounds per square inch of sectional area the strength 
 
 FIG. 45. — CAST IRON W.-\LL BR.^CKETS. 
 
 large enough to permit a man to enter easily, but not larger 
 than is absolutely necessary, as such a cut in the shell must 
 be strongly reinforced in order to preserve the strength of 
 the boiler. This reinforcement is accomplished in several 
 ways. In the older boilers a cast-iron supporting ring, as 
 shown in Fig. 43 was used. Due to the lack of homogeneity, 
 the low tensile strength and blow holes, which are frequently 
 found in iron castings, cast iron has gradually fallen into 
 disuse for any purpose in boiler work. It has been supplanted 
 by steel in this as in almost every other instance. The more 
 
 FIG. 46. 
 
 modem method of reinforcing a manhole is shown in Fig. 44, 
 where a liner plate is used. The liner may be placed either 
 on the inside or outside or on both sides of the shell. There 
 are a number of patent manhole covers, saddles and yokes on 
 the market to-day which are widely used for this purpose, 
 and might be said to give the best satisfaction, as they are 
 specially designed for a steam-tight joint and maximum 
 strength with a minimum amount of material. 
 
 A calculation which must frequently be made is that for 
 finding the size of liner necessary to compensate for the 
 strength lost by cutting the hole. Assume that the manhole 
 is II by 16 inches, which is the usual size, although 10 by 15 
 inches is also frequently used. The minor diameter sho\ild 
 
 FIG. 47. — LAYOUT OF FLUES AND BRACES. 
 
 of this section is 4.8125 X 60,000 = 288,750 pounds. The 
 shearing strength of the rivets being figured at 42,000 pounds 
 per square inch, the strength of one rivet, using 13-16-inch 
 rivets is .5185 (area one rivet) X 42,000 = 21,777 pounds. 
 Thus, 288,750 divided by 21,777 = 13-3 rivets. This would be 
 the number of rivets needed on each side of the center. 
 
 With 15-16-inch rivets (area .69), we would have 42,000 X 
 .69 = 28,980 pounds per rivet, and 288,750 divided by 28,980 = 
 10 rivets on each side of the center. 
 
 SUSPENSION OF THE B3ILER. 
 
 The two most common methods for suspending boilers are 
 by means of hangers and wall brackets. Cast-iron wall 
 brackets, as shown in Fig. 45, were formerly extensively used, 
 but patent steel brackets have replaced them in many instances 
 for the reason that equally strong steel brackets may be made 
 of lighter weight and at a less cost. Also a steel bracket may 
 be riveted to the shell by an hydraulic riveter, thus ensuring 
 tight rivets. The hanger in Fig. 46 is advocated by some au- 
 thorities to be used on one end of the boiler so that in the 
 event of the boiler getting out of place, due to the sagging of 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 55 
 
 FIG. 49. — DETAIL OF SEAM SHOWN 
 
 IN FIG. 52. 
 
 J 
 
 FIG. 48. — SECTIONAL VIEW OF COMPLETED BOILER. 
 
 FIG. SO- — DETAIL OF BRACING ON 
 LOWER PART OF BACK HEAD. 
 
 m 
 
 Keio 
 
 it 
 
 
 -Butt D 
 
 • o O 
 
 P. 
 
 4i 
 
 'Op^^f* 
 
 Fqi; bracket 
 
 k--E-- 
 
 p-JFor steam Ttozz]e 
 " i ^2.373 Pitch 
 
 Equal spaces 
 
 ,000 Looo-sk-oc 
 
 , 3 
 
 FIG. 51. — LAYOUT OF OUTSIDE COURSE OF SHELL, WITH LONGITUDINAL SEAMS FIGURED ACCORDING TO PRACTICE OF THE HARTFORD 
 
 INSPECTION AND INSURANCE COMPANY. 
 
 00000000000000000 
 
 o o o-o-o-ois-o-e-o 0000000000000000 
 
 »0000000(poo0000000 
 
 o°c 
 
 I I IT-^-B — - 1 
 
 0000000 
 
 52. — LAYOUT OF INSIDE COURSE OF SHELL, WITB LONGITUDINAL SEAMS FIGURED BY LIMITING RULE. 
 
56 
 
 LAYIXC ni'T I'OR r,Oir,F.R ^[AKERS 
 
 the brick wall, it can bo adjusted by merely tightening up the 
 nuts on the U-bolt 
 . The general practice has been with wall brackets to place 
 them staggered on the boiler so that a number of boilers 
 could be placed side by side, and the wall brackets clear each 
 other. Many are to-day advocating the use of wider walls, 
 permitting the brackets to be placed in the same relative po- 
 sition on both sides of the boiler. The distance from the end 
 of the boiler at which the bracket or hanger should be placed 
 is sometimes made one-quarter of the length of the boiler. 
 It is claimed that this will not cause any undue strain on the 
 center circumferential seam. This rule will not apply to a 
 two-course boiler, however, as the quarters at each end have 
 the additional weight of the flue heads, flues, and braces. 
 These weights and also such fittings as the dome, steam noz- 
 zles, etc., should be considered in determining the position of 
 the brackets and hangers, rather than any arbitrary rule, such 
 as making the distance from the end of the boiler to the 
 hanger 25 percent of the total length. 
 
 NUMBER OF RIVETS IN THE HANGER OR BRACKET. 
 
 The rivets in the brackets or hangers will be in single shear, 
 and in order to find the number required it is necessary to 
 know the weight of the boiler and its contents, including all 
 fittings and fixtures. It is the general practice to figure that 
 one-half of the brackets or hangers are to carry the whole 
 weight, as it is considered that at some time the boiler may 
 be displaced from its true setting so that an excessive strain 
 will fall upon one end. 
 If ^^ Total weight upon the rivets, 
 B = Area of one rivet, 
 
 C= Shearing strength of one rivet in single shear, 
 D = Number of rivets for one end, 
 F= Factor of safety, 
 
 AXF 
 
 then D = 
 
 BXC 
 Assuming as the total weight for the boiler and details 12 
 tons or 24,000 pounds, and using 54"'nch rivets and a factor of 
 24,000 X 12 
 
 safety of 12, we have for D = 13.2 or four- 
 
 .5185 X 42,000 
 teen rivets. This makes seven rivets on each side. It is gen- 
 eral practice to have an equal number in a bracket and this 
 would require eight rivets. The adding of the extra rivet will, 
 of course, increase the factor of safety. 
 
 THE COMPLETED BOILER. 
 
 In the preceding work one boiler has been worked out de- 
 gree by degree, covering all the vital points of boiler con- 
 struction for this class of boilers. More might have been 
 written on each and every subject than has been presented, 
 but as the subjects treated are part of the everyday work of a 
 boiler maker, no one should experience a great deal of trouble 
 in applying the rules which have been given to other sizes of 
 boilers. Having figured the size and strength of all the dif- 
 ferent parts, we are now ready to lay out the completed boiler. 
 Practical considerations will determine for any particular case 
 
 which of the many possible forms of construction should be 
 used for any individual part. It is sufficient that the boiler 
 maker understands the advantages and disadvantages of the 
 different forms of construction, and is able to figure the theo- 
 retical strength of each so that he may judge in a practical 
 way which should be used. With this combination of theo- 
 retical and practical knowledge, as outlined in the preceding 
 work, a boiler maker has taken a long step toward a thorough 
 understanding of boiler making. 
 
 LAYOUT OF SHEETS, SHOWING METHOD OF LOCATING THE 
 BRACES. 
 
 In Fig. 47 is the layout of the flues and the braces. The let- 
 ters A, B, C, D, E and F represent the distances from the 
 braces to the top center line of the boiler. Since these dis- 
 tances are measured along the arc, it will be noted that they 
 are obtained by lines drawn from the center of the head to 
 the shell, passing through the center of the braces. 
 
 In Figs. 51 and 52 we have the shell sheets as they appear in 
 the flat. The center line of Figs. 51 and 52 is the top of the 
 boiler, hence the distances A, B, C, D, E and F are the dis- 
 tances as taken from Fig. 47. The letters G, H, I, represent 
 the lengths of the braces. Attention is directed to the rivets 
 marked X, Y and Z. The location of the braces here coin- 
 cides with the seam. The dotted rivet holes near the rivets 
 marked X X indicate where the brace comes. As the seam 
 will not permit of this location the brace is moved to one 
 side. Some place the brace on the outer row of rivets, as 
 shown in Figs. 51 and 52. Attention is also directed to the 
 braces at E. In this case the length of the manhole makes it 
 necessary to either shorten the braces or move them to one 
 side. The dotted rivet holes indicate where they should come 
 and the solid lines indicate where they are located. 
 
 The letters M, O, J, P, L and K represent the location of 
 the hangers, brackets, blow-off, manhole and safety nozzle. 
 The circumference, as explained, is generally figured from the 
 mean diameter of the boiler, called the neutral diameter. It 
 is the writer's practice to make a small allowance between 
 the large and small sheets. After ascertaining the circum- 
 ference of both courses, it has been my practice to make one 
 course about 3-16 inch or % inch shorter or longer than the 
 difference found by figuring the circumferences from both 
 mean diameters. This allowance is generally made, or taken 
 off the small course, as in Fig. 52. 
 
 LONGITUDINAL SEAMS. 
 
 In Fig. 51 is shown the longitudinal seam worked out ac- 
 cording to the practice of the Hartford Insurance Company. 
 In Fig. 52 the longitudinal seam is worked out, the pitch bemg 
 governed by the limiting rule as stated in previous work. The 
 pitch as worked out by the former is 6,43 inches, which gives 
 85,4 efficiency (say 85 percent). The pitch as worked out by 
 the limiting rule, as in Fig. 52, gives 5.952 inches with 84 per- 
 cent efficiency. With the first rule we get a working pres- 
 sure of 177 pounds, while with the latter we get only 175 
 pounds pressure. 
 
 In Fig. 49 is a detail of the longitudinal seam, shown in Fig. 
 
HOW TO LAY OUT A TUBULAR r.OILER 
 
 57 
 
 52. Some question has arisen as to the distance from the cir- 
 cumferential scams to the first rivet. This distance is in this 
 case 4.464 inches, while the length of the net section of plate 
 is 5.592 inches. The arrows in Fig. 49 indicate the direction of 
 force. Naturally the distance A is weaker than B, but in 
 order to break the plate at A, it becomes necessary to shear 
 the rivets in the circumferential seams as marked. Thus, the 
 strength of the rivets of the circumferential seams adjoining 
 A so assist A that it is not a weak place. 
 
 Fig. 48 represents the general make-up of the boiler, showing 
 general layout of these parts as indicated in Figs. 51 and 52. 
 In this view two end to end braces are shown. Fig. 50, show- 
 ing a view of the rear head, with double angles. As already 
 pointed out, welded braces are allowed 6,000 pounds per 
 square inch of sectional area. Therefore, the area under the 
 flues that will be subjected to pressure, multiplied by the 
 pressure, will give the total pounds- pressure to be provided 
 for, the rivets in Fig. 50 being in tension. The manner of 
 figuring the braces, brace pins, angles and rivets having 
 been fully brought out in previous work, there is no need of 
 taking this up further. Thus, the blank spaces of the di- 
 ameter, area and value of the pins will depend upon the area 
 and the pressure. 
 
 The Piping and Fittings for a Tubular Boiler. 
 
 THE MAIN STE.\M OUTLET. 
 
 In order to figure comprehensibly on the piping and fittings 
 for any boiler it is obvious that we must have some data as 
 a basis for such calculations. Let u's use for the basis of the 
 following calculations an ordinary multi-tubular boiler, such 
 as has been described in the preceding chapter, namely, a 
 60-inch by 14-foot boiler having 74 3-inch tubes. Having this, 
 and knowing that the ratio of heating surface to grate area in 
 boilers of this type ranges from 30 : i to 40 : i, we can readily 
 figure the grate area. The heating surface must be figured 
 first, and it may be approximately found from the formula : 
 
 2 2 
 
 THS — C X L X h'^-l Xo — 2X sectional 
 
 3 3 area of tubes. 
 Where : 
 
 THS = total heating surface 
 
 C =^ Circumference of boiler in feet. 
 L r= Length of boiler in feet. 
 
 A = Area of surface of tubes in contact with water. 
 = Area of tube sheets. 
 
 In the problem under consideration this will amount to 916 
 square feet. Now, taking the mean of the ratios of the heating 
 surface to grate area, namely. 35 to I, we have for our grate 
 area : 
 
 916 
 
 ^ 26.2, or say, 27 square feet. 
 
 35 
 Having the above data as a basis we will now proceed to find 
 the size of the steam opening. 
 
 The size of the steam opening depends, of course, on the 
 amount of water that the boiler will evaporate under normal 
 
 working conditions. Sometimes this opening is figured accord- 
 ing to the size, speed, etc., of the engine for which the steam 
 is generated. As we have not taken any engine into account 
 we will merely observe the method used without applying it 
 to our case. To prevent undue reduction in pressure (there is 
 bound to be some) between the boiler and the engine, due to 
 the frictional resistance opposing the flow of steam, condensa- 
 tion, etc., the velocity of steam through a pipe of moderate 
 
 
 SIMPLEST FORM OF REINFORCING PLATE. 
 
 length and with several bends should not exceed 85 feet per 
 second, or 5,100 feet per minute. Then the area of the steam 
 pipe may be found from the formula : 
 a X -s' 
 
 A = 
 
 5.100 
 
 Sf earn pipe flistr?(fe 
 
 
 FIG. 2. — SADDLE BENT TO FIT SHELL AND PLANED TO RECEIVE 
 PIPE FLANGE. 
 
 Where : A =r Sectional area of steam pipe in square inches. 
 a = Area of piston in square inches. 
 J = Piston speed, feet per minute. 
 Another formula which will be applicable in our case is 
 A^ X V X 144 
 
 A = 
 
 r's X 62.42 
 Where : A = Sectional area of main steam pipe in square 
 inches. 
 N = Number of pounds of water evaporated per 
 
 minute. 
 V = Relative volume of steam. 
 Fs = Velocity of steam, feet per minute. 
 
 Note: — The relative volume of steam at any pressure is the 
 
58 
 
 LAYING OUT FOR BOILER MAKERS 
 
 folume of I pound of steam at that pressure as compared with 
 the volume of i pound of distilled water at the temperature of 
 maximum density. 
 
 We have seen what F« should be, namely, 5,100 feet per 
 minute, and the value of V may be found from any table of 
 the properties of saturated steam, so it only remains for us to 
 determine X. 
 
 In multi-tubular boilers the amount of coal burned per 
 square foot of grate surface varies from 12 to 24 pounds per 
 hour, mean 18 pounds. The amount of water evaporated per 
 
 CtK/f//?a ///Kr 
 
 FIG. 3. — C.\ST STEEL SADDLE FITTED WITH TEE BOLTS. 
 
 pound of coal varies from 8 to 12 pounds, the mean being 10 
 pounds. We have found the grate surface to be 27 square feet, 
 therefore we can figure on 10 X 18 X 27 = 4,860 pounds of 
 water per hour, or 81 pounds per minute. Hence, substituting 
 these- figures in our formula we have 
 
 Si X 169-3 X 1-44 
 
 A ^ = 6.21 square inches, 
 
 5,100 X 62.42 
 169.3 being the relative volume of steam at 150 pounds pressure. 
 
 ■t^P/fie f/an^ her^ 
 
 FIG. 4. — C.\ST STEEL SADDLE FITTED WITH STUDS. 
 
 Diam. 
 
 A 
 
 6.21 
 
 ^ 2.81, or 2 13/16 inches. 
 
 ■7854 
 
 Having found the diameter of the steam pipe necessary for 
 our boiler we will now consider the ways and means of fasten- 
 ing it to the shell. If this pipe had been found to have been 
 smaller than 1V2 inches in diameter it would be considered 
 good practice to screw it directly into the boiler shell, and if it 
 had been between VA and 2j^ inches in diameter we could also 
 fasten it direct to the shell, but the hole would be better if 
 reinforced with a piece of plate riveted on so that the thread 
 would have enough metal to secure a good hold. Fig. i shows 
 such a reinforced hole. 
 
 As the diameter of our pipe is 2 13/16 inches we must attach 
 it to the boiler by means of flanges, and there must therefore 
 be some sort of seating block or saddle to overcome the cylin- 
 drical shape, and provide a flat surface for the flange of the 
 
 pipe. There are several ways of providing this flat surface. 
 First, we could take a thick piece of boiler plate, and after 
 bending it to fit the boiler have it planed off on the convex 
 side until it presented a flat surface equal in diameter to the 
 diameter of the flange on our pipe. This piece is then riveted 
 to the boiler and studs furnished for the pipe flange (see 
 Fig. 2). This saddle is sometimes made of cast iron or cast 
 steel, adapted either to the use of bolts with tee heads, as 
 in Fig. 3, or with studs as in Fig. 4. These castings must be 
 provided with a calking liner of thin steel or sheet iron placed 
 between the casting and the boiler shell, so that the joint may 
 be made tight by calking, as the castings themselves cannot 
 be calked. 
 
 Instead of a saddle we may use what is commonly known as 
 a nozzle for attaching the steam pipe to the shell. One ad- 
 vantage gained is that the diameter of the rivet circle is 
 smaller, necessitating fewer rivets, and then bolts may be used 
 instead of studs, which is very advantageous. Such a nozzle 
 is shown in Fig. 5. These may be made of cast iron, cast steel 
 or brass. The latter metal is generally specified for marine 
 boilers where a very high class of work is demanded. 
 
 The thickness of the metal in a cast iron steam nozzle to 
 suit our case is given by the formula : 
 
 T = + .5 
 
 4,000 
 Where : T = Thickness of metal in inches. 
 
 P = Pressure in pounds per square inch. 
 D '= Internal diameter of nozzle in inches. 
 Substituting our figures we have 
 2,81 X 150 
 
 T — h -S = -6054. say, §4 incb- 
 
 4,000 
 
 The finished thickness of the upper flange may be 1.3 times 
 this thickness : 
 
 1-3 X .6054 = .787, say, 13/16 inch. 
 On account of the lower flange being riveted to the shell 
 and thus being subjected to the vibratory strain of driving the 
 rivets, and the great strain due to the contraction of the rivet, 
 it is well to add from 40 to 50 percent to the flange thickness 
 thus found up to I'A inches. Then our bottom flange becomes 
 .787 + .394 = 1. 181, say, VA inches. 
 
 THE SAFETY VALVE. 
 
 The next fixture of the boiler to consider is the safety valve. 
 The types of safety valves in use may be classed under the 
 following heads : Lever, dead weight and spring loaded 
 valves. Lever safety valves are frequently used on stationary 
 boilers, but they have the objection that the friction of the 
 joints cause an extra resistance, and consequently an increase 
 of steam pressure when the valve is rising. To reduce this 
 friction to a minimum the bearing of the fulcrum on the 
 fulcrum link and other bearings should be of the knife edge 
 type. Dead weight valves are also used on stationary boilers. 
 This type of valve is efficient and sensitive, and it is difficult 
 to tamper with it by the addition of further weights than the 
 valve is designed to carry. Spring-loaded valves are suitably 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 59 
 
 adapted to all types of boilers. They are of two kinds: one 
 in which the spring is not exposed to the action of the steam 
 when working, and the other in which the spring is exposed 
 to the action of the steam when working. It is advisable to 
 furnish all safety valves with a lifting device by which the 
 valve may be raised from its seat from time to time, so as to 
 prevent the moving parts from becoming corroded and stick- 
 ing, thus preventing the free action of the valve in performing 
 its duty, which is to relieve the pressure in the boiler when it 
 exceeds that at which the boiler is designed to work. 
 
 The safety valve should have a large area, in order to pro- 
 vide a large opening, for the escape of steam, with a small 
 lift of the valve, otherwise the pressure of the steam may con- 
 siderably exceed the pressure under which the valve began to 
 rise before the valve lifts sufficiently to permit the free escape 
 of the steam. The valve should not allow the pressure of the 
 steam to rise above a fixed limit, and when this limit is reached 
 it should discharge the steam so rapidly that very little or no 
 
 VPipe flar?cfe holis 
 
 CtivlkmtT-Jmer 
 ^ She/f 
 
 FIG. S. — STEAM NOZZLE. 
 
 increase in the pressure of the steam can take place, no matter 
 how rapidly the steam may be generated. 
 
 The area for the safety valve of a boiler may be determined 
 from the grate area by the formula : 
 
 ^ X 4 
 a = 
 
 Where: a = Area of valve in square inches. 
 
 P =: Working pressure in pounds per square inch. 
 
 A = Area grate surface in square feet. 
 Substituting our figures we have 
 
 27 X 4 108 
 
 a := ^ = 8.825 square inches. 
 
 Diam. 
 
 A- 
 
 V 150 
 
 7854 
 
 12.24 
 
 = 3-3S. say, 3J4 inches. 
 
 From the evaporative power of the boiler the area of safety 
 valve may be found approximately by the formula 
 £ 
 a = 
 
 40 X vT 
 
 Where : £ = Evaporating capacity of boiler in pounds per 
 hour. 
 P ^ Working pressure. 
 Substituting we have 
 
 4,860 
 
 a ^ = 9.920 square inches. 
 
 40 X V ISO 
 Whence diameter = 3.55, say, s'A inches. 
 
 Another formula for the area of safety valves used by 
 the British Board of Trade is 
 
 37S X A 
 
 a = 
 
 Gp 
 Where : a = Area safety valve in square inches. 
 A = Grate area in square feet. 
 G p ^ Absolute pressure =^ boiler pressure -f- 14.7 
 In our case 
 
 37-5 X 27 
 
 a = ■ — =: 6.14 square inches. 
 
 164.7 
 Whence diam. := 2.80 inches, say, 3 inches. 
 The weight of steam that will escape in an hour through a 
 
 (>- 
 
 -<> 
 
 w 
 
 FIG. 6. 
 
 square-edged opening, like that occurring in a safety valve, may 
 be approximately determined from the formula : 
 AP 
 
 W = 
 
 .023 
 
 Where : TV = Weight of steam in pounds discharged per 
 hour per square inch of opening. 
 A P ■= Absolute pressure of steam in pounds per 
 square inch. 
 The weight on the lever of a lever and weight valve is easily 
 found by finding the total pressure on the valve, due to the 
 pressure at which the valve is to open. This found, the prin- 
 cipal of the lever and fulcrum is applied (Fig. 6). 
 Let W ■:= Load on valve due to steam pressure. 
 
 w = Weight of ball. 
 
 X = Distance of ball from fulcrum in inches. 
 y ^ Distance of point of contact of valve spindle 
 with lever from fulcrum, 
 then X y^ w =■ W y, y 
 W X y 
 or IV = 
 
 X 
 
 Having found W and decided on the distances x and y, the 
 weight of ball may be found by substituting these values in the 
 formula. In dead-weight valves the weight of the valve and 
 dead-weights is, of course, equal to the total pressure on the 
 
6o 
 
 LAYING OUT FOR BOILER ^[AKERS 
 
 valve, which is equal to the area of the valve multiplied by the 
 pressure at which the valve is to open. 
 
 In spring-loaded valves the size of the steel of which the 
 spring is to be made maj' be found from the formula 
 
 =V 
 
 S X D 
 
 is also provision made in the boiler itself to separate the steam 
 from the water. 
 
 In Fig. 7 is shown a very simple and usually effective way of 
 doing this. This separator, or "dry pipe," as it is called, should 
 be for the boiler under consideration (60 inches by 14 feet) 
 about 5 feet long, 8 inches wide and 6 inches deep. On the 
 two sides are punched rows of holes from Ys lo Yi inch in 
 
 , Steam No ^^\e. 
 
 ^ •XDro,~ 
 
 Drcun*^ 
 
 FIG. 7. — BOX FOK.M OF UHV PIPE. 
 
 Where : 
 
 5 =: Load on springs in pounds. 
 
 D = Diameter,, of. spring in inches from center to 
 
 center of wire. 
 d = The diameter, or side of square, of wire in 
 
 inches. 
 C ^= 8,000 for round steel, 11,000 for square steel. 
 
 diameter. The area of these holes should aggregate at least 
 two to three times the area of the steam outlet, so that the 
 passage of the steam through them will not be hurried nor 
 restricted. The material used is No. 12 or No. 14 gage sheet 
 iron, and it is held in place against the top of the shell by 
 three or four rivets on either side. Some makers put separat- 
 
 FIG. 8. — CYLINDRIC-VL DKV PIPE. 
 
 The pressure or load on a spring-loaded safety valve may 
 be found by the formula 
 
 d' X 2 
 
 = s 
 
 D 
 
 Where : d = Diameter of wire in sixteenths of an inch. 
 
 D =^ Diameter of spring in inches from center to 
 
 center of wire. 
 S = Load on spring in pounds. 
 
 ing washers on these rivets, thereby leaving a narrow space 
 around the top between the shell and the dry pipe. 
 
 The writer knows of one instance at least where the boiler 
 with a dry pipe made with an open strip around the top gave 
 a good deal of trouble by priming. The steam space was rather 
 limited, and it was suggested that the water was drawn by the 
 steam (aided by capillary action) around the shell through 
 this opening into the steam pipe. Whether this was the case 
 or not, this dry pipe was removed and one similar to the one 
 
 Prom in iee 
 
 ^^ 
 
 i% 
 
 y h'-^f^p 
 
 ^^■^Qmia 
 
 c—- 
 
 Ij-- 
 
 FIG. 9. — DRV PIPE IN WHICH THE M.MN STE..\M PIPE IS COMPLETELY SURROUNDED. 
 
 The Dry Pipe. 
 In connection with the steam outlet of a boiler there is 
 usually some arrangement made whereby the steam drawn 
 frorh it is freed as far as possible from the particles of water 
 siispended therein, which would cause trouble if allowed to get 
 to the engine. There is, of course, the "separator," which is 
 usuaiUy placed in the steam line close to the engine, but there 
 
 shown in Fig. 8 was put in. The boiler, since then, has given, 
 no trouble, by priming, so it would appear there was some 
 truth in the suggestion as made above. 
 
 The ends do not have to be absolutely water tight, nor the 
 work expensively careful, the main idea being to form a 
 series of corners that the steam must turn, thereby throwing 
 out the suspended particles of moisture by centrifugal force. 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 6 1 
 
 A more elaborate form of dry pipe is shown in Fig. 9. S 
 is the steam pipe, a branch of which passes through the casting 
 A, which fits snugly about it and is held in place by the set 
 screw B. C is the dry pipe proper, and is about two or three 
 sizes larger than the steam pipe. This is threaded on each end, 
 one end being furnished with a plug or cover and the other 
 screwed into the casting over the ste^m pipe. The pipe C is 
 perforated as usual above its center line, but there are no holes 
 for some distance on either side of the end of the steam pipe, 
 as shown by space D. The ends of this pipe are stayed to the 
 
 FIG. ID.— CUP-SHAPED SCUM BLOW-OFF. 
 
 boiler with stay-bolts, as shown, and when the pipe 5 is of 
 considerable length this pipe is centered in the dry pipe by 
 means of two or three set screws, as shown in the sectional 
 view at the left of Fig. 9. 
 
 These separators or dry pipes are largely responsible for the 
 modern practice of making boilers without domes, as they per- 
 form practically the same office and are considerably less ex- 
 pensive to make. 
 
 The Blow-Oif. 
 
 As the water fed to boilers is always more or less impure, 
 and as there is also a precipitation of solid matter on account 
 of the high temperature of the water in the boiler, there must 
 be some arrangement made for cleaning the boilers when in ser- 
 
 FIG. II. — FUNNEL-SHAPED SCUM BLOW-OFF. 
 
 vice and for getting rid of these impurities or solid matter. This 
 function is performed by the "blow-off." There should be two 
 furnished, one to take care of the solid matter which sinks and 
 one to take care of the lighter substances which float on the 
 surface. The former is placed at the bottom of the boiler near 
 the back head (which is always set an inch or so lower than 
 the front), and the other one in the back of the boiler, either 
 at or a little below the water line. The openings should be 
 ample, and pipes leading from them furnished with a special 
 valve, which is generally of the plug type, as there is less 
 liability of valves of this type becoming clogged by the passage 
 of sediment through them. The pipes should lead as directly 
 as possible to the place of discharge with the least possible 
 number of bends in them. 
 
 The scum cock, as the top blow-off is usually called, may 
 have an area equal to the evaporative power of the boiler in . 
 pounds of water per hour X .00053. The boiler end of the 
 scum blow-off pipe is usually funnel or cup-shaped, as shown in 
 Figs. 10 and 11. . , 
 
 The bottom blow-off should have a little larger area than the 
 
 upper one, and it is found by multiplying the evaporative power 
 of the boiler in pounds of water per hour by .00082. 
 
 The blow-off cocks are preferably of gun metal or similar 
 metal, and if made of cast iron they should have linings of this 
 metal for the plugs to work in, the plugs themselves being of 
 the same metal as the linings. 
 
 The taper of the plugs in scum cocks should be about i in 
 8. For blow-off cocks up to 90 pounds steam pressure I in 6; 
 vip to 180 pounds steam pressure i in 8; for higher pressures 
 I in 10. As blow-off cocks are liable to stick fast they should 
 
 /qs/r fM'nj 
 
 FIG. 12. — ARRANGEMENT OF PIPING FOR SCUM AND BOTTOM 
 BLOW-OFFS. 
 
 be opened regularly, and the plugs should be kept clean and 
 the stuffing boxes always adjusted. 
 
 Fig. 12 shows the relative position of the scum and blow-off 
 cocks leading to the same discharge point. Although it is 
 better to have the scum blow-off pipe conning out directly, as 
 shown by the full lines, if the back arches or brick work 
 interfere, it may be brought out, as shown by the dotted lines, 
 without much loss of efficiency. Sometimes the system is ar- 
 ranged as shown in Fig. 13, in which, if the cocks A and S 
 are opened and C closed there will be a circulation through the 
 pipes tending to keep them clean. At the same time either one 
 can be used independently of the other if so desired. 
 
 The Injector. 
 Now, we will consider the ways of replenishing the water in 
 the boiler to make up for the steam used. We may either use 
 an "injector" or boiler-feed pump or both. Generally both are 
 supplied with large boilers or a battery of boilers, so that one 
 can be used as an auxiliary for the other, or when the other 
 is being repaired. The principle on which the injector acts 
 depends on the fact that steam rushing through a narrow pas- 
 sage creates a partial vacuum and draws the water in with it, 
 imparting a sufficient momentum to the water. to. overcome the 
 
62 
 
 LAYING OUT FOR BOILER MAKERS 
 
 pressure due to the steam in the boiler. The water is passed 
 into the boiler through a pipe supplied with a check valve and 
 shut-off valve. The check valve opens towards the boiler by 
 the water pressure, but as soon as the steam pressure is 
 greater than the water pressure the valve shuts, thus stopping 
 the steam from escaping, or the water from returning. Fig. 14 
 shows an outline of a common flap-check valve. The shut-off 
 valve is placed between the check valve and the boiler, so that 
 
 ^Sco/n /3/ovf off 
 
 Ro¥-f-otyi fi/orfa/V 
 
 senvr 
 
 FIG. 13.— ARRANGEMENT OF VALVES IN BLOW-OFF PIPING. 
 
 in the case of break-down or the check needing repair the 
 system can be completely shut off from boiler pressure. 
 
 The action of feeding water into a boiler tends to lower the 
 temperature of the water already in the boiler, and thus cause 
 an extravagant use of fuel to keep the pressure normal on 
 account of the time it takes to raise the temperature of the 
 feed to the temperature of the water in the boiler. Thus it will 
 be seen that rapid or intermittent injection of feed water is not 
 so efficient as a slower, regular movement, and that the tem- 
 
 will start back quicker after the momentum of the incoming 
 water is lessened, and will cause the check valve to close vio- 
 lentl}', or in engine room parlance, "will pound the checks to 
 pieces in no time." 
 
 To aid the water in the boiler in raising the temperature of 
 the feed, the feed water should be dispersed inside the boiler 
 
 FIG. 14. — DETAILS OF CHECK VALVE. 
 
 in as small quantities as possible, and to accomplish this some 
 makers run the feed-water pipe a considerable distance into the 
 boiler, and have the end connected to a branch full of small 
 perforations, the aggregate area of which should be at least 
 twice that of the feed pipe, to allow a considerable margin 
 against some of them becoming clogged up. 
 
 Another way is to lead the feed into a box having a per- 
 forated cover (below the water line), which may be removed 
 from time to time and cleaned. This is probably the best way. 
 
 FIG. 15. — LOCATION OF WATER COLUMN AND CONNECTIONS 
 
 perature of the feed water should be as high as possible before 
 
 entering the boiler. In using an injector the steam that oper- 
 ates it passes with the water into the boiler, and thus warms 
 it, which is one advantage of the injector over a pump. To 
 get warm water into a boiler by using a pump the water must 
 be passed through a heater on its way from the pump to the 
 boiler. 
 
 The Feed Pipe. 
 The feed water should not enter the boiler at the bottom, as 
 this tends to increase the amount of "dead water" at that 
 point. The best place on a multi-tubular boiler, such as the 
 one we are considering, is near the back end, about 4 or 5 
 inches below the water line. If it enters above the water line 
 the steam, being quicker in action than the water in the boiler. 
 
 as the box acts as a "catch all" for sediment entering the boiler 
 with the feed water. 
 
 The Feed-Water Pump. 
 As the feed pump is not a direct connection of the boiler 
 (although an important adjunct to the boiler room), I will 
 merely give a few of the principal features, such as size, speed, 
 etc. 
 
 The size of the plunger of a boiler-feed pump may be ap- 
 proximately determined by the following formula : 
 A = E X 002. 
 Where A = Area of plunger in inches. 
 
 E = Evaporative capacity of the boiler in pounds of 
 water per hour. 
 
HOW TO LAY OUT A TUBULAR BOILER 
 
 63 
 
 The length of stroke should be from one to one-half 
 times the diameter of the plunger. 
 
 The speed of the plunger should never exceed 100 feet per 
 minute, from 50 to 60 feet per minute being the best rate, 
 although pumps are frequently run at higher speeds with good 
 results. The slower the speed the greater the efficiency and 
 the less the wear and tear on the pump valves. As pumps will 
 pump warm water only with great difficulty, owing to air 
 troubles, etc., the water, if warm, should enter the pump cham- 
 ber by gravity, so that the pump will only have to force the 
 water and not lift it. 
 
 The indicated horsepower required to work a feed pump 
 may be determined by the use of the formula : 
 
 I. H. P. — 
 
 33,000 X 60 X -5 
 Where 
 
 /. H. P. = Indicated horsepower. 
 
 JV = Weight of feed water in pounds per hour 
 H = Head of water in feet. 
 
 Note. — The value of H may be found by multiplying the 
 pressure against which the pump must work by 2.31. 
 
 THE WATER GAGE AND TEST COCKS. 
 
 Now, we have seen that it is very important that the water 
 level in a boiler should be kept constant, so we must have 
 some means of ascertaining the position of this level at all 
 times, and this we have in the water column, gage glass, test 
 cocks, etc. 
 
 Fig. 15 shows the position of the water column and its con- 
 nections on the boiler. The gage glass is connected between 
 two gage cocks, which should be made of good, tough metal, 
 such as brass, bronze or gunmetal, as inferior metals become 
 brittle with the heat. The passages for the water to and 
 from the water column should be ample, seldom, if ever, as 
 small as j4 inch diameter. The glass is usually from 10 to 12 
 inches long, and so placed that when the water is just showing 
 in the glass its level is 3 to 4 inches above the top of the tubes. 
 The normal level is generally at the center of the glass. The 
 bottom gage cock should be furnished with a valve so that 
 it may be opened and steam blown through to clean the system. 
 Both gage cocks should be made so that in case the glass 
 breaks the glass passage can be shut ofif from the column. In 
 a case like this there must be some way of ascertaining the 
 water level while the glass is out of commission. This is 
 managed by means of try cocks or test cocks. These should be 
 at least three in number, the top one being placed about an 
 inch above the top of the gage glass, one an inch below and 
 the third midway between the other two. On account of the 
 liberal expansion of the glass the glands of its stuffing boxes 
 should be at least 1/16 inch greater in diameter than the glass. 
 
 THE STEAM GAGE. 
 
 To ascertain the pressure of the steam in the boiler we have 
 the steam gage. This is placed either in direct connection 
 with the boiler (the best way) or on top of the water column. 
 There are two principles employed in the steam gage. One 
 
 is where the movement of the index finger on the dial Ts 
 derived from the movement of an elastic corrugated plate, 
 caused by the pressure of the steam against it. The other is 
 where this movement is derived from the movement of a bent, 
 flattened tube of metal which is straightened under internal 
 steam pressure. 
 
 The latter principle is the Bourdon, and the one most gen- 
 erally used, as it is both simple and reliable. If a tube thus 
 flattened be closed at one end and bent in the form of the 
 letter U, the application of pressure internally tends to change 
 the shape of the tube to a circular section, which change can 
 only be effected by the partial straightening of the tube, and it 
 is this tendency to unbend that is made use of in the Bourdon 
 pressure gage. One end of the flattened tube is connected to 
 the steam or pressure inlet of the gage and the free end (the 
 
 FIG. 16. — SECTIONAL VIEW OF DAMPER REGULATOR. 
 
 closed end), which is allowed to move with the internal pres- 
 sure, is connected to a lever, on the other end of which is a 
 toothed segment. This segment gears into a pinion on the 
 spindle which carries the pointer. To prevent steam from 
 entering the gage and causing injury by heat, the pipe to the 
 gage is usually furnished with a siphon-shaped bend in which 
 the steam condenses, furnishing a cushion of water against 
 which the steam acts but which prevents the steam entering 
 the gage proper. 
 
 HIGH AND LOW-WATER ALARMS. 
 
 We have seen what precautions are taken against the change 
 in the water level, but sometimes the engineer or fireman may 
 become lax or forget to keep an eye on the gages, water col- 
 umn, etc. To prevent accidents occurring through this negli- 
 gence there is sometimes furnished what is called a "water 
 alarm," both for high and low water. 
 
 One of the principles on which these operate is that a 
 large hollow ball suspended on the water in the water column 
 is connected by levers to a whistle, electric bell or similar 
 alarm, so that when the ball rises or falls to the danger zone 
 
64 
 
 LAYTXG OUT FOR P.OILER :\IAKERS 
 
 the alarm is sounded to acquaint the negligent fireman of the 
 fact. These alarms are also connected to the steam valve of 
 the feed pump, so that when the ball raises above a certain 
 foint the pump is shut ofT, and when it approaches low water 
 
 the pump is put into action again. 
 
 THE DAMPER REGULATOR. 
 
 To automatically regulate the boiler pressure we have the 
 damper regulator, which regulates the heat of the fire. One 
 style of damper regulator is shown in Fig. i6. The valve 
 chamber B is connected to the boiler. The spring is adjusted 
 
 so that iL just counteracts the normal pressure on the valve. 
 When this pressure is exceeded the vaK'e lifts, steam is ad- 
 mitted into the cylinder, presses down the piston, thereby rotat- 
 ing the shaft and closing the damper. As the steam pressure 
 falls the damper is brought back to its original position by 
 means of a counterbalance weight on the end of the damper 
 lever. 
 
 There are many dififerent types of patent regulators on the 
 market. Nearly all work on much the same principle as has 
 been briefly outlined above, and may be depended upon to do 
 their work efifectually. 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 The work of laying out a locomotive boiler is becoming 
 more difficult year by year. There was a time when the lo- 
 comotive was designed, in a measure, to suit the boiler. To- 
 day, however, the boiler is designed to gain certain tractive 
 results. The increased power required to draw the heavy 
 trains, both freight and passenger, requires larger boilers and 
 larger fire-boxes. The weight of the boiler filled with water, 
 
 Belpaire tire-boxes are often very complicated, and therefore 
 difficult to lay out. In treating this subject, the various parts 
 of the boile-r will be taken up in their turn, and each one of 
 the pieces forming these parts will be laid out. 
 
 DOME. 
 
 The dome of the locomotive boiler is usually built in three 
 parts. First, pressed steel dome ring; second, dome sheet; 
 
 together with all the fixtures belonging to it, forms a large 
 percentage of the weight of a complete locomotive. 
 
 In order to obtain a certain tractive effort, a definite amount 
 of weight is necessary on the drivers, thus the boiler must be 
 shifted backward or forward and often distorted to gain this 
 desired end. For thi* reason we find boilers varying widely in 
 general construction. Some of the boilers for light and me- 
 dium weight locomotives, ^with narrow fire-boxes, are very 
 simple in construction, and comparatively easy to lay out. The 
 heavy locomotive boilers, however, with large Wooten and 
 
 third, pressed steel dome base. The former and the latter are 
 sometimes made of steel castings. The dome base is made in 
 two different ways, one being circular on top, and the other 
 being curved down to the radius of the boiler. 
 
 Fig I shows a very common construction for a dome with 
 the dome base circular on top. Fig. 2 represents the dome 
 ring. This sheet is flanged in the hydraulic press, and the 
 length L along the neutral line of the sheet after being bent 
 is the same as the radius of the sheet on the flat plate. Allow- 
 ance must be made for irregularities in the sheared plate. 
 
66 
 
 LAYING OUT FOR BOILER MAKERS 
 
 Fig. 3 represents the flat sheet as it would be ordered from 
 the mills. With a radius of about half the width of the sheet, 
 strike off four arcs at the center of the plate and thus locate 
 the center C. Now strike a circle on the outer edge of the 
 sheet, and if the center is not properly located, shift it one 
 way or the other so as to give the central position. Strike a 
 circle with a radius equal to L, Fig. 2, plus Y^ inch. Also 
 strike a circle with a radius R minus Yf, inch. No holes will 
 be put in the sheet before flanging, but the sheet must be 
 turned off inside and outside to the lines which have just 
 been laid out. After the sheet is flanged, as shown in Fig. 
 2, it is mounted on the boring mill and is turned off at the 
 finish marks, F , to the correct outside diameter ; the sheet being 
 flanged a little large so as to give sufficient metal for turning. 
 A cut is now taken off on the bottom, the top and in the bore. 
 The holes for attaching the dome are now laid out to the 
 radius given on the card, the holes beginning either on or 
 between the center line. 
 
 The holes are either scribed off from the dome sheet and 
 then drilled, or the dome sheet is shrunk onto the dome ring 
 and the holes drilled in place. 
 
 The dome sheet for this dome is welded at the seam. All 
 the holes can be punched in the sheet except those that come 
 near the weld. Fig. 4 shows the sheet as it is ordered from 
 the mills. We first measure this sheet for the proper length 
 and the width. The drawing calls for 31^ inches inside di- 
 ameter, or 32 inches neutral diameter, as the thickness of 
 sheet is Y2 inch. This compares with 100.531 inches, plus a 
 small amount which is necessary for welding. Draw a center 
 line CC the entire length of the sheet. Bisect this line, and 
 at the center draw DD at right angles to CC. Lay off one- 
 half the length of the sheet on each side of the line DD , and 
 draw the lines CG and HH also at right angles to CC. Draw 
 ££ and FF midway between the other lines which have just 
 been laid down. This sheet is now quartered. Draw the top 
 and the bottom lines of the sheet parallel to the center line 
 II inches apart, and draw the top and bottom rivet lines i^ 
 inches from the edge. 
 
 The drawing calls for forty-four rivets in the top and the 
 bottom row. This gives eleven rivets to each quarter. The 
 top and bottom line of rivets are to start on the quarter 
 center lines. Step off eleven equal spaces in each quarter, and 
 center punch for rivet holes. All these holes will be punched 
 e:;cept on the vertical seam center line. Lay off a distance 
 from the vertical seam center line so as to give sufficient 
 metal for welding. All the extra metal on "ibis sheet is to be 
 trimmed away and the sheet is to be planed to the lines laid 
 down. The seam will be placed on one of the side centers, let 
 us say the left-side center, and therefore the 2-inch pipe tap 
 will be laid out on the line FF , as all work will be laid out on 
 the outside of the sheet. Four rivet holes for the liner will be 
 laid off to suit the drawing. 
 
 The dome base. Fig. i, is made of ij4-inch steel. Two 
 views of this dome base are shown in Fig. 5 ; the dimensions 
 R and R are the same in the two views. Before the plate is 
 flanged, the outer line is circular in form and of a radius R; R. 
 Fig. 6, corresponds to R of Fig. 5. Lay out full size on a 
 
 spare sheet the two half views of the flange shown in Fig 5.. 
 Lay off the neutral line of the sheet and determine the dis- 
 tance A : in a similar way get the length of the neutral line B. 
 Referring to Fig. 6, find the center of the plate by striking 
 several arcs from the outer circumference, then with the ra- 
 dius R, see if this center is correct, as no portion of the circle 
 can extend bej'ond the sheared edges. Draw a line CC through 
 the center with a straight edge. From the center of the sheet 
 strike off arcs on each side, and from these points as centers 
 strike off two arcs at l and 2, and draw the center line EE 
 through these points. Lay off the distance A, equal to A and 
 B, equal to B. We now lay out an ellipse corresponding to X 
 and y. 
 
 The metal inside of this line is to be cut out. This is done 
 by punching a line of holes within ^g of an inch of the line of 
 the ellipse. This sheet is turned off on the outside and milled 
 off on the inside to these lines and is then ready to be flanged. 
 After the sheet is flanged the inner surface is planed to fit 
 the exact radius R of the boiler. It is also turned out on the 
 inside to fit the exact outside diameter of the dome ring. 
 
 The forty-four rivet holes. Fig. i, are usually laid off from 
 a templet, or the dome sheet is slipped into place, and the 
 holes are marked off from this sheet. With a back marker 
 the holes are transferred to the outside of the sheet. The 
 holes are then drilled and countersunk under the radial drill. 
 After the sheet has been turned off. Fig. 6. a center-punch 
 mark is put into the sheet along the edge corresponding with 
 the center line CC. These marks are used for locating the 
 sheet in the dies, for flanging and various other operations. 
 They are also used for centering the dome on the boiler. The 
 dome flange is lowered into position, and the holes are center- 
 punched from the inside of the boiler. All these rivet holes 
 are then drilled and counter sunk. 
 
 Fig. 7 shows another type of dome that is largely used. It 
 will be noticed that the dome base is dropped down on each 
 side following the radius of the boiler. Two views of this 
 dome flange are shown in Fig. 8. The radius A corresponds to 
 half the diameter of the boiler, 74 inches, or R is equal to 37 
 inches. The height of the dome flange is 6 inches, and there- 
 fore the upper curve of the flange in the right-hand view 
 has a radius of 43 inches. A is equal to 235^2 inches radius. 
 This means that the dome base is a circular plate outside be- 
 fore being flanged. 
 
 The flat plate is shown in Fig. 9 ; the radius .4 corresponds 
 with A in the previous figure. Lay out one-half of the two 
 views shown in Fig. 8. These should be laid out full size on 
 any boiler plate which is convenient. Measure off the length 
 of the neutral lines B and C; these two dimensions should be 
 the same. There may be a slight variation in the radius in 
 the top portion of the dome base in order to bring these two 
 dimensions the same, but usually the top line follows closely 
 to the curvature of the boiler. 
 
 Lay off By, Fig. 9, equal to S, and strike a circle with a ra- 
 dius D as shown. It will be noticed that the hole in the dome 
 base is circular instead of elliptical, and therefore the sheet can 
 be turned off on the outside and the hole bored out to suit 
 the radius D. Place heavy center-punch marks on the outer 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 ^7 
 
68 
 
 LAYING OUT FOR BOILER MAKERS 
 
 'edge of the sheet on the hne CC for centering the dome base 
 for the various operations. The thirty-two rivets shown in 
 ihe double row, Fig. 7, will be marked off by slipping the dome 
 nheet into place, also the double row of forty-eight rivets will 
 6e marked off frt m the inside of the boiler. 
 
 There is a difference in regard to whether the rivets on the 
 outside of the dome base are to be countersunk or not, de- 
 pending upon the construction of the lagging, casing, etc. 
 This is either shown as a detail on the boiler print or on a 
 special dome card. 
 
 The dome sheet shown in Fig. I is welded along the seam, 
 while that shown in Fig. 7 is double riveted along the vertical 
 seam. Specifications usually mention which seams are to be 
 caulked inside or outside. The edge of the sheet must be 
 bevelled, and if this can be planed, it should be kept in mind 
 in laying out. This seam is shown on the right-hand side of 
 
 y-iy. 
 
 the dome. The 9-16-inch plate will probably be ordered from 
 the mills with only sufficient stock allowed for working the 
 sheet up nicely. 
 
 Fig. ga gives tlie outline of the sheet. The lower edge will 
 be an irregular curve, the vertical lines A, B, C, D, etc.. 
 being of dift'erent lengths. On a spare sheet make a lay-out 
 full size, Fig. gb, of the dome sheet, the lower edge follow- 
 ing the radius of the boiler. We now lay off A, B, C, D, etc., 
 in both views and determine the length of the sheet at va- 
 rious points. From the table of circumferences of circles, we 
 find that the neutral circumference of the sheet, which is 
 31-7-16 inches in diameter, is 98.764 inches. 
 
 We also need 2yi inches on each side of the seam center 
 line for the seam. We therefore take the total length of this 
 sheet, and the greatest width A, Fig. gb, and measure up the 
 sheet to see if sufficient allowance has been made in ordering. 
 Draw a line along the top portion of the sheet, allowing about 
 % of an inch for planing. Now draw a line along the left- 
 hand edge at right angles to it, also allowing about J/s of an 
 inch for planing. Draw the center line CC, which will be 
 half the distance A from the top line, measure off 2i/i inches 
 from the left-hand line and draw the q-iarler line, number 4. 
 
 Measure off distance L 98.764 inches along the center line, and 
 draw the quarter line O; now bisect this distance L and draw 
 the quarter line number 2, bisect each half and draw the 
 quarter lines i and B. Mark the quarter line 3, front, and 
 quarter line I, back. 
 
 Now lay off the lines A, B. C, etc., and step off their cor- 
 responding length from the full size lay-out. Fig. gb. Bend 
 the steel straight edge so as to pass through these points, and 
 draw a nice smooth curved line for the bottom line of the 
 sheet. 
 
 Draw the two parallel rivet lines ll4 inches and 2}i inc'.ies 
 from this line. Draw the top rivet center line lYz inches from 
 the top line, and the vertical rivet center lines Ji inch on each 
 side of the quarter line as shown. Mark off a distance for 
 scarfing on the top right and bottom left-hand corner. This 
 material will be necessary to draw out to form the scarf. 
 Forty rivets are desired on the top row, beginning midway 
 between the quarter lines: this gives ten rivets to each quar- 
 ter. With the dividers, step off ten equal spaces in each 
 quarter. 
 
 The lower line of rivets begin on the quarter line, tliirty- 
 two rivets in all, eight rivets in each quarter ; with the di- 
 viders step off eight equal spaces in each quarter along the 
 lower rivet line. The second row of rivets is spaced midway 
 between these ; open up the dividers so as to have exactly half 
 the space and step off this second row of rivets from the 
 first. 
 
 Referring to the left-hand end of the sheet, locate the lower 
 and top rivets in vertical seam so that the head will clear the 
 flange and cap, so that you can get at the beam with the 
 caulking tool. The other rivets have five equal spaces. A 
 4-inch hole is desired on the front center line, together with a 
 liner, which is held in place by six rivets ; this hole is laid out 
 9 inches from the top line. A 2-inch hole is desired on the 
 right-hand \side, 6^ inches from top line at 45 degrees, also 
 four holes for attaching the flange. 
 
 Without any other information this completes the lay-out 
 of the dome sheet. If there are any detail cards of whistle, 
 taps, steam-pipe connections, etc., these should be looked up 
 and laid out before the sheet is finally passed. 
 
 DOME LINER. 
 
 When the dome. Fig. i, is used, it is common among some 
 builders to weld the seam on the top center and reinforce the 
 sheet at this point with a dome liner. Fig. gc shows the donii; 
 liner that would be used in connection with the dome. Fig. I. 
 This 5^-inch sheet would be ordered from the mill as a shaped 
 sheet, and with a liberal allowance for trimming. Measure up 
 the sheet for width and length, be sure that everything is 
 correct. Draw the center line CC. and draw the front line of 
 the dome liner, allowing about 1-16 inch of metal for truing up. 
 Draw the left-hand line of the sheet, allowing about J-^ inch 
 for planing. 
 
 The boiler print gives location of rivet holes, and in order 
 to match up with the corresponding holes which would be 
 put into the dome course, a full size view of the first course 
 and dome liner is laid out on a spare sheet. We will settle on 
 laying out the holes to scale along the neutral line of the 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 69 
 
 dome liner B, Fig. 10. When these same holes are laid oflt 
 on the first course, the holes correspond with the dome liner, 
 as laid off along the neutral line B, the radial lines are drawn 
 to A. The run of the line A is obtained with the wheel, as 
 there will be considerable difference between the lines A and 
 B, the further the holes are from the top center. 
 
 Lay off the dome center line DD, Fig. go, 3054 inches back 
 from the front line ; 3 inches from this line we strike a 2S-inch 
 circle for the throttle-pipe hole. We now ftrike a 14-inch 
 radius from this hole, and lay off six equal spaces for rivets 
 as shown. From the dome center E, we strike the outer and 
 inner line of the dome flange, as all the rivets must be kept out 
 of this line. Draw a rivet line around the sheet i^ inches 
 from the edges. Lay off si.x equal spaces in the right and 
 left-hand side, and five equal spaces along the tapered portions. 
 The remaining rivet holes are laid off from these lines to the 
 figures given. 
 
 In welding the top seam of the dome course, a number of 
 the rivet holes near the seam are omitted. These are laid off 
 and drilled after the seam is welded. After all the holes arc 
 put into the first course, the liner is brought from the bend- 
 ing rolls, and put into position in the dome course, and all 
 these holes are punched off from the outside of the dome 
 course. 
 
 FRONT TUBE SHEET. 
 
 The front tube sheet will come from the mill, ordered with 
 about ]/4 inch for truing all around. Fig. 11 represents two 
 viewis of this sheet. We measure off the length B along the 
 neutral line of the sheet and strike the radius B, corresponding 
 to it from the center of the circular half-inch sheet. Draw a 
 center line CC, and at right angles to it draw the center line 
 AA; 285^2 inches on each side of AA, draw the tube center line. 
 Divide the distance between these center lines into twenty-one 
 equal spaces, and 145^ inches above and 27% inches below the 
 center line CC draw the limiting tube center line. 
 
 Divide the distance between these two lines into fourteen 
 equal spaces, draw tube circles at each one of these points. 
 Now lay out the five tubes at the extreme right and left side ; 
 these are spaced midway between the center tubes. Li a sim- 
 ilar manner, we lay out the three tubes marked E, and then 
 the four tubes marked F, and five tubes marked G, and finally, 
 the three remaining tubes and 2-inch pipe tap for wash-out 
 plug. These tubes will be laid out on each side of the center 
 line. In a similar manner we lay out the four tubes marked 
 H, the three tubes marked /, and the four remaining tubes, 
 all of these being marked out on each side of the center line. 
 We now have all the limiting tubes outlined. Draw the di- 
 agonal lines as shown : the intersection of each one of these 
 lines gives the location for another tube. 
 
 In order to be sure that the construction is correct, draw 
 vertical and horizontal lines corresponding with tube centers : 
 if the construction is accurate, all of these lines will cross at 
 a point. This is a good check on the work. 
 
 The steampipe hole is shown 10 inches in diameter ; this 
 will be laid out to suit work, and also six rivets in a circle 
 13 inches in diameter. We now lay off six rivet holes on each 
 side of the center from the tee-iron connection, and also the 
 
 two holes marked L for the stay-rod connection, the figures for 
 these rivet holes being given on the boiler card. In some 
 shops the majority of these holes are punched before the 
 sheet is flanged. Those holes coming too near the flange are 
 omitted and are punched after the sheet is flanged. 
 
 All the center-punch marks for tubes and rivets along the 
 outer edge must be checked after flanging, and these centers 
 which are drawn must be correct. Center-punch inarks are 
 put into the sheet locating the center line CC and BB. Lay 
 off twenty-five equal spaces in each quarter, beginning holes 
 on center line and 2% inches from back of sheet. Also lay 
 off line along the sheet 4^ inches from the back edge. This 
 sheet is now turned off to this line and the steampipe hole is 
 machined to size. Also tube holes are either drilled or reamed, 
 as the case may be, according to practice or specifications. 
 
 CHAPTER II. 
 
 The various parts of the dome, front sheet, etc., have been 
 laid out, and we will now take up the laying out of the first 
 course of the locomotive boiler. The method of attaching the 
 first course to the smoke-box sheet varies, depending upon the 
 size of the boiler, and also with the methods of attaching the 
 various parts, and in many cases is made to suit the taste of 
 the master mechanic. 
 
 A common construction is shown in Fig. 12, where the first 
 course continues on through and is riveted direct to the 
 smoke-bo.x sheet. The tube sheet is set back with an even 
 spacing of the rivets and is riveted directly to the first course. 
 
 Another construction which is frequently seen is to have a 
 ring about i inch thick, and in length about 12 to 15 inches. 
 The front tube sheet is riveted to this ring while the first 
 course enters inside the ring and is riveted to it, the smoke- 
 box sheet being riveted to th'^ front end. Still another con- 
 struction which is frequent on medium and small-sized boilers 
 is to have the first course extend on through far enough to 
 receive a solid steel ring from 3 to 4 inches wide, and from 
 154 to 3 inches thick, the smoke-box sheet being riveted out- 
 side 01 this ring. 
 
 The locomotive boiler shown in Fig. 12 is a 64-inch boiler, 
 which has recently been put in operation on one of the West- 
 ern roads. It shows the boiler "fore shortened." The first 
 course is shown 64 inches outside diameter, by 106 11-16 inches 
 long. Also this sheet is to be 11-16 inch thick. The neutral 
 diameter of the sheet, therefore, is 63 5-16 inches. From the 
 table of circumferences we find the figures corresponding with 
 63 5-16 inches, as follows : 
 
 Circum. corresponding to 63^ inches diameter is 198.706 
 " " 1-16 inch diameter is .196 
 
 " " 63 S-16 inches diameter is 198.902 
 
 This will be the length of the sheet when it is laid out on a 
 flat surface. The sheet as it will come to the laying-out bench 
 will have an allowance for trueing all around the edges. We 
 now measure up this sheet for length and width. If every- 
 thing is found correct, we draw a line along the top about 
 li inch from the edge for planing. On each end of the sheet 
 measure off a distance 10611-16 inches and draw the back line 
 
70 
 
 LAYING OUT FOR BOILER MAKERS 
 
 of the sheet. Now bisect the distance between these two lines 
 and draw the center Hne CC of the sheet. With the trams 
 and a liberal radius A square off the end line of the sheet, 
 allowing about % inch for planing. Now measure off on the 
 center line a distance of 198.706 indies. The drawing calls 
 for this seam on the right side 20 inches up from the center. 
 Measure off this distance from the left-hand edge of the sheet 
 and draw the right quarter center line. Measure off a dis- 
 
 everything is correct. Mark the quarter lines as shown, and 
 mark the front end of the sheet "Front." 
 
 Draw a rivet-center line I'/i inches from the top line. Draw 
 another rivet-center line 4 inches from the top line. These 
 rivet-center lines are for "the front tube sheet and smoke-box 
 sheet connections. The drawing calls for 100 "g-inch rivets, 
 which will give twenty-five for each quarter. As nothing is 
 specified to the contrary, both rows of rivets will begin on 
 
 Fis. 13 
 
 tance of one-quarter of the length of the sheet, or 49,677 
 inches from the right quarter line and draw the bottom quar- 
 ter line at right angles to C-C. Also lay off this distance from 
 the bottom quarter line and draw the left quarter line. If the 
 construction has been accurately made the distance from the 
 top quarter line to the right-hand edge of the .sheet should be 
 29.677 inches. This distance, together with the 20 inches at 
 the left-hand edge of t'.ie sheet, should equal one-quarter the 
 length of the sheet. Check these distances over to see that 
 
 quarter center lines. Divide the distance between both quarter 
 lines and right quarter line into twenty-five equal spaces. Lay 
 off twenty-five equal spaces in each one of the other two 
 quarters. Lay off nine equal spaces from the right-hand line 
 to the left-hand edge, and lay off sixteen equal spaces between 
 the top quarter line and the right-hand edge of the sheet. The 
 rivets in the first and second row will corhe opposite each 
 other all around the sheet. 
 
 Lay off a center-rivet line i 11-16 inches from the bottom 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 71 
 
 line, also another rivet-center line 39-16 inches from the hoi- 
 tom line. The center lines are for the rivets on the rear end 
 of the sheet. The drawing calls for fifty-six i>^-inch rivet.s. 
 This will give fourteen equal rivets in each quarter. Begin 
 the front line of rivets on the quarter-center line, and lay 
 off five and one-half equal spaces from the riglit quarter line 
 to the left-hand edge of the sheet. Now lay off eight and one- 
 half equal spaces from the top quarter line to the right-hand 
 edge of the shett. In the front row of rivets strike ofi, with 
 the dividers, the rivets in the back line, half a space from 
 those in the front line. 
 
 Draw three rivet-center lines on each end of the sheets to 
 correspond with figures for the triple riveted seam. Divide the 
 distance between the front and the back inner row of rivets into 
 twenty-six equal spaces, and run a line of center punch marks 
 along the front row of rivets to correspond with the points 
 
 GUSSET SHEET. 
 
 The g.isset, or slope sheet, is a very common sheet on a 
 locomotive boiler, as there are very few large boilers that do 
 not have a gusset sheet. Fig. 12 shows one of these sheets 
 uniting the dome course with the first course. This sheet, 
 when rolled out flat, is curved on the edges, and in order to 
 get the sheet to match up properly the surface must be de- 
 veloped. 
 
 A larger view of the gusset sheet is shown in Fig. 14. After 
 this sheet comes from the rolls the front portion must be 
 flared out and the back portion drawn in, in order to bring the 
 surfaces correct for riveting. The bending line is made about 
 I inch from the line of the sheet, front and back, or 6}4 inches 
 from the front, and 6J-2 inches from the backs will be the line 
 of the sheet. L will be the length between the bending lines. 
 The total length of the sheet will be 605-16 inches. 
 
 laid out. With the dividers step ofT the rivets in the second 
 line half a space from these. Now lay oiif the rivets in the 
 third line, omitting every other space as shown. The rivets 
 in the right and left-hand side of the sheet are laid out ex- 
 actly the same. The drawing calls for injector check openings, 
 right and left, on the side-center lines, 62 inches back from the 
 center line. Strike a 354-inch circle for the hole, also strike 
 a 6j/2-inch circle and lay ofif six rivets 12 inches back from the 
 tube sheet rivet center line. Lay ofT a 2V2-inch taper tap 
 hole on bottom center. 
 
 This sheet will require six stay-foot connections : from the 
 detail of the front tube sheet we get the distance these stays 
 come from the top center lines, 15, 18 and 22 inches respec- 
 tively. We lay ofif these six pairs of rivet holes to suit, to the 
 right and the left of top center line. In the absence of any 
 further information this completes the laying out of this sheet. 
 Several sand-box studs will be required : these will be marked 
 ofif from the casting and drilled to suit. 
 
 Let D be the front neutral diameter of the sheet and D° 
 the back neutral diameter of the sheet. In order to get the 
 shape of this sheet when it is laid out on a flat surface, we 
 proceed as follows: Select a nice clean sheet and draw a base 
 line CK, Fig. 15. This line must be continued so as to obtain 
 the center C from which the reference circles are struck. The 
 length R depends upon the shape and the diameter of the 
 boiler, and is found as follows : 
 
 Let D = front neutral diameter, 
 V° = back neutral diameter, 
 
 L = distance between bending line of sheet. Note 
 that this distance is not the total length of 
 the sheet. 
 D" : R :: (D'—D) : L, 
 RX(D°-D)=LXD' 
 D" 
 
 R = LX 
 
 D°~D 
 
LAYING OUT FOR BOILER MAKERS 
 
 We now substiUitc tlic values D" and L and obtain 
 
 7IJ4 
 R~4y 9-16 X 
 
 7154 — 64 J4 
 47.563X71.75 
 
 R-- 
 
 = 487.52 inches. 
 
 We could not, consequently, lay this out full size, nor will it 
 1)0 necessary to do so. This construction will be made to a 
 scale of V/z or 3 inches = i foot, depending upon the size 
 sheet that we may have at hand. Referring to Fig. 15, draw 
 the line D and D° at right angles to CK, making D = 64^4 
 inches and D° = yi^i inches, and making L = 479-16 inches. 
 Lay off the radius R = 487.52 inches, and thus determine the 
 center C. ' All the elements of this cone-shaped surface will 
 point to the center C. Continue the top slope line EE with a 
 
 the pumt 8° with the second dividers strike off tlie arc i"-.. ; 
 with a pair of dividers measure off the distance from the small 
 reference circle to the point 7i. From the reference circle 
 strike off an arc locating a point i^. In a similar way strike off 
 an arc from the large reference circle and determine the point 
 1°.... These are two points of the developed surface. From !■■ 
 strike another arc with the first pair of dividers, from 1".^ 
 strike an arc with the second pair of dividers. Now transfer 
 tlie distance from the reference circle to point 6,, and thus de- 
 termine the location of the points 2, and 2°.,. These arc two 
 more points of the developed surface. Continue this opera- 
 tion until the points 8:: and 8°= are arrived at. If the construc- 
 tion is properly made, the line 8= and 8% if continued will pass 
 through the center C. This is a check on the construction, and 
 if it does not come out right the work will have to be gone 
 over again. 
 
 Bend the steel straight edge, so as to take in these points. 
 
 <V 
 
 Fig. 20 
 
 straight edge. This should pass through C. We now check 
 up this construction to see that everything is correct. 
 
 Strike a semi-circle on D and D° , and divide each one of 
 these half circles into any number, say eight, equal parts. Num- 
 ber the points from zero to eight on the small circle and from 
 0° to 8° on the large circle. Put the point of a pair of trams 
 on the point zero, and strike an arc from i to i. Similarly 
 strike an arc to points i, 2, 3, 4, etc., and in the same way 
 project the points in the large circle on to the diameter D". 
 Number these points ii, 2,, 3,, etc., and 1°,, 2°i, 3°i, etc. 
 
 From zero, with the trams on the center C, strike the small 
 reference circle, open up the trams and strike the large refer- 
 ence circle from the same center. Look up from a table of 
 circumferences the half circumference of D, and lay this out 
 along the straight line. With the dividers, step this off into 
 eight equal parts. In a similar manner lay down along another 
 straight line the length of the large half circle. Step this oft' 
 into eight equal parts with another pair of dividers. From 
 point 8, with the dividers, strike off an arc i--, and from 
 
 and draw the two smooth curved lines. This represents one- 
 half of the tube sheet, EC being the top center line and AH 
 being the bottom center line. We will now hunt up the sheet 
 which was ordered for this gusset plate, and measure off the 
 over-all length and width of the development, to see if it is 
 large enough. To make this clear we will refer to Fig. 16. 
 
 The two curved lines which have been laid out in the pre- 
 vious figure are the bending lines of the sheet. To this must 
 be added 6]/x inches on the front and 6'j inches on the back, 
 for the seam. The drawing calls for butt seam on the top 
 center. Therefore, this sheet will be symmetrical about the 
 line CH. On a previous layout, draw the reference line XY 
 at right angles to CH. Draw perpendicular lines about 8 
 inches apart for ordinates. Number these ordinates i, 2. 3, 
 etc. Stretch a chalk line XY on the giisset sheet and shift it 
 back and forth until the best position is found. Then draw 
 the line XY the full length of the sheet. Lay off the ordinates 
 from the original layout to correspond with the otlier dimen- 
 sions, I, 2, 3, etc. Bend the straight edge and draw :i line 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 73 
 
 through these points. Step off the width of the seam from 
 tlie bending line and draw the outer edge of the sheet. 
 
 The portion at 5' and T will be drawn parallel to CH. We 
 now proceed to lay out the rivet holes. Draw a curved line for 
 rivet centers i 11-16 inches from the top edge. Draw another 
 curved line 2 inches from this line. The drawing calls for 
 sixty-four rivets ij-^ inches diameter. This gives sixteen rivets 
 in each quarter. We now divide the sheet into four; equal 
 parts. Along the top and bottom lines draw the right and the 
 left quarter line through these points and also the bottom 
 . center lines. Draw the two curved lines for rivet centers along 
 the bottom of the sheet i 11-16 inches from the edge and i^s 
 inches from this line. The drawing calls for fifty-six rivets, or 
 fourteen in each quarter. Begin the front row of rivets on 
 center lines and step off fourteen equal spaces in each quarter. 
 
 We now have the rivets to lay off on each end of the sheet 
 to correspond with the butt triple-riveted seam. We lay off 
 the rivets on each end to correspond with the blue print for 
 this seam. Four more lines should be marked off on this sheet 
 m-'dway between the quarter lines, which should be used for 
 lining up the sheet in the rolls. 
 
 When the seam does not come on the top center, the work 
 of laying out the sheet is somewhat different than that shown 
 in Fig. 17. We will take the case where a seam is desired on 
 the right-hand side of the boiler at 45°, as shown in Fig. 18. 
 We make the layout for. the development for this sheet as 
 shown in Fig. 19. The development is made the same as that 
 shown in Fig. 15. A, B, C, D represents the development of 
 the sheet up to the bending line, and E, F, G, H represents the 
 sheet, including the seams ; GH is the top center line, and EF 
 is the bottom line ; midway between these two we draw the 
 side center line KL. Midway between the top center line and 
 the side center line, we draw the seam line MN. Having this 
 construction completed, we can proceed to lay out the gusset 
 sheet with the seam on the side 45° up from the center line. 
 
 On a spare sheet, with a scale of ijX inches to the foot, lay 
 out this sheet as follows: Draw a bottom line. Fig. 20; from 
 Fig. 19 measure off FL and EK, and transfer these dimensions 
 to Fig. 20, laying out the points on each side of the bottom 
 center line. We now have the sheet laid out up to the right 
 and left quarter lines. Transfer the portion K, L, N, M to the 
 right-hand side of the right quarter line. Transfer the portion 
 K, L, G, H to the left-hand side of the left quarter line, making 
 the line KL coincide with the left quarter line. The extreme 
 portion of this figure will give the top center line of this sheet. 
 Now transfer the portion M, N, G, H to the left of the top 
 center line, making HG correspond with the top center line. 
 We thus have the complete layout of the gusset sheet. 
 
 Draw a reference line the entire length of the development, 
 and lay off ordinates the same as in Fig. 16. This gives the gen- 
 eral outline of the sheet, and from this we can lay out the work 
 of the sheet which has been ordered for the purpose. Fig. 20 
 shows the sheet as laid out. Mark off eight equal spaces to 
 the left of the top line and punch the holes to correspond. 
 Lay off the top rivets half a pitch from these. Repeat this 
 operation on the right-hand top portion of the sheet. Lay 
 out seven equal spaces on the lower left-hand portion and 
 
 locate the rivets in the next line half a pitch from these. Re- 
 peat this operation in the lower right-hand portion. The rivets 
 for the butt seam are laid out to suit the detail drawings of 
 the seam in the same way as in the previous case. 
 
 The most difficult seams to keep tight about a locomotive 
 boiler are those around the fire-box. No matter how good a 
 job is made of these seams, we are sure to have more or less 
 trouble with them after the boiler has been in service for 
 some time. For this reason special pains should be taken 
 with these seams in order to make an extra good job. We 
 will take up the fire-box sheets in their order as follows : The 
 fire-box back sheet, the fire-box front or tube sheet, fire-box 
 continuous crown or side sheet, fire-box side sheet and fire-box 
 crown sheet. 
 
 THE FIRE-BOX BACK SHEET. 
 
 Fig. 21 shows a fire-box back sheet. The rear end of the 
 boiler is sloped off to the front as shown. The center line 
 of the boiler is 1&V2 inches down from the top of the crown 
 sheet. In order to get the length of the sheet before flanging, 
 measure off the length of tlie neutral line L. For width, lay 
 off in a similar manner the length of the neutral line around 
 the sheet at the line of the greatest width as shown at A. 
 This portion must be wide enough to go around the first 
 through rivet of the water space frame. 
 
 Fig. 22 gives the shape of sheet. Draw the center line CC, 
 also the boiler center line EE. From the center line meas- 
 ure a distance 3o;4 inches and draw the line DD. We must 
 now lay off the fire-door holes A and B. These holes are oval, 
 16 inches by 20 inches inside. Lay this fire-door out full 
 size and get the length of the neutral line A, Fig. 21, of the 
 sheet after the door has been flanged. From the distance B, 
 and also from the other section of the door, we can obtain 
 the distance C. These two figures are the length and the 
 width of the oval sheet before flanging. 
 
 Lay out these ovals, Fig. 22, as shown. These holes will be 
 punched out and the outer edge milled off smooth before being 
 flanged. Draw the limiting line of the sheet, which will have 
 sufficient metal for seams, plus an allowance of from yi to yi 
 inch for trimming after the sheet has been flanged. If the 
 back fire-box sheet is not bent too sharp, the holes can be 
 laid out and punched before the sheet is flanged. But where 
 the metal draws considerably in flanging, these holes will 
 have to be laid out and punched after the sheet comes from 
 the press. 
 
 The layout of this sheet is given in Fig. 23. Draw the center 
 line of the sheet CC and draw out DD, the center line of the 
 fire-doors. On the center line lay off a distance corresponding 
 with the bottom line of stay-bolts. Draw the line EE, laying 
 off nine equal spaces on each side of the center 4 inches apart. 
 On the center line CC, lay off two 4 inch spaces and draw the 
 center line FF and GG. Lay off nine equal spaces on the 
 third line 36^4 inches on each side of the center, draw lines to 
 locate rivets FF as .shown. From the figures on the boiler 
 card lay off the rivets around the fire-doors. Lay out the 
 holes in the intermediate points ; draw center lines HH and 
 lay out holes to suit. Continue laying out one row of rivets, 
 one after another, until tlie top of the sheet is reached; check 
 
74 
 
 LAYING OUT FOR BOILER MAKERS 
 
 up the length vertically to see that you are not gaining or 
 losing in the overall distance, also draw two lines along the 
 bottom of the sheet and lay off twelve equal spaces on each 
 side of the center line to correspond with the first through 
 rivets on the mud ring corner. Lay out rivets in top row and 
 space from these as shown. After the sheet is flanged, the 
 holes for the rivets for the side and crown sheets will be 
 laid out. 
 
 FIRE-B3X TUBE SHEET. 
 
 The fire-box tube sheet in many boilers is a plain sheet, 
 the outer edge being flanged to make the connections to the 
 
 to get the full length of the sheet necessary. These lower 
 taper lines at A and A will become nearly straight when the 
 sheet is flanged. The amount to allow depends upon the set 
 of the sheet ; the greater the set and the deeper the flange, the 
 greater the allowance will have to be. To get the full length 
 of the shett through the deepest portion of the flange, meas- 
 ure ofT the neutral line M at this point. This is the greatest 
 width of the sheet. 
 
 Now lay out the outer line of the flanged sheet from the 
 boiler card and lay off the width of the flange outside of this. 
 We now obtain the outer line B and B of the sheet. Draw 
 the center line CC on the plate which has been ordered for 
 this sheet, allowing at least % of an inch for trimming at 
 the top of the sheet. All the e.xtra metal is to be removed 
 and the outline of the sheet must be smooth before it can go 
 to be flanged. 
 
 Fig. 25 shows this sheet as it will appear laid out on a fiat 
 sheet. All the holes will be laid out and center punched be- 
 fore the sheet is flanged. Draw the main center line CC of 
 the sheet ; at right angles to CC draw the boiler center line 
 DD. All the boiler tubes are to be located from the^e two 
 lines. The highest tubes are 11^ inches above the center, and 
 the lowest tubes 305^ inches below the center. Divide this 
 distance into fourteen equal spaces. The extreme tubes are 
 28j^ inches on each side of the center; divide this distance 
 into eleven equal spaces, draw the tubes on the center lines 
 as shown, then begin on top and lay out the limiting tubes one 
 
 side and crown sheets. In other boilers, however, the fire-bo.K 
 tube sheet is quite complicated for laying out and flanging. 
 Fig. 24 represents a sheet which is commonly seen on heavy 
 locomotive boilers. The sheet has a set of 7^ inches and the 
 flange on the bottom is 6 inches deep. Lay out the cross 
 section of the sheet on the J/^-inch plate, which has been or- 
 dered for this sheet. 
 
 ^Measure off the length L of the neutral line of the sheet. 
 To this length must be added the taper portion at A in order 
 
 after the other, keeping the boiler card in front of you as you 
 go along. The five extreme tubes on each side fall midway be- 
 tween the tubes on the center line. Follow on down along 
 the curve of the boiler and lay out all the limiting tubes in the 
 lower portion ; repeat this same operation on the other side. 
 
 Draw diagonal lines through these limiting tubes as shown 
 in Fig. 25. These lines should cross the tube centers on CC, 
 also these intersections should form straight lines vertically 
 and horizontally. Before laying out any of the remaining 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 75 
 
 t-.bes, see that all these lines check up properly ; if they do 
 not true up, they must be shifted and corrected. The re- 
 mainder of the tubes can now be laid out with reasonable as- 
 surance that everything is all right. Draw two parallel lines 
 along the lower edge of the sheet for the water-space rivets. 
 
 -Lay out eleven equal spaces along lower line, spaced on each 
 side of the center to the first through rivets. Step oiT the 
 next row half a space from these ; draw four parallel lines at 
 right-angles to CC to the figures given. Start on the right- 
 hand side and lay out. all the rivets on the lower line. Sum 
 up the dimensions and check the overall to be sure that you 
 have neither gained nor lost in laying out these given units. 
 
 Lay ofif the rivets to the figures, one row after another; 
 
 three pieces ; this gives two longitudinal seams, one on each 
 side of the boiler. In order to overcome the disadvantage of 
 these two seams, the side and crown sheets are made in one 
 continuous piece as shown in Fig. 26. This sheet is laid out in 
 the following manner : Referring to the right-hand view, we 
 lay out the neutral line of the front and back of the sheet. 
 Lay off points I, 3, s, 7 and 8 on the front neutral line, and 
 points o, 2, 4, 6, 8 on the back neutral line. Also lay out these 
 points on the left-hand view and number them i, 3, 5, etc., 
 and 0, 2, 4, etc., connect these points by diagonal lines as 
 shown. 
 
 Lay out a right-angle A, B, C, and lay off the length of the 
 element o-i along BC as shown at X. Measure off the dis- 
 
 draw a circle with 345^^ inches radius and step off the desired 
 number of spaces. Also draw a circle with 40 inches radius. 
 Lay off the remainder of the stay-bolt holes for these rivets. 
 Complete on each side of the sheet; first measure off the ex- 
 treme rivets to see that every thing checks up with the figure 
 on the boiler card. With a pair of trams transfer this con- 
 struction to the other side of the sheet. The holes AA fall 
 on the curved portion of the sheet along the corner and would 
 be laid off after the sheet is flanged, also the holes for the 
 rivets for the side and crown sheet would be laid off after 
 the sheet is flanged. 
 
 FIRE-BOX SIDE AND CROWN SHEET. 
 
 The fire-box is subject to such high temperature that the 
 sheets gradually burn away, and the thicker the sheet the 
 quicker it will burn away. The seams have a double thick- 
 ness at this place. For this reason these seams are difficult to 
 keep in order. The fire-box top and side sheets are made in 
 
 tance o-i on the right-hand view and lay this off along BA as 
 shown at Y. Measure the length of the diagonal Z. This 
 is the true length of the element o-l. In a similar manner 
 obtain the true length of the elements 1-2, 2-3, etc. 
 
 Having determined the true length of these elements we 
 can proceed to lay out this sheet. Draw a center line CC on 
 a good large sheet, Fig. 27. From O, with the true length of 
 the first element B-i as a radius, strike off an arc as shown. 
 Measure off the length of the neutral line K-l, Fig. 26, and 
 strike off an arc from the center line CC, Fig. 27, cutting the 
 first arc at I, draw the line O-i. From zero with a radius 
 equal to the length of the neutral line from o to 2, strike off 
 an arc, and from i as a center with a radius equal to the true 
 length of the second element, strike off an arc. This locates 
 the point 2. In a similar manner we strike the length of the 
 neutral line 1-3 and the true length of the element 2-3. Con- 
 tinue this layout until we get to the element 8-8 on the right- 
 hand side. From this element on down to the bottom of the 
 
76 
 
 LAYING OUT FOR BOILER MAKERS 
 
 sheet, the plate is straight, :ind therefore we transfer this por- 
 tion to Fig. 27. The length of the diagonals M and N are the 
 same as found in Fig. 26. Having laid ont this much of the 
 sheet we can determine the overall length and overall width 
 of the sheet. 
 
 If this sheet has hcen ordered from the mill it will prob- 
 ably have plenty allowance for trimming all arovnid. If the 
 sheet has not been ordered, we take a stock plate as near the 
 size as possible and make the layout exactly as shown in Fig. 
 27. All the holes for the stay-bolts and rivets will be laid 
 out on this flat sheet in a similar manner given for the layout 
 of the side and crown sheet, which will be given directly 
 
 FIRE-BOX SIDE SHEET. 
 
 Fig. 2S represents a fire-box side sheet with a longitudinal 
 seam for the crown sheet connection. On a much larger 
 
 for 2^-inch space, start at the top rivet along the left-hand 
 line and step off one space after another and see if the bottom 
 rivet comes out far enough above the water-space frame to 
 clear the head. This will rarely come out exactly right; we 
 now either increase or decrease the space of the dividers and 
 make another trial. This will be repeated until the last rivet 
 comes exactly right. All the points will now be center- 
 punched to suit the last spacing. 
 
 In a similar manner we lay out the rivets along the right- 
 hand edge of the sheet as nearly 2j-4.-inch pitch as the even 
 spacing of the rivets will allow. Draw two lines parallel to 
 the lower edge of the mud-ring rivets. The drawing calls for 
 thirty-seven equal spaces between the first through rivets in 
 the corners. Measure ofT the length of this line, divide this 
 distance by the number of spaces and get the pitch of the 
 rivets. Set the dividers as near this distance as possible and 
 
 1 
 
 
 3 
 
 5^0 
 
 T| =^= = 
 
 'r— _ , 
 
 ... ,_ 
 
 
 
 
 
 
 Pig. 31 
 
 plate than the one that has been ordered for this sheet, we 
 make a large layout of the fire-box, showing mud ring and 
 front and back tube sheet. This will be used after the front 
 and rear sheets have been flanged to lay out the rivet holes 
 in these flanged holes. Having made this layout as shown in 
 Fig. 28, that portion which pertains to the side sheet itself can 
 be transferred to the actual sheet, Fig. 29, upon which this 
 layout is to be made. Draw a line along the top of the sheet, 
 allowing about % inch for planing, measure up the length and 
 width from the large layout and find the best position on the 
 sheet. Draw a parallel line i inch from the top for the longi- 
 tudinal seam ; also draw lines parallel to the edges, front and 
 rear l inch from the edge of the sheet for the fire-box seam 
 rivets. The boiler card calls for fire-box rivets spaced 2j4- 
 inch pitch ; measure ofif the length of the top rivet line, divide 
 this length by 254, and obtain the nearest number of equal 
 spaces and step off these spaces to suit. Now set the dividers 
 
 run off a trial spacmg; this will rareiy come out right; with 
 the slow-motion screw, increase or decrease the space and 
 make another trial; finally this will come out exactly right 
 and the rivets will be center-punched to suit the last spacing. 
 
 Step off the second row of rivets half a space from these. 
 The lines for the stay-bolts are not parallel, the spaces being 
 wider at the front. Lay off from the figures on the boiler 
 card, the distance front and back for the top line of stay-bolts. 
 Draw this line the full length of the sheet. In a similar man- 
 ner lay out the location of the second line, and so on. Sum 
 up the overall length to see that you do not gain or lose, as 
 the lower line must be a definite distance from the lower edge 
 of the sheet. Too much care cannot be taken in laying out 
 these lines, for there are often furnace bearers, pads, etc., re- 
 quired, and unless the rivets come exactly right these parts 
 will not match up properly. 
 
 Beginning on the left-hand side of the sheet, draw the line 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 77 
 
 AB; this has a row of rivets all the way through. Then draw first rivet on the left begins on the diagonal center lines; the 
 the line CC, divide the distance between these lines into twenty- rivets are equally spaced; the last rivet coming on the ex- 
 seven equal spaces and draw parallel lines at right angles to treme right hand. Now lay out the rivets in the lower right- 
 
 
 
 
 
 ''iV ' 
 
 
 ^" 
 
 
 
 ,-.',' 
 
 
 
 'rS'~" 
 
 
 .Si^ 
 
 ' 
 
 
 \o 
 
 
 o~-- 
 
 o 
 
 i 
 
 
 o 
 
 
 
 o 
 
 \ 
 
 
 
 ■ ■■■ "-^ 
 
 Q Q5 [ 
 
 ^ 
 
 the bottom line. The intersection of every vertical line with hand corner and those on the left-hand end of the sheet to 
 the longitudinal line gives the location of a stay-bolt. Lay suit the figures on the card. All the work on this sheet should 
 out the rivets in the second row from the top as shown. The be thoroughly checked to make sure that everything is correct. 
 
LAYING OUT FOR BOILER MAKERS 
 
 FIRE-DOX CROWN SHEET. 
 
 The crown sheet connecting the side sheet shown in Fig. 
 28 is represented in Fig. 30. The neutral line of the front and 
 back of the sheet is shown in the left-hand view. Select a 
 large sheet and draw a top reference line AB. At right angles 
 to this, draw a center line CD. Lay out the two views of the 
 crown sheet to the figures on the boiler card. Lay off on the 
 front neutral line points o,, 2i. 4,, etc. Lay off on the back neu- 
 tral line ii, 3i, 5,, "i. Connect these lines by diagonal lines in 
 both views. Lay off the angle ABC. Lay off a distance X 
 equal to the length of the ordinate O-l. Lay off a distance 
 equal to the perpendicular height in the left-hand view. The 
 diagonal Z is the true length of the first element. In a similar 
 manner we get the length of each one of the elements. 
 
 We now make a layout on the plate which has been ordered 
 for this crown sheet in a similar manner to that shown in 
 Fig. 27. Strike off arcs with the radius equal to the length of 
 the neutral line from one point to another, using the true 
 length of the element as diagonal connecting lines. We thus 
 obtain the length of this sheet as shown in Fig. 31. Draw the 
 center line CC in such a position as to leave about ^ inch 
 for planing at A. Draw the rivet center line along the right 
 and left-hand side l inch from the edge. In a similar man- 
 ner draw parallel lines I inch from the front and back edges. 
 Now measure off the length of the rivet center line B, divide 
 this by 2^:4 and determine the nearest number of rivets ; set 
 the dividers as near the distance as possible and step these 
 spaces off along the right-hand line. With the measuring 
 sheet, get the length of the rivet center line on the rear end. 
 Divide this by the pitch and get the number of equal spaces. 
 Step these off to suit. 
 
 In a similar manner get the run of the front line of the 
 sheet and lay off these rivets as nearly 2>4-inch pitch as pos- 
 sible. From the center line CC lay off a number of spaces 
 corresponding with the figures for the stay-bolts for the front 
 of the sheet. In a similar manner lay off figures correspond- 
 ing to the figures for the rear end of the sheet. Draw straight 
 lines through these points ; measure up the overall, and if 
 everything is correct, transfer these lines to the left-hand side 
 of the sheet. 
 
 On a center line lay off 24 equal spaces 4 inches apart to 
 suit the drawing. Also lay off these same spaces along the 
 line C and D. Now bend the straight edge to take in the points 
 on the center line and the two points C and D. While the 
 straight edge is held in this position, run the pencil around and 
 mark out this line. In a similar manner, draw all the other 
 parallel lines. This gives the location of nearly all the stcy- 
 bolts in this sheet; the few extra holes at the rear end of the 
 sheet will be laid out to suit. 
 
 MUD-RING. 
 
 The water space frame, or mud-ring, is frequently made of 
 wrought iron. The design is made as simple as possible, in 
 order to make a cheap forging. When the water space frame 
 must be arranged with flanges and expensive off-sets, they are 
 now being made of steel casting. The frame is machined all 
 around the inside and the outside. 
 
 Fig. 32 shows a rather complicated frame. This is a steel 
 casting, and these castings often come from the steel works 
 considerably out of line. This frame must be strengthened, 
 and oftentimes it is necessary to heat the frame in order to 
 get it into line. 
 
 Lift the frame upon the surface plate, and block up one end 
 to give the desired slope, and, with the surface gauge, level up 
 the frame; now lay off the length 118 inches, and scribe a 
 line across the top and bottom of the frame to which the ends 
 must be machined. Now lay off the width of the frame inside 
 76 inches and the thickness of the sides 4J^ inches, and scribe 
 these four lines. Referring to detail drawing of the frames, 
 lay out the radius for the corner inside. Then lay out the 
 slope portion and the radius for the outside of the corner. 
 This frame is now ready to have the corners milled and the 
 sides planed. Before doing this, however, measure up the 
 flanges, projections, etc., to be sure that the casting will hold 
 up all around. After the casting comes from the planing 
 machine, lay out two parallel lines on each side for the rivets. 
 'Step off twenty-seven equal spaces on the top line between 
 the first through rivets ; now step off the rivets in the lower 
 row half a space from these. Lay out both sides of the 
 frame exactly the same. Draw two parallel rivet lines on the 
 front end, and step off nineteen equal spaces between the first 
 two through rivets, also step off the lower row half a space 
 from these. Lay off two lines on the back end and step off 
 nineteen equal spaces. A number of holes are required on the 
 flange portion for attaching the boiler to the Jj-inch furnace 
 bearer plates. With the surface gauge draw the lines for 
 these holes. Lay out these holes to suit the figures on the 
 detail drawings, also lay out the places A and B, as these plates 
 are apt to come solid. In a similar manner lay out holes in the 
 flange on the front end. Now lay out two holes on the flange ' 
 at each corner; all these holes must be drilled. When more 
 than one boiler is built from the same design a sheet-iron 
 gauge is made by which these holes are all laid out. 
 
 WATER SPACE CORNERS. 
 
 Considerable difficulty is experienced in keeping tight joints 
 around the corners of a water space frace. Various designs 
 ha»'e been used with indifferent success. There are two de- 
 signs of corners that are largely used ; in the first the frame is 
 milled out on the side and the throat sheets are set in with 
 square corners, as in Fig. 33 ; in the second, the side sheet and 
 the throat sheet are scarfed as in Fig. 34. 
 
 Frequently among builders of locomotives the boiler shop is 
 supplied with corner cards; these give the details of the corners 
 up to the first through rivets. Fig. 33 represents such a boiler- 
 corner card. The patch bolts P are spaced around the corner 
 at the outer circumference at about the same pitch as the 
 through rivets. After the boiler is assembled, it is a rare 
 thing that the corners will fit up nice and neat, therefore this 
 must often be heated and pounded up tight against the frame. 
 These holes are now laid off and drilled and tapped in position. 
 The front tube sheet is pounded in close to the frame, and 
 the hole T is laid off and tapped through the sheet into the 
 frame. 
 
HOW TO LAY OUT A LOCO^IOTIVE BOILER 
 
 79 
 
 Fig. 34 shows a corner where the side and the throat sheet 
 are scarfed. The corner has a 3-inch radius on the inside ; this 
 enables the use of through rivets around the corner. T and 
 T are the first ihrough rivets that are run at right angles 
 through the frame. A, B and C are through rivets, which hold 
 the inside sheet close to the corner. After these sheets have 
 been set into place, place a surface plate against the bottom of 
 the frcime, and with a surface gauge mark out the top and 
 bottom rivet lines. Lay out these spaces to suit the figures 
 on the corner card. The front and rear corners are in general 
 very similar, except whatever change is necessary to accom- 
 modate the difference in width of the frame. 
 
 On the Wootten boiler the rear corner is different in shape, 
 as shown in Fig. 35. T and T are the first through rivets, and 
 are placed as near the corner as possible. The patch bolts are 
 stepped off so as to maintain the same pitch as the through 
 rivets, if possible. The bolt A is tapped through the sheet 
 into the ring in order to make a tighter job around the corner. 
 Too much care cannot be given to laying out and finishing 
 the work on the corner, because if there is any possibility of 
 a leak it is sure to be found near the corner. 
 
 In Fig. 36 is shown a corner plug. This is laid off 6J4 inches 
 along the outer circumference of the sheet. Space this off 
 either with the dividers or with a steel tape. This hole must 
 be drilled and tapped for a 2;4-inch taper tap. If the corner 
 has a small radius, the threads are cut away so that you get 
 but one or two full threads. In this case the sheet is often 
 drifted out, as shown in Fig. ^y. Lay off a hole to suit the 
 location given on the drawing. The size of this hole must be 
 obtained from shop experience in drifting out and upsetting 
 the ends. A great deal depends upon the thickness of the 
 plate, the radius of the corner and the size of the plug. 
 
 In addition to the regular through rivets in the water space 
 frame, frequently special rivets are required which extend all 
 the way through, and form the support for the grate. Fig. 
 47 shows such a bolt. In the layout these special bolts should 
 be marked with a cross or circle on the sheet. 
 
 Fig. 39 shows another method which is often used to sup- 
 port the grate. The studs are laid off a certain distance up 
 from the riyet center line. These holes can be laid off on the 
 sheet and punched, as the side frames have elongated holes to 
 take care of any variation in the casting ; also in addition to 
 the stai'-bolts, air pipes, Fig. 40, are required. The holes are 
 laid off on the diagonal lines between the stay-bolts, and they 
 are usually punched with the rest of the holes and bored out 
 with the drill to the dimensions given on the drawing. Many 
 fire-boxes have tubes, as shown in Fig. 41 ; the holes are laid 
 out the same way as in Fig. 40, except that the holes are larger 
 than the tubes in the fire-box sheet and considerably larger on 
 the outside sheet. 
 
 The drawing does not always show the details for these 
 holes, and much is left to the judgment of the man who is 
 laying out the work. Therefore, in settling on the size for 
 these holes one must be sure that the tubes can be entered 
 into place, rolled and beaded, and also that the tube can be 
 removed in case a repair becomes necessary. The large holes 
 in the outside sheet are to be plugged. 
 
 FIRE DOORS. 
 
 More care is necessary in laying out the fire door than is 
 ordinarily supposed, as a lot of trouble will arise from a lack 
 ot good judgment. 
 
 Fig. 42 shows a rather simple fire door layout. L is the 
 length of the neutral line along the curve. Lay off M equal 
 to L, and get the diameter D; from this diameter must be 
 taken a certain amount for trimming the sheet. This should 
 not be less than Vs. inch all around. Lay out the center lines 
 of the fire door BB and CC, and strike a diameter that coin- 
 cides with the one just decided upon. Where there are a 
 number of boilers going through at the same time, these sheets 
 may be punched out with a large special punch, otherwise the 
 metal m the inside is removed by punching a series of ^ or 
 ^^-inch holes all around the outside. 
 
 Fig. 43 shows another style of fire door. The holes in the 
 outer sheet are laid out precisely the same as those shown in 
 Fig. 42. The hole in the inner sheet depends upon the length 
 of the stretch in making this hole. Usually where the flange 
 is deep the sheet is heated, and it is stretched on the flanging 
 press; afterwards the hole is laid out, depending in size alto- 
 gether on the experience in flanging. This particular sheet is 
 very difficult to flange in Js-inch stock when the flange is very 
 deep, and more than one sheet has been lost in flanging. Fig. 
 44 shows another t\'pe of fire door opening. The oblong ring 
 becomes worn with the firing tools, etc., and the opening is 
 made in this way so that these parts can readily be renewed. 
 The inner sheet is laid out in the same way as in Fig. 42. The 
 outer sheet has a plain elongated hole in it. The angle is 
 forged to required shape and welded. The holes in the leg 
 of the angle which fit against the plate are marked off from 
 this sheet. The other holes are laid out for the rivets through 
 the ring. The inner f^-inch elongated sheet is bent up and 
 welded along the seam. The holes on the flange of the inside 
 sheet are marked off from this ring and punched to suit. 
 
 Fig. 45 IS a style of fire door which is seen extensively on 
 boilers ot all sizes. This hole is laid out in exactly the same 
 manner as Fig. 43, except that the hole is elliptical instead of 
 circular. The holes are laid out in the flange of the fire-box 
 back sheet and punched. The holes are marked off in the 
 flange of the back head in position. These rivets must be 
 hand-driven before the stay-bolts around the fire-box are put 
 into place. 
 
 CHAPTER IV. 
 
 OUTSIDE FIRE-BOX SHEETS. 
 
 Various fire-box sheets have been laid out in a previous 
 chapter, and now we come to those sheets which surround tlie 
 fire-box, commonly known as the outside fire-box sheets. Some 
 of these sheets are similar in a way to the inside fire-box sheet, 
 but differ in many details. The back head and the throat 
 sheet are flanged, and these sheets present by far the most 
 difficult part of the work. The various sheets that will be 
 shown presently are taken from a 67-inch Belpaire boiler 
 which has been in operation, drawing the heaviest trains on 
 one of the large Eastern railroads. 
 . Fig. 46 shows a longitudinal section of the fire-box end of 
 
8o 
 
 LAYING OUT FOR BOILER MAKERS 
 
 tliis boiler, and Fig. 47 sliows the cross-section of the same. 
 It has been selected for several reasons. First, it has on it all 
 the work which a much plainer boiler would have, and. sec- 
 ondly, in addition to this, it has a great deal of difficult work 
 which one meets with on boilers which are out of the ordinary 
 run. 
 
 THRO.\T SHEET. 
 
 The throat sheet on this boiler is shown in detail in Fig. 48. 
 This sheet is usually ordered with liberal allowance for trim- 
 ming. We will assume that the size of the sheet is correct, 
 and with a straight edge draw the center line CC. This is 
 done by striking off arcs from the corner with the trams as 
 shown, and drawing the line CC to suit the position thus 
 found. Lay off the .line D to suit the boiler card, so that the 
 corners at E have at least 5^ inch for trimming. Measure off 
 a distance 4 feet 6 1-16 inches from this line, and draw the 
 center line CC of the boiler. From the center K strike a 
 
 out the five bridges A'' as shown. All the metal is to be 
 punched out along the circle except at these bridges. Make 
 the bridges that remain about 2 inches wide. These are used 
 for holding the sheet together when it is being flanged. 
 
 Measure off the distance i' on the right-hand view, and 
 fay off a distance U + yi inch on the left-hand view. Also lay 
 out a plan view of the lower part of the sheet and measure 
 off the length of the neutral line X. Lay off the distance 
 A' -|- I inch as shown. In a similar manner lay off several 
 intermediate sections and determine the length of J' and W, 
 and lay out T + '4 inch and IF + yi inch as shown. Through 
 these points draw the outline of the sheet, thus completing tho 
 work until it comes from the flangers. 
 
 TOP THROAT SHEET. 
 
 The top throat sheet of this Belpaire boiler is represented 
 in Fig. 49. CC is the center line. Strike off arcs from each 
 
 Fig. 45 
 
 Kg. 43 
 
 ■circle with a radius of 3 feet V2 inch. Strike another circle 
 fi inch outside of this, and draw the outside lines of the 
 sheet as they would appear when flanged. 
 
 Now lay out the flat portion at LL, and draw the lines M 
 and M to suit the dimensions on the boiler card. Also lay out 
 the right hand view of Fig. 48. This can be done either on the 
 throat sheet or on some other sheet. Measure off the dis- 
 tance P along the neutral line of the sheet. Now lay off this 
 distance P -\- 14 inch, as shown along the center line CC. In 
 a similar manner measure off the distance R on the right-hand 
 view, then lay off a distance R -\- Yz inch, as shown on the 
 left-hand view. Measure off the distance 5" and lay out the 
 distance T in a central position. To get the length of T, take 
 the average length of 5 and R + Yz. Now find a radius which 
 will pass through these points and strike a circle to suit. Draw 
 another circle i inch from the inner edge of the flange, and lay 
 
 side of the sheet at E and E, and draw the center line DD. 
 Lay out the rig?f-hand portion full size on the sheet, and 
 measure off the length of the neutral line A. This distance is 
 measured off from the straight line of the sheet around the 
 curve to the end of the flange. Project the starting point on 
 the left-hand view and Uy oK A -\- Y2 inch. This flange has 
 the same width all the way around. Draw the outline of the 
 sheet all around, at this distance from the line of the sheet 
 when flanged. In a similar manner we determine the neutral 
 line B of the front flange. Lay off a distance B -)- ^-inch as 
 shown. Strike a radius R from the limiting line of the inside 
 of the sheet, also lay out the bridges i, 2, 3, etc., to hold this 
 sheet together while the outside is being flanged. In trimming 
 off the extra metal around the outside, sheer close to the line 
 at G around the corner, but allow a liberal margin, say, Y2 
 inch, at all the other places. When the sheet is flanged the 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 metal will crowd around at G, so that we get more metal here 
 than the flat sheet would indicate. 
 
 After this sheet comes back from being flanged, level it on 
 the layout bench and measure it to see if it will hold up to 
 drawing sizes all around. With the surface gauge, run around 
 the outside and lay off the front and back line of the sheet. 
 Frequently the drawing gives sufficient details to locate some 
 of these rivets, but often this is left entirely to the layout man. 
 In case nothing is specified, begin the front and back rivets 
 on the top center, also settle on the location for the rivets on 
 the bottom of the sheet. With a measuring wheel get the run 
 of the boiler inside on the front between these extreme rivets. 
 Punch this on the sheet, and see that the same checks up with 
 the sheet, to which this top throat sheet is to be riveted. With 
 the dividers lay off the desired number of rivets ; all will be 
 equally spaced unless otherwise specified. 
 
 BACK HE.^D. 
 
 The back head of a locomotive boiler with a medium width 
 fire-box is shown in Fig. 50. The flange is 554 inches deep 
 
 1 
 
 Fig. ■19 
 
 pjk. 4; 
 
 and the plate is J-^ inch thick. The fire door is oval, and is 
 flanged in. The connection for fire door to back fire-door 
 sheet is made in such a way that the flange of the back head 
 telescopes the flange of the fire-box sheet. The whole thing 
 is riveted up similar to the fire-box sheet shown in Fig. 46. 
 
 Lay out the left-hand portion of Fig. 50, either on the sheet 
 which has been ordered for this head or on a neighboring 
 sheet, measure off a distance R along the neutral line of the 
 sheet, after having laid out the center lines CC and DD. 
 Strike the radius R -\- 'A inch for the outline of the upper 
 portion of this sheet. Lay off the distance A, which cor- 
 responds to the "out-to-out" distance of the head when flanged. 
 Lay off a distance C on each side corresponding to B, and 
 draw the limiting line of the sheet all around. Also measure 
 down from the center line a distance 26^ inches for the fire 
 door. Measure off the distance E along the neutral line and 
 lay ofl E -\- 14 inch as shown ; the distance G is central with 
 the fire door. We can now measure off the distance K, which 
 is necessary for forming this flange. With the dividers set 
 to the distance K, strike off 10 or 12 arcs from the outline of 
 the fire door and draw a smooth oval through these points. 
 The oval hole GH must now be punched into the sheet, and 
 the outline must either be chipped or milled smooth. The 
 lower edge of this sheet must be planed off at a level for calk- 
 ing, also the sides M and M. The remainder of the metal 
 must be trimmed away. The sheet is now ready to be flanged. 
 Where the flange is short the majority of the holes for stay- 
 bolts, rivets, etc., can be punched into the sheet before it is 
 flanged. Those holes which come close to the curve and are 
 liable to draw are put into the sheet after it is flanged. 
 
 The layout of this back head is shown in Fig. 51. The 
 outline of the sheet and the fire door have already been set- 
 tled on. Draw two parallel lines along the bottom of the sheet 
 for the water space rivets. Measure off the distance to the 
 first through rivets and step off the number of equal spaces 
 called for on the drawing. 
 
 Measure up a distance yl4 inches from the bottom and draw 
 the line for the bottom row of stay-bolts. Measure off 2 inches 
 for the first stay-bolt, and then step off 7 spaces each 4 
 inches as shown. Lay off the lines of holes one after the other. 
 In laying out every second and third line sum up the figures 
 
82 
 
 LAYING OUT FOR BOILER ^lAKERS 
 
 from the bottom and measure off this over-all distance, to 
 make sure diat you are not gaining or losnig. Three 2j4-inch 
 taper taps are called for, and are located on the center of the 
 diagonal lines. Measure off a distance 25 inches from the 
 center line, and strike a 3^-inch hole for throttle connections. 
 Lay out the four stud holes as shown. In laying out the rivet 
 holes for the T-iron and crow-feet it is well to lay out the 
 outline, as these pieces come very close in some instances, and 
 when laid out full size there may be some interference of one 
 part with another. The location of each group of rivets is 
 given over from the center line DD and up from the center 
 line CC. In laying out each one of these groups separately, 
 where the dimensions are given at i, 2, 3. etc., check the over- 
 all dimensions to be sure that these are correct, for many times 
 fittings, gauge cocks, etc., are laid out with small clearance for 
 these stay-bolts. These connections are not shown on the 
 boiler card, and therefore, if these rivets are not laid out 
 carefully the layout man will be held to account when the 
 boiler gets into the erecting shop. 
 
 SIDE SHEET. 
 
 The outside side sheet for the boiler shown in Fig. 46 is 
 represented in Fig. 52. Hunt up the plate that has been or- 
 dered for this sheet and lay it on the bench with the side con- 
 
 taining the maker's stamp, tensile strength, etc., up. Havt 
 another sheet underneath projecting a foot or so on each end. 
 Clamp the sheets together in several places so they cannot 
 slip. Draw the bottom line of the sheet, allowing about J/j inch 
 for planing. From this line measure off vertically the dis- 
 tance to the center of the boiler, and draw the line CC parallel 
 to the bottom line of the boiler. 
 
 Lay out the left-hand portion of this sheet. It will be noted 
 that the taper will be 6 3-16 inches. The left-hand view gives 
 the shape of the sheet at the front and back. Make the con- 
 struction for the back head and throat sheet to the figures as 
 shown. Draw the inside line of the flange of the back head 
 and measure off a distance 39-16 inches from this line, and 
 draw the back slope line of the sheet. In a similar manner 
 draw the back straight line of the sheet. Also draw the back 
 line of the throat sheet, and lay off the back slope line and 
 straight line of the sheet at 39-16 inches from the line of the 
 flange. The dimensions A and B are obtained from the draw- 
 ing, and must be measured off around the neutral line of the 
 sheet, as shown on the left-hand view. 
 
 The outline of the sheet has now been mapped out. Draw 
 two parallel lines along the lower edge for the water space 
 rivets and step off the desired number of equal spaces. Draw 
 two parallel lines along the back and step off a number of 
 equal spaces as near the pitch called for as possible. In a 
 similar manner lay out the top row of rivets and the two rows 
 of rivets along the front edge. Begin to lay out the stay-bolts 
 by drawing the lower line parallel to the bottom line of the 
 sheet. The first hole is 95^ inches from the back of the water 
 space frame, and the front holes 2J/8 inches from the rivet 
 center line as shown. All the holes below the lines EE and 
 FF are equally spaced lengthwise of the boiler. The other 
 holes are laid out to suit the figures on the drawing. Lay out 
 the next line of holes and mark off the holes from the first 
 line. Also note that the lines for rivet holes are parallel 
 vertically but not horizontally. Each line must be laid out 
 to suit the dimensions given, and these dimensions should be 
 laid out along the left-hand view. The holes at A' are for the 
 long stay-bolts, which are run through the boiler and stay 
 the upper square corners of the Belpaire boiler. The sheet will 
 be bent to shape in the bending rolls. 
 
 FIRE-BOX CROWN SHEET. 
 
 Fig. 53 shows the fire-box crown sheet. It is 5 feet 9 inches 
 over-all in width. The radius m the corners is 7 inches, and 
 the length of the sheet along the slope is 8 feet 6% inches. 
 F'g- 54 gives the outline of this sheet. This we lay out by the 
 triangular method shown in a previous issue. Having set- 
 tled on the outline of the sheet, we draw two lines along the 
 side 4^ inches from the rivet center lines ; also draw two 
 lines parallel to the edges, front and back, lYi, and iJ4 inches 
 as shown. Draw the center line CC and lay out the outline of 
 the group of holes as shown. 
 
 Draw the parallel lines for the stay-bolt holes to the di- 
 mensions given. Mark out all these holes and then lay ofj 
 the four wash-out plug holes, and strike a circle to correspond 
 with the tap called for. These holes must be drilled a special 
 
HOW TO LAY OUT A LOCOMOTR'E BOILER 
 
 83 
 
 diameter as they come on the curve, and when the sheet is 
 bent the outside will open up. Therefore, care must be taken 
 to have sufficient metal so as to have full threads. 
 
 STAYING FIRE-BOX SHEETS. 
 
 The layout of the inside and outside fire-box sheets has now 
 been given, but nothing has been said in regard to the con- 
 nections and details of these sheets. There are many methods 
 of staying the various sheets of a locomotive boiler, and a 
 number of the methods which are in common use will be 
 shown. 
 
 Not all the surfaces of the locomotive boiler need to be 
 stayed. The outside cylindrical sheets will keep their shape 
 
 liveted over cold, in place. Such renewals are not easily 
 made. All the stays which have just been mentioned are 
 round stays. The front and back head are often stayed with 
 plates, bar iron, and numerous patented shaped braces, as the 
 Huston, McGregor, etc. 
 
 Fig. 55 shows the common form of stay-bolt which is used 
 around the fire-box. These stays are machired in standard 
 lengths, varying by ■/^ inch for short stays and several inches 
 for long stays. They are turned down in the center at A or 
 else upset from rough bar iron at a diameter equal to A so as 
 to give the necessary thread on each end. In Fig. 56 is illus- 
 trated one of these stays just after it has been screwed into 
 place. It is nicked at A'" by hand and is then broken off, or is 
 then clipped off with pneumatic stay-bolt clipper. The stay- 
 bolt is cut off inside and outside, leaving sufficient metal for 
 riveting over. The safety hole is drilled in the center, as 
 shown in Fig. 55. 
 
 The six central rows of crown stays are nearly all made 
 radial to the crown sheet. Fig. 57 shows this stay. It is i]/i 
 inches at the threaded part and 15-16 inch in the center. 
 These stays are headed up in the bolt machine and are usually 
 gotten out to suit the boiler for which they are intended, and 
 thus vary but little in length from what is actually required. 
 This stay must have a 3-32-inch fillet on the inside of the inside 
 sheet and on the outside of the outside sheet. The threads 
 are V shaped, 12 threads per inch, and the holes in the sheet 
 must be tapped so as to give a full thread. In punching the 
 
 FIG. 53. 
 
 FIG. 54- 
 
 without staying. Side cylindrical sheets with a pressure act- 
 ing all around must usually be stayed, as these sheets are apt 
 to collapse. This is not always true, however, especially when 
 the cylinder is small. But when the cylinder is of large diame- 
 ter some method must be used to prevent it from collapsing. 
 
 The Morison corrugated boiler needs no staying. The 
 method of staying determines the different varieties of boil- 
 ers. The Belpaire boiler is rendered simple from a standpoint 
 of staying for the reason that all crown stays are radial or 
 pass through the sheet at right angles to it. The head on the 
 stay can be formed up to much better advantage, as the nut 
 and washer bear evenly all around. This radial staying is 
 different from that which must be employed in the common 
 form of locomotive main fire-box, for the reason that these 
 stays pass through the outer shell at an angle and must be 
 
 sheets, care must be taken that the holes are punched small. 
 When these are reamed out and tapped, we should have a 
 full thread all the way through the hole. It is often the case 
 that these holes are scrimmed on and not enough time is spent 
 in reaming them and forming good threads. 
 
 After the radial stay is screwed into place and every bit of 
 slack is taken up, it is riveted over on the outside and finally 
 brought down to the shape specified. Another style of stay 
 is shown in Fig. 58. The crown stays of many boilers are 
 made this way throughout. The heads H and K are all stand- 
 ard size and are made up under the hammer in large quanti- 
 ties. They are threaded, screwed into place and riveted over 
 the same as the regular stay. Where these stays pass through 
 the sheet at an angle, care should be taken in reaming and 
 tapping so as to bring the center line of the link and head in 
 
84 
 
 LAYING OUT FOR BOILER MAKERS 
 
 one line, otherwise there is a bad pull sideways which will lathe or in the pipe machine, in order that we can be sure of 
 break off the head just where the head portion enters the getting a square bearing all around. 
 
 k=L.," 
 
 Fig. a) 
 
 fig. 61 
 
 fati* BtronK IljdrmUc Pipa 
 
 Kg. 62 
 
 Fig. 69 
 
 sheet. The holes in the head and link are reamed and the 
 bolts should be turned to a nice fit. 
 
 Another method, which is commonly known as the sling stay, 
 is represented in Fig. 59. C is the crown bar which is bent 
 to the curvature of the crown sheet, and is bolted to it at a 
 fixed distance of 3 or 4 inches from it. The T-iron D is bent 
 to fit the outside shell of the boiler and is riveted to it with 
 common button-head rivets. The holes through the T-iron 
 and links are reamed, and the bolts should be turned to make 
 a neat fit. 
 
 In assembling, the T-iron is bent approximately to fit the 
 curvature of the boiler. It is then taken and tried in place. 
 It must be bent one way or another so as to conform neatly 
 with the lines of the boiler. The holes are marked off from 
 the boiler shell and are drilled to suit. The T-iron on the 
 shell of the boiler is riveted in place with a hydraulic machine. 
 The T-iron C is attached to the crown sheet as illustrated in 
 Fig. 60. This T-iron is a heavy section 6 by i inch on the 
 bottom flange and iJ4-inch web. T is a taper portion through 
 which the crown sheet and the bolt is entered into place, so 
 that the head bears up tight all around. The thimbles A are 
 cut off from extra heavy hydraulic pipe, and the ends should 
 be square and free from fins. The holes K are drilled 1-16 to 
 Yi inch larger than the bolt. Put in the outside bolts first, 
 but do not draw these up until the thimbles and other bolts 
 are put in place. Screw up all the bolts tight, and then take 
 out every bit of slack with a hammer and go all over the nuts 
 and tighten them up again. 
 
 Fig. 61 gives a detail of the bolt, which is i>^ inch in diame- 
 ter in the nut. It is 5 7-16 inches long. The head must be 
 faced off true where this rests against the sheet and the nut 
 must be faced off on the bottom. Fig. 62 shows an extra 
 heavy hydraulic pipe. These should be cut off either in the 
 
 CHAPTER IV. 
 
 BRACING THE CROWN SHEET. 
 
 The flat crown sheets are often stayed as shown in Fig. 63, 
 where the entire load is taken up on the side sheets. The 
 bars B must be forged approximately right and then shaped 
 and filled to fit exactly in place. At least 3 inches is allowed 
 for the circulation of the water. 
 
 The long through stays of the Belpaire boiler are shown in 
 Fig. 63a. They are lYs inches in the body and i 5-16 inches 
 tap. They are screwed into place with a pipe wrench. A 
 washer IV is placed against the sheet and a nut N pulled up 
 tight against it. This is used when the sides of the sheet are 
 parallel. 
 
 Thus far nothing has been said in regard to staying the 
 front tube sheet and the back head. The method commonly 
 used is to rivet the section of the T iron to the head and then 
 stay the T iron to the sides of the boiler. Where the T iron 
 does not work in to good advantage, several different kinds 
 of crow feet are used. These are made to standard sizes and 
 made up in large quantities and are kept in stock. 
 
 Fig. 64 shows a two-rivet foot for a i-inch stay-rod. This 
 style is used largely for staying around the outer curve of 
 the back head, and is used for staying the throat sheet, around 
 the curve where the sheet is attached to the dome course. 
 
 In Fig. 6s is illustrated a stay-rod which is used for staying 
 the outer shell to the back head. It is convenient, as one can 
 run this stay around at an angle and reach places which could 
 not be stayed with through stays. This stay is also made as 
 shown in Fig. 66. This often works in to better advantage 
 than either of the stays just mentioned. This is especially 
 true around the outside of the Wooten boiler, where the sur- 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 85 
 
 face runs at right angles to the line of the stays. In staying 
 the back tube sheet, there is a section which cannot be reached 
 with the tubes nor with the regular stay-bolts, therefore a line 
 of special through stays must be used. 
 
 A throat stay which is used largely for this purpose is 
 shown in Fig. 67. This stay-bolt is screwed through the 
 sheet into the foot. The foot is riveted to the side of the 
 boiler with two button-head rivets. Care must be taken in 
 laying out the holes on this course to suit the number of stays 
 required. This figure calls for 3 inches center to center of 
 rivets. The holes are punched into the sheet and drilled into 
 the foot by jigs. There should be no difficulty in getting 
 these holes to match up properly when they are ready to be 
 
 At X is shown a two-rivet stay which works in to excellent 
 advantage. These T irons are stayed to the side of the boiler 
 with rods which vary in diameter from i inch to ij/ inches. 
 
 Fig. 69 shows a 154 -inch rod. The head H of these rods 
 is made in proportion to the body of the rod, so as to give 
 a uniform strength throughout. Also, the diameter of the 
 rod varies with the diameter and number of rivets which the 
 rod must support, and the diameter of the bolt must be made 
 in keeping with the strength of the rod. In some shops these 
 things are all nicely worked out and good drawings are at 
 hand for these details; but in other shops they depend entirely 
 upon the good judgmeat of the boiler maker. In this case, 
 the boiler maker must be careful that he does not get one 
 
 Fig. 73 
 
 Kg. '1 
 
 riveted into place. Numerous other devices are used for 
 staying the throat sheet at this point. In some instances the 
 stay shown in Fig. 66 is used. The foot is riveted to the back 
 tube sheet with an extra heavy pipe furrow between to allow 
 for a free circulation of water. Still other stays are used 
 where the main body is a flat bar and the end is forged into 
 a round head. Into this head is fastened the rivet which 
 passes through the tube sheet. The main part of the staying 
 of the front tube sheet and the back head is done either by 
 means of heavy T iron or else by plate gusset stays. 
 
 A good example of T-iron staying is shown in Fig. 68. 
 The rivets are laid out in groups 4 inches center to center one 
 way, and 4 inches to 5 inches center to center the other way. 
 A, B, C show the places at which the stay-rods are attached. 
 
 part too weak for another. The T-iron sections are made of 
 different weight, depending on the boiler pressure and the 
 size of the surface to be stayed. 
 
 The stay-rods must be swung out radially against the sides 
 of the boiler. The rod D, Fig. 68, would be quite short, 
 while F would be a very long rod, and would extend back and 
 would probably be attached to the dome course. Here, again, 
 this matter of locating the stay-rod is left to the boiler maker. 
 In laying out the various courses, therefore, the location of 
 the foot for these stay-rods must be settled on. Also, care 
 must be taken in locating these feet, as there are a number 
 of things that this rod could interfere with. 
 
 In Fig. 70 is shown the construction of a stay-rod and foot 
 which is largely used. This shows the connection of the rod 
 
86 
 
 LAYING OUT FOR BOILER MAKERS 
 
 to the foot and the method of attaching the foot to the boiler. 
 Two I -inch rivets are required for a l^-inch rod. Fig. 70a 
 shows an excellent end with three rivets instead of two, used 
 where the stay-rod is short, and the angle which this rod 
 makes with the side of the boiler is small ; the foot is made 
 solid, as shown in Fig. 71. The section of T iron shown in 
 this figure is a very heavy one, and the jaw for this i;.:(-inch 
 rod is made wide enough to take in the flange, which is iji 
 inches thick. The turned bolt is l^ inches in diameter. This 
 is often used for the top stay-rod, as shown in A, D, G, etc., 
 Fig. 68. The arrangement of a l}4-inch rod with a two- 
 rivet foot is illustrated in Fig. 72. This would be used when 
 the rod is swung out radially against the side of the boiler. 
 
 Figs. 72 and 7Z show two styles of three-rivet crow feet. 
 By using one of these crow feet, it is possible to stay a 
 large surface to excellent advantage. In fact, some boilers 
 have been built where nearl}' the whole of the stayed surface 
 of the front tube sheet and back head have been stayed with 
 one or the other or both of these two styles of crow feet. 
 
 In all of the staying which has just been described, bars are 
 used for taking up the pull. There is another method of 
 
 Fig.74 
 
 Fig.7li 
 
 Staying which is held in high esteem by many engineers and 
 boiler makers. This consists in using gusset plates instead of 
 bars. This method of staying works in to excellent advan- 
 tage on the back head of Belpaire boilers. The plates are riv- 
 eted to angle-irons and angle-plates, and these in turn are 
 riveted to the shell and surface to be stayed. Large holes are 
 then punched through these gusset plates to clear the large 
 through stay-rods which pass through the top of the boiler. 
 
 Fig. 74 affords a good example of such staying. A !/2-inch 
 liner is used for stiffening up the back head ; 4-inch by 4-inch 
 angles are riveted to the back head and to the gusset plates. 
 These plates are Yz inch thick and are bent over on top so 
 that they can be riveted to the shell of the boiler. 
 
 The angle-irons are riveted to the gusset plates and then 
 each one of these gusset sections is riveted into place sepa- 
 rately. One of these gusset sheets which are used for staying 
 the back head is shown in Fig. 75. The spacing of these riv- 
 ets is usually shown on the drawing and is not left to the 
 judgment of the layer-out. The boiler card gives the loca- 
 tion of the rivets along the top line A ; these must be laid out 
 on the shell together with the crown stay, and the holes are 
 to be punched to suit. In using this method of staying on a 
 Belpaire boiler, the part A is attached to the outer shell of 
 the boiler in several different ways. These gusset plates are 
 all vertical and are all attached to the outer shell along paral- 
 
 lel lines. A U-shaped sheet is bent so as to fit in between 
 these vertical plates. Another U-shaped piece is entered in 
 between the next set of plates, as shown in Fig. 76. The 
 plates are fastened to the U-shaped piece by rivets R, and 
 these pieces are fastened to the shell by rivets K. This whole 
 arrangement makes a very rigid method of staying, but is 
 Yot so easily repaired as some of the other methods that have 
 been shown. 
 
 SMOKE-BOX. 
 
 The smoke-box of a 74-inch Belpaire boiler is illustrated in 
 Fig. 77. 7? is a ring, uniting the first course with the smoke- 
 box sheet, and also used for making connections to the front 
 tube sheet. The smoke-box sheet is usually Vz inch thick for 
 the average boiler. While this sheet is thick enough to serve 
 its purpose as a smoke-box, it is too thin to be bolted directly 
 to the cylinders. The sheet would bend, and the whole thing 
 would be too flims}'. Therefore, this sheet is nearly always 
 reinforced with a smoke-box liner. These liners vary in thick- 
 ness from 54 to ^ inch, and in some cases, which will be 
 shown presently, they are made up of plates which are con- 
 siderably thicker than this. 
 
 The cylinder opening D must be made large enough to take 
 in the flange of the cylinder. The size varies with the ar- 
 rangement of the steam pipe and exhaust pipe connections. 
 The size of the opening is usually given on the drawing; when 
 it is not given the layer-out should make a full sized layout of 
 the cross-section of the boiler through the cylinder flange. 
 From this layout and the boiler card the opening can be readily 
 determined upon. On this same layout the cylinder bolts 
 should be laid down as well as the cylinder flange. Any rivets 
 which would be put through the smoke-box sheet and liner 
 will have to clear the cylinder bolts by a reasonable amount. 
 Any rivets which would come underneath the cylinder flange 
 would have to be countersunk so as to clear the casting. 
 
 In reference to the cylinder bolt, there are in general two 
 methods used for putting these holes into the sheets, depending 
 upon the different boiler shops. First, these holes are laid out 
 on a flat sheet and then punched, and finally when the cylinder 
 is chipped to fit the boiler and the boiler is entered into place, 
 these holes are reamed out to size. Second, when the layout 
 of the flat sheet is made, the cylinder bolt holes are laid out 
 so as to be sure that there will be no interference with rivets 
 which might be put through the sheet to hold the liner. The 
 cylinder-bolt holes are not punched. The cylinder is chipped 
 and the boiler is lowered into place. The bolt holes are then 
 drilled through the sheet, using the holes in the cylinder flange 
 to guide the drill. 
 
 The layout of a smoke-box sheet, as it appears before being 
 bent, is represented in Fig. 78. Draw a line along the top, 
 allowing sufficient metal for planing, and measure off a dis- 
 tance of 43 inches, at each end of the sheet, and with a straight 
 edge draw the bottom line. Mark one side of the sheet, front, 
 and mark the right and the left-hand side as shown, measure 
 off a distance 205/2 inches from the front line, and draw the 
 cylinder center line DD. Look up in the table of circumfer- 
 ences and get the circumference corresponding to the neutral 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 87 
 
 diameter of the sheet. The drawing calls for 74 inches out- 
 side diameter. The neutral diameter, therefore, is 72{4 inches, 
 and the circumference corresponding to this is 230.908 inches. 
 Lay out this distance along the line DD. Draw the end line 
 at right-angles to DD; bisect this distance and draw the bot- 
 tom center line CC ; bisect each one of these halves and draw 
 the right-side center line FF and the left-side center line EE, 
 and draw the two front rivet center lines. The drawing 
 calls for forty-eight ^4-inch rivets ; this gives twelve rivets in 
 each quarter. Begin the rivets on the top center line, making 
 twelve equal spaces as shown. Begin the front row of rivets 
 on the top center line, and step off twelve equal spaces in each 
 quarter. Step off the rivets in the second row a half a space 
 from these. 
 
 The drawing calls for a cylinder opening 15 inches by 2 
 
 front end of the boiler. The cylinder flange and all the bolt 
 centers will be laid out as in Fig. 80. The dimensions, 4^, 
 4^2, etc., are measured along the outer circumference of the 
 smoke-box sheet B. With the trams draw the neutral line of 
 the liner, beginning on the center line CC, and with a measur- 
 ing wheel run along the neutral line and mark off between 
 the center lines the distance corresponding to this measure- 
 ment. Begin on the center line CC and run over the neutral 
 line D, and get the total measurement to the extreme rivet 
 center line E. Add up the intermediate dimensions and see 
 whether they check with this over-all measurement. Make 
 wliatever alterations that are necessary in these intermediate 
 figures and then the holes can be laid out on the fiat sheet 
 In marking the size of holes on the layout for the cylinder 
 bolts, be sure that they are punched small enough to allow 
 
 -D-fc\ .■ 
 
 :gc?g»-feg:J5£::Q-g 
 
 Left 
 
 -® (jl- 
 
 
 A .(j, — (!)_.(?> — o — ej) — A — 0— i) 
 
 ^ I O— 9-t-<3 Q— ;;0- 
 
 Cylinder 
 I I Bolt 
 
 
 rttfl 
 
 I U ili 
 
 4 f I 
 
 i — <? S-L-i-^? <?- °\ 
 
 O ,.0 . .Q—,0 ;Q— mO ^ — "^ '©-fn 
 
 =^ i 
 
 feet 3 inches. This is laid off symmetrically with the cylinder 
 center line DD. Also lay out the smoke-stack hole with ii-inch 
 radius. Lay off four bridges as shown, and mark the rest of 
 the metal to be punched away. Now begin on one side of the 
 bottom center line and lay out one line of the cylinder bolt 
 holes after another, until all these holes are laid out on one 
 side, then transfer this layout to the opposite side. Also lay 
 out a line of rivets on each side of the center line CC for at- 
 taching a ^-inch liner. This smoke-box has an extension, and, 
 therefore, we will not require any holes for the cleaning pipe 
 connections. A line of rivets must, however, be laid out on 
 each end for riveting up the top seam, and these are laid out as 
 shown. 
 
 The smoke-box liner is laid out complete in Fig. 79. The 
 holes for the cylinder bolts are 1% inches in diameter, and 
 must be reamed to size. In order to lay out these holes on the 
 flat sheet, it will be necessary to make a full-size layout of the 
 
 for some variation in the holes when the parts are assembled. 
 When these holes are reamed out we should have a clean, 
 straight hole. 
 
 The smoke-box liner shown in Fig. 79 is taken from a 70- 
 inch boiler. The first course extends on through by the tube 
 sheet, and the smoke-box sheet is riveted to it. A ring, 4% by 
 lyi inches thick, being used between the two courses, where 
 they are telescoped over each other, the liner butts up against 
 this intermediate ring and butts up against the smoke-box front 
 ring in the front. Draw the rear line along the edge of the 
 sheet, allowing sufficient metal for planing. Measure off a 
 distance 53^ inches at each end of the sheet, and draw the 
 front line of the sheet. Measure off from the front line 27 
 inches at each end of the sheet, and draw the cylinder center 
 line CC; note that this is not the center line of the sheet, as 
 there is 26^4 inches from the center line to the back line of the 
 sheet. Measure off along the center line a distance 62 
 
88 
 
 LAYING OUT FOR BOILER MAKERS 
 
 Fig. 93 
 
 inches for the length of the sheet; square up the end 
 of the sheet and draw the center line DD at right 
 angles to the cylinder center line. First, we lay out the 
 cylinder opening; this is 41 inches long and 19 inches wide at 
 the center, and 14 inches wide at the ends. It will be remem- 
 bered that the dimensions, which are given in these illustra- 
 tions, are to be measured on the outer circumference of the 
 smoke-box sheet. These dimensions would, therefore, be 
 varied somewhat, depending upon the full-size layout which 
 would be made for this boiler, and would be similar to Fig. 80. 
 The longitudinal dimensions would be laid out exactly like the 
 figures given. Mark all cylinder bolts with a dash of paint or 
 circle, according to the practice of the shop. Draw the front 
 and rear center line 2% inches from the edge, and lay out these 
 rivets in accordance with the dimensions which have already 
 been settled upon. Draw the left and right center line 
 parallel to the edge at a distance from the center line DD, cor- 
 responding with the measurement obtained with the wheel 
 along the neutral line of the sheet. We now lay out these 
 rivets, which will be equally spaced 7 inches apart. The 
 necessity of strengthening the smoke-box where it is attached 
 to the cylinder has been mentioned. The liner which has just 
 been shown is S/^ inch thick; but these liners have been made 
 three-fourths of an inch in some boilers, in order to get the 
 desired stiffness. 
 
 In Fig. 81 is shown a method for stiffening up this part of 
 the boiler for a smoke-box which is 81 inches outside diameter. 
 The cylinder bolts pass through the shell and through stiffen- 
 ing bars B. These bars are lYs inches thick, and are made 
 wide enough to take in the cylinder bolts and a few extra 
 ^-inch rivets. The dotted line C shows the outline of the 
 cylinder flange. These bars are too heavy to be punched, and, 
 therefore, these holes will be laid out in the smoke-box sheet in 
 a similar manner to that shown in the smoke-box liner. These 
 bars are then bent in the bending rolls to conform to the 
 proper diameter. The holes are then marked off from the 
 smoke-box sheet and drilled to suit. Practice varies in dif- 
 ferent shops, depending upon the facilities for doing various 
 classes of -vork, and, therefore, what would be considered the 
 best plan in one shop would not work out in another. All 
 the bolt holes in these sheets in some shops would be drilled 
 in the erecting shop ; the plates would be riveted to the smoke- 
 
 box sheet with a few countersunk rivets, as shown, so as to 
 hold these plates in place, until the cylinder bolt holes are 
 drilled and reamed. In the latter case little layout work is 
 necessary, except to locate the rivets so that they will surely 
 clear the cylinder bolt holes. 
 
 The smoke-box sheet seam is invariably on the top center, as 
 shown in Fig. 82. The rivets are spaced about 254 inches 
 center, and the single welt strip is used. A good, tight job 
 must be made of this welt strip, and this is true of all the 
 other seams of the smoke-box. If the smoke-box is not tight 
 air will leak in, and the soot and the unconsumed coal will 
 take fire. This trouble has happended on many locomotives, 
 and oftentimes caused serious annoyance to the running of 
 trains. If the spacing of these rivets is not shown on the draw- 
 ing, care should be taken in laying out the rivets so that the 
 sheets will be drawn up tight. This illustration shows four 
 holes which are necessary for attaching the smoke-stack and 
 also circular opening of the smoke-stack. 
 
 The method of connecting the smoke-box sheet to the smoke- 
 box front ring is illustrated in Fig. 83. The front end of the 
 sheet is planned at an angle for calking, and the sheet is set 
 back % inch for calking. The rivets are usually % inch 
 diameter, and are frequently required to be countersunk on the 
 outside at certain places, if not all the way round the boiler. 
 The holes are marked off on the ring from the sheet and are 
 drilled to suit. 
 
 Fig. 84 shows the construction which is used for connecting 
 the first course to the front tube sheet and also the connec- 
 tions to the smoke-box sheet. /? is a forged ring, I inch thick 
 by IS inches wide, which is used for making the connections 
 for these three sheets. The ring is welded at the seam, and is 
 turned off along the outside back edge for calking. Two rows 
 of rivets are required, there being sixty-eight in each row. 
 Begin the front one of these two rows on the top center line; 
 as there are sixty-eight rivets there will be seventeen in each 
 quarter. These will be stepped off with the dividers, making 
 the spaces equal. The run of the outside of the sheet must be 
 taken after the seam is welded; this must be checked up with 
 the run for the first course. This must be done in order to be 
 sure that the sheets will match up when the ring is put into 
 place. The front tube sheet is riveted to the ring by i-inch 
 rivets. The drawing calls for eighty-five rivets in the cir- 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 89 
 
 cumference. Step off seventeen equal spaces, beginning on the 
 top center line, and ending on the top center line. Divide each 
 one of these spaces into five equal parts. A double row of 
 rivets is also used for connecting the smoke-box sheet; fifty- 
 four rivets are required in each one of these rows, and these 
 rivets are laid off to suit. 
 
 The smoke-box extension is often made of lighter sheet than 
 the smoke-box proper. The connection between these two 
 sheets is made by an intermediate ring, shown in Fig. 86. 
 These rings are welded, and are turned off to the inside 
 diameter of these two courses. Forty-five rivets, 11-16 inch 
 in diameter, are wanted in the back row and forty-nine rivets 
 in the front row. In reference to this odd spacing of rivets 
 it should be mentioned that in some shops it is customary to 
 make the number of rivets in the circumference always divisi- 
 ble by four. This gives a certain number of rivets in each 
 quarter, and thus assists the layer-out in laying out his work. 
 
 Fig. 87 shows an intermediate ring, which has an off-set 
 forged along the lower part; this is extended to receive the 
 bolts which pass through the cylinder flange. The ring is 
 symmetrical throughout except for the spacing of the cylinder 
 bolt holes. A plan view of this ring is shown in Fig. 88. The 
 remainder of the rivet holes are equally spaced to suit the 
 number of rivets called for on the boiler card. 
 
 The necessity for reinforcing the smoke-box has been men- 
 tioned, and a number of methods for doing this has been 
 shown. Liners are also required to stiffen up the sheet in the 
 water space where the furnace bearers are attached to the 
 boiler liners. The studs which pass through the furnace bearer 
 are tapped through the sheet into the liner. Reinforcement 
 is often required for making the connections for blow-off 
 cocks, whistle elbows, injector checks, etc. 
 
 Fig. 8g shows a !^-inch liner which is used for stiffening up 
 the sheet for injector check. It is held by four ^-inch rivets, 
 and six studs are tapped through the shell into the liner. The 
 pilot and front bumper are stiffened up with a smoke-box 
 brace, and this brace has a flat foot in connection with the 
 bumper at one end and a round eye for connection with the 
 boiler at the other. Fig. 90 shows the connection for the 
 boiler; this eye is riveted to the boiler with four rivets as 
 shown. In order to make a good, stiff job of this brace a liner 
 is used on the inside of the sheet. The four rivet holes are 
 laid off and punched into the shell. These are then scribed off 
 on the liner and the holes are punched into the liner to suit. 
 The eye of the brace is now heated and pounded up into place 
 all around. The holes are then marked off and drilled to suit. 
 
 Oftentimes cylinder pockets are required on a boiler, and 
 the drawings do not indicate it. In laying out the smoke-box 
 or the extension this must be looked into in order to provide 
 an opening for the pocket and holes for the rivet. In Fig. gi 
 is shown one of these cylinder pockets. The hole is circular, 
 and the rivets are laid out in a circle on a flat sheet. When 
 the boiler comes to the erecting shop, the cylinder pocket is 
 chipped to a good fir all around, and the holes are scribed off 
 on the casting and drilled to suit. The cleaning hole must also 
 be looked up if this is not shown on the boiler card, as it will 
 be placed near the front end of the smoke-box sheet. 
 
 In Fig. 92 is illustrated a cleaning hole. In the absence of 
 any information care must be taken in laying this out, so that it 
 will not interfere with the necessary parts that go with it. In 
 the layout for the first and second course, usually waste sheet 
 and guide-bearer sheet supports are required. These are 
 usually made of T-iron or angle-iron. In Fig. 93 is shown 
 a T-iron connection. This is bent to fit the boiler, and the 
 holes are scribed off from the sheet and drilled into the T-iron. 
 An angle-iron connection is represented in Fig. 94. The holes 
 are marked off in a similar manner, and where the material 
 is light the holes are punched. After the holes are punched 
 the angle will spring and will not fit the boiler. It must be 
 bent one way or another so as to fit up snug all around. The 
 waste and guide-bearer sheets are trimmed short enough so 
 as to give % inch clearance all around, for ease and fitting up. 
 This sheet is then bolted to the angle or T-iron by a series of 
 bolts similar to that shown in Fig. 94. 
 
 CHAPTER V. 
 
 SMOKE-BOX FRONT DOOR, ST.VCK. ETC. 
 
 In the present issue the smoke-box front door, stack and ac- 
 cessories will be treated. There is almost an endless variety 
 of smoke-bo.x front ends in use, and one can point out in so 
 brief a space only those which are in common use, and which 
 are accepted as being generally satisfactory. 
 
 One of these methods is shown in Fig. 95. This front end 
 is made of pressed steel, and is formed in the hydraulic flange- 
 press to the desired shape. It is then turned off on the edge 
 as shown by the finish mark f. The door is very stiff, and 
 when the surfaces are properly machined the joint remains 
 good and tight all around. It has been during only the past 
 few years that this door has been used to any great extent in 
 this country, but it has been used abroad for a good many 
 years. The door is held in place by a ij4-inch T-head bolt in 
 the center. The handle H is tapped to fit the bolt and acts as 
 a nut. By unscrewing the handle the T-head bolt can be 
 given a quarter turn, and the door can be swung open. In 
 the present construction a hole is machined into the door and 
 the number plate is riveted over. The hinges H are made of 
 forged steel or hammered iron, and must be fitted in place. 
 
 A detail of these holes is shown in Fig. 96. The part ex- 
 tending over the door is made 3 inches wide, 5-16 inch thick 
 on the end, and s^^-inch thick at the hinge. The center line 
 CC of the hinges must pass tangent to the door at A. in order 
 to clear the door when it is swung open. This brings the 
 hinge away from the smoke-box sheet a considerable dis- 
 tance, as shown in this figure. The amount of the overhang 
 depends upon the size of the boiler and the available space 
 for fastening the hinge ; generally the overhang is greatest on 
 the boilers which have the largest diameters. 
 
 The strap is forged approximately to drawing sizes, the 
 door is then put in place and the hinge is heated to a red 
 heat and pounded up against the door and the smoke-box 
 in its proper position. The holes are laid off on the strap to 
 the best advantage and drilled. They are then marked off on 
 the door and the smoke-box sheet, and these are put in with 
 either the ratchet or a portable drill. 
 
90 
 
 LAYIXG OUT FOR BOILER MAKERS 
 
 Another form of front end is illustrated in Fig. 97. F is a 
 flat sheet which is cut out of a steel plate on the rotary shear. 
 It is then turned off on the outside edge and faced to fit the 
 ring. The hole H is cut into the plate, of the required di- 
 ameter, and the plate is faced ofT on the outer edge for the 
 door. Strike a circle on this plate 53 inches in diameter. 
 Draw two center lines AA and CC at right angles to each 
 other. The drawing calls for twenty-four ?/s-inch bolts ; this 
 gives six bolts to each quarter. As nothing is stated to the 
 contrary, we will begin the bolts on the quarter lines and 
 step off six equal spaces in each quarter. In a similar man- 
 ner strike a circle 38 inches in diameter and lay ofT twelve 
 equal spaces for the clamps. The hinge is made up of a strap 
 and block. The strap is forged to fit the door and is riveted 
 
 as shown in Fig. 98. An angle-iron is sometimes used for this 
 purpose. As few boiler shops, however, have angle-bending 
 rolls for bending these angles, the solid ring is preferred. In 
 addition to this the solid ring makes a stiff, strong front end, 
 and this is desirable, as a smoke-box brace is usually at- 
 tached near this ring. It is faced on the outside diameter and 
 on the front, as shown by the finish marks f, Fig. 98. 
 
 The smoke-box is 54 inches in diameter, and the ring is 
 3!4 l^y 3 inches in the rough, or 3;-^ by 2?'8 inches finished. 
 The smoke-box sheet is kept back Y^ inch from the edge so as 
 to give an edge for calking. Fifteen-sixteenth-inch holes are 
 drilled through the ring for ^-inch rough bolts. The illustra- 
 tion shows button-head rivets inside and outside. Oftentimes 
 these heads are specified countersunk on the outside, and in 
 
 to it; the block is turned off so that it will pass through the 
 door in the form of a stud, and is held in place by a nut on 
 the inside. 
 
 The ring R is made of forged steel and is faced off on the 
 outer edge and outside diameter only. Twenty-four holes are 
 laid off to suit the smoke-box front, and forty-eight 54-inch 
 rivets are required for the fire-box sheet. These will be laid 
 off between the center lines as shown, i 7-16 inches from the 
 outer edge. The drawing calls for ^■^-inch rough bolts, and, 
 therefore, the holes will have to be drilled i-16-inch large. 
 Where there are a number of boilers to be built with the same 
 size front, a sheet-iron gauge would be made, and with this 
 gauge the holes would be laid out, both on the snioke-bo.x 
 front and on the smoke-box front ring. The alinement of the 
 holes is thus more certain, and the work of laying out is sim- 
 plified and made much stouter, also affording the advantage 
 of getting out a number of fronts complete without fitting the 
 same to each boiler. 
 
 The front smoke-box ring is usually made of forged steel. 
 
 any case these rivets should be looked up by the lay-out man, 
 and the smoke-box sheet and ring should be marked to suit. 
 
 Fig. 99 shows a cast-iron front. The casting is set upon 
 the boring mill and faced off on the top and bottom as shown 
 at /. The holes for the 54-i'ich bolts are twenty-four in 
 number, and will be laid off either from a metal gauge, or as 
 shown in Fig. 97. The lugs for hinges are cast on the front, 
 and the door has an extension which fits in between these, 
 and also cast on the door. The door must be faced off so as 
 to form a tight joint. The clamps C are drawn up by 5^-inch 
 rough square-head bolts which fit in pockets, cast in front so 
 as to keep the bolts from turning. A handle for opening and 
 closing the door, and a number plate for the locomotive are 
 usually a part of the front door. 
 
 In Fig. 100 is shown a general view of a smoke-box ex- 
 tension, together with intermediate rings, extension liner, etc. 
 The cleaning hole is required on the left-hand side, 10 inches 
 up from the center. A cinder pocket is located on the bottom 
 center line, 10 inches back from the front. 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 91 
 
 The smoke-box sheet is J/2-inch thick, and the extension is 
 5-16-inch thick. The smoke-box Hner is j4-i"ch thick, and the 
 extreme liner jX-inch thick. A layout for this extension is 
 shown in Fig. lor. This sheet will be planed on all four sides. 
 It will be square on the back edge and on each edge of the 
 seam, and will be beveled off for calking on the front edge. 
 The sheet will be i7-)4 inches wide when finished. Draw the 
 front line of the sheet, allowing about l4 inc'i for planing. 
 Measure off 17^ inches at each end and draw the back line of 
 the sheet ; bisect this distance at each end of the sheet and 
 draw the sheet center line CC. This seam butts together on top 
 and has a welt strip on the inside only. 
 
 The print calls for the smoke-box e.xtension to be s feet 
 ID inches outside diameter. The sheet being S-i6-inch thick, 
 we will have 69 11-16 inches for the neutral diameter. We get 
 the length of the sheet by looking up the circumference cor- 
 responding with 6911-16 inches. By referring to the table of 
 circumferences of circles we have. 
 
 Circumference of 69^ inches = 218.341 inches. 
 
 Circumference of 3-16 inch = .589 inch 
 
 Circumference of 6911-16 inches = 218.930 inches. 
 
 We, therefore, measiu"e off this distance along the center line 
 
 CC, allowing yi inch for planing on the edge. The other edge 
 
 will be sheared off, and both ends will be planed off to the 
 
 line. We now bisect the distance and draw the bottom center 
 
 |^--!2---J 
 
 
 T 
 I f 
 
 Em4-4i 
 
 rig. 100 
 
 !^Bon» 
 
 
 I 
 
 > 
 
 
 4 
 
 f 
 
 
 t 
 
 \< 
 
 
 T 
 
 i 
 
 1 
 
 " ,. 
 
 
 
 ] 
 
 3 
 
 
 FIG. 108. 
 
 FIG. lOI (top). fig. 102 (ceNTER). 
 
 FIG. 104. 
 
 FIG. 103. 
 
 line DD ; bisect the left half and draw the left side center line and also calls for the rivets spaced off center. We therefore 
 
 EE; bisect the right side and draw the right side center line set the dividers by trial, and step off eighteen equal spaces in 
 
 EF. The blueprint calls for seventy-two Ii-i6-inch diameter one quarter. Lay off each rivet midway between these points, 
 
 rivets for the front ring. This gives eighteen to each quarter, In a similar manner lay off eighteen rivets in the other three 
 
LAYING OUT FOR BOILER MAKERS 
 
 quarters. The blueprint calls for forty-nine Il-l6-inch di- 
 ameter rivets for the intermediate ring. These rivets are also 
 to be spaced off center on top. Set the dividers as near the 
 pitch as possible, and step off these forty-nine spaces. As a 
 check on the accuracy, the bottom space should come on the 
 line DD, and the rivets should come in a similar position along 
 the right and left side center lines. In laying out the holes 
 for the cinder pocket it will be found that these will interfere 
 with the bottom center line, and in its place will be used the 
 holes for the cinder pocket. These holes are laid out 9-)4 
 inches back from the front line on the bottom center line. 
 Step off the twelve equal spaces, beginning to space midway 
 between the center line. The hole required is 8^ inches in 
 diameter. Measure up the distance lo inches from the left 
 side center, and 8;4 inches back from the front rivet center 
 
 We now come to the stack of the locomotive boiler. Many 
 of these on modern well-equipped roads are simple indeed, con- 
 sisting frequently of a short cast-iron cylinder, bolted either 
 directly to the sheet of the smoke-box or attached to a cast- 
 iron base, as shown in Fig. 103. 
 
 Many stacks, however, are built up of steel plates with 
 spark catchers, etc. These are often complicated and require 
 considerable time and patience on the part of the lay-out gang. 
 
 Little work is required for laying out a cast-iron stack, es- 
 pecially when it is of the type that is bolted directly to the 
 sheet of the smoke-box. The laying-out work consists of lo- 
 cating the holes for attaching the stack, and seeing that these 
 fit the boiler. A cast-iron smoke-box base is shown in Fig. 
 103. D is the hole in the smoke-box sheet. This must be 
 made larger than the base by }4 to J^ inch all around, in order 
 
 line, and lay out a hole 5!^ inches in diameter. Draw a rivet 
 center line lYs inches from the end line, and lay off five rivets 
 equally spaced between the center lines. In a similar manner 
 lay .off five rivets on the other end of the sheet. Draw two 
 rivet center lines 27 inches apart, and lay off four rivets on 
 each line, equally spaced. These will be marked for 11-16- 
 inch rivets. 
 
 Lay out a liner, Fig. 102, on J'l-inch plate. Mark the length 
 40 inches and the width 14^^ inches. This liner must fit in 
 between the intermediate ring and the smoke-box front ring. 
 Draw a center line DD ; measure back a distance jYi inches 
 from the front line and lay out a circle 8^2 inches in diameter. 
 This circle will be cut out from the flat sheet. The holes will 
 be marked from the shell and punched to suit. The sheet will 
 have to be planed along the front and back line, but will not 
 need to be planed along the end line. 
 
 that the base may clear nicely on the sides when the sheet is 
 bent. The casting has an allowance for chipping at 5. It is 
 placed on the boiler and properly leveled. It is then marked 
 off and finally chipped so as to fit the boiler "nice and neat" all 
 around. Four bolts, B, are Used for attaching the base to the 
 smoke-box. The top portion is machined off as shown, and 
 the stack is bolted to the base by four bolts, C, each J4 '"ch 
 diameter. 
 
 A sheet-metal stack is shown in Fig. 104. The body B is 
 bent up in the rolls and riveted along the vertical seam by a 
 single row of ^'s-'nch rivets. The top of the stack T would 
 vary in size, depending upon the fuel, location, etc., but in 
 general construction would resemble the illustration. The 
 base B is flanged out of the single sheet, and is riveted di- 
 rectly to the smoke-box. The body of the smoke-box is 14 
 inches in diameter inside, and the sheet is ^-inch thick; the 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 93 
 
 neutral diameter, therefore, is 14^ inches. By looking up the 
 table of circumferences, we find 
 
 14 inches circumference = 43.9824 inches 
 l4 iuch circumference = -3927 inch 
 
 14'-^ inches circumference ^ 44.3751 inches 
 Referring to Fig. 105, the distance between the rivet lines 
 would be 44.38 inch. The width of the seam is 11-16 inch on 
 each side. This sheet will not need to be planed, and should 
 come from the squaring shears with very square edges. If 
 the edges come bad. however, allow only sufficient metal for 
 trimming; if the edges are reasonably straight, work clear to 
 the edge of the sheet, and do all the trimming on the two 
 sides. Draw the center line CC and the quarter center lines 
 DD and EE. The distance between the top and bottom center 
 lines is 46 7-16 inches. Allow 7-16 inch from the width of the 
 seam on the top and the bottom. Draw the top and bottom 
 center lines. Step off six equal spaces on each quarter 
 for the circumferential rivets. Step off twenty-four equal 
 spaces for the vertical rivets. This completes the work on 
 this sheet. The sheet must, however, be scarfed where it 
 enters the base and top, and, therefore, these two corner holes 
 should not be punched until after the sheet has been scarfed 
 out. Where standard stacks can be used, this laying out is all 
 done by metal gauges. 
 
 In order to lay out the cone portion of the top of this stack, 
 sketch out a cross-section of this cone full size. Fig. 106. Draw 
 the cone center lines, which continued will give the center O 
 of the cone. Project the flange at A upon the neutral line, 
 and thus obtam the length of the radius R. Also project the 
 flange at B upon the neutral line and thus obtain the length 
 5' of the element of the cone. From the extremity of the pro- 
 jected portion at Bj lay out the neutral diameter D of the cone 
 at this point. With these figures we can proceed to lay out 
 this sheet. Fig. 107. Select the proper sheet for the purpose, 
 and draw the center lines CC and AA. Strike a circle 
 with radius R in Fig. 106. Strike an outer circle with a radius 
 equal to R plus 5_, Fig. ic6. From the table of circumferences 
 look up the circumference corresponding with D. Beginning at 
 X with the wheel, run around the outer circle a distance equal 
 to one-half the circumference which has just been found, and 
 thus obtain the point Y. In a similar manner, run around 
 the other side and obtain the point Z. Now begin at Y and 
 run around the circle and see that this checks up with the 
 total distance. Draw YK and ZK to the center of the circle. 
 These are the rivet center lines. 
 
 Lay off the end line of the sheet 11-16 inch from the rivet 
 center line. Strike two circles i and ^ for the bending line 
 of the sheet. Divide this distance between these lines into 
 nine equal spaces and. locate a rivet midway between the 
 spaces thus laid out. Several other rivets will be required, 
 but these will not be put into the sheet until after it has been 
 flanged. Both of the top sheets will be laid out in this man- 
 ner, as also many of the spark catchers, deflecting sheets, etc. 
 The base, Fig. 108, is flanged out of a single sheet, and the 
 holes are marked off on it from the stack, and from the smoke- 
 box, and these holes are then punched to suit. 
 
 CHAPTER VI. 
 
 DEFLECTING PLATES. 
 
 Various methods are used for deflecting the gases in the 
 smoke-box in order to get a more uniform distribution of heat 
 throughout the tubes. A gas in motion follows pretty much 
 the same law as a solid does when it is in motion — it tends to 
 move in a straight line, and if it is desired to bend it out 
 of this line, some outside influence must be brought to bear 
 upon it. 
 
 Without any deflecting plates in a locomotive boiler, a 
 heavy flow of gases will take place in the upper tubes, while 
 there will be scarcely any flow in the lower tubes. This un- 
 equal flow causes unequal heating, and consequently unequal 
 expansion of the tubes. This gradually loosens up the setting 
 of the tubes, and will start the joints leaking. All this is bad 
 and, in addition to this, the operation is more economical 
 when the gases flow more uniformly through the tubes. For 
 this reason a deflection plate is placed in the smoke-box, in 
 order to dampen or check the draft in the upper tubes, and 
 thereby increase the draft in the lower tubes, as shown in 
 Fig. 109. 
 
 The air passes up through the grate in order to produce 
 combustion, and the hot gases are bent over and pass through 
 the tubes. The deflecting plate D bends the flow of the gases 
 of the upper tubes downward, and then the strong draft pro- 
 duced by the exhaust drives these gases out of the stack, to- 
 gether with a lot of sparks, soot, etc. It is the sparks, soot 
 and unconsumed coal which is the source of great annoyance 
 in nearly every locality. And the extent of this annoyance 
 often determines the arrangement of the smoke-box, screens, 
 spark arresters, etc. Stringent laws are enacted in some locali- 
 ties specifying that some arrangement must be used in order 
 to arrest sparks, soot, etc. The deflecting plate, spark arrest- 
 ers and screens of the smoke-box, are often looked upon as 
 being unimportant, but there is scarcely anything about the 
 locomotive that has been the source of so much litigation be- 
 tween the railroad and the locomotive builder, and between 
 the public and the railroads, and therefore great care should 
 be exercised in the design and construction of these parts, 
 whether it is a locomotive works building an engine for an 
 outside party, or whether it be the railroad's home shops. 
 
 A cross section of a smoke-box as used extensively is illus- 
 trated in Fig. 1 10. D is the deflecting plate, which is fastened 
 permanently to the boiler. .S' is a slide, F is the opening for 
 the exhaust pipe, A and B are sheets of metal or perforated 
 plates having meshes or openings varying according to the 
 fuel, size of the boiler and locality. C is an angle-iron which 
 is bolted to the tube sheet ring. £ is a piece of bar iron 
 which supports the netting : it passes across the boiler and is 
 bolted to the side of the boiler. The door B is hinged at H, 
 and drops down in front, so that persons can readily get to 
 this part of the smoke-box. Nearly all these sheets and net- 
 ting run at an angle, and are therefore quite irregular in shape. 
 Just what shape any particular sheet will have is difficult to 
 tell, even by the most experienced men on this class of work, 
 and the exact shape can be obtained only by a careful layout 
 for the required conditions. In order to facilitate the work 
 
94 
 
 LAYING OUT FOR BOILER MAKERS 
 
 of laying out these sheets and fitting them into place, they 
 are made in two pieces, with the seam in the center. Each 
 piece is fitted separately into place, and then the sheets are 
 matched up along the center line. 
 
 In Fig. Ill, 5"5' are slots for adjusting the slide. Make a 
 full-size layout of that part of the smoke-box which contains 
 this sheet, laying out only those lines which would be crossed 
 by this sheet ; also make a front view of the end. These 
 views can overlap each other for economy of space, so long as 
 the layout remains clear. 
 
 Strike the circles corresponding with all parts of the smoke- 
 box, intermediate ring, etc., which would be crossed by this 
 sheet. Now lay all points along the neutral line of the sheet, 
 and mark off the spaces i, 2, 3, etc., to points where dimen- 
 sions are to be obtained, and project the same over to the 
 other view, and then measure off the width of the sheet from 
 each one of these points to the center line GG, as shown at 
 A, B, C, etc. These dimensions can now be laid off on the 
 flat sheet. If the curved portion where the sheet fits along 
 the boiler is long" several intermediate points should be se- 
 
 the several positions must have countersunk heads, which 
 must be flush with the surface of the sheet. 
 
 In laying out the slide, care must be taken to have enough 
 clearance on the side of the slide to admit of adjusting it to 
 its fullest extent without interference on the side of the boiler. 
 .\lso, this cut-out in the sheet should be not more than re- 
 quired, as a considerable gap is necessary in some cases in 
 order to get the desired adjustment. This gap in its worst 
 position allows the gases to rush past its side, instead of 
 deflecting them. 
 
 Fig. 113 shows the slide in its top and bottom positions. 
 We measure off the distance Ai, 5i, etc., from the center line 
 to its outer edge in its upper position. In a similar way from 
 the same points on the slide we measure off these distances 
 on the bottom position. Lay out on the front sheet the least 
 distance which has been obtained in these positions from the 
 lines corresponding with A, B, C, etc. Then draw a curve 
 through these lines and trim off the sheet to these lines, al- 
 lowing about ^-inch projection beyond the center line for 
 matching up. Usually the two halves of these sheets are sym- 
 
 lected. These would then be projected to the other view, and 
 the width of the sheet at these points should be measured off. 
 It will be noted that this sheet is bent at an angle of about 
 60 degrees, about 4 inches from the top edge. In ordering 
 these sheets, be sure to specify the sheet so that the bend will 
 cross the sheet at right angles to the length, as it is rolled. 
 If this sheet is bent lengthwise of the rolled sheet, it is very 
 apt to break. 
 
 Fig. 112 shows one of these sheets as it would appear when 
 it is laid out on a fiat surface. This sheet fits around the shell 
 of the smoke-box without any interference of lines and rings, 
 and therefore the outer edge will be a smooth curved line. 
 A 2 by 2-inch angle is bent to fit the boiler and the deflecting 
 plate, and is attached to the deflecting plate by a series of 
 rivets spaced 4 inches center to center. An angle is often 
 used at A along the top edge, for holding the sheet in place. 
 A hole H, Ii-l6-inch in diameter, is laid off for the slide; also 
 a series of holes is laid off, about 5s '"^h from the center 
 line, for the seam rivets. All rivets covered by the slide in 
 
 metrical, and one lay out is all that is necessary. If there are 
 any projections, heating pipes, etc., which would make one 
 side different from the other, the sheet must be laid out for 
 each side separately. Where the cut-outs are numerous and 
 complicated, much time is saved by taking the sheet to the 
 smoke-box, placing it at the proper angle and position, and 
 then marking out with' a scriber the parts that are to be cut 
 out. The metal is then pared away to these preliminary lines, 
 and the sheet is then taken back and put in position, and 
 again carefully scribed off from the side of the boiler and 
 projections, so that when this metal is cut away the sheet will 
 slip back into place and fit snugly all around. 
 
 The door D, Fig. no, is usually made of wrought iron ^ 
 by 3 inches, and is bent to fit the boiler along the outer edge 
 and is welded together at the corners — see Fig. 114. To get 
 the shape of this in a flat piece, we lay off points, i, 2, 3, etc., 
 along the neutral line, and get the distances A, B, C, etc. On 
 a flat sheet, Fig. 115, draw a center line CC and a base line 
 DD. Lay off on CC 0=. ij. 2i, 3,, etc., and draw lines parallel 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 95 
 
 to DD. On each side of the center line CC lay off distances 
 .-/:, B-. Ci, etc., corresponding with dimensions obtained from 
 Fig. 114. Draw a smooth curve through these points. 
 
 The door is then forged from 5^ by 3-inch stock to con- 
 form with these lines, and a piece is welded in to form the 
 bottom. When netting is used, a frame is placed on the net- 
 ting and the netting cut to suit. Holes are placed in the 
 frame for 5-16 or J^-inch bolts, and washers are used between 
 the head and the netting. The frame is hinged on the bottom, 
 and is held in place on the top by a key and strap bolt — see 
 Fig. 116. The bolt is 1^ inches in diameter and has a split 
 key ?^ by l^ inches. The strap portion is 5^ by 3 inches, 
 and is riveted to the sheet by two 5^-inch rivets. Care must 
 be taken in settling on the position of this door, in order that 
 it will clear the side and the ring as it sweeps through the 
 radius R from the center of the hinges. Never skin too close 
 on the clearance allowed, as there is always bound to be more 
 or less variation in the fitting up of these parts, and then you 
 
 be bent in around corners enables one to cut the paper out in 
 a short time and make a very nice job. This is ^hen trans- 
 ferred to the netting or perforated plate, and the latter marked 
 off and cut to suit. 
 
 Oftentimes it is necessary to cut a large hole out of the 
 plate or netting, and then fit an extra small piece in around 
 the parts, and bolt this to the main part of the screen. Also 
 this is often rendered necessary in order to make it easy to 
 get these sheets in and out of place. A hole must be cut into 
 this sheet in the center so as to fit around the exhaust pipes. 
 The screen is usually bent up and bolted to the deflecting plate 
 D. The usual arrangement of the steam pipes is shown in 
 Fig. 117. The part of the sheet extending behind the steam 
 pipe at K and K would be fitted in by the small piece which 
 has just been referred to. 
 
 Sometimes a basket ABC is arranged out of netting; AC, 
 being a part of the cone, would be laid out by continuing these 
 two lines to their intersection, and then by measuring off the 
 
 Fig. 119 
 
 will have trouble with the door interfering with other por- 
 tions of the boiler. Generally, if the end of the door clears 
 the ring at iv by 1% or 15/2 inches, the rest of the door v;ill 
 clear also. But this is not always true, especially when the 
 slope of the door is made very steep. The inside circle of the 
 ring should be laid out on the cross section, and several points 
 should be projected on the outer edge of the door in its top 
 position. Now rotate the door and project these points to 
 the cross section. You can immediately see whether the door 
 clears or fouls. 
 
 One of the meanest things to fit up in connection with the 
 netting or perforated plate, is the flat plate A, Fig. no. This 
 illustration does not show the steam pipes which pass down 
 along each side. There are also frequently special pipes, an- 
 gles, etc., which this sheet must fit around, and therefore the 
 fitting in of these sheets often become a tedious and trouble- 
 some job. Ordinarily the laying out of these parts is made 
 easy by the use of stiff paper. Several boards are leveled up 
 in the position of this sheet, and the paper is cut so as to fit 
 around the parts nicely. The ease with which the paper can 
 
 inner radius to the point R and the outer radius to the point 
 P. We then strike these two circles, look up the circumfer- 
 ence corresponding with D and then measure off this distance 
 along the outer circle. Draw two radial lines from these 
 points to the center, as shown in Fig. 118. 
 
 Now lay out this cone on the cross section and determine 
 the distance K on the drop back from the top line. Lay off K, 
 Fig. 118, on the right and left side center lines, and with the 
 straight edge draw a nice, smooth, curved line as shown. To 
 this sheei must be added a sufficient amount for flanging and 
 attaching the basket to the boiler. We now bend the basket 
 in shape and bolt the ends together. Raise this in position in 
 the smoke-box, and with the scriber mark off the depth of the 
 flange down from the shell of the boiler, running all the way 
 around the sheet. We now bend the flange back, and then 
 place the basket in position and pound the flange up nice and 
 neat all around. The bottom of the basket would be flanged 
 up on the inside and bolted fast, and the bottom would be cut 
 out to fit the exhaust nozzle, or whatever the drawing calls 
 for. 
 
96 
 
 LAYING OUT FOR BOILER MAKERS 
 
 A common construction of steam pipe is shown in Fig. 119. 
 This shows a flange connection to the T. There will always be 
 some variation in the machining of parts and fitting up, and 
 therefore the ball joint arrangenur.t is used, A, B, and C. 
 Part A is shown in section ; both the sheet and the T are 
 reamed with a ball reamer to 9J4 inches radius. The drop of 
 the T, which is shown as 3 inches, may vary !/< inch or so 
 one way or the other, and the steam connections will still re- 
 main perfect. 
 
 In fitting up the deflecting plates, screens, etc., some allow- 
 ance must be made for this variation. A sheet which will be 
 just right for one boiler will not fit in exactly in another, al- 
 though the drawings for the two may be exactly the same. 
 Also, there will be some variation in the pipes, due to expan- 
 sion, which will also require some clearance. 
 CHAPTER VII. 
 
 LAGGING. 
 
 This section deals with the lagging of the locomotive boiler. 
 There are a number of methods used for lagging boilers, each 
 of which has its own peculiar advantage. In some cases this 
 means an advantage in ease of putting on the lagging, which 
 
 of the boiler which we intend to lag is sent to the lagging 
 manufacturer. Here, a full size layout is made, showing 
 thickness of plates, slant, diameter of sheets, etc. The various 
 courses are then gotten out so that they can readily be put to- 
 gether in the erecting shop. Each piece is about 5 inches 
 wide, and in length varies from 2j4 to 3 inches, depending 
 upon the length of courses, position of dome, throat, sheet, 
 etc. The number of pieces required for any given course, as, 
 for instance, the first course in Fig. 12a, would be obtained as 
 follows : The boiler is 64^ inches outside diameter ; lagging 
 to be I J/2 inches thick. This gives 65 J4 inches to the neutral 
 diameter of the lagging, or 206.56 inches circumference. With 
 sections 45^2 inches wide we would have forty-six pieces. A 
 little more than the exact amount is furnished in order that 
 the last piece may be sawed and fitted. The various sections 
 are held to each other, and the whole thing is bound together 
 by the use of corrugated pieces of steel, as shown in Fig. 121. 
 The lagging for the dome is shown in Fig. 122. The sec- 
 tions are tacked to each other and built all around the body 
 of the dome. The whole thing is then inclosed by a dome 
 casing, C, which is made of thin sheet iron. The top of the 
 
 ,n,,,^,,,,,ff. 
 
 is, of course, an advantage to the builder. In other cases the 
 lagging is more expensive, and of course serves its purpose 
 as a covering to more excellent advantage. 
 
 On small locomotives, for plantation and light locomotive 
 work, wood is often used for lagging. The pieces are sawed 
 in strips about 3 inches wide, and in length and thickness to 
 fit courses. These are held in place by hoop irons, which are 
 wrapped around the boiler, nails being driven through the 
 hoop irons into the wooden strips, thus securing the lagging. 
 After the boiler is thus covered it is surrounded with a sheet 
 iron covering. This is an inexpensive lagging, and is used a 
 great deal. 
 
 Various compositions are used also, in the form of sec- 
 tional lagging. Some of these are good enough for medium 
 size boilers. On large locomotive boilers, however, for heavy 
 freight and passenger service, magnesia sectional lagging is 
 largely used. 
 
 Fig. 120 shows an outline of a locomotive boiler which is to 
 be covered with sectional lagging. . . A drawing or sketch 
 
 dome is frequently plastered over by a mi.xture of the same 
 material which makes up the sections. The back head of the 
 boiler in many cases is not covered with lagging, the lagging 
 proper extending to the edge of the outside sheet. An angle- 
 iron A, Fig. 123, is bent to fit the boiler, and is held in position 
 by screws and clamps. The lagging is fitted underneath the 
 leg of this angle. This holds it securely in place, and also 
 protects the lagging from ill usage in the cab. 
 
 This same style of angle-iron is also used along the cab 
 board, down along the throat sheet, and across the bottom of 
 the throat sheet, in order to hold the lagging firmly in place 
 at these limiting places. When the back head is specified to 
 be covered with lagging, care must be taken to bind the sec- 
 tions firmly together and tie them securely to the side of the 
 boiler. This is usually done by means of wire and clips to 
 hold the ends together. In putting on the fittings, such as 
 whistle, elbows, blow-ofT cocks, cleaning plugs, etc., care must 
 be taken to have these fittings made longer, so that they may 
 pass through the lagging. After all the lagging has been put 
 
HOW TO LAY OUT A LOCO^^IOTR'E BOILER 
 
 97 
 
 on the boiler, whether this lagging be wood, magnesia sec- 
 tional, or plastered on, the entire surface must be covered with 
 sheet iron, usually Russian iron sheets are used for this pur- 
 pose. 
 
 Illustration Fig. 124 shows a portion of the barrel of the 
 boiler with the lagging and sheet-iron cover in position. The 
 breadth of the sheet would be determined by the character and 
 shape of the boiler. The length would be determined as fol- 
 lows: In the illustration the drawing calls for a boiler 54 
 inches inside diameter, and the shell is to be 9-16 inch. This 
 would make the outside of the boiler 55"/^ inches in diameter. 
 The lagging is to be i^ inches. This would make the diame- 
 ter over the 'lagging 58-)^ inches. In the table of circumfer- 
 ences we find that sSj/^ inches diameter, which is l4 inch more 
 than is required, would give us 183J4 inches, to which we add 
 4-inch lap, which would give us 1S7J4 inches, or 15 feet 754 
 inches. This would be made up of several sheets riveted to- 
 gether, the lap being made in such a way that the outside 
 sheets hang down over the top of the other sheets, thus shed- 
 ding the water. This style of sheet is by far the easiest thing 
 
 around the boiler and pulling it up tiglit in place. The holes 
 are then marked off from the clips. The exact location is a 
 matter of judgment on the part of the fitter and must be 
 sufficient to take out the slack of the band when the bolt is 
 pulled up tight, and still allow sufficient thread for adjusting 
 in case of an additional stretch of the band or contraction in 
 the different courses. 
 
 The lagging on the front end is held in position by the leg 
 of the angle. This angle is bent around the boiler and is held 
 at a number of places by bolts. In order to give a finish at 
 the front, where this lagging ends, a flange sheet, Fig. 129, is 
 used. This is bent to fit the radius of the smoke-box and 
 should fit up nice and tight all around. The back portion 
 reaches over the back sheet, and the whole thing is bound 
 equally together by a set of clamps and bolts. 
 
 Another style of ring for finishing off the front end is illus- 
 trated in Fig. 130. In getting out these rings, and especially the 
 latter, care must be taken that there are no button-head rivets 
 where this sheet rests against the box. When there is a row 
 of button-head rivets around the boiler where this ring would 
 
 Tig. 126 
 
 Fig. 139 
 
 to make. The covering for the gusset sheet, dome course, back 
 head, etc., are considerably more difficult. 
 
 The sheet for the dome course extends on in as near the 
 body of the dome as possible, and the seam is lapped over on 
 the top as shown in Fig. 125. The width of this sheet, W, 
 would be made sufficient to cover the dome course, and give 
 from I to I J/2 inches between this sheet and the one that 
 covers the ne.xt course. When the sheets are put in position, 
 they are held in place by a circular band. Fig. 126, about 3 
 inches in width, and in length to extend all around the boiler 
 and allow 4 or 5 inches lap. These bands are beaded on the 
 ends, first for appearance, and, secondly, in order to make a 
 neater fit between the band and the sheets which it holds in 
 place. 
 
 A section of the beading is shown in Fig. 127. A is the 
 portion that is bent down and rests on the sheet, thus closing 
 up the air-space and making the covering very tight. The 
 band is clamped together by means of bolt B, Fig. 128, and a 
 pair of clips, C and C. The clips are riveted to the band by 
 several quarter-inch rivets. The one clip is placed near the 
 end of the band, and the other clip is placed from the end 5 
 or 6 inches, depending upon the amount of the lap. The exact 
 location for the second clip is obtained by placing the band 
 
 -Fig. 130 
 
 naturally come, the lagging must be brought a little further 
 ahead, or stopped off a little further back, in order that this 
 ring may rest against the boiler without interfering with the 
 rivets. The lagging cover for the gusset sheet is to be laid out 
 as shown in Fig. 131. Get the drawing for the boiler and 
 make a sketch for the large and small neutral diameter, and 
 also the distance of these diameters from each other. Now, 
 to these figures add the thickness of the shell and the thick- 
 ness of the lagging, and to this add % inch extra on account 
 of the inability to fit up the lagging and the covering and 
 some air space. These figures give us the size of the cone for 
 slope-sheet covering. 
 
 We lay out these figures as shown in Fig. 131, and continue 
 the slope line C D until it strikes the bottom line A B at the 
 point C. This is the center of the cone. From this point 
 strike two reference arcs AE and BF. Also draw semi-circles 
 on BD and AC, and divide these into four equal parts. From 
 A and B as centers, with the trams project these points on the 
 diameter. From the point B, with a radius equal to the length 
 of the arc B-2, strike a circle as shown. Now measure off 
 the radial distance from the reference circle to the point z, 
 and step off this distance from the reference circle and de- 
 termine the point li. 
 
98 
 
 LAYING OUT FOR BOILER MAKERS 
 
 In a similar manner strike another arc and measure off the 
 distance from the projected point 2 to the reference circie. 
 Lay off this distance from the reference circle and determine 
 the point 2\. Continue this construction until the point 4\ 
 is located. In a similar manner we make the construction of 
 the small end. We thus have four points each for the large 
 and the small end. Draw a smooth line through these points 
 and add about 2 inches for lap. This represents one-half of 
 the sheet. The other half would be symmetrical to this. 
 
 Where a number of these sheets are being laid out for 
 boilers for slightly different dimensions, a person can often 
 judge about what curve to give these lines, and thus the 
 whole sheet is laid out in this time. The number of pieces 
 that one of these sheets would be divided into would be de- 
 termined by the size of the stock on hand, and the general di- 
 mensions of the boiler. Sufficient allowance must be made 
 on the separate sheets so that when riveted together they will 
 make up one complete sheet of the size required. 
 
 Fig. 132 shows this complete lagging cover for the slope 
 portion of the boiler. The dome covering is represented in 
 Fig. 122. The straight portion of the cylinder is made of one 
 plain rectangular sheet. The ends for seams are sheared 
 square and true. The sheet is bent up and the seam is riveted 
 up with a covering strip on the inside, and the counter rivets 
 on the outside. This seam is made very neat, and when 
 finished and painted it should be impossible to see the joint. 
 The top portion is made from pieces which are hammered out 
 by hand and fitted together. Each one of these sheets is 
 riveted up with strips on the inside, and the whole thing is 
 riveted to the cylindrical portion of the dome covering. In a 
 similar way the flange portion is built up. The whole of 
 this casing is made to fit down neatly over the outside cover 
 of the dome course. Holes must be provided for whistle el- 
 bows, throttle valves, rod connections, etc., which might be 
 required on the dome. 
 
 CHAPTER VIII. 
 
 BOILER MOUNTINGS. 
 
 The mountings for the locomotive boiler are numerous, and 
 usually require considerable thought and good judgment on the 
 part of the erector, in order that the whole thing may go to- 
 gether nicely. Too often the work of laying out these parts is 
 not done thoroughly enough, and therefore there is a good 
 deal of tearing down and tearing out necessary to fit things 
 together. 
 
 In the list of these mountings is included such parts as fur- 
 nace bearers, waste sheets, etc., which will be attached to the 
 boiler proper when it comes to the erecting shop, but which 
 are no part of the boiler itself. In laying out these mountings 
 many unusual things turn up. In laying out the various 
 courses, the exact length called for on the drawings cannot 
 always be obtained, for a number of reasons. First, a sheet 
 may be ordered a little too narrow ; or, on the slope sheet, 
 when the layout is made, we may not have quite enough metal 
 for the full width of the seam. Thus there are many things 
 which change conditions far from the ideal. These changes 
 may never be noticeable, or may never change the working of 
 the lioiler or the fitting up of the different parts. The man in 
 
 the erecting shop is rarely "on to" any of these things until 
 he gets "up against it" in setting the boiler up in place. Any 
 juggling of the stay-bolts is noticeable, on account of the shift- 
 ing of the stud-bolts for furnace bearers. 
 
 Fig. 133 shows a boiler which has been lowered onto the 
 cylinder, and which is ready to be marked off so that the 
 cylinder flanges can be chipped to fit the smoke-box sheet. 
 The erecting card gives the distance B from the center line of 
 the cylinder to the throat sheet. This distance must be ex- 
 actly right. The erecting card always gives C , from the top 
 of the frame to the bottom of the mud ring, or to some fin- 
 ished surface on it. These figures must be checked up, to- 
 gether with the distance A from the center line of the cylin- 
 der to the front ring. If there is any discrepancy due to any 
 one of the causes which have been mentioned, the matter 
 should be taken up carefully, so that the discrepancy will be 
 thrown in such a way as to least affect the mounting. Having 
 once determined definitely what these figures are to be, the 
 chipping line for the cylinder is laid off, and the outline of 
 the furnace bearer marked out a suflScient height above the 
 frame to allow the boiler to drop down when the cylinders 
 are chipped out. Having thus carefully laid out the furnace 
 bearers, break-hanger supports, etc., the boiler is removed, 
 the cylinders are chipped down to the lines by means of 
 straight edge, and the boiler is put into place and leveled. 
 The dimensions are now all done over again, and if everything 
 is all right, the boilers are laid off for the cylinder flange bolts. 
 The method of putting in these holes varies in different shops. 
 This has been referred to in a previous issue, and therefore 
 it will not be necessary to go over that matter at this time. 
 The thing to remember, however, is, be careful and get the 
 height of the boiler correct, and also the exact position longi- 
 tudinally; and also be careful and get the center line of the 
 boiler in line with the center of the frames. 
 
 The furnace bearer is often made of steel plate, bent as 
 illustrated in Fig. 134. A is a filling-in piece between the out- 
 side sheet of the boiler and the frame. The boiler should 
 be lowered into place, and the thickness of the sheet would be 
 made to suit the measurement taken at this point. This sheet 
 must be fitted to the boiler by means of patch bolts. The 
 furnace bearer B is machined off where it sets on the frame, 
 and is allowed to project over the frame a sufficient distance 
 to cover up the plant. 
 ' The exact length of the foot is to be marked off in position, 
 and the plate is then planed down to this line. The bearer 
 will not fit up snugly against the boiler until it is countersunk 
 in the back a sufficient amount to clear the head of the stay- 
 bolt, as shown in Fig. 135. 
 
 Put a daub of white lead or moist flour on each of the stay- 
 bolt heads which would be covered by the furnace bearer o'l 
 the frame in its proper position lengthwise of the boiler, and 
 push it back against these heads. Tap the bearer sufficiently 
 to mark an impression at each one of these stay-bolts. Some 
 of these points will be marked all right and others will not 
 touch. Give these low heads an extra daub of white lead and 
 apply the furnace bearer again. The furnace bearer is now 
 to be center punched and taken to the drill press. 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 99 
 
 With a fiat-nose drfti, as shown in Fig. 136, each one of 
 these center punch marks is to be countersunk, as shown in 
 Fig. 137. One can soon judge about the depth necessary, and 
 when all holes have been countersunk, the furnace bearer is 
 taken back and tried in place. This flat-nose drill is always 
 sure to creep one way or the other, so that the bearer will 
 not clear all the stay-bolt heads. By using white lead on the 
 heads and trying the bearer in place, you can find out where 
 the interference is. Sometimes by countersinking deeper the 
 ones that interfere, the bearer can be brought up in place. 
 When they are very much out, however, draw the center line 
 over with a round-nose chisel, or tilt the bearer up at an 
 angle, sa that the center will run in the desired direction ; 
 also see that the angle of the drill is about the same angle 
 as the stay-bolt heads. 
 
 The bearer will rarely fit up snugly against the side of the 
 boiler until it is bent to the side sheet, either by bending it 
 
 high spots until a reasonably good contact is attained all 
 around. The arrangement of the clamp in this illustration is 
 such that it is not bolted to the boiler itself. The distance, T 
 however, must be made to match, as the width^ of the 
 boiler will be constant, though the fire-box will vary more or 
 less. 
 
 Often the furnace bearer takes the form of that shown in 
 Fig. 139. 5" is a steel casting which is attached to the side of 
 the fire-box by means of studs. The drawing usually shows 
 the location of these holes, which should be spaced to avoid 
 interference with the stay-bolts. The casting is chipped to the 
 boiler in a similar manner to that shown in Fig. 138, and 
 countersunk to clear the heads of the stay-bolts. Sometimes 
 these castings extend on down, and take a bearing on the mud 
 ring. A pad is arranged on this ring, and is machined, as 
 also is the lip on the steel casting. 
 
 This takes the weight off the studs, and makes the work of 
 
 © © ® @ 
 
 + + -<■ + + f 
 
 ® © © ® @ 
 
 H * + -I- -^ -t- ^ 
 
 @ @ @ @ e 
 
 @ © © @ © 
 
 Fig.134 
 Chipping Strip 
 
 ....J 
 
 rig.136 
 
 Flg.138 
 
 cold, or by heating it and pounding it back in place. The 
 clamp D, Fig. 134, is machined along the side and on the 
 bottom, where it rests against the frame. The distance E, 
 from the top of the frame to the bottom of the finished sur- 
 face, is not always a definite figure, even on locomotives which 
 are built to the exact design. The forging may come full r^t 
 .-nis point, or it may not, and when the frames are slotted 
 this* surface is merely trued up, irrespective of dimensions. 
 The clamp, therefore, should be laid out at E so that it can 
 be marked and planed to fit. The holes for attaching the 
 furnace bearer and clamp are laid off on the diagonals be- 
 tween the stay-bolts, and are usually drilled a little large, so 
 that there will be no interference with the studs. 
 
 Steel castings are also used for furnace bearers ; see Fig. 
 138. These are usually harder to fit up than the forged steel 
 bearers, as they are heavier and harder to handle. The cast- 
 ing is usually made with chipping strips. If the steel casting 
 is not badly warped, these strips can be chipped off on the 
 
 Fig.135 
 
 lining up the casting much easier. P is a forged steel pin,, 
 which is forced into the casting and riveted over. L is the 
 link, which takes the weight of the boiler, and also allows the 
 boiler to expand and contract. W is the washer next to the 
 link, and C is a split cotter, to keep the whole thing in place. 
 The fire-box must be girded sidewise by a suitable cross-tie,, 
 which is machined out to suit the; frame. 
 
 Most fire doors are made of cast ■ iron,, with J4 to M inch 
 chipping strip all around the edge. Fig. 140. The casting is 
 raised in position, placed against the back head and leveled. 
 The location of the holes H is then settled, in order to clear 
 the stay-bolts. These holes are then drilled for % or i-inch 
 bolts, as the case may be. The casting is then raised again in 
 position, and the holes H are scribed off. These holes are 
 drilled and tapped, and the studs are screwed into place. The 
 high parts of the chipping strip and the strip are then chipped 
 down as near to this line as possible. The casting is then 
 applied to the back head and the high spots noted. These 
 
100 
 
 LAYING OUT FOR BOILER AIAKERS 
 
 high spots are tlien chipped and filed until the casting has j 
 good bearing all around. 
 
 For the Wootten boilers, and other boilers with wide fire- 
 boxes, the arrangement shown in illustration in Fig. 141 is 
 largely used for supporting the fire-box end of the boiler. 5 
 is a sheet Vz inch thick, and L, K and M are lugs on the mud 
 ring. These are machined off and the rivet holes H are laid 
 off to the dimensions called for on the detail of the mud ring. 
 These holes are then drilled for about ^ or i-inch bolts. T 
 is a cross-tie made either of steel casting or steel forging, 
 depending upon conditions, and machined off on the bottom 
 to suit the frame, and on the side to receive the "/j-inch plate. 
 The plate is machined off on the lower edge and allowed to 
 rest on the lower frame. This gives a good starting point for 
 laying out the holes on this sheet. The boiler will be lowered 
 
 machinery and the parts to be cleared. The illustration is 
 taken from a common construction in use on the average size 
 locomotive. The plate is about Y^ inch thick. The knees 
 are machined at B for the plate C. They are machined to fit 
 the frame. Usually a card accompanies a drawing, showing 
 the size of this sheet. The radius R of the sheet is made from 
 y% \o Y:^ inch larger than the radius of the boiler, so as to 
 admit of ease in fitting up. This sheet is planed along the 
 lower line D, where it rests on the knees, and in line central 
 with the boiler. 
 
 Scribe off any projection that there may be of the sheet 
 beyond the knees. The bolt holes for securing the sheet to 
 the knees are now scribed off from the knee. While the 
 sheet is being held in position by several clamps, get the waste 
 angle-iron G, and try it to the boiler. This will rarely fit up 
 
 rig.139 
 
 z /// 
 
 rig.HO 
 
 into place and blocked up so as to be in perfect alignment. 
 The cross-tie T is placed over the frame in position. 
 
 The exact location of the cross-tie would depend on the 
 size of the boiler, the amount of expansion, etc. The total 
 expansion and contraction would have to be taken care of by 
 the bending back and forth of this sheet ; on the average size 
 boiler about yi inch would be required. The cross-tie would 
 be located J4 inch back from the vertical line, so that when 
 the boiler is headed up and in working condition, the lugs on 
 the mud ring would be yi inch back from the cross-tie, or the 
 expansion would be about central with this cross-tie. 
 
 The locomotive frames at the strongest are very flexible 
 and flimsy sidewise, and for this reason they are tied together 
 with numerous cross-ties, waste sheets, etc, Throughout the 
 whole construction, however, a certain amount of expansion 
 must be provided for. 
 
 Fig. 142 shows a waste sheet. There is one or more of these 
 sheets on nearly every boiler. The method of attaching the 
 sheet to the boiler and frames depends somew;hat upon the 
 
 Effb 
 
 Flg.lll 
 
 ^ 
 
 ■F ^ B 
 
 Fig,y2 
 
 properly without being bent one way or the other. It is often 
 necessary to heat the angle-iron to get it to fit up nicely on 
 all sides. A certain number of equal spaces is laid off along 
 the angle-iron and the hoies are punched. In this connection 
 it should be mentioned that punching these holes in the outer 
 leg will distort the angle in some cases, so that it will not fit 
 the boiler. Therefore, these holes should be punched before 
 the angle is bent and fitted to the shell. Having placed the 
 angle-iron in position, and secured it with several clamps, 
 wedge it up at several places tight against the boiler, also 
 wedge the sheet D down tight against the knee. Now mark 
 off the holes for the angle on to the waste sheet. If the angle- 
 iron projects, or the sheet projects beyond the angle, lay off 
 a line on the sheet so that when this is sheared off the whole 
 thing will present a neat appearance. Remove the clamps 
 and trim off the extra metal from the sheet. Set the angle- 
 iron against the boiler a little to the front, so that when the 
 boiler is heated up it will stand a little to the back, depending 
 upon the amount of expansion required at this point. 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 lOI 
 
 The guide bearer sheet, Fig. 143, rigidly ties together the 
 frames, guide bearer, and boiler. This illustration shows 1 
 single sheet extending clear across the guide bearer, This 
 can often be seen on medium size boilers. On very largo 
 locomotives the shell comes down close to the frame, so that 
 the guide bearer must be cut out to clear the boiler. In this 
 case two guide bearer sheets will be used instead of one. Ihey 
 are placed out near the end of the guide bearer, and extena 
 
 FIG. 143. 
 in radically against the boiler. The expansion of the boiler 
 at this point is not much. This is a good thing, as these 
 sheets often get to be very narrow, and could not deflect much 
 without straining the parts. 
 
 The radius R of the sheet is made from ]/% to y^ inch large • 
 than that of the boiler. Place the sheet in part against tli 
 guid^ bearer, and fasten it with several clamps. Measure up 
 to see that the projection on either side is the same, and 
 bump the sheet one way or the other so as to bring it central. 
 Mark off the holes H from the guide bearer. Place the angle- 
 iron A in position. Fit this to the boiler as in Fig. 142, and 
 mark off the holes K. Scribe off any projection there may be 
 of the angle beyond the sheet, or of the sheet beyond the 
 angle. The sheet can now be taken down and sheared to 
 these lines, and the holes can then be punched. 
 CHAPTER IX. 
 
 TUBES AND PIPING. 
 
 This section deals principally with the tubes and piping. 
 There are many annoying things in connection with maintain- 
 ing the locomotive boiler in good condition. Not a little of 
 this annoyance comes from the tubes and their setting, and 
 at the joints where the pipes are connected for steam and 
 water. This is largely due to the heavy strain to which the 
 locomotive boiler is subjected. When we consider that a 
 single locomotive boiler can give forth a constant flow of 
 steam to the equivalent of 1,000 horsepower, and then con- 
 sider the small space occupied by the boiler in comparison 
 with the space occupied by stationary boilers for power plants, 
 it is really a wonder it holds up as well as it does. The fixing 
 up of the tubes consumes a considerable part of a repair- 
 man's time. These repairs are largely increased by inferior 
 material in the tubes, and by improper methods of expanding 
 the tubes in position. 
 
 Fig. 144 shows the 2-inch tube in position. The tube sheet 
 is shown yi inch thick. The edge of the copper ferrule should 
 be 1-32 inch back from tlie fire side of the tube sheet. The 
 scale from the outside of the tube should be removed, so as 
 to form a clean metal joint. The projection of the tube L 
 should be S-16 inch full. The copper ferrule should be clean 
 and true. All the scale should be removed from the flue hole, 
 leaving the metal bright and clean. 
 
 The tubes will not all be of the same length, although the 
 front and back heads are parallel. A large number of them, 
 however, will have approximately the same length. With the 
 measuring stick, which has been marked off to scale, begin on 
 one side of the boiler, as at A, Fig. 145. Place this measuring 
 stick through the front tube sheet, and through the cone flue 
 hole through the back sheet. Make the proper allowance for 
 beading, as at A and B, Fig. 146, on each end, and thus deter- 
 mine the length of the tube for this position. 
 
 We now shift the measuring stick back and forth and get 
 the length of the next tube. Owing to the irregularities whidi 
 there will be in the tube sheet, these lengths will vary some- 
 what, but they can be grouped in sections, each section being 
 marked off, as in Fig. 145, with chalk. After all these tubes 
 have been marked off, it will be found that we will require 
 several batches of tubes. These tubes are then cut to length, 
 those of each batch being kept by themselves. The flues are 
 now put in place and pared out. They must then be expanded 
 with some style of roller expander. The particular form to be 
 used depends upon the success which the particular shop or 
 railroad has had with the different expanders. Expand the 
 tube until it sets firm all around, the copper gasket being by 
 this time about flush with the fire side of the tube sheet. The 
 outer edge is then to be beaded with the regular beading tool. 
 
 In beading over the flue, care must be taken to bring the 
 outer edge up tight against the flue sheet, as otherwise the 
 fire will get in behind the bead and burn out the tube. The 
 excessive high pressure carried by many of the large locomo- 
 tive boilers, together with a forced draft due to the exhaust 
 while running, bring very heavy strain on the flue. The first 
 cost of such a flue is a considerable item, but in some cases 
 it is required, and when the brazing is properly done and a 
 good job is made setting the tubes, the repairs will be con- 
 siderably less. 
 
 Much trouble also arises from the use of poor water. In 
 some localities it is necessary to use muddy water. This mud 
 settles around the tube and thus shuts off the circulation of 
 water. At the same time, the flues, not being in contact with 
 the water, are raised to a higher temperature, thus sooner 
 or later are burned out. In order to get rid of this mud and 
 sediment from the use of hard water, a number of cleaning 
 plugs are placed in the boiler in such a position that they can 
 readily be taken out in order to clean the boiler. Fig. 148 
 shows the front tube sheet, with the tube admitted at A, and 
 in it a brass taper-plug. Holes are also provided on top of the 
 tubes at B. In order that a person can get at these tubes with 
 a hose and wash away the accumulation of mud and dirt, a 
 hole corresponding with A is usually placed in the opposite 
 
102 
 
 LAYING OUT FOR BOILER MAKERS 
 
 tube sheet, depending upon the location where the boiler is 
 to be used. This affords a clear passage through the boiler 
 and enables one to better see the condition of the tubes. It is 
 not infrequent, however, to have a cleaning plug on one 
 sheet and no hole whatever on the other. The sediment set- 
 tles in the lowest part of the boiler; where the fire-bo.x is be- 
 tween the frames, the lowest part of the boiler is around the 
 mud-ring, and it is here that the mud collects sometimes in 
 large quantities. 
 
 In Fig. 149 is shown a blow-ofi cock, which should be placed 
 close to the bottom, as shown at A. The valve portion is 
 usually cone-shaped. Various methods are used for lifting 
 the cone slightly out of its seat while the valve is being turned 
 on or off. When the valve is shut off, further pressure forces 
 the valve down in its seat and thus makes the joint tight in 
 order to resist the heavy boiler pressure. In some localities 
 
 A number of cleaning plugs, Fig. 152, must also be placed 
 on the outside sheet. These should be located in such a po- 
 sition that a hose could be played onto the top of the crown, 
 C. These are particularly important, as the crown sheets are 
 usually very flat, and thus afford a good place for the dirt to 
 lodge, and also the seam should be kept clean, as otherwise 
 the excessive heat will burn away the rivets and sheets at this 
 point. 
 
 Anyone who has any thing to do with the running of a lo- 
 comotive boiler knows the difficulties attending the use of 
 hard or muddy water. The mechanical methods for over- 
 coming these difficulties have been pointed out to some ex- 
 tent. Of course one cannot change water conditions very ma- 
 terially, ar;d therefore the boiler maker is obliged to build a 
 boiler which will meet these difficulties. Another source of 
 considerable annoyance lies in the method of getting the 
 
 cleaning plug S^ pipe tap 
 Fig 148 n Th'dB. per inch Jlg.lbl 
 
 Flg.149 
 
 Eig.i4r 
 
 the accumulation of mud in the water space is so great that 
 this blow-off cock will remove only a certain portion of the 
 mud. That which remains settles to the bottom and becomes 
 hard, which is a cause of the side sheets burning out. In 
 order to remove the mud from the bottom of the water space, 
 cleaning pipes, as shown in Fig. 150, are used. Large holes H 
 are placed in the corners of the fire-box, and through these 
 holes the cleaning pipes are put in position. 
 
 Blow-off cocks are attached at several places, as at B and 
 C. When these cocks are open, the boiler pressure forces the 
 sediment into numerous little holes which have been drilled in 
 the cleaning pipe, and thus the mud, together v/ith the water, 
 is carried away. The holes H are tapped out, and brass taper- 
 plugs are screwed in to close the opening. The pipes must 
 not rest down on the bottom of the mud-ring, but should be 
 supported several inches above the mud-ring, as shown at L, 
 Fig. 151. The bolt B has a taper thread at the taper, and, the 
 body being turned down to about 11-16 inch diameter, four or 
 five form a sufficient support for the pipe for the one side of 
 the fire-box. 
 
 Fig.150 
 
 water into the boiler, and this matter must be carefully 
 studied out by the boiler maker. 
 
 The general arrangement of feed pipes, injectors, etc., is as 
 shown in Fig. 153. The steam for the injector is taken from 
 the dome through a dry pipe D. This pipe must be secured 
 with several wrought-iron strips to the boiler. The upper end 
 E should extend to about the level of the intake of the throt- 
 tle valve. The injector steam valve is connected to the pipe, 
 and from this valve a copper pipe conducts the steam to the 
 injector I, Figs. 153 and 154. The copper pipe is sweated to 
 a brass fitting, F, see Fig. 155. This fitting is screwed onto the 
 injector, and the joint is made steam tight by grinding the 
 joint. 
 
 Be sure that yovir steam pipe has at least as large an open- 
 ing at D as the steam connection on the injector, so that there 
 will be no lack of steam to force the water. Also be sure that 
 the dry pipe D and the injector steam valve S have their 
 smallest openings at least equal to the inside diameter of this 
 pipe. Run a copper pipe C from the injector to the check, K, 
 with a flange similar to Fig. 155 sweated on the pipe at the 
 
HOW TO LAY OUT A LOCOMOTIVE BOILER 
 
 103 
 
 injector. No portion of this pipe must have a smaller open- 
 ing than the delivery end of the injector. Also run a supply 
 pipe R from the injector to the rear end of the boiler and con- 
 nect the same to the hose fitting from the engine to the tender. 
 This pipe is frequently made of copper, but there is a strong 
 tendency toward using iron. 
 
 In order to get the exact length and shape for these pipes, 
 "block up the injector in about the position called for on the 
 erecting card, and line up properly. Now take quarter-inch 
 round iron wire and bend it so as to lay along the desired 
 center line of the pipe. Mark off the length of the pipe to suit 
 the fittings. In a similar way, bend up a piece for the other 
 
 of the boiler, from 20 to 30 inches from the front tube sheet. 
 Of course, there are a number of other things which the lay- 
 out man has to do on the locomotive boiler. There is the 
 necessary steam pipe and valve for the blower for the air pipe, 
 and for heating. Also, he often has more or less with lo- 
 cating the lubricator pipes, sand-box, bell ringer, etc. Most 
 of these latter details are best taken care of when the locomo- 
 tive is well under way in the erecting shop, the exact loca- 
 tion for the various pipes being settled to suit the convenience 
 of the engineer, etc., and also depending upon the ease with 
 which these things can be put together and taken apart. One 
 can judge the general lines of a finished locomotive better by 
 
 Flg.153 
 
 ■pipes. Mark each one of these pieces for the size, class, num- 
 ber, etc., of the boiler. These pipes are then bent to suit 
 these templets and must then be brought to the boiler and 
 tried in position. Any unevenness in the bend, or inaccuracy 
 in shape, can then be corrected. 
 
 The injector check is shown in Fig. 156. This illustration 
 shows a brass flange F, which is riveted to the boiler and 
 ■calked tight around the outside. The check is then attached 
 to this flange by four or six studs, and the connection is se- 
 cured by means of a ground ball joint. The check C lifts up 
 and falls by gravity. The valve is usually provided with sev- 
 eral guides, which are curved like a screw, so that the 
 motion of the water through the valve will rotate the valve, 
 and thus prevent it from seating in the same place every 
 -time. This check should be located along the center line 
 
 placing these things on so that they will look right with the 
 other parts of the locomotive. 
 
 Thus we have completed, in the limited space allotted, the 
 general lay-out of the various sections of the locomotive 
 boiler. Before bringing this series to a close, however, this 
 one thing should be remembered, that no matter how well 
 things may be described or illustrated for the direction of 
 laying out a locomotive boiler, there is still that large ele- 
 ment of judgment, depending upon experience, which will 
 oiftweigh everything else. It is this personal contact with the 
 actual work of laying out which brings to one that knowledge 
 which enables him to meet these various difficulties of error, 
 of inaccuracy, of defective material, and a hundred and one 
 other things which go together to make a good, substantial, 
 and commercially successful locomotive boiler. 
 
104 
 
 LAYING OUT FOR BOILER MAKRHS 
 
 A FLUE AND RETURN TUBULAR MARINE BOILER, II FEET 6 INCHES DIAMETER BY 26 FEET 4 INCHES 
 LONG, EQUIPPED WITH SUPERHEATER 9 FEET 6 INCHES DIAMETER BV ip FEET HIGH; STEAM PRESSURE, SO 
 POUNDS PER SQUARE INCH; HEATING SURFACE, 3,842 SQUARE FEET; GRATE AREA, 92 SQUARE FEET; 
 RATIO, HEATING SURFACE TO GRATE AREA, 41.9 TO I. 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 With boilers as with other things, the tendency of the times 
 has been, and is a survival of the fittest. Of the innumer- 
 able classes and types of boilers for the generation of steam 
 for use in marine installations, none has attained the degree 
 of all-around efficiency and excellency as now represented by 
 a modern and well-designed boiler of the Scotch type. This 
 statement applies to a greater or less extent to boilers for sta- 
 tionary uses, although, for reasons of expense principallv. the 
 
 suggestions on the subject of "laying out" a Scotch boiler of 
 an average size, such as might be used for a modern marine 
 plant. To illustrate, suppose we were asked to design a Scotch 
 boiler from the following data, diameter 12 leet inches in- 
 side ; grate surface, 54 square feet; steam pressure, 175 pounds 
 per square inch. The boiler to furnish steam to a triple ex- 
 pansion engine developing 600 I. H. P. 
 Of course it is necessary to make a drawing the first thing, 
 
 A TYPICAL THREE-rURNACE SCOTCH BOILER. 
 
 This boiler is 13 feet 6 inches diameter by 12 feet long. It is fitted with three Morrison corrugated furnaces connected to one combustion 
 chamber, the total heating surface being 2,925 square feet and the total grate surface, with 6-foot bars, 57 square feet. The boiler is designed 
 for 125 pounds pressure. 
 
 adoption of this type for land purposes has been confined to 
 very narrow limits. Naturally then the designing of the 
 Scotch boiler for use afloat has been given more attention 
 and has reached more nearly that degree of perfection desir- 
 able than has been attained in the designing of this type of 
 boiler for use on shore. 
 
 The writer, therefore, in the limited space and time avail- 
 able for the subject, will endeavor to present a few ideas and 
 
 as the arrangement has to be worked out and the details 
 shown properly, so that a list of all material can be taken ofif 
 and the material ordered. As the plates will be the first ma- 
 terial wanted in the shops, the' order for this can be taken ofif 
 the drawing as soon as the outline is made ; ordering the rivets 
 and tubes next, the drawing can then be finished up so that 
 the stays and braces can be ordered. 
 
 The first thing in making the drawing is to show the out- 
 
io6 
 
 LAYING OUT FOR BOILER MAKERS 
 
 line giving the diameter of sliell ; this as given is 12 feet 
 o inches ; after this we want to arrange for the furnaces ; as 
 we have 54 square feet to furnish, we see that to put tv^o fur- 
 naces in, they would have to be quite large in diameter, so we 
 will arrange for three, making 18 square feet to each furnace; 
 taking out the length of grate of 6 feet (as this is about the 
 maximum length that can be worked efiiciently), we would 
 have a furnace of 36 inches inside diameter. 
 
 ARRANGEMENT OF FURNACES. 
 
 Now we fix the position of the furnaces in the shell, as the 
 diameter is known. Suppose we arrange for a water space 
 between the furnace and shell of 6 inches^ less the thickness of 
 furnace (as from experience this seems to give very good re- 
 sults), this would be 6 inches plus 18 inches (half the diameter 
 of furnace), or 24 inches from the inside of shell to center of 
 furnace ; as the radius of boiler is 6 feet, the center of furnace 
 will be 4 feet from the center of boiler. If the front end of 
 the furnace is made 36 inches inside diameter, there will be 
 sufficient space between it and the shell to turn the two flanges, 
 one for securing head to furnace, and one for securing head to 
 shell, as shown in Fig. i. We have now fixed the position of 
 the middle furnace, the center being 48 inches from the center 
 of boiler; with a pair of dividers, draw .an arc through the 
 center of middle furnace, extend it up on each side, using 
 the center of boiler for a center ; this line will show the dis- 
 tance out for the wing furnaces; now to fix the distance be- 
 tween the furnaces, suppose we made the water space 6 inches 
 from inside of furnace to inside, about' what we had between 
 the furnace and shell; this will give a distance of 42 inches 
 from center to center of furnace. We now measure from the 
 center of middle furnace up 42 inches on each side, and where 
 this crosses the 48-inch radius will.. give us the position of 
 center for wing furnaces. Now we draw in the three fur- 
 naces, that is, the three circles showing the inside diameter of 
 each, 36 inches. The positions of the three furnaces are now 
 located in the end view. 
 
 SIDE ELEVATION. 
 
 We now start on the drawing showing the side view, to fix 
 the length of boiler, furnaces, tubes, etc. 
 
 The length of grate we fixed at 6 feet, and allowing for dead 
 plates, bridge walls, say we arrange for a length of tube of 7 
 feet 3 inches between tube sheets. We then run over it 
 roughly, with this length of tube, to see if we can get the 
 number of tubes in ; to give the proper amount of tube heating 
 surface we want to get a total of about 30 square feet of heating 
 surface to I square foot of grate surface; the tube surface is 
 usually about 80 per cent, of the total surface. In going over 
 this we find that by using tubes of 2j4-inch diameter we can 
 get them in the length between tube sheets to be 7 feet 3 
 inches, so the back tube sheet is drawn in at this distance, as 
 shown on the drawing. 
 
 The next thing is to arrange for the combustion chamber; 
 this should average about 26 inches, between tube sheet and 
 back head of chamber, as this depth in a boiler of this size 
 gives very good results. 
 
 The width of water space back of the combustion box should 
 
 average about ylA inches ; this will give a water space at bottom 
 of 6 inches, and at the top of 9 inches in the clear, which seems 
 to be ample. With the thickness of plates added to these 
 lengths we find that the length of boiler will be about 10 feet 
 3V2 inches. With this length of boiler we can make the shell 
 plate run from head to head in one piece (as plates of this 
 width can be rolled without very much trouble), thus doing 
 away with the middle circumferential seam, which is a con- 
 stant source of trouble, by leaking at the bottom, due to ex- 
 pansion and contraction. 
 
 There is a great difference in temperature between the 
 water in the top and that in the bottom of a Scotch boiler, es- 
 pecially so on first starting fire and getting steam; if the fires 
 are forced to get steam quickl}', when steam has formed, the 
 water in the bottom will be comparatively cold. 
 
 While making the shell plate reach from head to head adds 
 materially to the life of a Scotch boiler, it does not add to 
 the cost and is a much better job throughout. It does away 
 with one long seam, the working under of butt straps and many 
 rivets. 
 
 As we have the length of boiler now, ;we can draw in the 
 outside of each head and shell, connecting the outside of lower 
 heads with the inside of shell plate with a 3J4-inch radius. 
 
 Furnace 
 
 Sheu Plate, 
 
 and the top head with a 2j4-inch radius ; as it is customary to 
 make the top of heads heavier on account of the bracing, we 
 arrange to put the top part of head on the inside of bottom 
 part, as .shown. 
 
 The lower part of heads we will make 54-'nch thick, the back 
 tube sheet 54-'nch tbick, and the combustion chamber plates all 
 9-16-inch thick ; all inside laps should be arranged for single 
 riveting ; the calculations for thickness of plates and the rivet- 
 ing will be shown later, the idea being to have the drawing in 
 outline, and then go over all the calculations when this is 
 finished. 
 
 We have located the position of the back tube sheet, so will 
 draw it in, arranging to turn the top flange down (for top plate 
 of combustion chamber or "wrapper) at a distance from center 
 of boiler of 31'A inches ; this gives a space between top of com- 
 bustion chamber and top of shell of approximately 28 per cent, 
 of the diameter of boiler, which is about as small as can be 
 made with good results ; should it be made any smaller it 
 would decrease the water surface and steam space of boiler. 
 
 We now have the top of combustion chamber located, and 
 the bottom is fixed by the bottom of furnaces, so we can pencil 
 in the back sheet, which is 6 inches in the clear from the back 
 head at bottom and 9 inches in clear at the top; this head is 
 flanged, using a radius of lyi inches. 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 107 
 
io8 
 
 LAYING OUT FOR BOILER MAKERS 
 
 ARRANGEMENT OF TUBES. 
 
 We now have the location of combnstion chamber in the 
 side view of boiler; we will arrange for each furnace to have 
 a separate combustion chamber, so will start to draw them in 
 on the front view of boiler. We draw in the line showing 
 the top 31^ inches up from the center line of boiler, and 
 roughly arrange the tubes to see just where the wide water 
 spaces will be (between the nests of tubes) ; in the center nest, 
 we find that we can get 7 vertical rows, that is, over the middle 
 furnace. 
 
 Over the wing furnaces we find that we can get 10 vertical 
 rows over each ; this will give us 85 tubes in the middle nest 
 and 86 tubes in each wing nest, making a total of 257 tubes. 
 
 The tubes are arranged with a space of i inch between them, 
 vertically, and l^ inches horizontally, making the pitch 3^ 
 inches vertically and 4 inches horizontally. The tubes form- 
 ing the wide water space are spaced 14 inches from center to 
 center; this allows a water space between the plates of com- 
 bustion chambers above furnaces of 6}4 inches, the center of 
 
 Flange on lube Sheet 
 Wrapper 
 
 Lap , showing Tube 
 Sheet drawn down 
 
 Flange on Furnace 
 
 outer rows being 3 5-16 inches from the inside of these plates. 
 The outside of wing chambers is formed by a radius of 6554 
 inches, drawn from a center i]4 inches below center of boiler, 
 as shown, and runs into the back end of furnaces forming a 
 fair curve for the wrapper. By dropping this center below the 
 center of boiler the water space between it and the shell in- 
 creases toward the top and does not reduce the number of 
 tubes. 
 
 Connecting the outside corners to top with a radius of 45/2 
 inches, and the inside corners to top with a 3!/2-inch radius, we 
 have the outline of box as shown. 
 
 The combustion chambers are novir outlined in this view ; 
 the next thing to do is to show in the tubes. 
 
 These we fixed 254 inches in diameter ; from the top of 
 tube-sheet flange we measure 3 7-16 inches down and draw a 
 line parallel to it ; this will be the center line of top row of 
 tubes, and as we have the pitch we can draw in the outline of 
 tubes. 
 
 In arranging tubes in a boiler care should be taken not to 
 place the tubes too near the furnace crowns, as there should 
 
 be a good space over the frrnaces to insure solid water there, 
 when forcing the fires. 
 
 The space between the tubes and furnace crowns should 
 never be less than that shown on drawing above wing fur- 
 naces. 
 
 BACK CONNECTIONS. 
 
 The back ends of furnaces, where they are flanged up to 
 join the tube sheet, are shaped as shown to make a fair line 
 for the outside plate of combustion chamber. As the tube 
 
 FIG. 3. 
 
 sheets are placed between the furnace flange and wrapper, it is 
 scarphed down to a feather edge and the furnace flange bent 
 back to allow it to go in between, as shown in Fig. 2. 
 
 The back end of furnace is flanged up back of tube sheet to 
 keep the flame from striking directly on the calking edge of 
 joint, as it enters the combustion chamber over bridge wall. 
 
 The joints of wrapper or outside plate of combustion cham- 
 ber are arranged, as shown where they lap on the tube sheet 
 and back head of combustion chamber, the inside plate is 
 flanged down to a feather edge, so as not to have a thick body 
 of metal there and to form a good calking edge. Where there 
 are three thicknesses of metal, in combustion chambers es- 
 pecially, one must be drawn down as thin as practicable, as it 
 is hard to keep a joint tight where the temperatures are so 
 high, as in back connections, if the laps are too thick. 
 
 STAY TUBES AND PLAIN TUBES. 
 
 In boilers carrying high pressures it is necessary to make 
 some of the tubes thicker than the ordinary ones ; these are 
 called stay tubes, and are fitted to stay the tube sheets. Stay 
 tubes are fitted in different ways ; some are plain, heavy tubes, 
 some are threaded and fitted with nuts, others are threaded. 
 
 fio. 10 B.W.G. 
 
 !^. Tube Sheet 
 
 ■ FIG. 4. 
 
 the back end having a parallel thread and the front end a 
 taper thread, both raised above the outside diameter of tube, 
 the tube is screwed into the tube sheets, expanded, and the 
 back end beaded over as shown in Fig. 3. 
 
 The plain tubes are generally swelled at the front end ; this 
 necessitates a larger hole in the front tube sheet than that in 
 the back one and permits passing the tube through the front 
 tube sheet into the back one without any trouble in forcing it 
 through. These tubes, after placed in position, are expanded or 
 rolled into the tube sheets, the ends beaded over. (See Fig. 4,) 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 109 
 
110 
 
 LAYING OUT FOR BOILER :MAKERS 
 
 —Smoke boztube obcct 
 
 Inaldc row ottt&jt. 
 SlecUJi'dla. 
 t2 thrcA^e per 1 ioaldc d 
 Nuts '5'. deep 
 
 Outsldo TOKS or aUjs. 
 
 12 tbre&da per 1 Inaldc and oulaldo 
 NuU 1/^0 deep 
 
 15X11 
 FRONT MANHOLE PLftTE 
 
 HALF CROSS-SECTIONS AND DETAILS OF TUBES, MANHOLES AND HANDHOLES OF A MODERN, FOUR-FURNACE, SINGLE-ENDED SCOTCH 
 BOILER, l6 FEET 6 INCHES DIAMETER BY 10 FEET 4 INCHES LONG. 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 III 
 
 LONGITUDINAL SECTION AND DETAILS OF RIVETING AND STAYING OF A MODERN FOUR-FURNACE^ SINGLE-ENDED SCOTCH BOILER, l6 
 
 FEET 6 INCHES DIAMETER BY 10 FEET 4 INCHES LONG. 
 
112 
 
 LAYING OUT FOR BOILER MAKERS 
 
 SHELL PLATES 
 
 Now to fix the thickness of the shell plates, suppose we pro- 
 vide for a tensile strength of 66,000 pounds per square inch. 
 The first thing to do now is to decide on the style of joint to 
 be used. Suppose we settle on a butt joint, using double straps. 
 
 -e- 
 
 -Q- 
 
 ^ 
 
 - -^ ^ -e- -e- 
 -e- ^- -e- ^- 
 
 -e- 
 
 -e- 
 
 ^- 
 
 FIG. 5. 
 
 with three rows of rivets on each side, leaving out ever\' other 
 rivet in the outer rows as shown in Fig. 5. 
 
 The formula for the strength of cylindrical steel shells is as 
 follows : 
 
 CX (T-2)XB 
 
 = IVP 
 
 D 
 C is a constant, and for this style of joint is 20. T is thick- 
 ness of material (shell plate) in sixteenths of an inch. B is 
 
 the least percentage of the strength of joint, of rivet and plate 
 sections, which in this case we have arranged for an 84 per 
 cent, joint. D is the mean diameter of shell in inches ; IVP is 
 the working pressure. Now to transfer the formula to get the 
 thickness of shell, for 175 pounds per square-inch steam pres- 
 sure, we would write it thus — 
 
 175 X 144 
 
 T = 2 + =17 
 
 20 X 84 
 that is 17-16 or i 1-16 inches thick for the shell plate. 
 
 The percentage of strength of joint is found as follows: 
 Where /> — pitch of rivets, d = diameter of rivet, n = num- 
 ber of rivets in the pitch, T = thickness of plate in inches, and 
 where rivets are in double shear 1.75 is used. 
 
 .'Ks we have arranged the riveting for a pitch of 7 1-16 
 inches, and the rivet holes to be drilled, i l-l6 inches diameter, 
 the percentage of strength of joint for plate will be found by 
 the following formula : 
 ip — d) X 100 6X 100 
 
 = per cent. of joint = = 84.9 per cent. 
 
 /, 7.0625 
 
 The percentage of strength of joint for the rivets will be 
 found by the following : 
 
 23 X rf' X .7854 X n X 1.75 
 =^ per cent. = 
 
 28 X /- X r 
 
 23 X 1-1289 X -7854 X 5 X 1-75 
 
 = 84.9 per cent. 
 
 28 X 7-0625 X 1-0625 
 As the rivet material is usually softer than that of the shell. 
 
 COMBL'SIION CH-VMBlikS .ANU FURN.\CES EOK AN EIGIIT-FUKNACE DOUBLE-ENDED BOILER 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 "3 
 
 and subjected to a shearing strain, a ratio of 28 to 23 is taken, 
 making an increase in rivet section over that of the plate ; this 
 ratio, if will be observed, is used in the above formula. 
 
 The factor of safety is found by the following : 
 Tensile strength of shell X thickness of shell X strength of 
 
 stop R vet 
 
 FIG. 6. 
 
 joint per cent, -f- steam pressure in pounds per square inch X 
 radius of shell in inches =^ 
 66,000 X 1.0625 X 849 
 ^ 4.7 factor of safety. 
 
 17s X 73 
 
 BUTT STRAPS. 
 
 The butt straps should be at least ^i times the thickness of 
 the shell plates, and are often made of the same thickness. 
 The straps should be rolled at the mill so that the grain runs 
 the same as the shell plates, as there is enough difference to 
 warrant this. We will make the butt straps in this case }s 
 inch thick, and to extend the full length of the shell on the 
 outside, the inside straps to be drawn down and fitted under 
 the flange of head and shell plate, as shown in Fig. 6. 
 
 A stop rivet, to be fitted at the end of each butt strap, as 
 shown in the sketch, Fig. 6, and on the sketch showing the 
 riveting for butt straps, the hole will be tapped with a fine 
 thread tap and a bolt (special) screwed in and riveted over 
 with a countersink inside and outside, this is used as a 
 stop-water for the butt of the shell plates. There is usually 
 
 Stop^^^vet 
 
 FIG. 7. 
 
 considerable trouble in making the ends of butt straps tight, 
 due to the expansion and contraction of the plates ; the stop 
 rivet seems to help this trouble, although not a sure cure. 
 
 CIRCUMFERENTIAL SEAMS. 
 
 The end or circumferential seams will be double riveted, 
 using I I -16-inch rivets, the holes being drilled to i}/^ inches 
 
 diameter, the center of the holes will be i 13-16 inches from the 
 edge of plates. The distance between the rows of rivets will 
 be I 25-32 inches, center to center. This will make a lap of 
 5 13-32 inches. The pitch will be 3 5-16 inches. This arrange- 
 ment of riveting will be used for securing the upper and lower 
 part of heads to shell plate. 
 
 The rivets for butt straps will be i inch in diameter, the 
 holes drilled l 1-16 inches, the pitch 7 1-16 inches, every other 
 rivet in the outer rows being left out, the spacing of the rows 
 will be, for outside row, i 19-32 inches from edge of plate to 
 center of rivet, from this to center of next row 2 11-16 inches, 
 to the next row i 27-32 inches, and to edge of plate again 
 I 19-32 inches, the same arrangement will be made on the 
 other side of joint, as shown in Fig. 7. 
 
 MANHOLE. 
 
 A manhole plate will be fitted in the shell, as shown on 
 the drawing. This must be located to give ample room for 
 getting in and out of the boiler between the through braces 
 in steam space. The opening cut in shell for manhole will 
 be stiffened by a wrought steel plate 30 inches by 32 inches 
 by I 1-16 inches thick; it will be flanged in and planed off to 
 form a face for the plate to bear on. Care should be taken in 
 
 FIG. 8. 
 
 flanging the metal over to keep the proper thickness for the 
 face for joint, as the metal is likely to stretch and be too 
 thin on the edge if not properly worked. 
 
 The opening in this plate will be 12 inches by 16 inches in 
 the clear, and it will be so arranged that the short diameter 
 will be in the length of boiler, in order to cut out as little as 
 possible of the shell plate, in a fore and aft direction. 
 
 This plate is shaped to fit the inside of shell plate, as shown, 
 being calked on both sides. 
 
 The plate shown is made of wrought steel, being grooved 
 to hold the packing and fit over the fiange of stiffening plate; 
 this style of plate is very good and not hard to make if the 
 proper tools are at hand. The plate bolts are i 3-8 inches in 
 diameter, having collars forged on , as shown, the bolts are 
 screwed into the plate and the ends riveted over into counter- 
 sinks and calked. If an eye-bolt is fitted to the plate between 
 the two bolts, it will be found a great convenience in handling 
 the plate, as it can be held in place, the dogs dropped over 
 and the nuts set up, with very little trouble, as the tendency of 
 the plate to slip from its original position is thus overcome. 
 Plates are not usually fitted with these eye-bolts, but the cost 
 is trifling, as compared to the time and labor otherwise neces- 
 sary when taking the plates off and replacing them. 
 
114 
 
 LAYING OUT FOR BOILER ^^lAKERS 
 
 LOCATING BUTT STRAPS. 
 
 In locating the butt straps for shell, care should be taken 
 to arrange them to clear the seams on head above tubes, and 
 the screw stays, from the combustion chamber tlirough shell 
 on bottom. If it is found that the stays will have to pass 
 through the lower straps, they should be arranged, if possible, 
 to pass through rivet holes, to avoid cutting extra holes in the 
 shell plate. 
 
 The straps, located as shown on this drawing, clears the 
 seams and screw stays too, but it will not always work out so. 
 
 THROUGH STAYS. 
 
 In locating the through stays in steam space, they have to 
 be far enough apart for a person to get between them for 
 cleaning, repairs, examinations, etc. The through stays in 
 this case we have arranged to pass through the heads, wash- 
 ers being riveted to head for each stay, the outside nuts set- 
 ting up on the large washers ; thin nuts and washers will be 
 fitted to the plates on the inside (see Fig. 8). The ends of 
 these stays are to be swelled or upset for the thread. As we 
 
 FIG. g. 
 
 have arranged to make the upper part of heads % inch 
 thick, and to fit ^g-inch thick washers for stays, we can now 
 get the spacing the stays should be from the following form- 
 ula : 
 
 For washers the same thickness as plate and 2-3 the pitch 
 for diameter = 
 Constant X thickness of plate", in sixteenths of an inch. 
 
 Working pressure 
 220 X 196 
 
 ■y' Pitch = =: -y/ 246.4 = 15.7 inches. 
 
 175 
 The constant in this case is 220. 
 
 We find that we can space these stays 15.7 inches from 
 center to center, or call this 155^ inches. 
 
 Taking the top row of stays of the combustion chamber 
 for the back head and the top row of tubes for the front 
 head, we find that we can place the first row of through 
 stays 8'/4 inches above the flange of back sheet or head of 
 combustion chamber, and the next row 155^ inches above 
 this. In spacing them the other way, we have to arrange to 
 suit the tops of combustion chambers, the crown bars and 
 water spaces between the tubes. In arranging them in this 
 
 case, we locate two on the center line, one above the otlier, 
 and 14 inches each side of this we locate two more, then 14J/2 
 inches from these two we locate two more, and 14^^ inches 
 from these we locate one more in the lower row. Now, to 
 find the load on each stay, we find tliat the maximum surface 
 for one stay to support is 14,5 inches by 15.^ inches, making 
 .226.5 square inches, this multiplied by 175 (the steam pres- 
 sure carried) gives a total strain or load of 39,648 pounds, and 
 to arrange for the stress on the stay not to e.xceed 9,000 
 pounds per square inch, we divide 9,000 into 39,648, which 
 gives a result of 4.4 square inches area. 
 
 To give 4.4 square inches area we find that we will have 
 to use a stay 2^4, inches diameter with 8 threads per inch. 
 This diameter need only be at the ends where the thread is 
 cut ; the body of the bolt can be of less diameter, just so that 
 it does not give an area less than 4.4 square inches. Where 
 
 a thread is cut the area is always taken at the bottom of the 
 thread. The body of these bolts we find can be made 2^ 
 inches diameter. 
 
 It is not often that fine threads are cut on these stays, as 
 coarse threads are better. 
 
 A loose washer is usually fitted under the inside nut ; this 
 is counterbored to hold packing, and held up in place by the 
 inside nut, as shown. 
 
 The outside washers we have made ioy2 inches diameter by 
 % inch thick and riveted to the head by six i 1-16 inch rivets, 
 on a pitch circle of 7^ inches. To give space to calk the 
 washers and seams on heads, a portion of the lower outside 
 washers is cut away, as shown on the drawing of the boiler. 
 
 The laps of the .heads are double-riveted, as shown in Fig. 
 9, and located near the tubes in front, and stays at top of 
 combustion chambers in the back head. The top section of 
 heads being on the inside, the lower parts are scarped down 
 at the lap ; for shell, this should be done very carefully, sO 
 that no unnecessary shaping will be required to the shell 
 plates over these laps, as the shell plate should not be heated 
 unless they are annealed after being operated upon. 
 
 The rivets securing the two sections of front head will be 
 arranged to be driven flush on the outside, as this saves con- 
 siderable trouble in fitting the smoke box or uptake, if the 
 stays and nuts are to be outside of the box. 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 "5 
 
ii6 
 
 LAYING OUT FOR BOILER MAKERS 
 
 The upper part of uptake will have to be secured to boiler 
 about over this cross-seam in front head of boiler, and if the 
 rivets are not arranged for and driven flush, considerable 
 trouble is found in making the connection. 
 
 BACK HEAD. 
 
 The wrapper and back heads of combustion chambers are 
 made of plates 9-16 inch thick and single riveted, as shown 
 above. 
 
 This style of joint is used for all the single riveting 
 throughout the boiler. The plates are stayed with i^-inch 
 and lJ4-inch screw stays, 12 threads per inch. (Fig. 10.) 
 
 The ij^-inch, 12-thread stays are fitted all around the edge 
 of back heads of combustion chambers, as these help to stiffen 
 up the wide spaces on back head. 
 
 All the stays on back heads of combustion chambers inside 
 of the row of ij^-inch stays are iJ4-'nch diameter, 12 threads 
 per inch; the stays through the wrappers are also iJ4-inch 
 diameter, 12 threads per inch. 
 
 To divide the space up for stays, we find that they will be 
 spaced about 654 inches by 6J4 inches ; this gives a surface of 
 42.18 square inches, and this multiplied by 175, the steam pres- 
 
 sure carried, will give a strain or load for one stay of 7381.5 
 pounds, which is a strain just over 7,000 pounds per square 
 inch; as the ends of the stays are in the fire, it is well to 
 keep the strain low. 
 
 These stays are tapped through the back head square, and 
 do not require a washer under the nuts. The inside nuts, on 
 account of the angle of plate, will require beveled washers 
 fitted under them, so that they will set up fair. 
 
 Washers should be fitted only where they cannot be 
 avoided, on the fire side, as they only act as a non-conductor, 
 and the liability of the nuts burning is increased. 
 
 The holes for stays are tapped out in place, with a special 
 tap, so that they will be in line, and the thread continuous in 
 both plates. 
 
 The stays are turned down between the plates, as shown, 
 as it is found that corrosion is much more liable to occur at 
 the bottom of the V-shaped threads than it is on cylindrical 
 surfaces. 
 
 After the stays are fitted in place, the plates are calked around 
 each stay, and the nuts screwed up tight. The nuts should 
 be about J4 inch thick, for if too thick there is a chance of 
 their being overheated, and another of starting the thread 
 in the plate when setting up on the nuts. 
 
 The stays should not extend through the nuts, but should 
 
 be just flush with the face of same; if fitted in this way, the 
 nuts can be removed with much less trouble, in case they have 
 to be taken off for repairs. Ordinarily, they would have to be 
 cut off. on account of the stays extending out through the 
 nuts and becoming burned. 
 
 BOILER SADDLES. 
 
 Care should be taken in arranging the boiler saddles to 
 see that the screw stays are not covered up, as it would make 
 repairs troublesome. These stays should not be spaced too 
 far apart, as the plates are liable to bulge between them, 
 especially so on the back head of combustion chamber, where 
 the flame strikes after it passes over the bridge wall. Seams 
 should never be located in this part of the head, as they will 
 always give trouble if the fires are forced much. 
 
 rhe crowns of combustion chambers are usually stiffened 
 by girders, with bolts through them, as shown in the sketch 
 above. 
 
 ORDINARY TYPE OF SADDLE FOR SCOTCH BOILER. 
 
 The girder, as shown above, is made o{ two 5^-1nch plates 
 riveted together, using sockets to keep them apart, and the 
 ends cut to fit the combustion chamber, as shown in Fig. 11. - 
 
 The bolts are tapped through the crown, calked and fitted 
 with nuts on the fire side. The upper ends pass through a 
 spanner, with a nut on top. A socket is placed between the 
 bottom of girder and crown, so that the stays can be set up 
 solidly. 
 
 The inboard and outboard ends of wing combustion cham- 
 bers have an angle stiffener or girder fitted to them, as there 
 is a small area of the plate to be supported, but not enough 
 to require a full girder. 
 
 It is desirable to keep the crowns as clear as possible, so 
 that the plates will be thoroughly protected by the water, and 
 access given for cleaning. 
 
 The bottoms of combustion chambers are stiffened by two 
 angles, 3 inches by 3 inches by 1/2 inch, riveted to the plates 
 and extended up. as shown. 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 117 
 
 ORDERING MATERIAL. 
 
 The next step necessary is to make up the schedule of ma- 
 terial for plates to send ofif to the mill. 
 
 As to the furnaces, they are not made by the boiler builder, 
 so a drawing is made of each, showing exactly what is desired 
 and giving the exact diameter where they are to fit into heads 
 or flanged openings. 
 
 All the work on the boiler can be progressed and arranged 
 to suit the furnaces even if they have not been received. 
 
 The furnace manufacturer is very careful to get the fur- 
 naces just as close to whrst the drawing calls for as it is pos- 
 sible to get them, knowing sometimes that all the work is 
 finished (flanged) ready for the furnaces. 
 
 It is customary for the furnace manufacturer to order the 
 plates for his work, so that the boiler builder does not order 
 this material. 
 
 We will now prepare the list Oi material for the plates of 
 the boiler. The requirements for the material are about as 
 follows : 
 
 The tensile strength of shell plates to be not less than 66, 
 000 pounds per square inch, with an elongation of not less than 
 22 per cent in 8 inches. The elastic limit not to be below 35,- 
 000 pounds. 
 
 The bending test will be made on a piece about 2 inches 
 wide by 12 inches long, cut from each plate ; this test piece 
 must bend cold around a curve, the diameter of which is equal 
 to the thickness of plate, until the sides of the piece are 
 parallel, without showing signs of fracture on the outside of 
 bend. 
 
 The requirements for the material marked "flange and 
 fire-box" are about as follows : 
 
 The tensile strength will be from 52,000 to 58,000 pounds 
 per square inch, with an elongation in 8 inches of not less 
 than 28 per cent. 
 
 The bending test will be made on a piece cut from each 
 plate, about 2 inches wide and 12 inches long; it will be heated 
 to a cherry red and quenched in water about 82 degrees F. 
 The piece must then bend over flat on itself without showing 
 cracks or flaws. 
 
 When ordering plates for boiler work, an additional amount 
 equal to the thickness of plate should be added to each end, 
 and one-half the thickness to each side, as the shearing in- 
 jures the material, and by allowing this margin to be planed 
 ofif in the boiler shop, the damage caused by the shearing is 
 removed. 
 
 LIST OF STEEL PLATES FOR BOILER. 
 
 No. Dimensions. Quality. Purpose. 
 
 2—230" X 117^" X I 1/16" Shell. .Outside shell. 
 
 2- I7H" 
 
 X 
 
 117H" 
 
 X 
 
 y&" ' 
 
 . .Butt straps (shell). 
 
 2- 17/3" 
 
 X 
 
 116" 
 
 X 
 
 %" ' 
 
 • . .Butt straps (shell). 
 
 I— 34" 
 
 X 
 
 30" 
 
 X I 
 
 1/16" ' 
 
 ' ..Manhole stiffening 
 plate (shell). 
 
 I— 17" 
 
 X 
 
 21" 
 
 X 
 
 iV%" ' 
 
 . .Manhole plate (shell). 
 
 24— 11/2" 
 
 
 Diam. 
 
 X 
 
 %" ' 
 
 ..Washers (through 
 braces). 
 
 I— 68" 
 
 X 
 
 39K2" 
 
 X 
 
 J4" ■ 
 
 . .Back tube sheet (mid- 
 dle)! 
 
 No. Dimensions. Quality. Purpose. 
 
 2 — 24" X 51" X 9/16" Shell. .Wrapper comb, cham- 
 ber. 
 
 2 — 26H" X 64" X 9/16" " . .Wrapper comb, cham- 
 ber. 
 
 2 — 27" X iii^" X 9/16" " . .Wrapper comb, cham- 
 ber. 
 
 X ^ "Flange and fire box" 
 Lower part of heads 
 
 X % "Flange and fire boi" 
 Upper part of heads 
 
 X Vie "Flange and fire box 
 Back heads wlHg comb, 
 chambers 
 
 X 9ot> " Flange and fire box" 
 Back head middle comb 
 chamber 
 
 >■ A" 
 
 X % "Flange and 
 fire box" Back 
 ■ ii tube sheets (wing; 
 
 -i - 
 
 I — 24" X 49" X 9/16" Shell. .Wrapper comb, cham- 
 ber. 
 
 I — 27^" X 204" X 9/16" " ..Wrapper comb, cha-m- 
 
 ber. 
 20— 11" X 28H" X ¥&" " ..Girders. 
 
ii8 
 
 LAYING OUT FOR BOILER MAKERS 
 
 This finishes up the plate order, the next step is to prepare 
 the rivet order. 
 
 The requirement for the rivets will be about as follows : 
 
 The rivets lor butt straps to shell will have a tensile strength 
 of not less than 66,000 pounds per square inch, and an elonga- 
 tion of at least 26 per cent in 8 inches. 
 
 Other rivets to have a tensile strength of from 52,000 to 58,- 
 000 pounds per square inch, and an elongation of 29 per cent 
 in 8 inches. 
 
 All rivets to be of open-hearth steel and true to form : 
 
 No. Dimensions. Purpose. 
 
 225 — i" diam. X 4 5/16" long Butt straps (shell). 
 
 70—1"' •■ X S'A" " Manhole stiff, (shell). 
 
 250—1 1/16" " X 3Vs" ■' Head to shell (top). 
 
 350 — I 1/16" " X 3/4" " Head to shell (bottom). 
 
 185 — I 1/16" " X 3 i/i6" " Across heads. 
 
 150 — I 1/16" " X 3 3/16" " Washers on heads. 
 
 490 — 15/16" " X 2j^" " Combustion chambers. 
 
 175 — 15/16" " X 2 5/16" " Furnaces to wrapper. 
 
 225 — 15/16" " X 2 9/16" " Tube sheet to wrapper. 
 
 75 — 15/16" ' X 2}i" " Tube sheet to furnace. 
 
 185 — 15/16" ' X 214" " Furnaces to front head. 
 
 150 — %" ' X 2 0/16" " Angles to heads. 
 
 80 — H" '■ X 2^" " Angles to comb, chamb. 
 
 SO— Vs" ' X 3%" " Girders. 
 
 The practical tests for rivets are: (rivets taken from the keg 
 at random) first one rivet will be flattened out cold under the 
 hammer to a thickness of one-third the diameter, without 
 showing cracks or flaws. 
 
 One to be flattened out hot under the hammer to a thickness 
 of one-fourth the diameter, without showing cracks or flaws, 
 the heat to be about the same as used to drive the rivet. 
 
 One to be bent cold flat on itself without showing cracks or 
 flaws. 
 
 Having completed the list of rivets we will now take up the 
 
 foot, and a thread on the other end fitted with nuts and wash 
 ers for securing to the front head. It is customary for most 
 boiler makers to make these stays themselves, although some 
 have them made outside : if they are made outside, a sketch is 
 sent them to work from. 
 
 We will now make up the schedule for material for the 
 screw stays. As it is customary to order the material for these 
 stays in long lengths, we will order the number of feet required 
 and have it made up from standard bar lengths. 
 
 The threading and cutting to length is done in the boiler 
 shop, the exact length being taken from the work. It is also 
 necessary that the threads at both ends be made continuous. 
 
 The requirements for this material are about as follows : 
 
 The tensile strength to be from 52,000 to 58,000 pounds per 
 square inch, and an elongation in a length of 8 inches of not 
 less than 29 per cent. 
 
 The bending test will be made on a piece Vi inch square, cut 
 from the bars, and must stand being bent double to an inner 
 diameter of lYi inches, after being quenched in water about 
 82° F. from a dark cherry red heat in daylight, without show- 
 ing cracks or flaws. 
 
 105 feet lYi inches diameter in stock lengths. 
 284 feet iJ4 inches diameter in stock lengths. 
 
 As this completes the order for the screw stay material, we 
 will next prepare an order list for the nuts for the screw stays. 
 
 Nuts to be hexagonal, faced square and tapped. 
 200 — T-i/i" tapped 12 threads per inch — 1" thick, 2 3/16" across 
 
 flats. 
 610 — 1I4" tapped 12 threads per inch — Y^" thick, 2" across 
 flats. 
 60 — lY" tapped 12 threads per inch — \Yi" thick. 2" over flats. 
 
 We will now make up the order for the angle stiffeners, the 
 
 No.lO 
 B.W.O. 
 
 --- 
 
 n 
 
 -+-i- 
 
 1 
 
 -:' 5K-'- 
 
 stay Tubes 
 12 threads per iiith. continuous 
 
 2-stays on braces as per sketch 
 -^ 8 threads per inch ^ ^ -^ , _>j 
 
 ??«'i c~.^.iv^^ . 
 
 FIG. 12. — ST.WS OR BR.\CES .\S PER SKETCH. 
 
 braces, screw stays and nuts and prepare the order list. 
 
 The requirements for this material will be about as follows : 
 
 The tensile strength of the through traces will not be less 
 than 66,000 pounds per square inch, and an elongation in 8 
 inches of not less than 22 per cent. 
 
 The bending test will be made on a piece Y2 inch square cut 
 from a bar, and must stand bending double, cold, to an inner 
 diameter oi 1Y2 inches, without showing cracks or flaws. 
 
 The two stays to the crow feet over the middle furnace are 
 •n be of iron with a jaw welded to one end for a pin to crow 
 
 ■■?« 
 
 FIG. 13. 
 
 requirements for these angles will be about the same as that 
 
 for the screw stay material : 
 
 2 — pieces angle zYt" x s" 
 
 2 — 
 2 — 
 
 4— 
 4— 
 
 3/2" 
 
 X S" 
 
 X Yi" 
 
 X 56 
 
 3Y2" 
 
 X 5" 
 
 X Ys" 
 
 X 51' 
 
 2Y2" 
 
 X S" 
 
 X Ys" 
 
 X 75' 
 
 3Y2" 
 
 X 5" 
 
 X Ys" 
 
 X 58' 
 
 3" 
 
 X 3" 
 
 X Y2" 
 
 X 62' 
 
 3" 
 
 X 3" 
 
 X Y2" 
 
 X 30' 
 
 3" 
 
 X 4" 
 
 X Y2" 
 
 X 30 
 
 long. 
 
 It is customary for the boiler maker to make the small wash- 
 ers, crow feet, etc., and to have patterns for manhole and hand- 
 hole plates, dogs, etc., if they are to be castings. The next to 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 IK) 
 
I20 
 
 LAYING OUT FOR BOILER MAKERS 
 
 make up, is the list or order for the tubes. These are to be 
 made of low carbon mild steel and vmiform in quality and 
 grade. 
 
 They will be of seamless, cold-drawn steel, 2-)4 inches out- 
 
 The requirements for these tubes are about as follows : 
 The tubes must be free from surface defects, generally, and 
 of uniform gauge all around. 
 The material must be of such a grade that a tube will stand 
 
 s9ioH3i/it "I'wnii 
 
 side diameter, the ordinary tubes of No. lo B. W. G. in thick- 
 ness. The stay tubes will be 2j4 inches outside diameter of No. 
 6 B. W. G. in thickness. The stay tubes will be threaded at 
 each end, as shown on the accompanying sketch (Fig. 13). 
 
 being flattened by hammering until the sides are brought par- 
 allel with a curve on the outsides at the ends, not greater in 
 diameter than twice the thickness of metal in the tube, with- 
 out showing cracks or fiaws. 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 121 
 
 A piece of tube one inch long will also be required to stand 
 crushing in the direction of its axis, under a hammer until 
 shortened to one-half inch, without showing cracks or flaws. 
 
 The material will be such, that a smooth taper pin (taper 
 one and one-half inch to one foot) can be driven into it until 
 the tube stretches one and one-eighth times its original 
 diameter without showing signs of cracks or flaws. This 
 test to be on a cold tube. 
 
 A tube heated to a cherry-red in daylight must stand, with- 
 out showing cracks, having a smooth taper pin (taper one and 
 one-half inches to one foot, the pin to be heated to dull-red 
 heat) driven into it, until it stretches to one and one-quarter 
 times its original diameter. 
 
 As the furnace fronts, doors and front linings are to be 
 of wrought steel, we will prepare the order for this material, 
 so that it will be delivered with the other plates. 
 
 It is not customary to specify any test for such material. 
 The furnace fronts are secured to the ends of the furnaces by 
 tee-headed bolts, riveted to the furnaces. A sketch, showing 
 this arrangement in detail, will be given later, the idea at 
 this time being to get the order for materials off with the other 
 orders. 
 
 Plate order for furnace fronts, doors, etc. : 
 
 X }i Thick, Furnace fronts 
 
 X 34 Thick, Front linings 
 
 X M Thick, Fumaoe doors 
 
 X */io Thick, Ash pan doors 
 
 The small fittings, such as door-hinges, catches, latches, 
 stiffeners and lazy bars we will make from stock in the boiler 
 shop, as they are usually made up in this way. 
 
 The next chapter will be devoted to the laying out of the 
 plates, after they have been delivered at the boiler shop ; also 
 to the planing, flanging and drilling of same. 
 
 CHAPTER n. 
 
 In the last chapter we made up the list of material required 
 for the construction of the boiler. 
 
 In this issue we will assume that all the material has been 
 delivered at the boiler shops, and will take up the work in 
 order, arranging for the laying out, flanging, drilling, rivet- 
 ing, etc. 
 
 We will take for granted that all the material has been in- 
 spected and tested, and that it passed all the requirements, 
 therefore work can be started on it as soon as received at 
 the shop. 
 
 SHELL PLATES. 
 
 The first work to take up will be to lay off the shell plates ; 
 there being two plates forming the shell, secured together at 
 the butts or longitudinal seams by double butt straps, treble 
 riveted. 
 
 These plates will be taken up now and laid off for planing 
 and drilling — thus : 
 
 The two plates are laid off first to the exact size to which 
 they are to be planed, lines drawn and marked with center 
 punch marks, as the lines are rubbed off in handling the plates, 
 and with the center punch marks there the lines can be readily 
 located when the plates are placed on the planer for planing. 
 
 The edges marked "back and front end" are planed to a 
 slight bevel for a calking edge between heads and shell. Next 
 the rivet holes are laid on these edges ; the edges for the 
 butts have a few holes marked off, the number being left to 
 the boiler maker, as these are only used for tack bolts to se- 
 cure the butt straps and shell together for drilling. The 
 tack bolt holes are laid off so they will come in a rivet hole in 
 the joint. 
 
 One piece of shell is to have a manhole through it, and rivet 
 holes for rivets in securing the manhole stiffening plate. The 
 opening for manhole is laid off to be drilled out ; the holes are 
 laid off so as to have a space between each hole, which is 
 caped through to form the shell. After the butts are riveted 
 this piece is removed by caping the metal left between each 
 hole; the edge is then chipped fair and usually arranged for a 
 calking edge. 
 
 After the plates are all layed off, the center of each hole is 
 marked with a center punch ; the plates are then taken to the 
 drill and the holes are drilled through the plates. 
 
 In laying off the riveting, care should be taken in dividing 
 up the space ; the length of the seam should be figured first, 
 and then divided up so as to make the pitch of rivets work 
 out right. In drilling the rivet holes care should be taken to 
 see that the drill follows through the plate straight and does 
 not work off to one side as it goes through. After the plates 
 are drilled, all burrs are removed before rolling is commenced. 
 
 All the holes for machine-driven rivets are drilled parallel 
 (with a slight counterbore just a little more than sufficient to 
 remove the burr). The holes for the hand-driven rivets are 
 counterbored to a depth usually about three quarters through 
 the plate. In the shell all the rivets securing it to the front 
 head will be drilled for hand driven rivets. 
 
 Now we will suppose the shell plates are drilled ; they are 
 next sent to the rolls and rolled to the proper radius to form 
 
122 
 
 LAYING OUT FOR BOILER MAKERS 
 
 the shell, usuallj' a template being made to which the plates 
 are rolled. The outside butt straps are now laid off, marking 
 the edges for planing and the center of rivet holes therein. 
 
 The straps are shaped to fit the shell plates, edges planed, 
 and rivet holes drilled, the ends of inside butt straps are 
 scraped down to a feather edge to go under the lap of shell 
 and heads, the end to e.xtend into the lap just past the first 
 row of rivets and tack bolt holes laid off to suit those in 
 shell plates. After this is done the two shell plates are put 
 on end and secured with bolts passing through the butt straps 
 and the tack bolt holes in shell and the bolts set up tight. The 
 shell plates and inside butt straps are then drilled in place 
 through the outside butt straps, care being taken to see that 
 the straps are properly fitted before drilling. The piece of 
 plate in the manhole is now removed, the edge being chipped 
 for a calking edge. 
 
 The manhole stiffening plate is then laid off, shaped, flanged 
 and edges planed ; it is then annealed, after which it is put 
 in place (after facing for manhole plate) and a few holes 
 
 lilted. To do the work as shown here the plates would have 
 clips bolted to them, so as to locate a center pin for them to 
 swing on (as the flanging is on a radius) a proper height and 
 shaped form fitted to the flanging machine, the plate fitted 
 properly so that it will swing around the cast-iron form ; after 
 this everything is ready for heating. The plate is heated 
 along the edge to be flanged (about three feet in length) and 
 located on the form so as to swing properly under the flang- 
 ing machine, the outside ram is lowered on the plate' to hold 
 it in position, the second ram is then lowered and turns the 
 flange, and the horizontal one squares it up so that the flange 
 is square and true to form. 
 
 The plate is moved around on the center pin as the flang- 
 ing is done. 
 
 The holes in the front head for securing furnaces are usu- 
 ally drilled out, the edge chipped and the flange made by 
 forcing a large punch through the head, a dye being under the 
 plate. The punch is secured to the two vertical plungers of 
 tlie flanging machine. The man and hand holes are put in the 
 
 A THREE-FUEN.\CE DOUBLE-ENDED BOILER. 
 
 marked off and drilled for tack bolts. This plate is then bolted 
 to the shell plate and drilled in place from the holes in shell, 
 it is then machine-riveted and calked, the back head of boiler 
 will be machine riveted to the shell, the front head will be 
 hand-riveted to shell. 
 
 FRONT AND BACK HEADS. 
 
 Now that the shell is all riveted up ready to receive the 
 other parts, we will ne.\t take up the heads. The laying off 
 will be as shown by sketch. 
 
 The plates forming the heads are laid off first, showing the 
 flanging circle and the amount to be planed from edges for 
 joint across heads. The next thing for back head is to lay off 
 the centers for screw stays, braces and stiffeners, rivet holes 
 for washers of through braces and seams. 
 
 The front head will be the centers of tubes, furnaces, man 
 and manhole plates, stays, stiffeners and rivets. 
 
 The flanging is usually done by machinery; the work as 
 shown here is done with a hydraulic flanging machine. This 
 machine has three plungers or rams, two vertical and one 
 horizontal. 
 
 They are arranged so tha*. different shaped heads can be 
 
 same as stated above for the furnaces. The corners of all 
 flange plates are usually finished by hand, as the metal can 
 be gathered in or upset much better. 
 
 All edges are planed after the flanging is done. Only one 
 sketch showing the top of head is necessary, as they are both 
 alike. 
 
 TUBE SHEETS. 
 
 The tube sheets will be ne.xt in order. 
 
 The tube sheets are laid off as shown in the sketches ; the 
 outside marks are the flanging marks ; the lower ends are for 
 joints to furnaces: the centers for holes for tubes and braces 
 are also marked. In this case the rivet holes for securing 
 furnaces to tube sheets are first drilled in furnace flange, and 
 the tube sheets fitted to them and drilled through in place. 
 The holes for tubes are first drilled with a three-quarter or 
 one inch drill ; this hole is used for a center to steady the cut- 
 ter used in cutting the proper diameter out of plate for tube. 
 This cutter is made from a flat bar, the lower end made to 
 suit the hole drilled in plate (or rather the hole made to suit 
 the cutter) and a cutter extending out far enough to make the 
 proper diameter for tube ; sometimes there is a cutter on each 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 123 
 
 \^-!,n-- 
 
 <--«sz---J 
 
124 
 
 LAYING OUT FOR BOILER MAKERS 
 
 side, tliat is, two cutters on ore bar (one opposite the other). 
 The upper end of this bar is 'made to suit the chuck in drill- 
 press. The cutter is lowered into a hole to steady it, and as 
 the feed is put on, the cutter goes through the plate, taking 
 out the metal in the shape of a washer. The tube holes are 
 chambered or counterbored on the outside where the tubes are 
 headed over. The stay-tube holes in this case are threaded ; 
 to have the thread continuous in the two plates (back and 
 front), they will have to be tapped in place. 
 
 B.-kCK HE.^DS OF COMBUSTION CHAMBERS. 
 
 The back heads of combustion chambers will be taken up 
 next. 
 
 They are laid out as shown, showing where they are to be 
 flanged, and a cross and center punch mark to show where 
 they are to be drilled for screw stays to pass through. 
 
 The edges are all chipped after the flanging is done, As 
 this finishes up all the flanging we will take up the annealing. 
 After the plates are flanged they are placed in a furnace and 
 iieated all over uniformly, as in local heating and flanging, 
 there are stresses and strains set up at different places in the 
 plates, and in heating the entire plate the metal becomes soft 
 and the strains are reduced and adjusted to a great extent. 
 The plate is then removed from the furnace and is straight- 
 ened and shaped up, then allowed to cool off gradually and 
 uniformly. The plates should not be worked in the fire again 
 after the annealing. All the work should be done before the 
 annealing, that is, the scraping, flanging, in fact all work that 
 has to be done at the fire. 
 
 In cases with plates like the lower front head, where there 
 is so much flanging, it is usually flanged around the edge for 
 the shell and the manholes and handholes flanged, then the 
 plate is taken back and annealed. After it is annealed it is 
 brought back again and the flanges for the furnaces turned ; 
 then it is reannealed. In a plate like this the strains set up 
 are enough to crack the plate at times and the risk is not 
 usually taken, without annealing twice, as stated above. 
 
 The two pieces of back head are now put together and ad- 
 justed to their proper places, and the holes for rivets in seam 
 across head drilled, the plates being held together by tack 
 Dolts. 
 
 •'All the edges being planed and chipped for caulking edges, 
 the burrs are removed from each side of the holes, just a 
 slight counterbore. 
 
 The plate is drilled for all stays (care being taken to get the 
 right size drill for the screw stay-holes, as these have to be 
 reamed and tapped in place). The two pieces of heads are 
 ne.xt riveted together by machine-driven rivets; the stiffeners 
 and washer rivets are driven in the same way. The back 
 head is now ready to fit into the shell, locating it in the proper 
 place with a few tack bolts. The holes in head (for joint of 
 head to shell) are drilled through the holes in shell, thus 
 making fair holes for all rivets. This head is usually fitted in 
 place first, machine-riveted to the shell, this being found by 
 experience to be the better way. 
 
 The front head is fitted in the same way, secured into the 
 shell and the rivet holes in head drilled through the shell to 
 
 make fair holes. After this is done the head is removed to 
 allow the combustion chambers, furnaces, etc., to be fitted in 
 place. 
 
 WR.^PPER PLATES. 
 
 The next to lay out are the wrapper plates for the com- 
 bustion chambers. 
 
 The plates for the center combustion chamber wrapper are 
 shown by sketches below. 
 
 These plates are laid out, edges planed and corners scraped 
 at laps, drilled for rivets and screw stays and shaped in rolls 
 
 Outside Lines" are Size of* 
 
 TOP PART OF HEAT) 
 
 plate s as ordei-ed from MillK-^14^-12^ ^g^^ glretch for Riveting 
 
 LOWER FRONT HE.A.D, 
 rOutsifle Lines axe Size of L q. a^^ ^ ,^, ,(i 
 Plates as ordered from Mill r-'^'i '^BM*: 
 
 Sketch for Riv eting 
 
 Flange Line 
 
 LOWER BACK HEAD " 
 LAYOUT OF FRONT AND BACK HEADS. 
 
 to suit the shape of the box to which they are connected; they 
 are fitted in place and secured with tack bolts, and the flange 
 plates are drilled through the holes in the wrapper plates, 
 -A-ll the riveting in the combustion chambers should be ar- 
 ranged for countersunk rivets, that is, to have about one-half 
 of the length of head of rivet countersunk, and the other half 
 the cone-shaped head. This gives a better chance to caulk 
 when necessary, and there is something to hold the plates to- 
 gether if the heads burn off. 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 125 
 
 The next are the wrapper plates lor the wing combustion 
 chambers (wing boxes). 
 
 These plates are shaped and fitted in the same manner as ex- 
 plained above for the wrapper plates for center combustion 
 box. The manhole plate stiffeners, the crown bars, washers, 
 etc., are minor details and will not be taken up. as they are 
 shown clear and in full on the drawing of boiler. 
 
 When the back connections are all riveted and caulked, the 
 furnaces fitted and riveted, they are fitted into the shell and 
 blocked to their proper position, the front head fitted in place 
 and riveted up. The rivet holes in flange of front head for 
 furnaces are drilled in place through the holes in furnace. 
 
 The length of screw stays is next taken and the screw stays 
 made and screwed into place. The metal is calked around 
 each stay on both sides, that is, on the outside of shell and on 
 the inside of combustion chamber plate. After the plate is 
 caulked around the stays, nuts (and washers if necessary) are 
 fitted and set up tight. 
 
 The braces, crown bars and tubes are next fitted. The next 
 chapter will take up furnace fronts, bearers, bridge walls, 
 grate bars, uptakes, etc. 
 
 FURNACE FITTINGS, ETC. 
 
 The fronts are usually made of wrought steel plates, secured 
 to the furnaces by studs (special) riveted to furnace, as shown 
 in Fig. 14. 
 
 The fronts thus secured, the front bearer bar, or dead plate, 
 is secured to them. The door frames are of cast iron, form- 
 ing a distance piece between the front plate and the lining, and 
 are made in three pieces for convenience in making repairs, 
 the center piece being the width of the fire-door opening; 
 this is 4^/2 inches deep. The lining is of wrought steel plate, 
 bolted through the frame and front, the heads of bolts being 
 
 The front bearer is of cast iron and shaped as shown ; it is 
 secured to the furnace front and frame, and is beveled to 
 receive the grate bars. 
 
 The grate bars are in two lengths, supported by two bearer 
 bars in center; these bearer bars are supported by two half- 
 round bars, made to fit in the corrugations, so that they will 
 not extend above them and interfere with the ash pan. The 
 upper ends are bent in and tied together by wrought steel 
 •plates ; these plates are notched to receive the bearer bars, 
 which are 3 inches by 54 inch, and let into the side plates so 
 as to support the ends of grate bars at the center of the 
 furnace. 
 
 The back bearer is formed by one casting, supported by 
 
 /T\ Fuini 
 
 I 
 
 
 
 
 1 
 
 u 
 
 ill 
 
 9 
 
 1 
 
 IK 
 
 T 
 
 
 
 ■—i}i^ 
 
 
 ( 
 
 ii 
 
 V-- 
 
 
 k 
 
 
 
 -\ 
 
 a- 
 
 
 ' For X Rivet 
 
 FIG. 14. 
 
 half-round saddles in the same manner as the middle bearers, 
 except that the supports are secured to the bearer direct, 
 flanges being cast on bearer for that purpose. 
 
 This casting is shaped so that a shelf is provided for the 
 bricks to rest on in building the bridge wall. 
 
 The bridge Avail is built up of brick and fireclay, the top 
 being crowned, allowing a clear opening over it of about 16 
 
 ARRANGEMENT OF FURNACE FITTINGS. 
 
 placed inside and the nuts outside, as the nuts should be kept 
 away from the fire. If the nuts were placed inside it would 
 be difficult to remove them for repairs, due to the threads being 
 burned. The fronts and linings are each in one piece, the 
 frame in three pieces. 
 
 The doors are of wrought steel, 3-16 inch thick, flanged and 
 drilled for air holes, slice bar door, sagging bolt from upper 
 hinge and latch for holding door open when firing the furnace. 
 The door is fitted with a cast iron lining, the lining having 
 sockets cast on it, through which the bolts pass ; the heads of 
 bolts are recessed into lining to keep them out of the fire as 
 much as possible. 
 
 The arrangement of door is shown in detail on drawing. 
 
 per cent, of the grate surface. With this area over bridge wall 
 there will be no trouble and the boiler will steam well. 
 
 With this arrangement of furnace fittings it will be noticed 
 that there are no fastenings into the plates or into steam or 
 water space, and, therefore, no chance for leaks around fas- 
 tenings. 
 
 Sometimes a plate is fitted to extend from the back end of 
 bridge wall to the back plate of combustion chamber on a 
 line with the grate bars. This plate is then covered with fire- 
 brick. If a plate is fitted in this way, care should be taken to 
 give clearance all around the edge of same, to allow it to 
 expand when fires are started. 
 
 Oftentimes a firebrick lining is built upon this base to ex- 
 
126 
 
 LAYING OUT FOR BOILER MAKERS 
 
 cend up the back head of combustion chamber to a height just 
 above the top of furnaces, so that the flame does not strike 
 direct on the plate as it passes over the bridge wall. 
 
 The brick lining fitted in this way should be the depth of the 
 screw-stay nuts away from the plate, leaving an air space 
 between the bricks and plate. 
 
 The arrangement as shown here is with a vertical plate from 
 the bridge wall down to bottom of furnace. With this ar- 
 rangement it is customary to fit a door in the plate at its 
 lower edge, so that the soot can be hauled out of the back con- 
 nection into the ash pan with a hoe ; the door must be made 
 to be handled from the fire room. 
 
 With this arrangement, as one will see, a much larger com- 
 bustion chamber, or a larger volume, is maintained, which 
 
 Two wrought iron bars, 2 inches by .;-^ inch, are shaped up 
 and secured to the front bearer, or dead plate, to support a lazy 
 bar. the bar to be iJ4 inches diameter, as shown on the 
 drawing. 
 
 The grate bars are in two lengths, 3^^ inches deep at middle 
 and 2->^ inches deep at ends ; they are ^ inch thick at top 
 with 5^2 inch air space, and are J4 i"ch thick at bottom in the 
 middle. 
 
 The side bars are made to suit the corrugations. The bars 
 are made double, although it is customary to carry some single 
 bars. 
 
 UPT.^KES. 
 
 Taking up the subject of uptakes, we have arranged for an 
 inner smoke pipe of 43 inches diameter, and an outer pipe, or 
 
 :K « 2« i % 
 
 ARR-\NGEMENT OF UPTAKES. 
 
 will result in a decided increase in the efficiency of the boiler 
 for making steam. 
 
 To form a smooth bottom for ash pan a ^ij-inch plate is 
 rolled to fit the bottom of furnace on top of the corrugations; 
 the top edges of this plate are shaped to fit the corrugations 
 on each side, as shown. This plate will extend the entire 
 length of the furnace, and can be readily removed. Sometimes 
 with this style of bridge wall and plate, bricks are built up 
 in the combustion chamber back of the vertical plate from the 
 bottom of furnace to top of bridge wall ; in this way the flame 
 does not touch the metal. This brick wall is very advantageous, 
 especially if the boilers are to be forced. The ash-part doors 
 are of 3-16-inch sheet steel, shaped as shown : theyare stiffened 
 up with f^-inch half-round bars, riveted all around the edge. 
 They are fitted with trunions and handles, and are often fitted 
 with cleats on the back for hanging up when not in place on 
 the furnaces. If they are thrown around the fire room floor 
 they soon get out of shape, therefore should be hung up when 
 not in use. 
 
 casing, of 52 inches diameter, giving an air space of 4^4 inches 
 between the two pipes. 
 
 The uptake is made square on top, a square plate riveted to 
 an angle-bar frame, the angle on the smoke pipe is on the out- 
 side, and will secure through the plate and angle at four points 
 and the plate only between these points. This makes very 
 easy construction for securing the pipe and also for making the 
 top of uptake. 
 
 The margin angle secured to the front of boiler for uptake 
 is a 2>4-inch by 2'/2-inch by a-^-inch angle in two lengths, the 
 joint being at center on bottom of uptake. This angle is 
 ofifset to suit the Z-bars and then extends up parallel with the 
 h.ead of boiler to top of uptake. The Z-bar is secured to the 
 front head of boiler, as shown on drawing. 
 
 In arranging the uptake the flame does not strike the front 
 head at steam space or the nuts for through braces. After the 
 angles and Z-bar are secured to the boiler the bottom plate 
 of uptake is then secured in place ; this usually has the margin 
 angles secured to it; these angles are 2j4 inches by 254 inches 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 127 
 
 by 54 inch in two lengtlis. the tcp ends being held in place l)y 
 c5races until the plates are secured. The bottom plate of up- 
 take is made of ;4-inch steel plate. The top plate is made 
 of the same thickness and material, all the otiier plates of 
 the box proper are made of No. S B. W. G. steel. 
 
 inches by 5-16 inch, is fitted from side to side; this angle also 
 makes a landing for the upper edge of doors. 
 
 To form a landing for the inboard edge of the outside door 
 and the sides of the middle door, T-bars are fitted 45^ inches 
 by 2'/< inches by }i inch, secured to the 3-inch by 2-inch by 
 
 The outside lining, or casing, is made of sheet iron or steel. 
 No. II B. W. G. in thickness; the casing, or lining, is set off 
 from the box proper 2y2 inches, bolts and sockets being 
 used, with heads on the inside ; the spacing of these bolts 
 is shown on the drawing. These bolts are ^4 inch in 
 diameter. 
 
 To stiffen the front of uptake an angle-bar, 3 inches by 2 
 
 5-16 inch angle-bar and extending down and secured to the 
 2j4-inch by 2j4-inch by J4-inch angle-bar at bottom; they are 
 offset at each angle, so as to be flush with the other angles, to 
 form a good face for the door to close tight. 
 
 Two T-bar stiffeners are fitted to upper part of, uptake, one 
 at front from the 3-inch by 2-inch by 5-16-inch angle to top of 
 uptake, and one at back from Z-bar to top of uptake. 
 
128 
 
 LAYING OUT FOR BOILER MAKERS 
 
 The doors are fitted with long strap hinges, which are also 
 used as stiffeners, Fig. 15. Each door is fitted with five lever 
 catches for securing it in place : catches made as shown in 
 Fig. 16. 
 
 Each door is also fitted with a ring bolt for holding the door 
 up when working in smoke-box. The ring bolt is fitted through 
 both plates, with a nut on the inside and a socket between the 
 plates. 
 
 Sometimes the air space around uptake, as shown here, is 
 filled with carbonate of magnesia, asbestos, or other non- 
 conducting material : where this space is to be filled in, the 
 openings at edge and ends are arranged to be closed so that the 
 non-conducting material cannot drop out. 
 
 Another style is to have a space of about 2 inches filled in 
 with a non-conducting material, and 2 or 3 inches outside of 
 this to have another casing or lining; in this arrangement 
 there are three sets of plates, or three separate casings for the 
 uptakes. This makes a first-class uptake, and adds materially 
 to the comfort of those in the fire room, making it cooler, 
 which means much in some cases. It adds considerable to the 
 cost, as an uptake with three casings is very much more ex- 
 pensive to construct. 
 
 Dampers are sometimes fitted in uptakes, but usually for 
 one boiler it is customary to fit a damper in the stack above 
 the uptake. 
 
 Now, as to laying off the plates for the uptake. The top 
 plate will be 48 inches square, with a 43-inch hole in it, so we 
 will not bother with making a sketch of this plate. 
 
 The side plates of outside casing will be made in one plate 
 for each side, from top of uptake to bottom, as shown on front 
 view of uptake drawing. 
 
 First, we will start and step off any number of spaces, say 
 4 inches apart in this case, starting at the top (front view) and 
 step all the way down to the bottom of plate, as in this view 
 we can get the full length of plate ; after we have stepped 
 off all the spaces we project them over to the side view. Now 
 we extend a line up to top of uptake, just fair with the outside 
 
 Z\W3 
 
 fffe- 
 
 Bolt or Rivet with P in in End. 
 
 FIG. IS. 
 
 of lower part of front head. After this is done take a stick 
 long enough to reach the longest measurement, start at the top 
 of box and mark off all the lengths on lines projected over 
 from front view. After all these lengths have been marked 
 off on the stick, two lines are laid off on the plate (as A. B. C. 
 on sketch) ; lay the stick on each line (the lines having been 
 laid off on plate 4 inches apart) and mark the exact length on 
 tach line; after this has been done bend a batten through all 
 the points and draw the line ; this gives the line to which the 
 plate is to be sheared. The holes for socket bolts and rivets 
 arc next laid off. After all marks are fixed with center-punch 
 
 marks, the plate is sheared to size and holes punched. It is 
 then shaped to the work or angles of uptake. 
 
 Sometimes the rivet holes are not put in until the plate is 
 shaped and clamped in place and holes marked off from angles. 
 This finishes the outside sheets at side, one right and one left; 
 they are both laid out from one template, the right and left 
 being made by the bending or shaping. 
 
 The side sheets for the inner casing are laid out in exactly 
 the same way, but these will have to join the bottom plate, so 
 
 as to close the space entirely; the joint, or seam, is just above 
 the radius at lower corners. These plates are rights and lefts 
 after they are bent the same as the outside plates. 
 
 The outside front plate at top is measured off on the side 
 view to get the true length ; the widths are taken from the 
 front view and the spots joined, forming a radius at top with 
 side lines. 
 
 The inside top plate front is laid off just the same as the 
 outside plate ; this laps the angle at top of uptake and extends 
 down to the 3-inch by 2-inch by 5-16-inch angle across the 
 front of box: it laps 154 inches on this angle, leaving 54 i"ch 
 lap for the door plate to rest on. 
 
 The back plate and lining can be taken from the front view, 
 as the exact shape of each is shown there. 
 
 The bottom plate, or bottom of uptake, will be taken up next. 
 First, start at center of box, on bottom (front view), step off 
 any number spaces all the way around to the joint at corner. 
 In this case we have taken 4-inch spaces. We need only laj' 
 out one-half of this plate, as both sides are the same; after 
 one-half is laid out we can use it as a pattern for the other 
 side. After spacing the 4-inch distances they are projected to 
 the side view, and the distance from the face of boiler out to 
 each spot will be the length or width of plate at that point. 
 Now, get these distances on a stick or batten, lay off the 4-inch 
 spaces on the plate, and from one square edge mark off die 
 neat length on each line taken from the stick ; after all the 
 spots are marked on the plate a batten is bent around and a 
 line drawn through all the spots. This will give the shape the 
 plate is to be sheared to. 
 
 The doors and door linings are next. The exact lengths arc 
 taken from the side views. The shape of the bottom edge is 
 given by setting off .spaces on the front view and projecting 
 them over to the side view, and measuring up on the slant 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 129 
 
 height from those spots. The door lining and casing above 
 hinges are left open, or a space given so that they will not 
 foul when the doors are swung open. The lever catches for 
 securing the doors in place are made to pass through both 
 casings, and secured by clamping angles and T-bars, as shown. 
 
 BOILER MOUNTINGS. 
 
 The designing of a Scotch boiler is thoroughly understood 
 by most engineers, although at times the arrangement, loca- 
 tion and manner of securing the fittings to the best advantage 
 are lost sight of, and after the boiler is placed in the vessel 
 some of the valves are in positions that are inaccessible, and 
 for this reason are not properly looked after. 
 
 The greatest amount of thought and care should be taken 
 with each valve to locate it where it can be readily reached, 
 and so that it can be properly overhauled and repaired when 
 necessary. 
 
 The valves that are generally lost sight of and placed in 
 inaccessible places are the surface and bottom blow valves 
 and the drain valve or cock. These valves are generally placed 
 on the shell, the bottom blow valve somewhere on the bot- 
 tom of boiler; this space is necessarily cramped, as there is 
 usually very little space between the bottom of boiler and 
 bottom of vessel or the coal bunker bulkhead. Taking, for 
 example, a vessel with only one boiler. The bunker bulk- 
 heads are usually located as near the boiler as possible to 
 gain the greatest amount of coal capacity. There is also lo- 
 cated in this space the boiler saddles, and in most cases 
 braces for securing the boiler from displacement in a fore 
 and aft direction, and the ash guards in front of the boiler to 
 keep the ashes out of the bilge, so that by the time all these 
 are located there is very little space left, and in some cases 
 there is not enough room for a man to get in to operate these 
 valves and they are fitted with extension stems or handles so 
 they can be operated from the fire room. The space over the 
 boiler is usually covered with some sort of a deck in the 
 deck house to utilize all the space available ; if the space does 
 not permit of headroom it is turned into locker room. 
 
 The boiler is almost completely covered in, and in some cases 
 there is only enough of the boiler extending from under this 
 deck upon which to get the steam connections. The surface 
 blow valve is usually located under this deck, in a very inac- 
 cessible position. With this kind of an installation the boiler 
 is very hard to take care of and in many cases is almost in- 
 accessible. Repairs are necessary on all boilers, and bills for 
 such are just as certain as the boiler is to generate steam, and 
 when the repairs are necessary the extra time necessitated by 
 working in cramped places means extra expense; very often 
 the space is too cramped to make a thoroughly good job and 
 a temporary job is made, which has to be remade over and 
 over again. In installing a boiler in a vessel it is well to give 
 sufficient room to get at all parts of the boiler so that it can 
 be taken care of regularly, and in doing this the repair bills 
 are cut down to a minimum. 
 
 The main steam-stop valve, the safety valve and the auxil- 
 iary steam-stop valve should be located on one nozzle, 
 branches being made on the nozzle for each ; with this arrange- 
 
 ment only one hole in the shell is necessary, thus saving time 
 and expense in fitting e.xtra flanges to the curved surface of 
 the shell, as these have to be chipped, scraped and fitted by 
 hand, whereas if they are secured to the casting, all the flanges 
 are faced by machine, thus taking much less time in fitting 
 up and making the joints. In using the nozzle another advan- 
 tage is that the shell is not weakened by cutting several holes 
 through it unnecessarily. 
 
 The dry pipe is usually a copper pipe (generally tinned in- 
 side and outside), secured in the highest part of the steam 
 space; the top of the pipe is perforated with small holes or 
 has saw-slots across it : the combined area through these 
 holes or slots should be the same as the area through the 
 casting — that is, equivalent to the area of main auxiliary 
 steam pipe. If the outlet is on the shell it can be located 
 anywhere in a fore and aft direction, according to the avail- 
 able space, although not too near to the end of the shell 
 plate as the tendency is to weaken the plate by being too near 
 the edge. 
 
 The branch on the dry pipe has a flange secured to it of 
 about the same diameter as the flange on the nozzle ; this 
 flange sometimes has a spigot end on it to pass through the 
 shell plate and just enter the nozzle, in this way covering the 
 two joints and also the shell plate in the steam passage. The 
 ends of the dry pipe are closed with solid discs and the pipe 
 is secured to the shell with steel bands or straps shaped to 
 the pipe and secured to the shell by tap bolts (the holes for 
 bolts not to be drilled through the plate), sometimes a small 
 hole is drilled in the bottom of pipe at the lowest point, to be 
 used as a drain. The flange of nozzle is chipped and scraped 
 to the shell so that a good bearing is made, and it is gener- 
 ally bolted in place, the bolts passing through the flange, the 
 shell and the flange on branch of dry pipe, the nuts of bolts 
 to be placed on the outside. 
 
 The nozzle is sometimes riveted on and calked on the inside 
 if it is made of cast iron ; if it is made of steel and riveted on, 
 it is calked on both sides. If the nozzle is riveted on, the 
 dry pipe is secured separately with tap-bolts, spaced inside of 
 the line of rivets. 
 
 The stop valve should be placed on the nozzle so that the 
 pressure is under the valve, and, if possible, there should be 
 a by-pass valve fitted where the stop valves are of large di- 
 ameter, this valve to be used when first turning steam in the 
 main steam pipe for warming up before getting under way, 
 thus reducing the chances of having the main stop valve 
 opened too suddenly when first turning steam to the engines. 
 
 The safety valve should be in a vertical position, and if the 
 area is large a more satisfactory job can be had by using two 
 smaller valves mounted on one ba«e, having one inlet and one 
 outlet. 
 
 With this arrangement the valves and springs are small and 
 give less trouble, the combined area through the two valves 
 must be the same as the one large one. 
 
 In securing these valves through bolts should be used where- 
 ever possible, as studs give much more trouble than through 
 bolts. 
 
 If a stud breaks off in setting up on the joint, the broken 
 
I30 
 
 LAYING OUT FOR BOILER AIAKERS 
 
 piece has to be drilled out and probably no studs of the size 
 will be found on board, or will there be time to drill it out, as 
 such things usually happen when there is little time for mak- 
 ing repairs. 
 
 The whistle valve should be secured direct to the boiler and 
 not to any other pipe. It should not be connected, to the dry 
 pipe, as it is a small pipe and will work satisfactory from the 
 boiler direct. It will work unsatisfactory if taken from one 
 of the branches of the auxiliary steam pipe, as there seems to 
 be water pocketed somewhere, and every time the whistle is 
 opened this water is picked up and blown out through the 
 
 shallow funnel-shaped disc, made of plate steel, from 12 to 
 16 inches in diameter; the pipe is connected somewhere at 
 the bottom according to the space available; the top of the 
 pan is usually located about 4 inches above the top of the 
 boiler tubes ; the outboard end of pipe is expanded into the 
 opening in shell (although some times it has a flange on it 
 and is held m place by the same bolts that secure the valve) ; 
 the valve flange has a spigot end on it which enters into the 
 pipe where it is expanded into the shell, and the flange se- 
 cured to the shell by through bolts, the nuts being on the 
 outside. 
 
 FIG. I. — END ELEV.\TIOX. 
 
 whistle, thereby delaying the time the whistle should sound 
 until all the water is blown out through it. 
 
 The surface blow valve should be located in some con- 
 venient place on the shell. 
 
 In reference to the manner of securing this valve there is a 
 difference of opinion among engineers as to having it se- 
 cured with the pressure under or on top of the valve ; if se- 
 cured with the pressure on top of the valve and the valve or 
 disc is guided with wing guides, it would seat in the case of 
 the stem breaking, which is an advantage, and about the 
 only advantage that can be claimed for securing it in such a 
 manner. The valve usually has an internal pipe fitted to it, 
 extending to about the middle or center of the water sur- 
 face; the inboard end is fitted with a scum pan, which is a 
 
 The bottom blow valve is secured in the same manner as 
 the surface blow valve, its internal pipe leading to the bottom 
 of the boiler; this has no pan on the end, just a square end on 
 the pipe. About the same can be said of the bottom blow 
 valve as was said of the surface blow valve, as to the man- 
 ner of securing it with reference to the pressure on top or 
 under the valve. The internal pipes are secured by iron 
 braces to the through stays to hold them in the proper posi- 
 tion. 
 
 The size of bottom blow valves range from l>^ inches to 
 2j4 inches and the surface blow valves from i}4 inches to 2 
 inches, according to the size of boiler. The surface and bottom 
 blow valves are connected together by pipes on the outside and 
 a branch connected to a sea valve on side of vessel, or if 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 131 
 
 passing through the side of vessel, above the water hne, no 
 valve is fitted to the vessel, but a flange is usually fitted with 
 a nozzle to direct the discharge down to the water, as to have 
 it blowing straight out is very unsatisfactory. 
 
 The drain cock should be located at the lowest part of the 
 boiler, if possible. This should be a flange cock with spigot 
 end, the cock to have a permanent handle, made to point 
 down vifhen the cock is closed. A cock is preferable to a 
 valve for drawing. 
 
 On account of the galvanic action set up in a boiler it is 
 customary to place a quantity of zinc in it. The zinc is held 
 
 and will burst the basket if there is not sufficient room for it. 
 These baskets are located in different parts of the boiler at 
 top and bottom, generally in the water spaces. The amount 
 of such zinc to be placed in a boiler is from 2 to aj-l pounds 
 per square foot of grate surface. 
 
 The solid bottoms in the baskets hold the zinc from get- 
 ting in the blow valve when it crumbles off and breaks up. 
 
 The gage cocks, if possible, should be located on the head 
 of boiler, as a much better arrangement can be made for work- 
 ing them from the fire room, and they are more protected there 
 than in any other place. If placed on the shell they are hard 
 
 FIG. 2. — SIDE ELEVATION. 
 
 in plate-steel boxes called baskets, the average size of these 
 baskets is 6J/2 inches wide, G'/i inches deep and 12J/2 inches 
 long, the sides and ends are perforated with ^-inch holes, the 
 perforations extend down to about i inch from the bottom, 
 the baskets have hangers riveted on for supporting them 
 from the through braces, the hangers being clamped to them ; 
 the joints should be carefully made so as to keep a thorough 
 metallic contact. The zinc plates average in size 6 inches wide, 
 12 inches long and yi inch thick and are dropped in the basket 
 and secured to it by a bolt passing through them with a 
 washer placed on the bolt between each zinc (fitting the zincs 
 properly is quite a tedious job). Thus is secured a metallic 
 contact with all the zincs. Care should be taken not to fill the 
 .baskets too full, as the zinc expands under chemical action 
 
 to operate and unprotected ; if placed on the water column 
 they are not direct, as they are connected to the boiler by 
 pipes and valves. 
 
 A stand-pipe is of very little use, except to hold the glass 
 in the bearings, and is very often done away with, using a 
 plate to keep the glass tube from pulling out of place, the 
 pipe connections being made to the end fittings or cocks direct. 
 
 The gage glass is located in some convenient place about 
 the center of boiler if possible; if this is impossible there 
 should be two gages, one on each side. 
 
 The top is connected to the steam space of boiler by cop- 
 per pipe and valve ; care should be taken not to locate it too 
 near other openings as it may reduce the pressure some and 
 give the wrong reading of water in the glass. The bottom is 
 
1 3-' 
 
 LAYING OUT FOR BOILER ^lAKERS 
 
 connected to the water space of boiler with copper pipe and 
 valve. Tlie automatic closing valves on the water column ii a 
 very good arrangement if properly made, as a glass tube is 
 liable to break at any time, and when it does the automatic 
 valve closes the opening in valve so that repairs can be made 
 without going through escaping steam and hot water to get 
 to the valves to shut them off. 
 
 If the gage cocks are placed in the head there should be 
 four fitted, three on one side and one on the other side, the 
 single one should be the same height as the lower one of the 
 three. The lower gage cock should be about on a line with the 
 highest heating surface and the other two placed 4 inches apart 
 above this one. A copper drip-pan with drain pipe leading to 
 the bilge should be fitted to the nest of three cocks and thor- 
 oughly secured in place, the single cock does not need a drip- 
 pan, as this one is not used as often as the others, it only being 
 used when the vessel is listed. 
 
 If the plates of the boiler are thick enough these cocks 
 should be screwed into the plate, for if flange cocks are used 
 the flanges require considerable space and the bolts for se- 
 curing them are necessarily small and liable to give trouble. 
 The cock properly screwed into the plate gives a more satis- 
 factory job. 
 
 It is a good plan to have a mark on the boiler, or some- 
 where on the uptake, showing the water level when it is just 
 covering the highest heating surface, with the vessel in 
 normal trim, as this is a good thing to know at times. 
 
 The feed-pipes are double, one the main feed and the other 
 the auxiliary feed, they should always be on opposite sides of 
 the boiler. They are fitted to the boiler in some convenient 
 place, either on the head or shell, but should be located so 
 that they can be operated from the fire room floor. The in- 
 ternal pipes are expanded into the opening in boiler plates, the 
 top valve flange has a spigot end. which enters the pipe where 
 it is expanded, the stop valve is secured in place with through 
 
 bolts, having nuts on the outside. The check is bolted to the 
 stop valve in a vertical position ; the check should be arranged 
 so that the lift can be regulated. 
 
 The internal pipes sometimes are separate throughout, and 
 sometimes they are connected together at the top and then 
 continued as one pipe. If connected together they enter a 
 Y-fitting at the center of boiler over the top of the tubes, and 
 then a single pipe extends back over the tubes to a T, and 
 from this T a pipe extends out on each side, with a cap on 
 the outboard end ; sometimes the outlets are made so as to 
 have one point down in each water space, sometimes the pipe 
 is perforated all along the bottom and sometimes there are a 
 row of holes on each side of the pipe, discharging the water 
 in a spray horizontally. Sometimes the feed is discharged all 
 in one place, the full diameter of the pipe, but this is not 
 good practice. If the main and auxiliary feed-pipes are con- 
 nected together on top of the tubes and then continue as one 
 pipe, there is much less room taken up and the arrangement 
 seems to work as satisfactory as two separate pipes. These 
 pipes are supported by iron hangers secured to the through 
 braces, in such a manner that the pipes will not be too rigid, 
 but will have some flexibility. There are several ways of 
 circulating the water or warming the water in the bottom of 
 a Scotch boiler when first getting up steam, but when there is 
 only one boiler none of these are of much use, as the heat, 
 which is the agent in all, is furnished from another boiler and 
 in a case of one boiler would have to be generated by that 
 boiler alone ; it helps some, as there is always dead water in a 
 Scotch boiler, even when steaming, as it generally causes a 
 circulation. 
 
 In some boilers a small weighted safety valve (called a 
 sentinel valve) is fitted ; this is about V^ inch area and is set 
 to blow at 3 or 5 pounds above the working pressure ; it is 
 another i-alve to look after and Aere is a question as to its 
 usefulness. 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 '33 
 
 Specifications for a Three-Furnace Single=Ended Scotch 
 Boiler. 
 
 The following is a typical set of specifications for a Scotch 
 boiler. While the figures quoted apply to a boiler which is to 
 be installed on the United States revenue cutter No. l6, the 
 requirements represent the best of marine boiler construction 
 at the present time. 
 
 The Boiler. 
 
 The general dimensions of the boiler will be: 
 
 Diameter of shell (inside), 13 feet 6 inches. 
 
 Length over heads (bottom), 10 feet 3 inches. 
 
 Number of furnaces, three. 
 
 Diameter of furnaces (inside), 40 inches. 
 
 Total grate surface, 60 square feet. 
 
 Total heating surface, 1,803 square feet. 
 
 The boiler shall be designed for a working pressure of 180 
 pounds per square inch. 
 
 The design of this boiler will be furnished by the govern- 
 ment. The various details will be worked out by the con- 
 tractor and submitted to the Engineer in Chief, U. S. R. C. S., 
 for his approval, before work is commenced on the construc- 
 tion of the same. 
 
 The boiler shell will be made in one course and will consist 
 of two plates i;4 inches thick. 
 
 Each head of the boiler will be made of two plates, the upper 
 one being 15-16 inch thick and the lower one 54 '"ch thick. 
 The front head will be flanged outwardly at the furnaces and 
 both will be flanged inwardly at the circumferences. The front 
 head will be stiffened by angle bars and the back head by 
 doubling plates riveted on, all as shown on the drawing. 
 
 The tube sheets will be 54 in<^h thick. They must be ac- 
 curately parallel, and all tube holes will be slightly rounded 
 at the edges. The holes for the stay tubes will be tapped to- 
 gether in place. 
 
 The boiler tubes will be of cold-drawn seamless mild steel, 
 the best that can be obtained on the market, and subject to the 
 approval of the engineer in chief. All tubes will be 3 inches 
 in external diameter. The ordinary tubes will be No. 10 U. S. 
 S. G. in thickness and will be swelled to 3 1-16 inches external 
 diameter at the front end. The ends will be expanded in the 
 tube sheets and beaded over at the back end. The stay-tubes 
 will be No. 6 U. S. S. G. in thickness and will be upset at 
 both ends to an external diameter of 3 3-16 inches, leaving the 
 bore of the tube uniform from end to end. They will then be 
 swelled at the front ends to 3 7-16 inches external diameter. 
 They will be threaded (twelve threads per inch) parallel at 
 the combustion chamber ends and taper at the front ends to 
 fit the threads in the front tube sheet. They will be screwed 
 into the tube sheets to a tight joint at the front ends and will 
 be made tight at the back ends by expanding and beading. All 
 the expanding will be done with approved tools. All of the 
 tubes will be spaced 4 inches from center to center vertically 
 and 4J4 inches horizontally. 
 
 There will be a separate combustion chamber for each fur- 
 nace in the boiler, as shown on the drawing; they will be made 
 of 9-16-inch plates at top and back and 19-32-inch plates at the 
 bottom and sides, as shown. The tube sheets will be as before 
 
 specified. The tops of the combustion chambers wil' be braced 
 by steel-plate girders, with the edges machined, as shown. The 
 plates will be flanged where necessary, and all parts will be 
 joined by single riveting. The holes for the screw stay-bolts 
 in the plates of the combustion chambers and sliells will be 
 drilled and tapped together in place. 
 
 The bracing will be as shown on the drawing. The com- 
 bustion chambers will be stayed to the shell of the boiler by 
 screw stays i}i inches in diameter over the threads, with 
 twelve threads to the inch, screwed into both sheets and fitted 
 with nuts, the nuts to be set up on bevel washers where the 
 stays do not come square with the plates. The washers will 
 be cupped on the side next to the plates and the joint will be 
 made with a cement of red and white lead and sifted cast-iron 
 borings. Where the nuts set up directly on the plates, they 
 will be cupped out and the joint made with cement. The com- 
 bustion chambers will be stayed to the back heads by screw 
 stays lyi inches in diameter over the threads around the edges 
 of the combustion chambers and ij^ inches diameter over the 
 threads elsewhere. When the nuts are up in place, the washers 
 must bear solidly against the plates with which they are in 
 contact. The holes for all screw stays will be tapped in both 
 sheets together in place. All joints around stays will be 
 calked tight under 100 pounds hot-water pressure before the 
 nuts are put on. 
 
 The upper through braces will be 2^^ inches in diameter, 
 upset on the ends to 2% inches in diameter, and threaded 
 eight threads to the inch. The nuts for the upper through 
 braces will be of wrought iron set up on washers, inside and 
 outside. The outside washers will be about 8yi inches in di- 
 ameter and 15-16 inch thick in the two upper rows, and about 
 754 inches in diameter and 15-16 inch thick in the lower row. 
 The washers will be riveted to the heads by six 54-111211 rivets. 
 The inside washers will be cupped for cement, as shown. No 
 packing will be used. 
 
 All screw stays will have the thread cut in a lathe, the length 
 between the plates being turned down to the bottom of the 
 thread, as shown on the drawing. 
 
 All braces will be of steel, "Class A," and without welds, 
 except the two 2-inch braces on the wing combustion cham- 
 bers which will be made of wrought iron, as shown on the 
 drawing. The crowfeet on the combustion chamber will be 
 made of wrought iron. The screw stays will be made of steel, 
 "Class B." 
 
 The longitudinal joints of the boiler shell will be butted with 
 ij4-inch straps, inside and outside, and treble-riveted, as shown 
 on the drawing. Joints of heads and joints of heads with shell 
 will be double-riveted, as shown. Joints in furnaces and com- 
 bustion chambers will be single-riveted. All rivets will be of 
 open-hearth steel, "Class B," except for the rivets in the longi- 
 tudinal joint for the shell plates, where the rivets will be of 
 "Class A." 
 
 The edges of all plates in the cylindrical shell and of all 
 flat plates, including the girders for the tops of the combustion 
 chambers, where not flanged will be planed. Edges of flanges 
 will be faired by chipping or otherwise, as approved. 
 
 Plates in cylindrical shell must not be sheared nearer the 
 
134 
 
 LAYING OUT FOR BOILER MAKERS 
 
 finished edge than one-half the thickness of the plate along the 
 circumferential seams and not nearer than one thickness 
 along the longitudinal seam. All rivet holes will be drilled in 
 place after the plates have been bent, rolled, or flanged to size, 
 and fitted and bolted together; after the holes have been drilled 
 the plates will be separated and have the burs around the 
 holes carefully removed. Hydraulic riveting will be used 
 wherever possible, with a pressure of 65 to 75 tons. In parts 
 where hydraulic riveting cannot be used, the rivet holes will 
 be coned on the driven side 1-16 inch. 
 
 Seams will be calked on both sides in an approved manner. 
 
 All joints will be as shown on the drawing. 
 
 Each furnace will be in one piece and corrugated. The 
 thickness and the diameter will be as shown on the drawing. 
 They must be practically circular in cross-section at all points. 
 They will be riveted to the flanges of the front head and to 
 the combustion chambers, as shown. 
 
 There will be manholes in the boiler of such size and loca- 
 tion as shown on the drawing. The top manhole will have a 
 stiffening ring, as shown. The manhole plates will be of cast 
 steel in dished form, except the top plate, which will be made 
 of steel plate, "Class B." Each plate will be secured by two 
 wrought-iron dogs and two ij^-inch studs, screwed into the 
 plate (twelve threads to the inch), fitted with collars, and 
 riveted on the inside, and fitted with nuts for setting up on the 
 outside. Each plate will have a convenient handle, and all 
 plates, dogs, and nuts will be plainly and indelibly marked to 
 show to what holes they belong. 
 
 The grate bars will be of cast iron and of an approved pat- 
 tern. They will be so fitted as to be readily removed and re- 
 placed without hauling fires. The bars at the sides of the 
 furnaces will be made to fit the corrugations. The bars will 
 be made in two lengths, resting on the dead plate in the front 
 and on the bridge wall in the rear of each furnace. They will 
 be supported in the middle by an approved framework made to 
 fit the corrugations. No holes will be drilled in the furnace 
 for securing the furnace fittings. The area of opening be- 
 tween the grate bars will be about 40 percent of the grate area. 
 
 The bridge walls will be made of cast iron, as shown, and 
 so fitted as to be readily removable. They will be covered at 
 the top with approved fire bricks laid in cement. The area of 
 opening above bridge walls will be about 16 percent of the 
 grate surface. The tops of the bridge walls will be slightly 
 crowned. 
 
 The furnace fronts will be made with double walls of steel, 
 bolted to a sectional cast-iron frame. The space between the 
 two walls will be in communication with the fire room. The 
 inner plate of furnace front will be perforated as may be di- 
 rected. The dead plates will be made of cast iron and so fitted 
 as to be easily removable. The door openings will be as large 
 as practicable. 
 
 The furnace doors must be protected in an appro-ed man- 
 ner from the heat of the fires. The perforations in the doors 
 and lines will be as directed. Each door will have a small 
 door near its lower edge for slicing the fires. There will be 
 two wrought-iron hinges to each door and the latches will be 
 of wrought iron. There will be an approved arrangement 
 
 fitted to each door to prevent them from sagging, and also to 
 hold them open when firing. The furnace-doo.' liners will be 
 made of cast iron ^i inch in thickness. 
 
 Ash pans of j4-inch steel plate, reaching from the front of 
 the furnace flue to the bridge wall, will be fitted to all the 
 furnaces. The edges of the ash pans will be made to fit the 
 corrugations of the furnaces. 
 
 The ash-pit doors will be made of 3-16-inch steel plate, 
 stiffened with angle or channel bars. They will be furnished 
 with suitable buttons, so as to close the ash pit tightly when 
 the furnace is not in use. Each door will have two wrought- 
 iron beckets to fit hooks on the boiler front. Wrought-steel 
 protecting plates J-^ inch thick will be fitted around the boiler 
 front, sides and passages, as before specified, to serve as ash 
 guards. 
 
 A lazy bar with the necessary lugs will be fitted to the front 
 of each ash pit, and there will be three portable lazy bars for 
 the furnaces. 
 
 The uptake will be made of double shells of steel No. 8 
 U. S. S. G., built on channel bars and stiffened with angles 
 and will be bolted to the boiler head and to the smoke-pipe 
 base. Outside of the uptake will be a jacket inclosing a 3-inch 
 air space. This jacket will be made of No. 12 U. S. S. G. 
 steel. The space between the plates of the uptake will be 
 filled with magnesia blocks containing not less than 85 percent 
 carbonate of magnesia. 
 
 The uptake doors will be made of double shells of steel 
 of the same thickness as the uptake and will have an air 
 jacket like the uptake. The space between the shells will be 
 filled with magnesia blocks. The hinges and latches will be 
 made of wrought iron. Each door will have an eyebolt near 
 its top for handling and one near the bottom for convenience 
 in opening. 
 
 The boiler will rest in two approved saddles, built up of 
 plates and angles. It will be secured to the angles by stand- 
 ing bolts screwed into the boiler shell, with nuts inside and 
 outside, the inside nuts setting up on snugly fitting washers, 
 with cement joints. These bolts will fit holes in the angle 
 bars of the front saddle snugly, but pass through enlarged 
 holes in the angle bars of the back saddle to allow for ex- 
 pansion. Chocks built up of plates and angle bars will be 
 fitted at each end of the boiler, as approved, so as to prevent 
 any displacement of the boiler. The boiler will be secured, in 
 addition to the above, by four ij4-inch holding-down bolts 
 connecting cast-steel palms bolted to the boiler shell and 
 riveted to tank tops and reverse frames of the vessel, as ap- 
 proved. 
 
 The boiler will be clothed with magnesia blocks, securely 
 wired in place and covered with galvanized iron, in an ap- 
 proved manner. 
 
 Boiler Attachments. 
 
 The boiler will have the following attachments of approved 
 design, viz., one main steam stop valve, one auxiliary steam 
 stop valve, one whistle-steam stop valve, one dry pipe, one 
 main-feed check and stop valve with internal pipe, one 
 auxiliary-feed check and stop valve with internal pipe, 
 one surface blow valve with internal pipe and scum pan, 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 135 
 
 one or more bottom blow valves with internal pipes, a 
 twin-spring safety valve, one steam gage, one glass and one 
 reflex water gage, both of the automatic self-closing type; 
 four approved gageoocks, one sentinel valve, one salinometer 
 pot, one or more draincocks, one aircock and zinc protectors, 
 with baskets for catching pieces of disintegrating zinc. 
 
 All the external fittings on the boiler will be of compobi- 
 tion, unless otherwise directed, and will be flanged and 
 through-bolted, or attached in other approved manner. 
 
 All cocks, valves and pipes unless fitted on pads or in other 
 approved manner will have spigots or nipples passing through 
 the boiler plates. 
 
 All the internal pipes will be of brass or copper, as ap- 
 proved, and will not touch the plates anywhere, except where 
 they connect with their external fittings. The internal feed 
 and blow pipes will be expanded in boiler shells to fit the 
 nipples on their valves or will be secured in other approved 
 manner, and will be supported where necessary and as di- 
 rected. 
 
 Steam-Stop Valves. 
 
 There will be approved composition stop valves 6 inches in 
 diameter for the main steam, 4 inches in diameter for the 
 auxiliary steam, and 2 inches in diameter for the whistle 
 steam, fitted to each boiler in an approved manner. These 
 valves will close toward the boiler, and approved extension 
 rods will be fitted to the hand wheels for the main and auxil- 
 iary steam-stop valves, so that they may be opened or closed 
 from a location outside of the fire room space. 
 
 Dry Pipes. 
 
 The dry pipe for the boiler will be of copper. No. 14 U. S. 
 S. G., and will be heavily tinned inside and outside. 
 
 The pipes will extend nearly the length of the boiler and 
 will be perforated on the upper side with longitudinal slits or 
 holes of such a number and size that the sum of their areas 
 will equal the area of the steam pipe. The valve end of the 
 pipe will be expanded into the main and auxiliary stop-valve 
 nozzles, or will be secured in other approved manner. The 
 pipes will be closed to the boilers, except for the slits or holes 
 above mentioned. 
 
 Feed-Check Valves. 
 
 There will be an approved main and an auxiliary feed-check 
 valve on the boiler, placed as shown on the general arrange- 
 ment. 
 
 The valve cases will be so made that the bottom of the out- 
 let nozzle shall be at least yi inch above the valve scat. The 
 valves will be assisted in closing by phosphor-bronze spiral 
 springs. The valves will have hand wheels and approved gear 
 where necessary for working them from the fire room floor. 
 
 There will be an approved stop valve between each check 
 valve and the boiler. 
 
 Blow Valves, Blowpipes and Pumping-Out Pipes. 
 There will be an approved Ij4-'nch surface blow valve on 
 the boiler, located as directed. The valve will close against 
 the boiler pressure. An internal pipe will lead from the valve 
 to near the water line in the boiler and will be fitted with a 
 scum pan. 
 
 There will be one or more approved ij^-inch bottom blow 
 valves on each boiler, located as directed. The valves will 
 close against the boiler pressure. Internal pipes will lead 
 from the valves to near the bottom of the boiler, as required. 
 
 An approved 2-inch copper pipe will connect the bottom 
 blow valves with an approved sea valve located where di- 
 rected in the same compartment. These pipes will have 
 iJ4-inch nozzles for the attachment of pipes from the surface 
 blow valves, and also 2-inch nozzles for the attachment of 
 the boiler pumping-out pipes. All joints will be flanged joints, 
 as approved. 
 
 There will be a nozzle with a flanged valve on the sea valve, 
 above mentioned, for the connection to the hose for wetting 
 down ashes. 
 
 An approved 2-inch pipe will connect the bottom blow 
 pipes to the salt-water suction manifold of the auxiliary feed 
 pump, and so arranged with approved valves in the various 
 pipes that the boiler may be pumped out when desired. The 
 suction pipes for the injectors will be taken off the pumping- 
 out pipes by means of approved branches, valves, etc. 
 
 Safety Valves on Boilers and Escape Pipe. 
 
 The boiler will have an approved twin-spring safety valve 
 (two valves), each 3 inches in diameter, and they will be 
 located as shown on the general arrangement. 
 
 Each valve will have a projecting lip and an adjustable ring 
 for increasing the pressure on the valve when lifted, or an 
 equivalent device for attaining the same result. They will be 
 adjustable for pressure up to the test pressure. Gags will be 
 furnished with each safety valve so that the valves may be 
 held seated when testing the boilers. 
 
 The springs will be square in cross-section, of first quality 
 spring steel. They will be of such a length as to allow the 
 valves to lift one-eighth of their diameters when the valves 
 are set at 180 pounds pressure. They will have spherical bear- 
 ings at the ends, or they will be connected to the compression 
 plates in such a manner as to insure a proper distribution of 
 the pressure. They will be inclosed in cases so arranged that 
 the steam will not come in contact with the springs. 
 
 The spring cases will be so fitted that the valves can be re- 
 moved without slacking the springs. The valve stems will fit 
 loosely in the valves, to bottom below the level of the seats, 
 and will be secured so that the valve may be turned by a 
 wrench or crossbar on top of the stem. The valves will be 
 guided by wings below and in an approved manner above. 
 
 The valves will be fitted with approved mechanism for lift- 
 ing them by hand from the fire room floor or the engine room, 
 as directed. The mechanism for each set of valves will be so 
 arranged that the valves will be lifted in succession. All joints 
 in the lifting-gear mechanism will be composition bushed. 
 
 The outlet nozzle will be in the base casing, so that the joint 
 at the escape pipe will not have to be broken when taking the 
 valves out. The casings and valves will be made of composi- 
 tion, the valve spindles of rolled bronze, and the valve seats 
 of solid nickel castings screwed into the top of the composi- 
 tion base. A drain pipe leading to the bilge will" be attached to 
 each safety-valve casing below the level of the valve seat. 
 
 There will be an approved 7-inch copper escape pipe, 
 
136 
 
 LAYIXG OUT FOR BOILER MAKERS 
 
 located abaft the smoke pipe, extending to the top, finished and 
 secured in a neat manner. This pipe will have branches lead- 
 ing to the safety valves on the boilers, and the auxilian,- ex- 
 haust pipe will also lead into the escape pipe, as elsewhere 
 specified. 
 
 Slcam Gages for Boiler. 
 
 There will be :n approved steam gage for the boiler, lo- 
 cated and secured in a conspicuous position on the fire rocm 
 bulkhead, as directed, so as to be easily seen from the fire 
 room floors. This gage will have dials 85^2 inches in di- 
 ameter and will be inclosed in polished brass cases. The gage 
 will be graduated to 360 pounds pressure and so adjusted that 
 the needle will stand vertical when indicating the working 
 pressure; this point will also be plainly marked with red. 
 
 The valve connecting the stcam-guge piping to thr boiler 
 will be fitted with a guarded valve stem and a detachable key 
 or wrench for opening or closing the same; also with an ap- 
 proved opening for the attachment of a test gage. 
 
 Boiler Water Gage. 
 
 There will be one approved glass water gage and one ap- 
 proved reflex water gage, both of the automatic self-closing 
 'ype, fitted to the boiler, as directed. Each gage will be 
 placed in plain sight, near the front of the boiler. The shut- 
 off cocks will have a clear opening of at least % inch in di- 
 ameter, and will be packed cocks, with approved means for 
 operating them from the fire room floor. 
 
 The blow-out connections will be valves and will have brass 
 drain pipes leading to the bilge, with union joints, >^-inch 
 iron-pipe size. 
 
 The glasses will be about 18 inches in exposed length. 
 They will be ^ inch outside diameter, will be surrounded by 
 brass wire-mesh shields and protected by guards. 
 
 Reflex gages must be designed to fit the water-gage fittings, 
 so that the two kinds will be interchangeable. 
 
 Gage Cocks. 
 
 There will be four gage cocks of an approved pattern fitted 
 on the boiler, with approved means of operating them from the 
 fire room floor. 
 
 Each cock will be independently attached to the boiler. The 
 valve chamber will have two seats, the inner one formed in 
 the casting, and the other movable, screwed into the casting 
 
 and furnished with a handle. The valve will have two faces 
 and will be closed by screwing down the movable seat and 
 opened by the pressure in the boiler when the outside seat is 
 slackened off. There will be a guide stem on each side of the 
 valve, the valve and stem being turned from ono piece of rolled 
 manganese, phosphor, or Tobin bronze. The stem will be cir- 
 cular in section where it passes through the movable seat, and 
 the outer end of stem will project 54 inch beyond the movable 
 seat and will be squared for a wrench. The inner end will be 
 of triangular section. The opening of the valve will be at 
 least 5's inch in diameter and the discharge from the chamber 
 will be at least J4 inch in diameter. 
 
 The gage cocks will be spaced about 4 to 5 inches apart, as 
 directed, and each set will have a copper or brass drip pan and 
 a j4-inch brass or copper drain-pipe connection leading to the 
 bilge. 
 
 Sentinel Valves. 
 
 The boiler will be fitted with an approved sentinel valve at 
 the front end J4 square inch in area. It will have a sliding 
 weight on a notched lever and will be graduated to 190 pounds 
 pressure. 
 
 Salinometer Pots. 
 
 There will be approved salinometer pots, fitted with brass 
 hydrometers and thermometers, connected to the boiler, as di- 
 rected. They will be located in the fire room or where re- 
 quired. 
 
 Boiler Drain Cocks and Aircocks. 
 
 The boiler will have one or more approved drain cocks, 
 placed so as to drain the boiler thoroughly. 
 
 The boiler will have at the highest point an approved 
 !>2-inch aircock. 
 
 Zinc Boiler Protection. 
 
 Zinc for the protection of the boiler will be held in baskets 
 suspended from the stays, or as approved ; these baskets will 
 be made of wrought iron, perforated on the sides and solid 
 on the bottom. The baskets in each boiler will contain suf- 
 ficient rolled zinc to make the total quantity for the boiler 
 not less than 100 pounds for each 15 square feet of grate sur- 
 face, and the baskets will be distributed as directed. Each 
 strap for supporting the baskets will be filed bright where it 
 comes in contact with the stays, and the outside of the joint 
 will be made water tight by approved cement. 
 
HOW TO LAY OUT A SCOTCH BOILER 
 
 137 
 
138 
 
 LAYIXG OUT FOR BOILER MAKERS 
 
 AN INTERNALLY FIRED RETURN FLUE MARINE BOILER. 9 FEET 8 INCHES DIAMETER BY 28 FEET 6 INCHES LONGj 
 FITTED WITH STEAM DOME 3 FEET IN DIAMETER BY 8 FEET HIGH, TWO FURNACES 3 FEET II INCHES WIDE BY / FEET 
 7 INCHES LONG, TWELVE FLUES I3;-4 INCHES DIAMETER, TWO FLUES 3lj4 INCHES DIAMETER, TWO FLUES 10 
 INCHES DIAMETER, STEAM PRESSURE 50 POUNDS PER SQUARE INCH. 
 
 A LARGE STATIONARY BOILER OF THE BELPAIRE LOCOMOTIVE TYPE, BUILT TO SUPPLY STEAM AT HIGH PRESSURE FOR HIGH-DUTY 
 PUMPING engines; TOTAL WEIGHT OF BOILER 7$ TONS. LENGTH, 33 FEET 7 INCHES; DIAMETER, gO INCHES; TWO FURNACES EACH 
 TO FEET 6 INCHES LONG BY 4 FEET 6 INCHES WIDE; 20I 3-INCH TUBES; HEATING SURFACE, 3,032 SgtIARE FEET; GRATE AREA, 68f^ 
 SQUARE FEET ; RATIO, 44.I. 
 
REPAIRING LOCOMOTIVE AND OTHER TYPES OF BOILERS 
 
 CHAPTER I. 
 
 In this series of articles the author proposes to deal with 
 the repairing of locomotive and other types of boilers, espe- 
 cially the water-tube. We will begin with the locomotive 
 boiler, and will assume that three locomotives have arrived in 
 the shop for a course of widely different repairs. We will call 
 these locomotives Nos. i, 2 and 3. No. i needs a set of half- 
 side sheets, a half-door sheet, a front flue sheet and a smoke- 
 box bottom. No. 2 needs two back corner patches, a couple of 
 patches on the side, a back flue sheet and the rivets in door 
 sheet to be backed out and redriven, and the mud-ring is 
 cracked. No. 3 needs a new set of radial stays, broken stay- 
 bolts to be renewed, flues replaced, a patch en the top of the 
 back flue sheet, a belly patch, a new stack, bulge in fire-box 
 to be heated and layed up, and bushings between stay-bolt 
 holes. In different shops, with their respective conveniences, 
 the manner of procedure will be slightly different. 
 
 Taking engine No. I, in a shop fairly well equipped with 
 pneumatic appliances, the half-door sheet would be removed 
 first, and this will enable the sides to come out by ripping in 
 a horizontal direction only, while if left in, it would be neces- 
 sary to cut till the flange of either the door or flue sheet was 
 reached, and then would rip down to the mud-ring. In taking 
 out the door sheet the first step is to decide how high up it is 
 to be cut off; if half-way up the door hole is left in. Mark an 
 even number of rivet holes up from the center on each side 
 and draw a line around the knuckle of the flange and con- 
 tinue toward the side sheets on each side, keeping in mind to 
 have an even slope and all stay-bolts out of the line of rivets.. 
 Count the same number of rivets up from the mud-ring on 
 each side till you are in line with the slope you wish to cut ; 
 if there are any stay-bolts in the way, move a rivet higher or 
 lower, till you can cut across and remove the bolt with the 
 defective portion; it will be a matter of judgment, based on 
 practice, to overcome this difficulty in every case. After having 
 closely center-punched this line, and noticed that the lap is up 
 high enough not to interfere with the removal of sides, and 
 also that four thicknesses of iron will not come together, cut 
 along the center marks with a cape chisel and ripper, then 
 center and drill out the rivets in the flange from mud-ring up, 
 as well as those in the door hole. In both cases go one rivet 
 higher than the cut for the lap rivet. After having gouged 
 out the burrs and knocked down the rivets, center-punch the 
 stay-bolts on the outside of back head that are to be removed 
 with the defective portion of door sheet. On one side of the 
 inside sheet drill an outside row from mud ring up to cut; 
 this is to enable the sheet to turn freely and prevent the bolts 
 from catching against the end of side sheet. After having 
 drilled all necessary bolts and knocked the rivets or.t of mud 
 ring, drive a lap wedge between ring and sheet at bottom far 
 enough to enter a longer wedge with more taper. A wooden 
 wedge about 18 inches long and 3 inches wide, tapered from 
 4 inches to nothing, will, if backed with sheet iron, give good 
 results. Drive this wedge up from the bottom until there is 
 quite a strain on the sheet, and then take a handle punch, and 
 
 working through all the drilled holes from the outside, break 
 the remainder of the drilled bolts out with a sledge ; as the 
 bolts break it will relieve the strain, making it necessary to 
 insert more wedges from top and bottom till all bolts are 
 broken loose from the back head. Now on the side on which 
 the bolts were drilled from the inside, wedge the sheet clear 
 out from the mud ring, and working a punch bar from out- 
 side holes, top and bottom, on one side only, gradually work 
 the flange clear till it drops in the pit. Fig. I shows how the 
 wedges are placed, what holes are drilled from the inside, and 
 how the metal is cut at top to avoid stay-bolts. 
 
 We are now ready to remove the sides. Draw a line pai • 
 alllel with the mud ring on the side sheet at sufficient height, 
 to remove the defective portion, and to keep lap as far from 
 fire as possible, and cut to just clear the upper row of stay- 
 bolts and rivet line to catch corresponding rivets in both flue 
 and door sheets without deviating from the horizontal, as shown 
 in Fig. 2. If the flue and door sheets are parallel, and at 
 right angles to rivet line in mud ring, it will be much easier 
 to lay out a new sheet. 
 
 The first step in removal will be to center and drill all stay- 
 bolts from the outside that come within the zone on both 
 sides of the boiler; if the mud ring rivets are driven counter- 
 sunk, it will be necessary to drill all of them at least as far 
 in as the counter-sunk portion. If they have been drilled 
 squarely with a J4"inch drill for a 13-16 rivet, it will not be 
 necessary to gouge out the counter-sunk burrs, for when a 
 punch is applied in the hole and hit with a sledge, if the rivet 
 is not extremely tight, it will burst loose the counter-sunk 
 portion and also force the rivet out. It will be well, however, 
 before the rivets are punched out of the mud ring on the 
 sides, to put two bolts in that portion in connection with the 
 back head, so that when the rivets are all out of the sides, the 
 ring will not sag and unnecessarily strain the flue and throat 
 sheet. However, in this particular case, it will be as well to 
 drill out the few remaining rivets in the back flue sheet and 
 drop the mud ring entirely. It will make things much easier 
 when riveting is begun, assuming that the mud ring is out and 
 the back flue sheet rivets drilled out to the required height, 
 and stay-bolts drilled a sixteenth beyond the sheet on outside. 
 They will be burst loose with a punch, and wedged out like 
 the door sheet. , In some places a crow-foot bar is used, and 
 two men working from inside the shell will break the bolts 
 down through the water space ; in either case the bolts will 
 have to be drilled outside just the same, and all burrs re- 
 moved with a gouge. With the door sheet removed, it will 
 be easy to drop the two sides by working the back ends to- 
 wards the center till there is sufficient space in the clear to 
 enable front end to pass outside of flue sheet flange and drop 
 to the floor. 
 
 Fig. 3 is a side view of the front end. It will be noticed 
 that the smoke-box is butted to front end and held in place by 
 a I by 8-inch wrought-iron ring. Before the flue sheet can be 
 removed it will be necessary to cut off the front section of 
 front end, including this ring, for the reason that the internal 
 diameter of ring is less than outside diameter of flue sheet. The 
 
I40 
 
 LAYIXG OUT FOR BOILER MAKERS 
 
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 Kg. 3 
 
 REPAIRING LOCOMOTIVE AND OTHER TYPES OF BOILERS. 
 
 most convenient method is to swing a block and fall over the 
 central portion, cut out the inside row of rivets and jack 
 front section and wrought-iron ring out in one piece, then 
 after having cut and backed out the rivets in the flue sheet it 
 will also be necessary to cut ofif about half the rivets along 
 the bottom in the row that holds the front end to the boiler 
 shell, because on account of their large heads the flange will 
 not clear them enough for the sheet to turn. 
 
 Assuming that this has been done, the next step will be to 
 drive two drift pins diametrically opposite each other, and at 
 a height of about the horizontal center line of the shell. 
 These will act as hinges and enable the sheet to turn freely 
 after having once started from its seat. After turning to a 
 horizontal position, remove the drift pins and the sheet will 
 then generally. slide out without any further trouble. 
 
 Putting on a half-bottom to the smoke-box will be much 
 easier now that it is disconnected from the boiler as it can be 
 rolled to a convenient place and marked for cutting. To mark 
 the cut, place the long blade of a square jamb against the door 
 ring as shown at A, and with a straight edge against top of 
 square, raise or lower till cut comes squarely in to rivet' R. 
 !Mark the line with crayon and proceed in like manner on the 
 other side ; sometimes the ring is warped, and in order to be 
 sure you are taking a square cut, get a piece of band, saw off 
 convenient length, and passing it around the smoke-box on 
 each side, mark the exact center of rivet that cut goes into, 
 then transfer this measurement to the front, if marks coincide 
 it is safe to assume that cut is square. After having removed 
 the defective portion, take a straight edge and holding it 
 against the raw edge, chalk the high spots, if they are as much 
 at % '"~h off, chip them level, if only a i-i6 or 1-32, upset 
 
 with a hammer and smooth and bevel slightly with a file ; keep 
 this up till the straight edge meets the cut well along on both 
 sides, and we will now be ready to lay out the new bottom; 
 
 Procure a strip of wood or some other flexible material the 
 exact thickness of the metal to be used, about 2 inches wide 
 and clamping it around the front ring in the space the patch is 
 to occupy, mark off to the exact dimensions and with a scriber 
 mark through the ring the rivet holes, and when this strip is 
 straightened out it will be the exact length of sheet in the 
 front. Mark back length and rivet holes the same way, and if 
 cut was made square the front and back lengths will be equal, 
 and the width can be measured with a rule. Procure a sheet 
 the right width if possible, and of sufficient length to allow of 
 bevel shearing at each end. With the strips just mentioned 
 mark off the rivet holes on each side, and at each end lay out a 
 row of holes for the butt strap, which are to be countersunk. 
 Cut the cinder hopper off the old piece, and with a piece of tin 
 cut and bent to the radius mark through the casting the 
 necessary bolt holes, straighten out the tin and locate the 
 hopper hole on the new sheet, then, while the puncher is get- 
 ting out the work, strip off the butt strap holes and allowing 
 about iJ4 times the rivet diameter from the edge, locate the 
 rivet line on each side, then center, screw, punch and counter- 
 sink. Make the butt strap out of material one and one-eighth 
 times the thickness of new plate. On account of the erosive 
 action of the cinders, the old plate will always be thinner than 
 the new, so to make a smooth joint outside, a thin strip is to 
 be placed between butt strap and sheet at top half only, but 
 on both sides. If the puncher has our sheet done, we will 
 procure a sweep of the desired radius and roll the sheet to 
 this curve on the inside, taking care that no flat places are 
 
REPAIRING LOCOMOTIVE AND OTHER TYPES OF BOILERS 
 
 141 
 
 left in the end, and that sheet is set square with the rolls ; 
 after rolling, that part that was sheared bevel at each end will 
 now be upset sufficiently to form a burr, so that the sheet when 
 riveted into place will look more pleasing to the eye ; this 
 burr is hammered flat and the surplus metal fills the little 
 interstices, and when carefully done the front looks like one 
 continuous band of metal. 
 
 As the process of bolting and riveting up this patch is 
 simple, we will again turn our attention to the side sheets. 
 As the sides go in before the door sheet, we will lay them out 
 by squaring up a sheet of the required dimensions. Mark off 
 the exact length of old sheet at top and bottom, and to get 
 correct height and fair rivet holes, bend a piece of f^ by i inch 
 iron till it conforms to the shape of the inside or water space 
 surface of the fine sheet. Mark through the rivet holes with 
 a scriber and allow at top an amount for riveting and lap. 
 Ciraighien out the strip and transfer measurements to the 
 new sheet, and do the same for back end. The stay-bolt holes 
 can be located by stripping the outside rows, and then trans- 
 ferring to sheet and connecting opposite points with solid 
 lines ; their crossings will be stay-bolt centers. After sheet is 
 punched, roll to same shape as old one and countersink the 
 top row of rivet holes so that rivets can be driven flush. To 
 enter sheets in place, fasten a scaffold bolt to top of fire-box 
 and hoist sides in to position with a chain block. Assuming 
 that the flanger has the flue and door sheet done, they are 
 now to be put in position and we will then be ready to rivet. 
 Before commencing to drive, however, be sure that the slack 
 places are pulled out of the sheets, and if the corners don't 
 lay up well it will be necessary to heat and upset into place 
 with a fuller. 
 
 There are several ways of holding on the rivets in the 
 water space; perhaps the easiest is with the pneumatic tool. It 
 consists of a wrought cylinder attached to an air supply pipe 
 and contains a piston die with a countersunk head to fit 
 rivet, so that when air is turned on it engages the rivet head 
 and the reaction is against the outside sheet. Wedge bars are 
 mostly used, however, and they may be worked from inside 
 or outside ; if worked from the inside of the shell, have the bar 
 made the length of fire-box plus 2 or 3 feet, and have the 
 wedge the thickness of water space minus the rivet spoon, 
 and minus i inch ; this inch is to be used for a back liner 
 and will ride on bolts placed through the water space. If 
 W'orked from the outside, it will be necessary to spring sheet 
 off from the bottom enough to allow the wedge to work 
 freely ; a sheet wedge with a longer taper will have to be used 
 in this case, so that when rivet is applied with a spring, tongs 
 cup put in place and wedge driven home, it will not be too 
 long to interfere with the free use of a sledge. All the rivets 
 in the water space can be driven this way, and as a precau- 
 tionary measure the wedge bar should have a flat space on 
 the end of about 4 inches, and also should have just taper 
 enough to put a couple of hundred pounds strain on the rivet 
 head ; if strained much more than that, it bulges the sheet, 
 and when wedge is released the sheet in straightening will 
 have a prying effect on the countersunk rivet heads which, 
 if they do not pop off while calking, the seam will be very 
 likelv to give trouble afterwardr,. 
 
 The flat space on the bar will allow it to ride when in 
 position and also enable the striker to judge the degree of 
 strain. ■ Putting in the water-space bar, riveting up front flue 
 sheet and connecting smoke-box to front end being compara- 
 tively simple, we will next take up Engine No. 2. 
 
 CHAPTER II. 
 
 Taking engine No. 2 and assuming that one man does the 
 work, for convenience of illustration, we will take down the 
 grates and ash-pan and remove fhe flues before commencing 
 on the large work. In this case, while the motor and drill are 
 connected, it will save time to do all the heavy drilling first. 
 To remove crown and back flue sheet, we will center and 
 drill all the stay-bolts in the outside of throat sheet and after- 
 wards break them down on the inside with a crow-foot bar. 
 In drilling out the rivets around the flue-sheet flange, a handy 
 appliance is shown in Fig. 4. It is made of 5^ by 4-inch spring 
 steel, split on one end about 4 inches, then opened out and 
 a finger put on each leg. In going around the sides and top 
 it is hooked in the flue holes and will accommodate any posi- 
 tion of the motor. 
 
 In drilling out the bolts and strays in the crown sheet the 
 most convenient method of securing backing for the motor is 
 to cut two fairly heavy planks just long enough to reach 
 across the fire-box above the 0-G bend. Place one at each 
 end ; then a plank placed lengthways on top can be shifted to 
 suit the position of the motor. After drilling out and knock- 
 ing down all the necessary bolts and rivets, the flue sheet is 
 removed by knocking the top towards the front far enough to 
 allow the bottom to turn sideways between the water spaces. 
 When this sheet comes loose it does so with a jump, and to 
 keep anyone from being hurt it is customary to tie it with a 
 rope to the dry pipe, or to a rod laid across the dome hole. 
 The crown sheet can now be dropped either by pulling out or 
 tilting one side until Ihe opposite edge comes in the clear, and 
 then lowering to the floor. 
 
 Before proceeding with the other work we will lay out and 
 flange the crown and flue sheets. In most places where much 
 of this work is done, flat sheets are kept in stock a little 
 larger than the required size, to allow for trimming. Fig 5 
 shows one of these sheets with the flue sheet in position ready 
 to mark off. To lay out, have the bottom of flue sheet ex- 
 tend within '/i inch of edge of the flat plate; see that the old 
 sheet is laying level and with flanged edge turned down to 
 meet new sheet all around. If the old sheet has wings at the 
 mud-ring corners it will be necessary to block up the other 
 end until both sheets have their planes parallel. Then with a 
 sharp crayon pencil mark the outlines of the old sheet on the 
 new, and it will also save time afterwards to mark the belly- 
 brace holes and the crooked outside stay-bolt holes with a 
 long tit punch, and using the old holes as guides. 
 
 Before the old sheet is removed, take a square and go 
 around the edges, and you will find at the top or crown sheet 
 end that the bottom does not meet the square by an amount 
 from 54 to ^i inch, varying in proportion to the number of 
 tube holes and the number of times they have been reset, as 
 A, Fig. 6. To find the difference a set of tubes will have in 
 affecting the lenprth of a sheet is easy by actual experiment 
 
142 
 
 LAYING OUT FOR BOILER MAKERS 
 
 "With the first set of new tubes you have occasion to put in, 
 tram the width and length of flue sheet carefully before the 
 coppers are rolled, and center-mark these measurements on 
 the side sheet. After the flues are completed, tram again and 
 you will find that the sheet has become longer and wider, 
 from 3/16 to J^ inch, according to the amount the tubes have 
 been worked. After a few cases like the above the steel 
 reaches its elastic limit, and does not return to its former 
 position ; and on account of the crown sheet with rigid sling- 
 stays and downward pressure holding the edge of the flange, 
 it soon begins to cup, and assumes the position shown in the 
 accompanying drawing Fig. 6. 
 
 Now in laying out the new sheet around this part, flangers 
 diflfer in opinion as to whether the new sheet should be 
 marked from the root of flange or the edge of sheet. In this 
 case we will mark it from the edge of sheet, because, first, it 
 will be a little easier to put in, and next, when it starts to 
 grow the second time it will not further strain the crown 
 sheet by having the advantage of a J/^-inch start, providing 
 the old crown sheet was left in. After marking the outlines, 
 remove the old sheet and center-punch lightly; assuming that 
 the flange has an outside radius of i^ inches, it follows that 
 the circular part of the flange will begin lyi inches on the 
 inside of this line. As tlie radius of the center of the flange 
 is lyi inches, then 1.25 X 31416 -^ 2 = 1.9635 inches, to be 
 marked and center-punched from the inside line. To this add 
 an extra amount equal to the depth of flange. While correct 
 in theory, this rule is not used much in practice, except for 
 heads and flanges of from 3 to S inches radius. Another rule 
 to get the flange line for small radius is to subtract twice the 
 thickness of metal from outside depth of flange wanted ; or 
 again the crayon line can be center-marked and brought down 
 with the flange one thickness of metal. An experienced 
 flanger may often do this way and bring the sheet out all 
 right. As the flange gathers on a convex radius and loses on 
 a concave one, it is customary to subtract a small amount 
 around the top, and add a little extra to the concave part 
 shown at c, Fig. 7. 
 
 Before flanging, it is customary to punch all the stay-bolt 
 holes, braces and flue centers. The flue holes are shown 
 partly laid out in Fig. 7. Apparently two methods are used; 
 although not alike in appearance they are similar in prin- 
 ciple, and owe their origin to the rule : One-sixth of the cir- 
 cumference of a circle stepped ofT equals the radius. To lay 
 out, locate the center line on new sheet, and with dividers set 
 to spacing of center to center of old holes, step off on center 
 line, and center-punch, taking care to start the same distance 
 from the bottom as the space is on old sheet, without chang- 
 ing dividers, and with each found point as center, scribe arcs 
 to the left, which intersect as shown. Continue as before till 
 outside is met. On the right side as noticed, 60-degree angles 
 are erected; their crossings denote flue hole centers, and if 
 laid out correctly will coincide with left half. The holes thus 
 found are not generally made full size till after flanging, es- 
 pecially as the outside holes have a tendency to become oval 
 in the process of flanging. 
 
 In flanging by hand over a former, the flat sheet is first laid 
 
 in position witli the edges projecting over the former the re- 
 quired amount to form flange. The clamp is then let down, 
 and a couple of lugs are bolted to the face of the sheet on the 
 other side, to butt against the clamp. The sheet is then 
 chalked where it is to be heated, and also several guide marks 
 are chalked on the sheet and clamps so that when coming 
 out in a hurry with the heat it will be an easy matter to set 
 the work in its exact position. About two feet at a time is 
 heated and flanged, in this way care being taken not to heat 
 the metal back too far, nor to hammer the flange more than 
 is needed. Both of these conditions coming together will 
 cause the sheet to buckle on account of unequal strains set 
 up in the material. After flanging, the sheet is aimealed by 
 heating to a low red and allowing to cool slowly. In this final 
 heat the buckles are removed by hammering on a face plate. 
 The flue holes are then finished and the calking edge chipped 
 bevel. The flange rivet holes are now marked from old sheet, 
 drilled and countersunk. 
 
 The crown sheet is marked and flanged much the same as 
 the flue S/ieet. If it is a crown-bar boiler, the four corners 
 before flanging will be scarfed — that is, drawn to a feather 
 edge — so as not to put too sudden an offset in the connecting 
 sheets. Sometimes the sides are turned down cold, the only 
 redeeming quality of this method is the low first cost. Com- 
 pared with a properly-done job it is an inferior article. The 
 crown sheet in this case, however, has a gradual roll. Per- 
 haps the easiest way to get out the new sheet is to cut a 
 sweep for the crown-sheet radius, and then run the old sheet 
 through the straightening rolls. In the absence of such, a 
 common roll will answer very well. Then clamp the old 
 sheet on the new, mark, punch and roll, and the crown and 
 flue sheet will be ready to put in. In the matter of corner 
 patches, if there are four to be put in the fire-box, the two 
 back ones are the easiest to apply; for in this class of engine 
 no plugs are put in the back corner, and the door sheet is 
 not so thick and hard to cut as the flue sheet. Cutting in a 
 horizontal direction just above the first row of stay-bolts will 
 generally take in all the defective material. In cutting down 
 to the mud-ring, care must be taken not to have a square 
 corner, and it will also make a better looking job to have the 
 downward cut slope at an angle. 
 
 Before the patches are applied we will drill and V-out the 
 rivet holes in the seam above the cut on door sheet, as shown 
 in Fig. 8. Two or three times the diameter of the rivet is al- 
 lowed to drive. In order to fill the countersunk and V, the hot 
 rivet is applied in the top hole with a spring tongs. The cap 
 c is then set on the head, and the wedge A driven home. 
 This wedge has a part turned over square on the end of the 
 handle to admit of its being more readily removed when the 
 rivet is finished. As the rivets are being driven lower down 
 they will be much easier to hold, and care must be taken not 
 to drive the wedge in too far, as it will crimp the driven head 
 of the last driven rivet and cause it to leak. No rivet is put 
 in the bottom hole, as it is a lap-rivet hole for the patch. Tlie 
 sheet is scarfed very thin at this point, as shown by shaded 
 portion, also at E. There are two reasons for doing this, 
 either one of which would warrant its being done in almost 
 
REPAIRING LOCOMOTIVE AND OTHER TYPES OF BOILERS 
 
 143 
 
 every case; first, it keeps three full thicknesses of metal from 
 the fire, and again, as mentioned before, relieves the sudden 
 ofifset. 
 
 Part of the ciit-out for the patch is shown in Fig, 8, also 
 the centers for describing the patch bolts. To locate these 
 centers, mark % inch from the raw edg« all around with 
 crayon; then for 13/16-inch patch bolts, set dividers V/s 
 inches, and trial space this line. If it does not travel cor- 
 rectly the first time, open or close dividers slightly until it 
 does come right. Then center the spacings, as they repre- 
 sent patch-bolt centers. 
 
 Now when the new patch is fitted to place, it will be im- 
 
 just alike. Nearly every boiler maker has little short-cuts 
 learned from experience. In a general way the length and 
 width are taken, and a piece of metal cut to this size. Now 
 the patch not only has to be bent to the radius of the corner, 
 but also offset inward at the bottom. The old-fashioned way, 
 and one that still makes the best and neatest looking job, is 
 to offset the material to follow the cut all around. The 
 method used mostly nowadays is to offset on the bottom only, 
 over a piece of Ys or ><-inch stuff, clear across in a straight 
 line to within 2 inches of the edge on each end; then agair 
 heating and putting crossways in the clamp, and bending over 
 to fit the corner. During the last operation it will be noticed 
 
 Fig. n 
 
 possible to see these centers; therefore some way must be 
 devised to transfer these measurements. Two simple ways 
 are shown; first, with dividers set (say) 6 inches, and with 
 each point in rotation as center, scribe arcs which cut each 
 other at XXXX. Then, when the patch is in position, and 
 using XXXX as centers with same radius, scribe arcs that cut 
 each other on the patch ; when these are centered and drilled, 
 they will correspond with the centers on old sheet. Another 
 method is shown for the four bottom holes. Where dividers 
 are not to be had, simply mark with a rule or straightedge a 
 standard distance (say 10 inches), center-mark and connect 
 the two points with a solid line. 
 
 The process of fitting up these corner patches requires 
 judgment and experience. No two men will do all the work 
 
 that the offset portion has a tendency to crimp down in the 
 clamp. To prevent this, bend a strip of 5^ or ^ by 2^/2 inches 
 to the curve of the mud-ring, putting this in the clamp and 
 setting the patch for final heat. Fit up the offset portion to 
 this curve. 
 
 It will also be necessary to lay a piece of 3/^-inch material 
 on the body of the patch ; if this is not done, the clamps will 
 have a bearing on the small offset portion only, and will allow 
 the patch to move or slew around while bending with a maul. 
 
 After flanging, the patch will be clamped to its position on 
 the boiler, and one stay-bolt and two rivet holes will be 
 marked on one wing only. Procure the necessary bolts, flat- 
 ter, fuller and wrenches, and have them convenient to use. 
 When the patch comes over hot, punch or drill these holes, 
 
144 
 
 LAYING OUT FOR BOILER MAKERS 
 
 then heat the punched side and tlie corner, not paying any at- 
 tention to the other wing. When the patch is hot, bolt it up 
 fast and tight in position, then, striking squarely against the 
 cold wing, drive and upset the surplus metal into the corner. 
 This is a much better way than fullering; however, some may 
 think to the contrary. While the metal is hot keep your at- 
 tention confined to the corner only, which is the real vital 
 point. When the patch commences to lose its color it will 
 no longer upset easily. Then it will be time to work the sides 
 in and tighten up the bolts more. A stay-bolt and rivet hole 
 can now be marked on the other wing. In marking the rivet 
 hole be sure to allow a little for draw, as the iron has not yet 
 entirely filled the corner. In this last heat both wings can be 
 worked up, iron to iron, and the draw hole will still further 
 crowd the iron into the corner. A fuller worked in the cor- 
 ner, both top and bottom, and a flatter on both wings will 
 complete the laying up. 
 
 Fig. 8 
 
 The patch bolt holes are now marked as mentioned before; 
 the mud-ring rivet holes are marked with a scriber from the 
 outside. The surplus metal around the edges is also marked 
 where it is to be cut off. It will be noticed that the wing on 
 which the last heat was taken has sagged at the bottom and 
 extends below the mud-ring about ^ inch, according to 
 length of wing. This sag is due partly to offsetting, and 
 partly to door or side sheet being out of perpendicular. An 
 experienced man will allow for this, and instead of cutting 
 and offsetting his metal straight at bottom, will move up- 
 ward on short wing something like ^ inch in 6. As all the 
 holes in the patch cannot be punched, have them drilled 23/32 
 inch, with the exception of mud-ring holes, which are to be 
 full size. 
 
 It is best to heat, patch and cut off surplus metal with a 
 hot chisel. The writer has spoiled two patches in his 
 checkered career by trying to shear them. It can be done 
 though. Even a corner patch can be sheared all the way 
 around on a common shears by blocking up under the blades 
 with small pieces of iron. But it is a risky thing to do, al- 
 though it saves much time and generally another heat. In 
 trimming with a hot chisel around the corners, it is almost im- 
 
 possible to leave the edge exactly as it was before. For that 
 reason a final heat is generally taken, and several more bolts 
 put in all around. A few well-directed blows at the high 
 spots will usually suffice to bring metal to metal all around. 
 
 However well the edges appear to be up, a view through 
 the wash-out plug hole will show how the patch really fits. 
 To insure fair holes, while the patch is in position and after 
 it is cold, drill through the patch-bolt holes into the shell with 
 a 23/32-inch drill. When this is done, have the patch holes 
 reamed out to ]4 inch, and countersunk for a 13/16-inch bolt. 
 While this is being done you can tap the holes in the shell 
 to suit the patch bolt. A patch of the bo.x style is shown in 
 Fig. 9. It owes its origin to the fact that the dished and sur- 
 plus metals conform to the strains of expansion and con- 
 traction better than the straight kind. It is used largely on 
 high-pressure engines by many roads. A copper gasket is 
 generally placed just inside of the row of patch bolts. It is 
 then not necessary to calk the outside edge, although in some 
 places it is done as a precautionary measure. The method 
 of flanging where no former is at hand is to get a piece of 
 flat iron the thickness of the top depth of dish wanted, and 
 draw it gradually down to nothing in the required length. 
 Then, cutting sheet to required size with a small allowance 
 for trimming, set hot sheet over former in the clamps, and 
 flange one side at a time until three sides are down. The 
 bottom is left straight so as not to form a pocket for sedi- 
 ment. The stay-bolt and patch-bolt holes are then put in as 
 shown. It is bolted up to place and drilled as in preceding 
 example. It will not often be necessary to heat this patch to 
 lay up, as the two flat surfaces will pull up to a close contact 
 without much trouble. Seven-eighth-inch patch bolts are 
 mostly used, and they may be spaced 1% centers, or as near 
 as will come out even in traveling the rivet line. 
 
 Sometimes in countersinking the patch at the drill-press the 
 holes will draw away from the center line. When this hap- 
 pens the patch bolt will not seat itself in a steam-tight joint. 
 To make a better job, a countersink reamer is screwed into 
 the bad hole. The cutting edge bears on the bad part only, 
 and is fed by a small nut or thumbscrew. A few revolutions 
 will make a good seat, and when patch bolts are pulled up 
 with white lead, the manner of joint can be determined by 
 the action of the lead in the countersink. It is customary 
 to. go around the outside edge and between the patch bolts 
 with a light hammer and bobbing tool. This lays up the small 
 bumps and helps to bring metal to metal. The patch bolts 
 may now be twisted off, riveted over and worked down with 
 a frenchman and facing pin. After calking with a round- 
 nose fuller, the job will be complete. As a precautionary 
 measure, however, if a copper-wire gasket is used it will pay 
 to watch it closely by feeling through the stay-bolt holes. In 
 some cases the vibration caused by working the patch bolts 
 will spring the gasket from its seat and cause it to work out on 
 one side and into the water space, even when soldered to the 
 patch. 
 
 Fig. 10 shows a bottom view of a cracked mud-ring. In 
 some cases a rivet is put in diagonally in the mud-ring, and 
 the crack then generally stops at the rivet hole. In that case 
 
REPAIRING LOCOMOTIVE AND OTHER TYPES OF BOILERS 
 
 145 
 
 the rivet is taken out and a number of plugs are drilled 
 lengthways into the crack from the bottom and riveted over. 
 Then, if the plugs have been drilled to intersect one another 
 and afterwards worked down with a saddle tool, it will make 
 a good job. The rivet hole is now drilled out again for the 
 purpose of cutting off the plug ends that may stick through 
 into the rivet hole. In case the ring is broken clear through, 
 it is generally necessary to patch it. A piece of J'^-inch steel 
 is cut to the required shape, then fitted up, drilled and counter- 
 sunk. The necessary holes in the mud-ring are drilled and 
 tapped for the given size of patch bolt. In this case the patch 
 proper is not tapped at all, but the countersunk portion is 
 made to fit the angle of the patch-bolt heads, so that when 
 the bolts are tightened it draws the patch more firmly to 
 place. If the crack stands open at the bottom, a better job 
 is made by dovetailing a copper strip into the crack before 
 the patch is applied. 
 
 To cut out the dovetail a cape chisel and a one-sided dia- 
 mond point are used. The cut is first made the necessary 
 depth with the cape chisel, and afterwards concaved with the 
 diamond point. A copper strip is then prepared and an- 
 nealed by heating and cooling off in water. If the dovetail 
 cut is smooth, the piece may be driven in endways. If not, it 
 will have to be entered from the bottom and upset enough to 
 fill the cavity. The cut is shaped ris its name implies, and 
 imder ordinary conditions is sometimes used on repairs of 
 this kind without a reinforcing patch at all, but when both 
 are used it makes the job doubly secure, and well worth the 
 extra trouble when costs and results are compared. 
 
 CHAPTER III. 
 
 On engine No. 3 the first step will be to remove the flues. 
 This is generally done by cutting the ends off flush in the 
 smoke-box, and in the fire-box chipping about two-thirds of 
 the head oft; this end is then ripped about 2 inches and closed 
 in with a lifting tool ; a flue-bar is then applied to each separate 
 flue in the front end, and the flues are knocked out and 
 back of the front flue sheet with enough clearance for each 
 end to swing over to the large hole, which is generally located 
 in the center row. Each flue is then pulled out through the 
 large hole and cleaned by rolling in the "rattler." 
 
 The radial stays are removed by drilling both top and 
 bottom ; the top to be drilled at least the thickness of the sheet, 
 and for the bottom the thickness of the head will generally 
 suffice. The heads are then knocked off with a side-set or 
 square punch. Two men working in the shell will now knock 
 them out by applying a crow-foot bar on each stay, about 
 one-third of the length up from the bottom. This will gen- 
 erally allow- the bottom end to pull out of the hole before the 
 top breaks. It is best policy to take out one of the sling 
 stays also, so that when the back half of the crown sheet is 
 reached a man can crawl in and hold up the bar. Otherwise 
 a longer and heavier bar will have to be used, and a great 
 deal of the force of each blow will be lost in vibration. 
 
 After the stays are down and the burrs removed, the holes 
 ;-e sometimes tapped with a long tap, as shown at P"ig. 17-A. 
 
 It has a square at eacli end, and is long enough so that when 
 one end is cutting the other end is projecting through the 
 corresponding hole in the other sheet, thus keeping the threads 
 in line. If the holes in crown sheet tap out 1% inches, and 
 in the "wagon top" i inch, then two taps will have to be used. 
 The bottom one is generally run up with a motor to full 
 thread. A man on top will then back the tap down with a 
 wheel or double ended wrench. While waiting for the tap to 
 be cleaned, oiled and finishing its cut through the next hole, 
 he may be tapping the top holes by hand. This method does 
 not guarantee the top and bottom threads to match; therefore 
 at times many bolts may have to be tried in one hole to procure 
 a proper fit. While no individual bolt can have its thread out 
 of alignment more than 1/24 inch, they will run from that 
 much off to a perfect fit. 
 
 For this reason the wagon-top end of the bolt is fitted 
 rather loose, so that when the bottom, which must be a steam- 
 tight fit, commences to seat, the loose end will adjust itself 
 slightly to the new conditions. A better method, but one 
 which may consume more time, is shown by using the spindle 
 taps in Fig. 17-B. Two shorter taps of the proper size are 
 drilled through their centers and tapped twelve thread. A 
 long piece of about ^-inch steel is threaded to fit the hollow, 
 and when both taps are in place with the spindle through their 
 centers it is next to impossible to cut threads that do not 
 match. If the stays themselves, though, are threaded in a 
 random way, no benefit will be derived from this method, for 
 they will fit as in the first instance. However, many machines 
 are in use which are constructed with this especial purpose in 
 view, viz. : to give a continuous thread. 
 
 Getting the length of these stays is also quite an important 
 matter. Taking a crown sheet with eight rows across and 
 twenty rows long, the slope to be S inches in 10 feet, and 
 assuming that each half would be alike; if crown sheet was 
 marked on longitudinal center line then 8 X 20 -^ 2 ^ 80 
 different lengths of stays. This is an amount which would 
 cause much confusion and assorting. 
 
 To overcome this difficulty the wagon top and crown sheet 
 are marked transversely into corresponding halves. A piece 
 of ;4-inch square iron is then cut about a foot longer than the 
 longest length, and a short lip bent over in opposite directions 
 on each end, as shown at M, Fig. 13. Each end is then 
 marked, as B and F, to distinguish between back and front. 
 The bend is then lowered through the extreme back holes in 
 first row, marked i, 2, 3, 4, Fig. 11. The length of each is 
 carefully marked with a scriber. An extra amount is added 
 for driving, and the new lengths are permanently marked on 
 the rod with a chisel. The rod is then turned end for end 
 and lowered through the cross row marked c-c. Fig. 12, and 
 each length is noted as before. This will make eight lengths, 
 and if the stay is machine made, like A, Fig. 13, with about 
 3 inches of straight thread on the small end, eight lengths 
 will be sufficient. When they are screwed to place they will 
 assume lengths similar to X-C-X, Fig. 12. 
 
 The first bolt in the end row for each length will extend 
 through just sufficient to drive. On account of the raise in the 
 crown sheet, however, the ends will project through further 
 
146 
 
 LAYING OUT FOR BOILER MAKERS 
 
 and further, till, when point C is reached. Fig. 12, the bottom 
 end of the top thread will have nearly reached its margin of 
 radius, and the front lengths will now commence to be put 
 in. In measuring each length for the bolt maker it will be 
 found that two, or sometimes three, lengths come within 
 % inch of each other. In this case we still have enough 
 margin to discard the j4-'nch short lengths, and double the 
 order for the next longest. As these lengths were taken from 
 one-half the crown sheet, it will be necessary to double the 
 number found for the other half, still making only six lengths 
 for 160 stays. 
 
 Owing to several causes the top of back flue sheet often 
 cracks from the flue hole into the rivet hole around the 
 Knuckle of the flange. As these cracks start from the water 
 side they are not generally discovered until they make their 
 
 just full flush. In the fire-box the plugs are made in sticks 
 of three or four each, with a square on the end, to admit of a 
 large wrench. The holes are all tapped the same size, and the 
 first plug on the stick is fitted to one hole. The others are 
 then turned to correspond, and are separated from each other 
 by a niche of suflicient depth to allow of their being broken 
 off easily, when the plug is screwed home. Both sides of the 
 plug may now be riveted over, and the patch cut out. 
 
 Instead of plugging the corresponding flue holes in the front 
 end, "short pockets" are used, which consist of a section of 
 ordinary tubing, from 10 to 20 inches in length, with one end 
 closed by pointing and welding. The other end is then 
 tightened in position by rolling. After cutting out the old 
 piece and scarfing, a strip of iron is bent to the radius of the 
 crown sheet ; also two short pieces are bent to the radius of the 
 
 rie. u 
 
 : ^i',^i',%',',iSi;ii;i',';, " - 
 
 
 B 
 
 Fig. 17 
 
 X X 
 
 l-lg. 16 
 
 Fig. 16 
 
 A 
 
 presence known by blowing. If allowed to continue, they 
 soon cause a honeycomb, to form over the top rows of flues, 
 thereby stopping them up, and rendering them useless as far 
 as heating qualities are concerned. Sometimes they may be 
 repaired by drilling along the cracked line, and screwing in 
 plugs. Where there are several of these cracks radiating from 
 one flue hole, and perhaps several flue holes in this condition, 
 a more lasting job is secured by entirely cutting avv^ay the de- 
 fective portion and patching, as shown at Fig. 14. 
 
 The rivets are first cut off and backed out. The defective 
 portion is then marked to be cut out. Before cutting, however, 
 it will be well to locate the lap and rivet line, as shown by 
 the shaded portion, Fig. 4. The lap will cross several flue 
 holes. These flues will then have to be removed. The holes 
 are tapped out, and a steam-tight plug is screwed into each, 
 
 flange. A piece of steel plate is now trimmed to the size and 
 flanged and bent to suit the templates. 
 
 Along the cut-out portion the flange should be cupped 
 slightly, to enable the patch to lay up and more readily fill the 
 space it is intended to occupy. Assuming that the necessary 
 rivet holes have been spaced and drilled, the patch will be put 
 in place and a few holes in one end marked. It is now heated, 
 and unless it is a small patch, one end is fitted up at a time. 
 As this patch is in an important place, and where small leaks 
 play havoc with the upper flues, it will be good policy to take 
 an a:dditional heat, so as to make sure the patch fits snugly. 
 The holes are now marked by scribing through the holes 
 already drilled. The patch is then taken down, drilled and 
 beveled for a calking edge on the emery wheel. 
 
 In this case we will put the patch in position with plugs. 
 
REPAIRING LOCOMOTIVE AND OTHER TYPES OF BOILERS 
 
 147 
 
 To do so it will be necessary to put a bolt in every third or 
 fourth hole, and draw up each one as much as it will stand. 
 Then, alter laying up edges of the patch again with a 
 flogging hammer, tighten bolts as before. The reason of this 
 extra work is that plugs having a continuous thread have no 
 pulling power by themselves, so it is essential that there must 
 be metal to metal before this operation is begun. After tapping 
 out and screwing in the plugs tliey may be riveted over on 
 each end. Then, instead of putting a fresh man to each 
 plug, the edges may be cut in by applying a ^-inch rivet snap. 
 
 A patch of this kind is generally put on with rivets, and for 
 the benefit of some who may think plugs would not have a 
 sufficient holding power, this calculation is made. Assuming 
 the patch to be 30 inches in length by 7 inches breadth around 
 the flange, then 30 — 4 = 26, 7 — 4 ^ 3, 26 X 3 =^ 78 square inches 
 exposed to pressure. At gauge pressure 200, 78 X 200 = 
 15,600 pounds, the magnitude of the force tending to dislocate 
 the patch from the seat. To counteract this force we have 
 forty J4-'nch plugs ; the force necessary to pull or blow a 
 54-inch plug through a J^-inch sheet is about 12,000 pounds. 
 Then 40 X 12,000 = 480,000 pounds, the magnitude of the 
 force tending to resist this pressure. Then 480,000 -=- 15,600 = 
 303/39; or, with a factor of safety of 6, showing the patch 
 to be about five times stronger than necessary. 
 
 In the neighborhood of the fire line Jt very often happens 
 that the sheet cracks around, and betw:;en the stay-bolt holes 
 occasionally a bulge will start, and deflect the plate from a 
 vertical plane an inch or more before being noticed. In that 
 case it is customary, if the plate seems sound, to build a char- 
 coal or coke fire on the spot, and force it back to its original 
 position. The stay-bolts around the boundary edges are left 
 in. To prevent the material from backing up beyond the de- 
 fective zone they are afterwards cut out and replaced. 
 
 In plugging cracks between stay-bolt holes, or other places, 
 recourse may be had to the method shown by illustration in 
 Fig. 15, in which A-D represents the crack. Set a pair of 
 dividers to spacing close enough to insure each plug a part of 
 the space occupied by its neighbor. Step and center punch 
 these distances from one end of the crack to the other. Now, 
 in drilling, we will skip every other center mark from one 
 end of the crack to the other, a.s X X X X. These holes may 
 now be tapped out, and plugs screwed in; the remainder of 
 the holes will now come between each two plugs, and if the 
 dividers were set properly the drill, in going down between 
 each two plugs, will cut about J^ inch off of each, thus drilling 
 the plugs into one another. This method makes the job 
 easier, and saves time over the other way of drilling and 
 putting in each plug individually; for in this case half the 
 drilling and half the plugging is completed in one operation, 
 and the other half completed in the next. 
 
 After riveting over and chipping level, a straddle tool is 
 used to smooth them up. Its shape is shown at C. It is 
 easily made from a worn-out beading tool. After the leg is 
 cut oflf it is concaved to the required size with a round file. 
 If the edges of the plugs are cut in with a square-nose tool, 
 this will make a very handsome job. It is perhaps unneces- 
 sary to add that the drilling must be done with a twist drill. 
 
 To locate and renew broken stay-bolts, wTicre there is i.c 
 regular inspector, the bolts are generally put in with the out- 
 side and drilled at least an inch in depth with a ;4-inch drill, 
 so that when the bolts break they will show up at the tell-tale 
 hole. The fire-box is sometimes chalked off into divisions, 
 and each division carefully sounded with a light hammer. The 
 positively broken bolts can be made sure of by most boiler 
 aiakers, but it takes much practice to locate the partly broken 
 ones. For this reason some men will not rely on sound 
 alone, but after chalking all that was found on the inside, will 
 examine all the tell-tale holes in sight on the outside, and 
 even get into the shell and look into the water spaces. Where 
 all three methods are used in conjunction there can be, but 
 few broken bolts that escape detection. 
 
 It is customary in some places to cut the heads off all 
 broken bolts in the fire-box, and then countersink the edges 
 slightly with a chisel. The holes are now drilled outside, and 
 the burrs removed. A long, keen half-round gauge is now 
 driven between the bolt and the sheet on the outside, Aus 
 tending to draw the bolt sideways out of the hole. The inside 
 counter-sink assists this action, and after the bolt is pulled 
 over to the limit of the reach of the gauge, a sma.'. hand- 
 offset tool will knock the bolt to the water space. In some 
 cases, where the engine is not stripped, this method could not 
 well be used. It is then customary to drill or cape the holes 
 through both sheets in the ordinary way. 
 
 Where there are many bolts to be removed, there will gen- 
 erally be a few known as "blind," or steam-tight bolts, owing 
 to the fact that they come behind the frame — pads — or other 
 places where the outside cannot be seen. They are sometimes 
 very difficult to put in. To remove a bolt of this description 
 the inside is drilled first, and the broken bolt then knocked 
 down into the water spaces. A wire lighter is then applied 
 through the hole, to observe the condition of the outside burr. 
 If the burr is level and even with the sheet, it is punched in 
 the center and drilled through the water space. If the center 
 is doubtful, or the bolt edges serrated, it will be necessary 
 to take the drill down a few times to watch its progress. After 
 being drilled the burr is removed with a water space gauge. 
 This operation requires much skill, as care must be taken not 
 to cut a groove in the outside sheet. Spindle taps are used to 
 rechase the thread in both sheets. 
 
 In some places the stay-bolt is tapered on the end, to make 
 a steam-tight fit ; and again the inside sheet may be tapped 
 slightly larger, and a straight bolt screwed to a steam-tight 
 fit in the outside sheet. In both cases the projecting end in the 
 fire-box is cut off and riveted over. In out-of-the-way places^ 
 where no suitable taps are to be had, an ordinary stay-bolt 
 may be substituted for one by caping a few slots on the end, 
 lengthwise of the body of the bolt, and afterwards dressing 
 and tapering slightly with a file. The end is now heated and 
 treated to a bath of potassium ferrocyanide, or, in other words, 
 case hardened and cooled quickly. This process makes steel 
 from iron for a depth of from 1/32 to 1/16 inch, according to 
 treatment. This bolt may now be used as a tap. 
 
 This method, like filing a square hole with a round file, 
 cutting left-hand threads with right-hand tools, and heating 
 
I4f5 
 
 LAYING OUT FOR BOILER MAKERS 
 
 a disc to make it smaller, is only a trick, yet at times quite 
 handy. These may be classed by some as trade secrets. The 
 writer has never seen them in print, and this will perhaps be 
 the means of information for many. 
 
 At times 'the bottom of the shell at the girth seams on 
 locomotives leak from various causes. Owing to the lagging 
 and jacket covering the leak and keeping it moist external 
 corrosion may take place, due to the aggravated conditions. 
 Ordinary chipping and calking the seams will not be of much 
 benefit if fitted badly. In that case a patch is riveted over 
 the exposed surface. The rivet line is first marked along the 
 shell on both courses. The girth rivets are then cut out, 
 and the girth seams scarfed in length for a distance equal to 
 the length of the patch. The scarfs are shaved extra thin 
 at the laps, to allow of a close fit at the calking edge. 
 
 As an ordinary plate, rolled to either particular course, 
 would not lay up to the adjoining sheet, it must be rolled 
 offset. To do this, two strips of iron of the thickness of the 
 required offset, are placed parallel, one on top and one on 
 the bottom of the straight plate, and in passing through the 
 rolls the sheet will be offset and rolled to the radius of the 
 inner and outer courses. The sheet is then jacketed or bolted 
 into place, and the girth rivet holes marked with a scriber. 
 The other rivet holes may be laid out to suit the diameter of 
 rivets used. 
 
 Before the patch is bolted to permanent position, the under 
 surface of the shell, coming within the bounds of the patch, 
 should be thoroughly cleaned and given a coating of red lead 
 and boiled linseed oil. This will generally stop further pitting. 
 The patch, after drilling, countersinking and beveling, may 
 be bolted to place, and the remaining holes drilled in the 
 shell. It is then riveted and calked. 
 
 The flues are first marked for length with a measuring 
 
 Fig. 38 
 
 pole, lengths are taken at each side, top, bottom ana center 
 If there is much variation each hole is measured individually, 
 and its division marked on the bridge. Afterwards chalked 
 circles are drawn around the areas, including measurements of 
 the same length. When the flues are cut off, annealed, 
 swedged and brought over to be put in, each flue bears a 
 distinguishing mark, in order to locate it in its alloted section. 
 In working the fire-box end. while the flues are being 
 welded, it is customary to roll coppers in all the flue holes. 
 One safe end then of several sizes, gauged by numbers, will 
 be found to average up among all the holes into a snug fit. 
 The flues are then swaged to this size. 
 
 In setting flues in the shell, if there are any new ones, they 
 .are put behind the steam pipe. A boy or man working in 
 
 the barrel will take the flues in through the big hole, and 
 transfer them to the sides, till steam pipes and door are in 
 clear. Then each flue may be entered in its own hole. For 
 beading length in the fire-box the rule is to allow 1/16 inch 
 for projection for every inch of diameter of flue. After the 
 flues are in, a man in the front end places a suitable pin in 
 each flue, and drives it back to suit the' judgment of the 
 boiler maker in the fire-box, who then clinches it in position 
 by turning a lip down on one side. After all the flues are 
 worked in this manner they are known as set. 
 
 It is next in order to expand and bead, where rollers and 
 expanders are both used, or prossers. It is then a matter of 
 judgment for the operator to decide the proper amount of 
 working for each tool. The flues are then turned over or 
 belled out and beaded. Beading tools on a well regulated 
 system are filed to a standard gauge for both back shop 
 and round-house work. 
 
 As beading tools are the hardest to make of all the boiler 
 makers' hand-tools, a few words as to their forging may not 
 be out of place. A piece of ^-inch hexagonal or octagonal 
 steel is cut to the desired length. The end is then heated 
 and upset about i54 inches from the point, enough to form 
 stock for the heel. It is then flattened and cut, as shown at 
 i'ig 18-A. Another mode of making two at once is shown 
 at Fig. 18-B. The length is made twice as great as before, 
 upset in the middle, and flattened to the desired thickness. 
 Two 5/16-inch holes are machine punched in the metal while 
 hot, on opposite sides, as shown. The cut is then made with 
 a hot chisel on dotted lines, as shown. They are then bent 
 slightly and swaged or filed rounding. 
 
 Boiler makers used to (and do yet in some small contract 
 shops) make their own tools. Therefore, it is well to be 
 prepared for an emergency, and, as in this instance, be pre- 
 pared to meet it. 
 
 In replacing the stock, the inside measure of the base is 
 taken and the sheet stretch-out is squared up as shown in 
 Fig. 16-A. The ends are butted and riveted with inside strap. 
 The only trouble likely to arise is getting the base rivet holes 
 in flat sheet. It may be done by stripping them off on a 
 piece of square iron the same thickness as the stack, and 
 marking their center on lines . 1-2, as shown. Care must be 
 taken not to turn the strip around after marking, or the holes 
 will not match when sheet is rolled. 
 
 CHAPTER IV. 
 
 FIRE ENGINE — STATIONARY. 
 
 Stationary boilers may be divided into two general classes, 
 known as water-tube and fire-tube. These again are sub- 
 divided into classes of their own. As the general principles 
 for which they are constructed in all cases remain the same, 
 no further classifications will be made. 
 
 Taking the two-flue boiler of forty years ago, shown in Fig. 
 19-A, simplicity of construction is its distinguishing feature. 
 What few of them remain in use at this date are not liable to 
 tax the skill of an ordinary boiler maker. The only operation 
 likely to cause trouble is the removal of the flues, and holding 
 on the rivets when the flues are again in place. The flues 
 
REPAIRING LOCOMOTIVE AND OTHER TYPES OF BOILERS 
 
 149 
 
 themselves may be made of telescopic plate sections, or inside 
 and outside courses riveted together, as shown in Fig. 19-B. 
 In either case one end is always belled or tapered to fit the 
 large hole generally located in the back. When the rivets are 
 cvit out of both ends and the flue blocked up at its small end, 
 to keep it from dropping to the bottom of the shell too soon, 
 the flue is pulled out of its own hole, large end first. After the 
 first section is in the clear, the rest of the flue will generally 
 pass without any further trouble. 
 
 Assuming that the necessary repairs have been made, and the 
 flues are ready to be put in place, one flue is first put in and 
 riveted up complete, the extra room gained that would be taken 
 up by the other flue, being enough to warrant this plan. When 
 the other flue is put in place there will be some of the rivets 
 on the sides and bottom very hard to hold without special 
 tools. For this purpose "spoon bars" are sometimes used. 
 They are made from a piece of wrought-bar iron, short enough 
 to handle crossways in the shell, and offset enough to conform 
 slightly to the curve of the flue. Leverage is obtained by 
 using a hook bolt in a hole several spaces in advance of the 
 rivet to be d: -ven. These rivets may also be held with a chain 
 having one or two especially prepared links. One end of the 
 chain may be fastened to an overhead brace by lapping with 
 and adjustable hook. The solid link is set to catch the rivet 
 head ; the other end of the chain is brought around the flue and 
 fastened to a bar with an S hook. A piece of iron laid cross- 
 ways over the flues will now make a fulcrum, and with the bar 
 acting as a lever any reasonable pressure desired may be 
 brought to bear on the rivet head. 
 
 The 6-inch flue boiler shown in Fig. 20 is but slightly dif- 
 ferent from the boiler shown in Fig. 19. In this case there 
 are twelve flues 6 inches in diameter, and riveted to the shell 
 as before. On account of the very small space in a 6-inch 
 flue in which to guide a hammer, especially made hammers are 
 used for this purpose, in which either the eye or the handle 
 is put in crooked, and the face bevelled to suit. As the head 
 holes are flanged inwardly to suit the diameter of the flue, these 
 flues are not beaded, but may be split-calked with a fine tool. 
 
 In boilers of this description, where the dome meets the 
 shell, the enclosed material is not often cut away, but simply 
 perforated enough to allow the free passage of steam. In 
 that case, if the dome head has to be removed, the rivet heads 
 cannot be held by a man on the inside. It will then be neces- 
 sary to cut a bar of iron of the length of the internal diameter 
 of the head, minus the thickness of two rivet heads. 
 
 This bar is then drilled in the center (cross-section) and 
 suspended through the "nigger head" hole. When the hot 
 rivet is in place, one end of the bar is applied to the head. 
 The free end is then swung to either side until it meets the 
 shell, and is then held in place by applying a bar to any of the 
 holes that may be in line. 
 
 An upright submerged flue boiler is shown in Fig. 21. Where 
 they are offset at the bottom to meet the outside shell, as 
 shown, scale and sediment settling on the inside have a ten- 
 dency to keep the water away from the sheet, thereby some- 
 times causing a bulge or pocket. Again, the corrosive effects 
 of sulphuric acid, which may be generated from wet ashes. 
 
 will sometimes cause a general pitting aroun^ the bottom on 
 the fire side. Both of these destructive agents working in 
 unison will sometimes cause the bottom to give out long before 
 the fire-bo.x proper would need replacing under ordinary con- 
 ditions. 
 
 In that case, if the rest of the fire-box and flues are in good 
 condition, the defective portion alone may be cut out to just 
 clear the first row of stay-bolts (as shown by dotted line) ; 
 and an ordinary mud-ring made of wrought iron of a thick- 
 ness to correspond with the depth of the water space may be 
 rolled and welded, and placed in position. It will not be neces- 
 sary to cut away any of the outside shell, as the mud-ring may 
 be readily calked in its new position. 
 
 If a new fire-box is needed, however, the flues are first re- 
 moved and the rivets and stay-bolts next cut out. After the 
 
 A 
 B 
 
 The Two Fluk Boileb. — 
 Tie. 19. 
 
 The Six Inch Flue Boilek. 
 
 Ft 6. 20. 
 
 box is removed and the size is taken, the flue sheet is first 
 laid out and flanged. It may then be wheeled and retraced on 
 the stretch-out of the envelope, and an extra amount added 
 equal to three and one-quarter times the thickness of the metal 
 used. The width may be found by adding one-half the depth 
 of the water space to the perpendicular height, as shown. The 
 stay-bolt holes may be stripped off and transferred to the 
 sheet; also the side seams are laid out to correspond, and the 
 flue sheet rivet holes marked and punched to match. The 
 sheet is then rolled and riveted, and the bottom is flanged to 
 the inside diameter of the shell. The mud-ring rivet holes are 
 then laid out, punched, and the box riveted to position. 
 
 In replacing the flues there will be a number of the ends in 
 the water jacket that come so close to the tapered connection 
 that they cannot be rolled at this end with a common roller. 
 In that case the cage with the enclosed rollers alone are set 
 in this end, and a long, tapered pin is worked through the flue 
 
LAYING OUT FOR BOILER MAKERS 
 
 ill the lire-box end. It is cither square on the projecting end 
 or has a few holes punched in its cross-section at an angle 
 with each other, to allow the use of a lever pin. The rod is 
 drh'en in until the rollers have a good grip. They are then 
 turned and redriven until the flue is rolled sufficiently. 
 
 A common make of a city fire engine boiler is shown in plan 
 and section in Fig. 23-A and B. Owing to the rapid steaming 
 qualities essential to its use, it differs in many respects from 
 all of the boilers previously described. The genera! principles 
 of its construction are to separate the enclosed volume of 
 water into small and communicating masses, by means of tubes 
 and drop flues. A large area of heating surface is obtained, on 
 account of the number of the drop pockets and tubes. Owing 
 to their peculiar construction and rough usage when in service, 
 they require especial attention, and much care is exercised in 
 their washing. 
 
 As shown in Plan B, Fig. 23, which is a plan view of the 
 top flue sheet, the flue centers are arranged in concentric 
 circles, the outside rows being iJ4 inches diameter, gradually 
 reducing to i inch in the center. In the fire-box shown in 
 section, Fig. 23-A, the flue bridges themselves are drilled and 
 tapped out to receive a hollow section of piping closing to a 
 square at the bottom end. They are arranged in lengths radi- 
 ally, as shown, to conform to the bed of coals. These pipes 
 inclose a section of galvanized or copper tubing of a size equal 
 to about two-thirds of their own internal diameter. These are 
 split and opened out at their bottom end to allow a free cir- 
 culation of the water, and to keep the upward and downward 
 currents from interfering with one another. An enlarged 
 view of one of these drop flues, with the piping in position, is 
 shown at C. 
 
 In case of repairs, the tubes, pockets and tools being of 
 such an odd size, are generally furnished by the builders. The 
 pockets will generally be the first to play out, as they collect 
 much sediment and cannot be emptied of either mud or water 
 without turning the boiler over. In running to or from a fire 
 the vibration acting on these pockets sometimes causes them 
 to eat through the threads and leak next to the flue sheet. 
 As the spaces between them are so small it is generally a diffi- 
 cult matter to tell which one is doing the leaking. It may 
 scmetimes be necessary to unscrew and take out several before 
 the right one is found. The defective part may then be cut off 
 and the pocket rethreaded and again applied. If too weak to 
 stand cutting, a new pocket or plug will have to be applied, 
 with a socket wrench. 
 
 If a full new set of tubes and pockets is needed, the boiler 
 is run into the shop under an overhead beam. The front 
 wheel trucks are disconnected and the boiler swung to a hori- 
 zontal position with a block and tackle. After the pockets are 
 taken out the flues are removed by grubbing with a steel bar. 
 This action is accomplished by cutting the flues loose on the 
 inside of the sheet with a tool like a cape chisel bar bent over 
 squarely. The burrs are afterwards cut out, and removed 
 through one of the large outside holes, care being taken not 
 to allow any of them to drop into the water space. As the 
 nud-ring is made of from }i to ll^ x 3-inch bar iron, bent 
 flat-ways, it leaves a very small water space, and any foreign 
 
 matter like burrs, nuts and washers is sometimes hard to fish 
 out. 
 
 As these flues and tubes are worked like the ordinary kind 
 we will now turn our attention to the self-contained oil-field 
 type of boiler, shown in Fig. 24, '■■ being a modification of the 
 locomotive. It possesses many advantages over all other types 
 of boilers for this especial purpose. Where first cost, free 
 steaming qualities and ease of transportation are essential it 
 has won out over all other competing makes. They are built 
 in sizes ranging from 30 to 50 horsepower, with shells from 
 14 to 5/16-inch steel. Instead of a cast or wrought mud-ring 
 the bottom is enclosed by a flanged shoe turned inwardly on 
 all four sides. On account of the lightness of the plates the 
 steam pressure is rarely allowed to go above no pounds. They 
 contain from forty-five to sixty 3-inch flues, ranging in length 
 from 7 to 14 feet. 
 
 By far the most expensive item in the repairs of these boilers 
 is the flue maintenance. In oil field districts, where the water 
 sometimes runs over 60 grains of impurities to the gallon, the 
 flues will last but a short time. As a new set costs between 
 $100 and $200. various ingenious methods have been devised 
 to reduce their cost rating to a minimum. Perhaps the most 
 general practice is to weld 6-inch new ends on the old flues 
 cut to the required length, and again apply to the boiler. Also 
 at times a long old flue is swaged to the internal diameter of 
 the fire-box ends, and cut to lengths of about l]i inches. Half 
 of the old flues are now removed in vertical rows by 
 skipping every other flue. The reinaining flues in position are 
 cleaned as well as possible and expanded in the back end. The 
 beads are cut off level and the ij^-inch ends driven tightly up 
 to beading length, then rolled, turned over and beaded. The 
 other half are then welded and replaced, or else put in new 
 out and out, thus keeping half a set of flues on hand all the 
 time. In the next case of retubing the bushed ends are re- 
 moved, and the other tubes worked vice versa. This method, 
 while appealing to the penurious, is not advocated by the 
 writer, and if used at all should be done only in isolated 
 places, and in cases where the low pressure would warrant 
 safety. 
 
 Where the tubes range in length over 9 feet they are some- 
 times cut off flush in the fire-box and front end, and are ripped 
 just enough for them to drop down and pull out at the front 
 hand-hole plate. The rivets are then cut out of the front flue 
 sheet, and the edge of the sheet corresponding with the lap is 
 jerked out enough to allow the seam to be scarfed back about 
 4 inches. Two rivets are then cut out of the lap, and the back 
 one redriven, countersunk on the inside. The flue sheet is 
 then moved back to this space, the shell marked and drilled, 
 and the flue sheet riveted in position. The old flues may now 
 be cut oflf to this length, cleaned and annealed, and applied as 
 before, care being taken to reverse them before setting. The 
 blank holes in the smoke-box may now be closed with either 
 bolts or rivets. After the sheet has been moved back several 
 times new ends are welded on the flues, and the flue sheet is 
 riveted in its original position. 
 
 In this type of boiler the fire-box is generally made in one 
 continuous sheet, having a flat crown sheet supported by 
 
REPAIRING LOCOMOTIVE AND OTHER TYPES OF BOILERS 
 
 driven stays. It frequentlj' occurs that the crown sheet bulges 
 or drops and may pull loose from three to four stays. After 
 heating and straightening the stays are counted and located 
 on the outside. Generally they will come somewhere under the 
 dome. A hand-hole is then cut, as shown at H. If it is a 
 through stay which is riveted on the outside of the dome cap, 
 as shown by dotted lines 1-2-3. they may be easily replaced ; 
 but if, as is generally the case, the wagon top is not cut away 
 under the dome, but simply perforated slightly, most of them 
 will be found riveted into a reinforcement plate on the wagon 
 top, in which case they are very hard to get at, and it does not 
 pay to remove them. 
 
 The bottom end is then pried away from the hole, and a 
 long drill inserted through the crown sheet. On account of the 
 curvature of the shell the drill may have to be set at an angle 
 with the crown sheet, to keep it from walking, but in no case 
 should this angle exceed 30 degrees. If a rivet hole in the 
 
 it will be best to measure the space in the clear betw'een the 
 mud-ring shoes, and mark the crown sheet to cut accordingly. 
 As this will seldom take in all the warped material, the sides 
 and flanges will have to be straightened. The new sheet is 
 then gotten out and placed in position by tilting the boiler 
 until the bottom is open enough to allow the sheet to pass and 
 enter the steam chamber. The side seams are marked, and the 
 crown plate pushed back on the flues. Then these holes are 
 either screw punched or drilled. 
 
 In order to more readily hold on the riveti! four hand-holes 
 are cut in the sides, their bottom coming on the dotted line 
 representing the level of the crown sheet, shown in Fig. 24-A. 
 Most of these boilers are equipped by the builders with a hand- 
 hole in the back head. In case the boiler in question has none, 
 it will be well to examine the arrangements of the braces in 
 the back and before cutting one in. Very often the rows of 
 T-irons will not allow a hand-hole to be cut above the crown 
 
 i 2 3 1-. ■ 1 ^^ ^ 
 
 Fig. 21 
 
 dome flange is found to come within this margin, it may be 
 tapped out and a hollow middle stay used. After the hole is 
 drilled, it may be found that there is not enough space to use 
 a spindle tap. A piece of round iron, small enough to go 
 through the hole, is then threaded and welded to a stay-bolt, 
 as shown at M. That makes, a steam-tight fit in the crown 
 sheet. Two nuts and washers are then screwed on the other 
 end of the bolt, one above and one below the wagon top. The 
 one coming below the wagon top may be fished into position 
 through the back head hand-hole plate, or strung through a 
 steam passage hole in the wagon top. As the holding power 
 in the thread of a J^-inch sheet is insufficient to allow the bolt 
 to be driven while held by its own tenacity, \t will be necessary 
 to use an off^set bar through the hand-hole while the bolt is 
 being riveted on the crown sheet. 
 
 Sometimes the crown sheet strips the bolts in its entire 
 length, and drops too far to straighten. It will then be neces- 
 sary to replace with a new one. Before cutting out, however, 
 
 sheet. In that case it may be left out, and an additional one 
 cut in the sides. The sheet is then bolted to place, the hot 
 rivets are applied with a spring tongs, and the head is held 
 with a semi-circular ended bar small enough to enter the hand 
 holes. The projecting position is measured for height from 
 the floor, and a plank cut to suit. When the rivet and bar are 
 in place, the plank slipped under the end will keep a heavier 
 and steadier strain on the bar than if held in position by main 
 strength. The rivets are driven overhead unless the boiler 
 can be turned easily. Like all other work subject to the flames 
 of oil, the lap and rivets are left as scant as possible. 
 
 Very often these boilers are made with a sheet or water 
 bottom, and a round fire-door and crown sheet. In that case 
 the last mentioned method will not apply. If the crown strip 
 is not much wider than the door it may be bent enough to 
 squeeze through and afterwards straightened. Some manufac- 
 turers place their longitudinal seam on the top or quarter at 
 the back end. This seam may then be ripped open enr>ugh to 
 
152 
 
 LAYING OUT FOR BOILER MAKERS 
 
 allow the old and new sheets to be transferred, and again 
 riveted bei'ore the crown plate is bolted down. If there is no 
 seam handy a rip may be made in the solid plate and after- 
 wards closed with an inside and outside butt strap. The vary- 
 ing conditions will, of course, govern the method to be used. 
 If the flues are worn out, it will, of course, be cheaper to re- 
 move them, also the front flue sheet, and apply the crown sheet 
 by way of the front end. 
 
 As most of these boilers blow off and feed through the pipe 
 in the bottom of the throat sheet marked D, it keeps the sedi- 
 ment in the shoe banked rgainst the sides of the curved ring, 
 thereby sometimes causing a burn or bulge as shown at Fig. 
 25. The burnt portion is removed, and a slip patch properly 
 applied has been found to give good results. The defective 
 portion is first marked and cut to dear the rivets, as shown at 
 A'-.Y, about 2 inches. On the inside of this cut at each end 
 make a parallel cut to enclose the U-shaped piece of metal 
 which is in view from the outside. When these two pieces are 
 removed the inclosed inside portion may be cut out with the 
 same tools, without raising the lap. A flat sheet is then laid 
 out to form the U-bend, and an amount added at each end 
 for lap. The four corners are then scarfed and the sheet bent 
 to shape. After heating and fitting to position the holes are 
 marked through the shell, and two additional holes are put in 
 each end to catch the old flange. 
 
 In this type of boiler there is always a hand-hole plate at 
 each of the four corners directly in line with the rows of 
 rivets. It is not large enough, however, to allow a full-size 
 wedge bar to be used in holding on the rivets. In that case a 
 cup is worked through the hand-hole in the other end, of a 
 sufficient thickness to allow the wedge to drive several inches. 
 In getting the four holes in the curved portion it will be neces- 
 sary to either block up under the wedge with strips of wood or 
 iron, or else insert plugs or patch bolts. When these boilers 
 are patched on the shoe, it is good practice to raise the fire 
 line above the patch, and also disconnect the feed from the 
 throat sheet, and locate it in the front ring about 22 inches 
 from the flue sheet, as shown at A', Fig. 24. 
 
 The writer has known cases where the boiler had sheet down 
 on account of leaks, and on changing the feed in this manner 
 to give no further trouble for months afterwards. Strangely, 
 occasionally two boilers, apparently exactly alike in detail, and 
 working under the same conditions side by side, will give re- 
 sults entirely unlike. In that case experimenting wi'.h the 
 burners will sometimes eliminate the trouble; usually there is 
 a short flue expanded into both sheets below the fire-door, as 
 shown. In this tube the spray burner is set and pointed at a 
 target made of brick checker work. This target splits the 
 flame and keeps the direct action of the fire from impinging 
 on the flues, as the sides catch the brunt of this intense heat, 
 varying around 3.000 degrees F. It causes very violent local 
 ebullition, and if the water space does not admit of free circu- 
 tion there is liable to be priming, and occasionally sharp re- 
 ports are heard, as if the boiler had been hit with a hammer, 
 thus indicating that the boiler is working under very unsatis- 
 factory conditions. 
 
 Experiments have shown that when the burner is placed 
 
 beneath the throat sheet and pointed at the door, the oil 
 globules mixed with dry steam spray will form a rolling flame 
 that acts on all the heating surface of the fire-box at once, thus 
 causing each part to contribute its own pro rata to the general 
 eflSciency of the boiler. This last mentioned method of firing 
 will often do much toward overcoming the defects in an ill- 
 behaved steam generator. 
 
 Perhaps one reason why this method of firing is not in more 
 general use is because it has been noticed on certain types of 
 boilers with a wide back head that the sheet has deflected from 
 the perpendicular around the door, by an amount varying 
 from I to 4 inches. Under the head of repairs the writer has 
 no solution to offer for this problem that would justify the 
 cost. Perhaps the best service for a boiler in this condition, 
 that has to be directly fired, is water heating. Even then 
 a sentinel valve should be placed on the boiler, and set to 
 screech at a few pounds below the operating pressure of the 
 safety valve. 
 
 In setting the safety valve the lever is generally graduated 
 and stamped for the different pressures. In case it is not, the 
 weight may be easily set, providing the principles involved are 
 understood. Referring to the skeleton diagram in Fig. 24-A, 
 F is the fulcrum, L the lever, W the weight, 5 the stem, V 
 the valve. 
 
 In calculations pertaining to the lever safety valve there are 
 five things to be determined, and it is necessary to know four 
 of these in order to find the fifth. They are the weight of the 
 ball, the area of the valve, the fulcrum, the steam pressure, and 
 the length of the lever. In this case the length of the lever is 
 to be determined, to know where to set the ball. Assume the 
 following data : Weight of ball, 10 pounds ; area of valve, 3 
 square inches ; fulcrum distance, 3 inches, and steam pressure 
 to be 25 pounds. 
 
 It is obvious that the area of the valve in square inches, 
 multiplied by the steam pressure in pounds, will be the 
 magnitude of the internal force, or 3 X 25 = 73 pounds. 
 It may then be readily understood that if a 75-pound 
 weight be placed at the point X, the forces will be in equi- 
 librium. Then if moved to the point H, which is five times the 
 distance F-X, it will take 5 X 75 = 375 pounds pressure to 
 raise the valve. Therefore, a much smaller weight may be 
 used. There is also a small amount to be subtracted from the 
 total upward force, due to the weight of the valve, stem and 
 lever, which may be found by calculation, or with a spring 
 scales ; in this case 15 pounds. 
 
 From the foregoing data the following formula is deduced: 
 
 r y, P — W^ 3 X ?5 — 13 
 
 D = X F. or • n: 3 = 18 
 
 IV 10 
 
 inches distance for the ball to be set to pop at 25 pounds. 
 
 If the length of the lever is given and the weight of the bal! 
 which will counterbalance a certain steam pressure is desired, 
 the above formula must be solved for W instead of D. 
 
 Having discussed the methods of making all usual re- 
 pairs which are necessary upon locomotive and stationary fire- 
 tube boilers, we will next take up the question of repairing 
 water-tube boilers. 
 
REPAIRING LOCO-MOTI\-E AND OTHER TYPES OF BOILERS 
 
 153 
 
 CHAPTER V. 
 
 A popular form of boiler used in the United Stales and 
 Europe is known as the water tube. This name is applied to 
 a class of boilers that contain water in stacks or nests ol 
 tubes of small diameter, which communicate with each other 
 and with a common steam and water chamber. The products 
 of combustion circulate around the tubes, and are usually 
 guided to their exit by baffle plates. There are many varie- 
 ties of this type of boiier in use ; however, they differ from 
 each other in detail rather than in principle of construction. 
 
 An early type of water-tube boiler is shown in Fig. 26. 
 Like all other boilers of the water-tube variety the principal 
 item of repairs is tube renewal. Owing to the bottom row 
 being more fully e.xposed to the action of radiant heat, they 
 will be the first to give trouble. Expanding alone will not 
 always stop the leak, as in this case the steam pressure has a 
 tendency to tighten the flue, and when leaking begins it is 
 often caused by the flue being eaten through at the header. 
 
 In renewing a tube in the bottom row, the corresponding 
 front and back header caps are removed, as shown at H-H. A 
 
 locating it as nearly as possible, however, all the tubes in the 
 immediate vicinity are also rolled. If that does not stop the 
 leak, it is customary to locate the leak from inside of the 
 furnace, while the boiler is filling with cold water. 
 
 In taking out a tube above the first row, the header caps 
 are first removed, and the tube is then split and closed in at 
 each end, care being taken not to scar the header. If the 
 building in which the boiler is situated has space enough be- 
 tween the boiler front and the wall to allow the flue to come 
 out the front way, it may be easily replaced. If, however, as 
 is often the case, it must go out the back way, on account of 
 the elevation of the boiler at the front end, the tube end, 
 coming out as it does at an angle, will often strike the ground 
 before the other end has cleared the water space. It will then 
 be necessary to dig a trench, or bend the tube to suit the 
 case. 
 
 In moving this type of boiler from place to place, each 
 nest of tubes is left in its own header, and the front and back 
 
 FIG. 26. 
 
 section of the bafHe plate is then cut loose at B-B. The tube 
 may now be cut loose at each header with a three-wheel pipe 
 cutter, or a ripper or chisel bar, as shown by dotted lines A'^. 
 After dropping in the clear, the old section may be pulled 
 out through the door. The burrs are then gouged out, and 
 the bearing surface of the header cleaned with a fine file. 
 After the new tube is set in position the surplus is divided 
 evenly for length in each end, and if necessary an iron or 
 copper shim is added to make a tighter fit in the hole, care 
 being taken to scarf each end of the shim, and see that none 
 of them are made of galvanized iron. 
 
 A peculiar form of expander is used to tighten flues on 
 most water-tube boilers. For this especial boiler an expander 
 with an adjustable slip collar small enough to enter the header 
 is used. There is also an extra pin furnished, with a link 
 combination that makes an almost universal knuckle. This 
 pin is used in combination with the roller cage for tightening 
 the bottom ends of the riser tubes shown at R-R-R. 
 
 After the expander is in place, it is manipulated in the same 
 manner as in the case of a fire-tube boiler. 
 
 In the case of tubes leaking among the central rows, as at 
 M-M, it is sometimes difficult to locate the exact one. After 
 
 FIG. 27. 
 
 risers alone are cut loose. After the boiler is again set up, 
 new risers are cut to the required length, and tightened to a 
 steam fit with the link pin previously mentioned. 
 
 Owing to various causes, the bottom of the steam drum 
 sometimes corrodes, and gets quite thin near the seam, as 
 shown at X. A slip patch may then be applied by first cut- 
 ting the rivets loose and then raising the seam with a couple 
 of lap wedges. A piece of boiler steel is then cut to the re- 
 quired dimensions, and scarfed back a few inches to a feather 
 edge. It is then rolled to the drum radius, and the thin edge 
 is driven home in the crescent opened by the lap wedges. The 
 holes are then m.arked and the patch taken down and drilled. 
 The seam holes may be moved outward slightly to allow for 
 draw. 
 
 After the bearing surface of the drum is well cleaned, it is 
 good policy to coat it with some non-corrosive adhesive mix- 
 ture, such as cement or red lead and oii. The patch is then 
 again put in place, and bolted up through the draw holes. 
 The body holes in the drum may then be drilled through the 
 patch in position ; the riveting and calking may then be done 
 as previously explained. 
 
 The Heine water-tube boiler shown in Fig. 27 differs in 
 
154 
 
 LAYING OUT FOR BOILER MAKERS 
 
 many respects from that shown in Fig. 26. The mud col- 
 lector is located in the steam drum, as shown at M. The 
 water legs are strengthened with hollow stays, as 5-5-5, and 
 the back water leg rests on rollers at R-R. As the deviation 
 froni the horizontal in this boiler is small, the tubes may be 
 readily renewed. After cutting out, as in the previous case, 
 an ordinary fire-tube expander may be used on this type of 
 boiler, providing the guard has been removed, and an exten- 
 sion fitted to the mandrel pin. 
 
 In isolated places, when a tube gives out and none are at 
 hanil, a temporary repair may be made by swaging a short 
 
 FIG. 29. 
 
 plied, and if handled properly will do the next best thing to 
 a permanent job. 
 
 A peculiar shaped, but very efficient, type of steam genera- 
 tor, is shown in Fig. 28. It is known as the Stirling water- 
 tube boiler, and consists of three upper steam and water cham- 
 bers, and one lower large drum, all connected by stacks of 
 nearly vertical 3^-inch tubes, as shown in the end view. The 
 hot gases strike the first row of tubes near the bottom, and 
 are guided by a partition throughout their length to the top, 
 where they cross over and strike the second stack of tubes 
 at C, thence ranging downwards to the bottom drum, and up 
 the last stack of tubes to the atmosphere. 
 
 The circulation of the water is rapid and positive, and takes 
 place as follows : The hot water, with the steam bubbles in 
 entrainment rise through the two front stack of tubes, and 
 descend in the rear. The top back drum delivers the feed 
 water downwards through the back nest of tubes. 
 
 The tubes themselves being of an odd shape and size, extra 
 ones are generally furnished by the builders. In replacing 
 old tubes, they are first ripped and closed in at each end from 
 inside the drums. The end is then knocked out of the top 
 hole until it is clear of the bottom of the drum. It may then 
 be turned enough to start through one of the side doors in 
 the boiler front. Where the proper expander is at hand, no 
 trouble will be experienced in resetting the tubes. When two 
 men do the work, the tubes are first assorted into groups of 
 
 FIG. 30. 
 
 section of tube or piping to a little more than the internal 
 diameter of the tube. From 4 to 6 inches may then be cut off 
 and split in a longitudinal direction. The split edges are then 
 draw filed, giving the corresponding end of each about a I to 
 8 taper. The two pieces may have to be tried in the hole sev- 
 eral times to form a nice fit. A distance piece is then set in 
 the split bushing, to keep the bearing edges from turning in. 
 It is obvious, then, that if the end of one of the scctio'.':s be 
 driven in witli a bar, the taper will cause the bushing to make 
 a snug fit in the tube end. 
 
 To make a more lasting job, a piece of No. 8 or 16 gauge 
 iron, 114 inches wide, is cut to a length equal to the inner 
 circumference of the bushing. A pair of roller tube expand- 
 ers of the next size below the original tube may then be ap- 
 
 the same length for each row. Marking the top end of each, 
 as the bottom and top are curved to a different radius, the 
 bottom end of the tubes may now be marked about }s inch 
 from the end, this mark serving as a guide for the man hold- 
 ing up the tube in position. When the mark is at the edge 
 of the hole in the bottom drum, the other man, working from 
 inside the top drum, will then clinch the flue in position, pro- 
 vided the lengths are running even. 
 
 In replacing from one to six scattered tubes, it often hap- 
 pens that the shop doing the work has on hand for the next 
 nearest size a 3-inch Dudgeon roller only. In case of com- 
 pulsion, they may be used, by cutting a 3-inch tube into lyi- 
 inch sections, and driving one section in each end of the tube 
 until its center is in the same plane as the tube plate. The 
 
REPAIRING LOCOMOTIVE AND OTHER TYPES OF BOILERS 
 
 155 
 
 flushing may then be rolled out until the enveloping tube is 
 a steam-tight fit. 
 
 A section side view of the Yarrow marine water-tube boiler 
 is shown in Fig, 29. As illustrated, it roughly resembles an 
 inverted V. The furnace is placed between the legs, thus im- 
 parting heat to the tubes and water by conduction and radia- 
 tion. The products of combustion flow between and around 
 the tubes, and the convection currents of water ascend the 
 inner rows, as shown at X-X-X-X. The bottom tube plates 
 connect with a semi-cylindrical drum or water chamber. 
 
 The drum not being of sufficient size to accommodate a man, 
 the tubes may be renewed by first disconnecting the chamber 
 body from the tube plate, and then cutting the tube ends loose 
 in one of several ways. They maj' be sheared off at the top 
 of the bottom tube plate, and ripped and closed in at the top, 
 or ripped or sheared top and bottom ; or cut at top or bottom 
 and pulled out of the opposite holi; through the furnace. 
 
 will sustain the weight of the water chamber without ad- 
 ditional blocking. These two last named tDoilers are of Euro- 
 pean make, and are used to a certain extent in foreign navies. 
 They are built in sizes ranging from 500 to 1,800 horse-power. 
 
 A cylindrical type of automobile boiler is shown in Fig. 31, 
 plan and elevation. The tubes are of copper, and of small 
 diameter. They are spaced in rows corresponding to con- 
 centric circles, as shown in plan. Being in reality a fire-tube 
 boiler, the tubes may be gruboed or ripped out, as explained 
 in a previous issue. 
 
 In tightening the ends of new tubes, a tempered steel pin 
 of small taper may be driven in each to suit the judgment of 
 the operator. A segment collar is then set in the tube, just 
 clear of the inner surface of the tube sheet. A drift pin is 
 then driven into the collar, thus opening it and enlarging the 
 tube so that when linear expansion takes place on account of 
 heat when the boiler is in service the tendency will be for 
 
 Fig. 31 
 
 Elevation 
 
 In resetting the new tubes, the bottom tube plate, being 
 loose, must be set in position by blocking or by leaving in a 
 sufficient number of old tubes to sustain its weight. Again, a 
 few new tubes may be divided throughout its length and rolled 
 in place. 
 
 The "hog-back" boiler, shown in Fig. 30, is built on the Yar- 
 row principle, but embodies several distinguishing features, 
 chief of which are ease of access to the tube ends, and con- 
 struction lending to the ready renewal of same. As shown, 
 each water chamber is provided with a manhole, thus enabling 
 the bottom tube ends to be rolled without inconvenience. Re- 
 ferring to side view, it will be seen that the curvature of the 
 tubes allows them to be readily withdrawn through the man- 
 hole located in the back of the steam chamber at A. Any in- 
 dividual tube may thus be cleaned, examined or renewed 
 without difficulty. 
 
 In renewing a full set, the large circulating pipes P-P-P 
 
 the tube to become tighter in the sheet. Through and through 
 stay-rods are sometimes placed between the bridges, as shown 
 at I-I-I-I. In case of renewal they may be drilled out and 
 replaced in the same manner as an ordinary stay-bolt. 
 
 The outside shell of the boiler proper is wrapped with oands 
 of ribbon steel, or they are sometimes reinforced with strands 
 of piano wire. These last mentioned details are factors in the 
 cause of safety-, and are used as a precautionary measure to 
 insure freedom from explosion. 
 
 Fig. 32 represents a type of boiler known as the nest-coil 
 semi-flash. It consists of a coil of 34-inch seamless tubing, 
 ranging in length from 30 to 60 feet. The feed-water is 
 delivered into one end of the coil at the bottom, in very small 
 jets, at varying intervals. It is almost instantly flashed into 
 steam, and in traveling through the length of the coil it is 
 further heated and delivers into the small drum C, in the 
 form of superheated team. 
 
IS6 
 
 LAYING OUT FOR BOILER MAKERS 
 
 Strictly speaking, this not being much of a boiler makers' 
 boiler, the repairs are more efficiently executed by the builders 
 themselves as their conveniences enable them to bend the 
 tubing easier and better than could be accomplished in most 
 boiler shops. 
 
 Boilers of the Fig. 31 and 32 type have a large margin of 
 safety, being tested with hydrostatic pressure in some cases 
 
 0M( 
 
 FIG. 33. 
 
 as high as 3,000 pounds per square inch. The ordinary work- 
 ing pressure varies between 200 and 450 pounds per square 
 inch. 
 
 It was a slight modification of the Fig. 31 type of boiler 
 that furnished power for the Stanley steam racer when it 
 
 broke the world's record by making a mile in 28 1-5 seconds, 
 the greatest speed attained by any self-propelled vehicle ever 
 built. 
 
 A peculiar combination of fire and water-tube boiler is 
 shown in Fig. 33. It consists of an upper and lower annular 
 steam and water chamber, connected by rows of vertical water 
 tubes. These again inclose fire tubes of a still smaller di- 
 ameter, which extend through the steam and water chambers 
 and discharge into the stack. The top and bottom steam and 
 water chambers are also perforated and contain short fire 
 tubes, not shown in the drawing, which allow some of the 
 gases to circulate around the outside of the water tubes. A 
 downward discharge of the water is provided for by means 
 of the circulating pipes P-P-P-P. 
 
 There being six tube plates confined within narrow limits, 
 the tubes may be more readily removed by first turning the 
 boiler over on one side. As the fire tubes will be the first to 
 play out, they may be removed as in the case of a locomotive, 
 except that these tubes will have to come out of their own 
 bole. Ordinarily a set -of the water tubes will outlast three 
 sets of fire tubes (according to the inventor, Robert Emmet,' 
 Fort Worth, Tex.) 
 
 If a full set of fire and water tubes is required, the bolts 
 B-B-B-B, holding the top and bottom tube plates are first re- 
 moved. The fire tubes are then cut off and closed in at each 
 end, but not pulled out. Each tube plate is then marked so 
 that it can be replaced in its exact former position. They are 
 then taken down and the fire tubes may be readily withdrawn. 
 The water tubes may then be taken out without fear of the 
 drums sagging any, as the circulating pipes will hold them in 
 position. All the tubes being I, 2 and 3 inch standard size, 
 the ordinary Boss roller and beading expander are all the 
 finishing tools required. 
 
 The 3-inch water tubes are first cut to length, then set and 
 rolled in position without beading or pressing. The tube 
 sheets are then bolted to place, using either a fibrous or me- 
 tallic gasket. The fire tubes are then applied and allowed to 
 come just flush at the bottom. The bearing portion of the 
 tube sheet being concave at this end, no beading is thought 
 necessary on the tubes, as this method allows the flames to 
 impmge upon the water-protected surfaces only. 
 
 Hand holes are provided at H-H, so placed as to be directly 
 in line with the opposite plate and also between tube rows. 
 These holes are spaced at regular intervals to facilitate clean- 
 ing. The circulating pipes are joined to the shell by riveted 
 connections, and seldom, if ever, need renewal. It may be 
 accomplished, however, by cutting at C and replacing with a 
 pipe of the same dimensions, containing a union, either 
 flanged, cast or wrought. 
 
THE LAYOUT AND CONSTRUCTION OF STEEL STACKS 
 
 Stacks, or chimneys, serve two objects, the first and most 
 important being that they create a draft or current of air 
 (equal in intensity to the difference between the weight of the 
 cohimn of hot gases inside the chimney and a column of air 
 outside of the same height and sectional area) through the 
 furnace, so that a sufficient quantity of air is brought into con- 
 tact with the fuel in a certain space of time to produce the 
 desired rate of combustion. 
 
 The factors which determine the capacity of a stack to pro- 
 duce a certain draft are the height of the stack, the difference 
 in temperature between the air outside and the gases inside, 
 and the friction opposing the flow of the gases through the 
 furnaces, boilers, up-takes and the stack itself, while the capac- 
 
 either the height or the area is assumed, the other quantity 
 may be determined from the following formula : 
 
 H. P. = 3.33 (A — 0.6 v~) vtt; 
 
 where H. P. = horsepower of the boilers, A ::= area of stack 
 in square feet, H = height of stack in feet. This equation, 
 which was deduced by Mr. William Kent some time ago, has 
 been widely used, and when the assumptions upon which it is 
 based and its limitations are fully understood it can be de- 
 pended upon to give very good practical results. The as- 
 sumptions upon which the formula are based are : That the 
 draft varies as the square root of the height of the stack, and 
 that the effective area shall be computed from a diameter 4 
 inches less than the actual diameter of the stack. The con- 
 
 k---17-0-Inalde-I)iar- 
 
 k — ^17-6-Bolt-ClrcIe 
 
 FIG. I. — METHOD OF ANCHORING SELF-SUPPORTING STEEL STACKS. 
 
 ity of the stack to handle various quantities of hot gases 
 depends upon the velocity and density of the gases and the sec- 
 tional area of the stack. Since the density of the gases de- 
 creases with an increase in temperature, it is evident that to 
 produce a strong draft the temperature of the gases should be 
 as high as practicable without undue loss of heat. Since, how- 
 ever, 550 degrees F. is the temperature at which the maximum 
 weight of gas will be delivered, the temperature will not have 
 any very appreciable effect in determining the size of the 
 stack. 
 
 The main points to be considered, therefore, are the height 
 and area. The height must be great enough to produce suf- 
 ficient draft to burn the kind of fuel to be used at a certain 
 desired rate of combustion, and the sectional area must be 
 large enough to carry off the gases produced at this rate of 
 combustion. 
 
 In laying out a stack for boilers of a certain horsepower, if 
 
 slants for this equation were determined from the performance 
 of a typical chimney, and are, therefore, entirely empirical. 
 
 Assuming a coal consumption of 5 pounds per horsepower 
 per hour. Table No. I was compiled by Mr. Kent, the values 
 being computed by means of the above equation. In any case, 
 if the horsepower is given and the height assumed, as is fre- 
 quently the case in the design of a stack, the efifective area E, 
 which is a section whose diameter is 4 inches less than the 
 diameter of the stack, may be determined from the following 
 formula : 
 
 .3 H. P. 
 
 E — 
 
 VlT 
 
 The area of the stack is frequently made equal to about one- 
 eighth the grate area and then the height is determined to give 
 the required draft. 
 
 Steel stacks are of two kinds, guyed and self-supporting. 
 
158 
 
 LAYING OUT FOR BOILER MAKERS 
 
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 -Gutslde-Dlam.-15-1>4- 
 
 DETAILS OF SECOND COURSE OF PLATING OF STACK I9I FEET HIGH BY 10 FEET DIAMETER, THE RING TO BE CONSTRUCTED OF FOUR 
 PLATES Yi INCH IN THICKNESS WITH DOUBLE-RIVETED CIRCUMFERENTIAL SEAMS AND SINGLE-RIVETED VERTICAL SEAMS. 
 
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 DETAILED LAYOUT OF ONE PLATE OF THE ABOVE RING, SHOWING METHOD OF OBTAINING CAMBER (SEE 
 PAGE 20), EXACT DIMENSIONS AND DETAILS OF RIVETING, SCARFING, ETC. 
 
THE LAYOUT AND CONSTRUCTION OF STEEL STACKS 
 
 159 
 
 T"^ 
 
 i, M— - 
 
 -L 
 
 10-ioH. 
 
 }-lo'll- 
 
 ^13 8>S-], 
 
 FIG. S. — SELF-SUPPORTING STEEL STACK, IQI FEET 
 HIGH BY 10 FEET DIAMETER. 
 
 GuvL-d Stacks deptiid for their stability upon ropes or wires 
 which are attached to the stack by means of an angle-bar or 
 Z-bar ring, at about two-thirds the height of the stack from the 
 ground. There should be at least four guys for a stack, the 
 rods being usually of 'A or %-inch iron, depending upon the 
 size of the stack, since the load which they are to support is 
 that due to the pressure of the wind upon the surface of the 
 stack. This is usually figured as 25 or 30 pounds per square 
 inch of projected area. If the stack is very tall, two sets of 
 guys should be used, fastened at different points on the stack. 
 Since a guyed stack must be only strong enough to sustain its 
 
 FIG. 3. — SECTION OF BASE PL.\TE USED WITH SELF-SUPPORTING 
 STACK. 
 
 own weight, it is a light and cheap form of stack to construct, 
 and is usually made in the form of a straight tube of in-and-out 
 rings. In that case all the sections can be rolled to a cylin- 
 drical shape and riveted up in the shop, and afterwards easily 
 erected in position without the aid of expensive scaffolding. 
 -As guyed stacks are seldom much over 100 feet high, the thick- 
 ness of plate used is usually No. 10. 12 or 14-gage. Due to 
 
 FIG. 4. — SECTIONAL VIEW AND FLANGE OF BASE PL.\TE. 
 
 their lightness, this form of stack does not require a substantial 
 foundation, and they are frequently set directly upon the 
 breeching of the boiler. 
 
 Self-supporting stacks, an illustration of which is given in 
 Fig. 2, require a more careful design, as they must sustain 
 not only the load due to their weight but also that due to the 
 pressure of the wind. They are usually given a taper of about 
 1/16 inch to the foot, and the bottom is flared out or made bell- 
 shape, to give added stability, the diameter of the base being 
 about one-tenth the height of the stack. The stack rests upon 
 a base plate usually of cast iron of the shape shown in Fig. 3. 
 This base is usually cast in four or more sections, which are 
 fastened together with bolts through the flanges or lugs, which 
 are cast on the ends of each section, as shown in Fig. 4. The 
 
i6o 
 
 LAYING OUT FOR BOILER MAKERS 
 
 base plate for small self-supporting stacks is sometimes cast in 
 one piece with cored rivet holes in the flange. The lower 
 course of the plating of the stack is then riveted directly to the 
 base plate, which in turn is anchored to the foundation by 
 holding-down bolts. This construction is, however, not re- 
 
 d 
 
 FIG. 5. — DET.MLS OF MANNER OF SUPPORTING LINING. 
 
 in Fig. I. The lower course of the stack simply rests in the 
 groove of the base plate without being riveted to it. The hold- 
 ing-down or anchor bolts are fastened directly to the shell 
 through steel brackets, as shown. Two bracket plates, of the 
 form shown in the detail. Fig. i, are fastened by angles to the 
 
 FIG. 6. — DETAIL OF RIVETING OF TCI' RINGS. * 
 
 e o _ oj^jo_6_q 
 
 FIG. 7. — DETAIL OF RIVETING ABOVE 65 FEET. 
 
 "X 
 
 liable, and should not be used for large stacks, since the wind 
 pressure brings a tension stress on one side of the stack at the 
 base where it is fastened to the cast-iron ring, and the cast iron, 
 which has a low tensile strength at best, cannot be relied upon 
 to sustain the load, as there are frequently blow holes or other 
 imperfections in the casting. 
 
 The construction which is now used to replace this is shown 
 
 shell a few inches apart. Riveted to the top of these brackets 
 is a heavy plate in which a hole just large enough to receive 
 the anchor bolt has been drilled. The tension stress is then 
 transmitted from the shell to the bolt through steel, whose 
 strength can be accurately figured, ajid which can be depended 
 upon to sustain the load for which it is designed. 
 The foundation for the stack depends upon the character of 
 
 TABLE NO. I. 
 
 a 
 
 c 
 
 Effective 
 Area 
 
 e=a-Va 
 
 Sq. Ft. 
 
 Height of Stack in Feet. 
 
 
 50 1 60 1 70 SO 1 90 1 100 | 110 125 | 150 175 200 225 | 250 | 300 
 
 5 
 
 Coratnercial Horsepower. 
 
 18 
 
 21 
 
 24 
 27 
 
 1-77 
 2.41 
 
 3-14 
 3-98 
 
 •97 
 1.47 
 2.08 
 2.78 
 
 23 
 
 35 
 49 
 65 
 
 2i; 
 38 
 54 
 72 
 
 27 
 41 
 58 
 78 
 
 29 
 44 
 62 
 83 
 
 66 
 88 
 
 
 
 
 
 
 
 
 
 
 3° 
 33 
 36 
 
 3^ 
 
 4.91 
 5-94 
 
 7.07 
 8.30 
 
 3.58 
 4.48 
 5-47 
 6.57 
 
 8 
 
 4 
 
 92 
 "5 
 
 141 
 
 100 
 125 
 152 
 '83 
 
 107 
 
 133 
 163 
 196 
 
 "3 
 141 
 
 173 
 208 
 
 119 
 149 
 182 
 2ig 
 
 156 
 191 
 229 
 
 204 
 245 
 
 268 
 
 
 
 
 
 
 42 
 48 
 
 60 
 
 9.62 
 
 ■2-57 
 15.90 
 19.64 
 
 7.76 
 10.44 
 
 13.51 
 16.98 
 
 
 
 
 
 
 2 
 
 16 
 
 
 23 
 31 
 
 
 245 
 330 
 427 
 536 
 
 258 
 348 
 449 
 56s 
 
 271 
 365 
 472 
 593 
 
 289 
 389 
 503 
 632 
 
 316 
 426 
 
 551 
 692 
 
 342 
 460 
 
 595 
 748 
 
 492 
 636 
 800 
 
 675 
 848 
 
 894 
 
 
 66 
 72 
 78 
 
 84 
 
 23.76 
 28.27 
 33 -18 
 38.48 
 
 20.83 
 25.08 
 29.73 
 34.76 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 694 
 835 
 
 728 
 
 876 
 
 1,038 
 
 1,214 
 
 776 
 
 934 
 
 1,107 
 
 1,294 
 
 849 
 1,023 
 1,212 
 1,418 
 
 gi8 
 1,105 
 1,31° 
 1. 531 
 
 981 
 1,181 
 1,400 
 1.637 
 
 1,040 
 1.253 
 1,485 
 1.736 
 
 1,097 
 1,320 
 1,565 
 1.830 
 
 1,201 
 I>447 
 1.71S 
 2,005 
 
 90 
 96 
 
 102 
 108 
 
 44.18 
 50.27 
 
 56.75 
 63.62 
 
 40.19 
 46.01 
 52.23 
 58.83 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1,496 
 1,712 
 1,944 
 2,090 
 
 1.639 
 1,876 
 2,130 
 2,399 
 
 1.77° 
 2,027 
 2,300 
 2.592 
 
 1,893 
 2,167 
 
 2,459 
 2,771 
 
 2,008 
 2,298 
 2,609 
 2,9,39 
 
 2,116 
 
 2,423 
 2,750 
 3.098 
 
 2,318 
 2,654 
 3,012 
 3.393 
 
 114 
 120 
 132 
 144 
 156 
 192 
 
 70.88 
 
 78.54 
 
 95 63 
 
 113.10 
 
 132-73 
 201 .06 
 
 65.83 
 73.22 
 89.18 
 106.72 
 125.82 
 192.55 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 2,685 
 2,986 
 3.637 
 4,352 
 5.133 
 7.855 
 
 2,900 
 3.226 
 3.929 
 4,701 
 5.540 
 8,483 
 
 3,100 
 3.448 
 4.200 
 5,026 
 5.924 
 9,066 
 
 3.288 
 3.657 
 4.455 
 S.331 
 6,285 
 9,618 
 
 3.466 
 
 3.855 
 4.696 
 S.618 
 6,624 
 10,137 
 
 3.797 
 4,223 
 5.144 
 6,155 
 7,340 
 11,090 
 
THE LAYOUT AND CONSTRUCTION OF STEEL STACKS 
 
 i6i 
 
 the soil upon which it is to rest, and should be designed by 
 some one who has had considerable experience in such work. 
 The opening from the flues leading from the boilers to the 
 stack should be located, if possible, underneath the stack, as 
 any opening cut in the shell greatly reduces the strength of the 
 stack. 
 
 Nearly all self-supporting stacks and some guyed stacks are 
 protected by firebrick lining. This lining is made sufficiently 
 heavy to sustain its own weight, and is not connected to the 
 
 a Riven ^_ 
 FIG. 8. — DETAIL OF RIVETING ABOVE 2$ FEET. 
 
 L_1 ^_|-Q— Q-0.ivg'__Q., 
 
 FIG. 9. — DETAIL OF RIVETING AT BASE. 
 
 shell except at intervals of 40 or 50 feet. A lining is seldom 
 continued clear tp the top of the stack, as the gases are suf- 
 ficiently cool by the time they have traveled about three- 
 quarters the length of the stack, so that no injury will result 
 from their contact with the steel. The sections of lining are 
 supported as shown in Fig. 5. A Z-bar ring is riveted inside 
 the stack, and to the inner flange of the bar a wide plate is 
 bolted, which extends several inches below the bar. The lower 
 section of the lining extends to within about ij4 inches of the 
 Z-bar, in order to allow for expansion and is supported by the 
 plate. The next section of lining rests upon the Z-bar, and is 
 supported through it by the shell. An inch or so of space is 
 left between the lining and the shell to allow for expansion. 
 
 The top of a stack is usually flared out for the sake of ap- 
 pearance to form a cornice or cap. This cap is made of light 
 plates and, of course, has nothing to do with the strength or 
 stability of the stack. In order to stiffen the top of the stack 
 an angle or Z-bar ring is usually placed around it, while just 
 below the cap another Z-bar ring is riveted to the shell to 
 provide a place for attaching scaffolding for painting the stack. 
 For this purpose also a light iron ladder is usually riveted to 
 one side of the stack. Sometimes in the case of a very large 
 stack a light spiral staircase runs part way up the outside of 
 the stack. 
 
 The stability of the stack may be determined as follows : 
 
 Find the total weight of the stack and lining. This may be 
 considered as a vertical force acting downward through the 
 middle of the foundation. Find the total pressure on the chim- 
 ney, which would be approximately 25 X the height X the 
 diameter. This may be considered to act in a horizontal direc- 
 tion at the middle point of the chimney, so that its moment 
 about the base would be the total force X 5^ the height of the 
 chimney. Divide this moment, due to the wind pressure, by the 
 weight of the chimney, and the result will be the distance from 
 the middle of the foundation to the resultant force due to the 
 combined forces of wind pressure and weight. For stability 
 
 FIG. 10. — CAP MADE WITH CONICAL RINGS. 
 
 this force should act within the middle third of the width of 
 the base. 
 
 The stress per lineal inch at any section may be determined 
 from the following formula : 
 
 The stress per lineal inch at any section = moment due to 
 wind pressure in Inch pounds -^ J4 X 3-1416 X (diameter in 
 inches)'. Assuming a safe fiber stress of 10,000 pounds per 
 square inch, the thickness of plate necessary to sustain this 
 stress may be figured from the following formula : 
 
 Thickness in inches 
 
 stress per lineal inch 
 
 10,000 X the efficiency of the horizontal joint. 
 
 The calculation for the stress per lineal inch should be made. 
 at a number of sections in order to be sure that the stress at 
 any point does not exceed the safe working stress of the ma- 
 terial. If desired, more elaborate computations may be made 
 for the strength of the riveted joints subjected to the bending 
 strain due to the wind pressure. In the case of the horizontal 
 joint the rivets on both the windward and leeward side of the 
 stack will be in shear, although the joint on the windward side 
 will be in tension and on the leeward side in compression. 
 
 In order to follow through the calculations which must be 
 made in the layout of a particular stack, assume that it is 
 required to build a stack for boilers which have a total horse- 
 power of 285 and a total grate area of about 60 square feet. 
 The effective area of the stack should be about one-eighth the 
 total grate area, or about 7% square feet. The diameter cor- 
 responding to this area would be about 9 feet 8 inches. The 
 actual diameter of the stack, however, according to the as- 
 
l62 
 
 LAYING OUT FOR BOILER MAKERS 
 
 sumptions which were made, should be 4 inches greater than 
 this, or about 10 feet. Using the equation 
 
 Horsepower = 3.33 (^ — .6 X V^) V^ 
 and substituting 285 as the value of the horsepower and 10 X 
 .7854 as the value for A, the height of the stack may be 
 determined : 
 
 285 = 3-33 (7-854 - -6 V 7.854) Vl7 
 
 V // = 13.8 
 
 H— 191 
 
 Therefore, the required dimensions of the stack are : Height, 
 
 191 feet; diameter, 10 feet. The details of a stack built to 
 
 these dimensions are shown in Fig. 2. The actual diameter 
 
 of the shell of the stack will be greater than 10 feet, since the 
 
 D 
 
 FIG. II. — LAYOUT OF CAP WITH VERTICAL STRIPS. 
 
 inside diameter of the lining should be at least 10 feet. As the 
 lining at the top should be approximately 4 inches thick, the 
 actual diameter of the stack at the point where the lining is 
 stopped should be about 10 feet gYz inches. 
 
 A computation should be made for the thickness of plate at 
 intervals of 25 or 30 feet throughout the height of the stack. 
 Using the formula quoted in the first part of the article for 
 the thickness of plate, we have at a height of 25 feet : 
 
 166 
 
 II X 166 X 30 X X 12 
 
 2 
 
 r = 
 
 T = .43, or, approximately, 7/16 inch. This is assuming a 
 mean diameter of 11 feet with a diameter of 12 feet 3 inches 
 at the height of 25 feet, and that the horizontal seam is double 
 riveted with an efficiency of 75 percent. 
 
 Making the same computation at a height of 65 feet, where 
 the diameter is 11 feet 7 inches, and the horizontal seam single 
 riveted with an efficiency of about 60 percent, T is found to be 
 about .344, or ^/i inch. At a height of 95 feet, where the 
 diameter is 11 feet 3 inches, T is found to be about .21 inch. 
 As it would not be advisable, however, to use anything less 
 than J4-inch plate, the next 30 feet of the stack should be con- 
 
 ■7854 X (12.2s X 12)' X 10,000 X -75 
 
 FIG. 12. — BELL SHAPED PORIION OF SELF-SUPPORTING STACK. 
 
 structed of 5/16-inch plate, leaving only the last 60 feet of 
 }4-inch plate. 
 
 The details of the riveting for the dififerent thicknesses of 
 plate are shown in Figs. 6, 7, 8 and 9. It will be seen that the 
 double-riveted horizontal seams give an efficiency of about 70 
 percent, while the single-riveted seams give an efficiency of at 
 least 60 percent. 
 
 The stack is constructed of rings each 60 inches wide, made 
 up of three plates. Where the diameter exceeds 12 feet each 
 ring should be made in four sections. Each ring is in the 
 form of the frustum of a right circular cone, and may be laid 
 out according to any of the methods described in the first 
 chapter under "conical surfaces where the taper is small." In 
 the stack shown in Fig. 2 each ring is an inside ring at 
 its lower edge and an outside ring at its upper"" edge. 
 This style of construction is frequently reversed. In de- 
 
THE LAYOUT AND CONSTRUCTION OF STEEL STACKS 
 
 163 
 
 termining the length of the plates which form a ring an 
 allowance of about seven times the thickness of the plate 
 should be made between an outside and an inside ring. 
 
 The plates are sheared, punched, scarfed and rolled in the 
 shop, but the plates which form a ring are not riveted together 
 until they are erected in place. The scaffolding is built up 
 on the inside of the stack, the plates being hoisted by means 
 of a short jib crane on top of the scaflfold. The seams should all 
 be calked after riveting, so that there will be no leakage of air 
 into the stack. This is one of the important advantages which 
 a steel stack has over a brick chimney, since the brick work in 
 a chimney frequently becomes loose and allows air to leak into 
 the chimney, impairing the draft. 
 
 A cap or cornice for a stack may be constructed in one of 
 two ways ; either as shown in Fig. 10 of narrow plates in the 
 form of circular rings, or, as shown in Fig. 11, of narrow strips 
 of plate which run lengthwise of the stack. In the first case, 
 the layout of each ring is obtained in the ordinary way for 
 finding the development of the frustum of a right circular 
 cone. The dimensions for the diameter at the top and bottom 
 of the ring and for the width of the ring being taken from a 
 full-sized sectional drawing similar to that shown in Fig. 10. 
 
 The plate used for these rings is seldom more than % or 3/16 
 inch thick, and, therefore, if made in narrow rings, the cap 
 will have a smooth appearance. The proportions governing 
 the general outline of the cap will depend upon the height and 
 diameter of the stack. 
 
 The plates which form the cap are supported by brackets, as 
 shown in the detail, Fig. 10. In this case eight brackets are 
 provided, made of zyi by 2j4 by J4-'"ch angle-bars, forged to 
 conform to the outline of the cap. These brackets are riveted 
 by clips to the shell of the stack. A 3 by 3 by S/l6-inch angle 
 is riveted around the upper edge of the cap after it has been 
 beveled to the proper angle. A similar angle is riveted at the 
 -nrner of the cap. The plates are riveted together and are 
 
 secured to the angle-iron brackets by 5/16-inch rivets spaced 
 at about 4 inches pitch. 
 
 The layout of the strips for a cap constructed according to 
 the second method is shown in detail in diagrams A, B, C and 
 D, Fig. II. The outline of the cap is first drawn full size, and 
 the arc 1-5 is divided into any number of equal spaces, as at 
 points 2, 3 and 4. These points are projected to the plan view 
 at A. In order to give a smooth appearance to the cap, it 
 should be constructed of from twenty to thirty strips. In this 
 case thirty-two have been taken, thus dividing a quarter of the 
 cap into eight equal strips. Having divided the quarter plan A 
 into eight equal spaces, the pattern for one of these strips may 
 be laid out as at C, where 1-5 is made equal to the length of 
 the arc 1-5 in the outline of the cap, and the offsets i-l', 2-2', 
 3-3', etc., are measured from the corresponding lines in A. 
 
 In a like manner the pattern for the lower part of the cap 
 may be obtained as at D, where the length of the strip 9-5 is 
 made equal to the length of the arc 9-5 in the outline, and the 
 offsets 9-9', 8-8', y-f, etc., are taken from the corresponding 
 lines in the plan view B. The laps and allowances which must 
 be made, due to bending the material, should be added to these 
 patterns. The brackets and frame work for this cap are 
 similar to those shown in Fig. 10. 
 
 Instead of making the lower rings of a very large and heavy 
 stack in the form of conical surfaces, a section from 15 to 20 
 feet high is frequently made bell shape, as shown in Fig. 12. 
 This gives the stack a' more graceful appearance, and it can be 
 so constructed as to give a firm foundation for the rest of the 
 stack. The bell portion, like the fancy top or cap shown in 
 Fig. II, is constructed of narrow strips of plate which run 
 lengthwise of the stack. These, as may be seen from the 
 illustration, are joined with lap seams, the alternate strips 
 being outside and inside. The layout of these strips may be 
 obtained in the same way as the strips for the cap, which was 
 described in connection with Fig. 11. 
 
i64 
 
 LAYING OUT FOR BOILER MAKERS 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 A Y=Breeching. 
 
 Figs. I and 2 represent a style of breeching that has been 
 in use for over thirty years. I believe it was first designed 
 by the Erie City Iron Works, of Erie, Pa. It is very simple in 
 construction and easy to make, and in ray judgment, when 
 properly proportioned, makes a very neat job. In some shops 
 whare a great variety of sheet iron work is done, there is gen- 
 erally a large number of pieces lying around the shop large 
 enough to make one of these breechings or the greater part 
 of it. By making it in small sections as shown, it is easily 
 worked up and put together. 
 
 To lay out such a breeching, first strike up one-half of the 
 side elevation. Fig. 3, the desired size as follows : First lay 
 down the center line JR. Then lay out the band or upper 
 
 Front Sjlevatlpn 
 
 Side Elevaiion 
 
 part. Then the branch piece; also sketch up the slope of the 
 connection at the bottom, as shown, and erect vertical lines 
 from where the circular part begins. This represents the round 
 part of the leg. Now, strike square lines across all of the 
 different pieces in Fig. 3, and on the round p^rt strike the 
 quarter circles and divide them into any number of equal parts 
 as shown, in this case three parts, and number them I, 2, 3 and 
 4. Then extend lines through these points at both ends as 
 shown. Now strike the quarter circle on top, which represents 
 the diameter of the part where the stack is to fit, and on the 
 side strike another quarter circle, as shown at 5 in Fig. 3, 
 equal in diameter to the round part of the leg, and divide it 
 into the same number of parts as at 9, 10, 11 and 12. Extend 
 these lines to cut the large circle as shown. Now drop the 
 dotted lines as shown to cut the lines on the leg, and a line 
 traced through these points will be the miter line, or, in other 
 words, will be the points where the leg will strike the main 
 diameter. We are now ready to lay out the plates which make 
 up the leg. You will note that each part, as lettered K, L, 
 M, N, P and Q in Fig. 3, has a similar letter on the plates 
 which are laid out. 
 
 TO LAY OUT THE LEG PLATES. 
 
 Take K, Fig. 3, and lay it out as shown in plate K. First 
 find the circumference and space it off in twice as many parts 
 
 as the quarter circle in Fig. 3 is divided into, and as shown in 
 plates K and Q, and number them as 4, 3, 2, i, 2, 3 and 4. 
 Then take the distance from the line OG, Fig. 3, to where line 
 I strikes the miter line, and mark off a corresponding distance 
 from line OG, plate K, on the center line. Now take the length 
 of line 2 from OG, Fig. 3, and mark off a corresponding dis- 
 tance on line 2 each side of the center line on plate K. Then 
 get the length of lines 3 and 4 from Fig. 3 and transfer them 
 to plate K. Then by tracing lines through these points you 
 will have the miter line on plate K, and by laying out rivet 
 
 holes on the miter line, also on the seam, and add for laps, 
 plate K will be complete. 
 
 To lay out plate Q, locate lines 4, 3, 2, i, 2, 3 and 4 and 
 make them any length longer than the plate. Now the shop 
 way of laying this out is to take a strip of iron, lay down on 
 Fig. 3, and mark the square line on either end, and then mark 
 the distance from the square line to the miter line on both 
 ends as found by the quarter circles on lines i, 2, 3 and 4, and 
 transfer these lengths to plate Q on lines 4, 3, 2, i, 2, 3 and 4, 
 and lines drawn through these points will be the miter line or 
 line of rivet holes. Now, by laying out the necessary rivet 
 holes around the edges and adding for lap, plate Q will be 
 complete. Plates P and L are laid out in the same manner. 
 
 TO LAY OUT THE FL.^T P.-VRT OF SIDES. 
 
 All that is necessary to develop the side pieces is to first 
 start on plate M and lay down the bottom line, then erect the 
 perpendicular lines, taking the miter line as the height, and 
 draw the miter line as shown in plate M. Then locate your 
 rivet holes on the seams and the miter line and add for lap 
 and plate M will be complete. 
 
 Plate A' is laid out in a similar manner, or, in other words, 
 transfer the lines on Fig. 3, plate A'^, to the sheet which you 
 
i66 
 
 LAYING OUT FOR BOILER MAKERS 
 
 wish to use for this purpose, locate your rivet holes, add for 
 •lap, and the development of the sheets for the leg will be 
 complete. 
 
 TO LAY OUT TOP, OK FIG. 8. 
 
 For this purpose Fig. 6 may be used. Fig 6 is a quarter 
 circle of the top ring divided into five spaces. Fig. 8 represents 
 one-half of the top spaced from Fig. 6 from i, 2, 3, 4, 5, 6, 
 5, 4, 3, 2 and I. The object of Fig. 8 is to show how to lay 
 out the hole where the round part of the leg, Fig. 3, strikes 
 the top. First take the distances marked T, U and V, Fig. 3, 
 
 ri^s 
 
 1 2 3 
 
 4 
 
 5 li 
 
 5 
 
 4 
 
 3 
 
 2 1 
 
 1 1 
 1 1 
 
 1 Fi^.8 
 
 ! 1 
 
 1 
 
 1 1 
 
 
 1 1 
 
 1 1 
 
 1 ij-. 
 
 1 
 1 
 
 [ 
 
 1 
 1 
 1 
 
 1 
 1 
 i 
 1 
 
 
 1 
 
 1/M i'' 
 
 Nj 
 
 " 7t.! t3 1 P> 
 
 f IT H 1 
 
 \ 
 
 and transfer them to Fig. 8 as shown. Now, take the lengths 
 of lines 9, 10, 11 and 12 on Fig. 3 from the quarter circle 5 
 and transfer them to Fig. 8, each side of the center line 6, 
 as shown at L, M and the bottom line; then a line traced 
 through these points will be the cut out of the hole. 
 
 TO LAY OUT THE BREAST PLATE. 
 
 First sketch up Fig. 4. Line JR is the center line. Then 
 strike the quarter circle and divide that portion where the 
 breast plate strikes into any number of equal parts, in this 
 case five, and number them as 1, 2, 3, 4, S and 6, and square 
 these lines down to the base of the main ring as denoted by 
 6. 5> 4> 3) 2 and /. Now extend these dotted lines to point K 
 and you are ready to lay out the breast plate. Fig. 5. One 
 way to develop this plate is on the same principle as a cone 
 is laid out. Another is by triangulation. To lay this out 
 by the first method is to extend line JK, Fig. 4, to the center 
 
 line O, and with radius OJ strike the curved line on Fig. 5, 
 using O as a center, and with dividers set around the circle, 
 Fig. 4, mark off points i, 2, 3, 4, 5 and 6, Fig. 5. Now get 
 the length of line JK, Fig. 4, and from point I of Fig. S mark 
 point K. Now draw lines from points 6-6 to K, and you have 
 the flange line. Now add for the necessary flanges and lay 
 out your rivet holes and the sheet will be complete. 
 
 TO LAY OUT THE BREAST PLATE BY TRIANGULATION. 
 
 Strike up Fig. 7 in the follbwing manner: First lay down 
 line PS and strike the perpendicular line PK at right angles. 
 Next take the perpendicular height. Fig. 4, from 6 to K, and 
 mark of? from P to K, Fig. 7. Now with Z, Fig. 4, as a 
 center, take the distances from Z to I, Z to 2, Z to 3, Z to 4, 
 Z to 5 and Z to 6, and mark off a corresponding distance on 
 line PS, Fig. 7, as shown, numbered i, 2, 3, 4, 5 and 6; then 
 extend lines from these points to point K, as shown by dotted 
 lines. Then you are ready to develop Fig. 5 by triangulation. 
 
 Take the distance from K to i. Fig. 7, and mark off a cor- 
 responding distance from K to i, Fig. 5. Now with 3'our 
 dividers set to spaces on the circle, Fig. 4 ; mark one space. 
 Fig. 5, each side of i as 2, 2. Then with tram points set from 
 K to 2, Fig. 7, mark off a corresponding distance from K to 
 2, Fig. 5. Then from points 2 mark off another space at 3 
 each side, and with tram points set from K to 3, Fig. 7, mark 
 off the same distance from K to 3, Fig. 5 ; then take the length 
 of the rest of the lines in Fig. 7 from K to 4, iv to 5 and K to 
 6, and transfer to Fig. 5, each time marking one space with the 
 dividers as shown, and you will get the same results as you 
 did by the first method. Then add for your rivet holes and 
 flanges and the sheet will be complete. 
 
 Layout of a Tank, 85 Feet in Diameter by 30 Feet 
 in Height. 
 
 Large steel tanks are seldom required to carry any pres- 
 sure except that due to the head of the. fluid which they con- 
 tain. Therefore, the first thing to do in laying out such a 
 tank is to determine the stress on the bottom of the shell, due 
 to the head of water, oil, or whatever fluid the tank is to 
 hold. The stress will be greatest, of course, on the bottom of 
 the shell, and the thickness of shell plates may be decreased 
 from the bottom to the top. 
 
 Let us assume that the tank is to be used for softening 
 boiler feed-water; that is, the tank must be strong enough 
 so that it may be entirely filled with water. The maximum 
 pressure on the tank will, then, be that due to a head of 30 
 feet of water. One cubic foot of water at ordinary tempera- 
 ture, 62 degrees F., weighs 62.352 pounds ; that is, a head or 
 depth of I foot of water will cause a pressure of 62.352 pounds 
 per square foot, or 62.352 -r- 144 = .433 pounds per square inch. 
 Therefore, a head or depth of 30 feet of water will cause a 
 pressure of .433 X 30 = 12.99 pounds per square inch at the 
 bottom of the tank. 
 
 We then have a cylindrical shell 85 feet in diameter with an 
 internal fluid pressure of 12.99 pounds per square inch. The 
 thickness of plate necessary to withstand this pressure may be 
 
MISCELLANEOUS PROBLEMS IX LAYING e)LT 
 
 167 
 
 found by the ordinary tormiila for finding the thickness of a steel of a fair amount of ductility should be used; therefore, 
 
 its tensile strength should be about 60,000 pounds per square 
 inch. If the vertical seams are made with a treble riveted lap 
 joint, an efficiency of 75 percent may be easily obtained. Sub- 
 stituting these values in the formula for the thickness of shell 
 
 boiler shell. 
 If 
 
 t = thickness of plate. 
 p = pressure in pounds per square inch. 
 D := inside diameter of tank in inches. 
 F = factor of safety. 
 
 Ts = tensile strength of the steel in pounds per 
 square inch. 
 
 plate, we have 
 
 12.99 X 1,020 X 4 
 
 * = == .588 inch. 
 
 00,000 X -75 X 2 
 
 Note: 16'opening located iu opposite 
 side of bottom in Pluto W 9 A in same 
 positiou aa 20 ' opening located in W 9, 
 
 FIG. I. — PLAN AND ELEVATION OF STEEL TANK 8s' BY 30'. 
 
 £ ^ efficiency of riveted joint. 
 A, £> X F 
 
 sr.-O'Dia. ^J 
 
 Then / = 
 
 Ts X E X 2 
 
 p in this case we have found to be 12.99. £> is 85 X 12, or 
 1,020 inches. F may be taken comparatively small, as the pres- 
 sure on the tank is small, and the wear on the steel will not 
 be excessive; 4 will be a sufficiently large factor to use. Mild 
 
 This is slightly less than % ; therefore, use ^-inch plate for 
 the bottom course. 
 
 As the tank is to be 30 feet high, and plates about S feet 
 wide can be easily handled in the shop, make the tank in six 
 rings or courses. Number the rings from bottom to top, I, 2, 
 3, 4, S and 6. The thickness of plate to be used for the second 
 ring must be computed in the same way in which the thick- 
 ness of plate for the first ring was found. The pressure on 
 
i68 
 
 LAYING OUT FOR BOILER MAKERS 
 
 this ring will be that due to a head of 25 feet of water, or 
 25 X-433 = 10.S25 pounds per square inch ; therefore, 
 10.825 X 1,020 X 4 
 
 t = ^ .491 inch. 
 
 60,000 X -75 X 2 
 Use H-inch plate for this course. 
 
 For the third ring, the pressure is that due to a head of 
 20 feet of water, or 20 X -433 = 8-66 pounds per square inch ; 
 therefore, 
 
 8.66 X 1,020 X 4 
 
 * '.=z = .392 inch. 
 
 60,000 X 75 X 2 
 Use 7/16-inch plate for this course. 
 
 4-33 X 1,020 X 4 
 
 t = - 
 
 = .212 inch. 
 
 60,000 X -65 X 2 
 
 On such a large tank it would not be advisable, for structural 
 reasons, to use plate less than J-rJ inch in thickness ; therefore, 
 make both the fifth and sixth rings of J^-inch plate. 
 
 The approximate pressure on the lower ring, due to the 
 weight of the shell, assuming that i-inch plate weighs 40 
 pounds per square foot, will be found as follows : 
 5(25 + 20+17.5 + 15 + 10+10) 487.S 
 = = 651 
 
 12 X .623 
 pounds per square inch. 
 
 12 X .625 
 
 i i 
 \t 
 
 1: 
 
 ^ 
 
 5th Ring 
 
 W 16-18-Plates X\ 62x"x 182Vio" 
 
 All x' Rivets 
 
 J 
 
 — 78-Spaces@ about 2K = 178'/io 
 
 m 
 
 .1^1 
 
 
 — -S9-Spaces® about 4H"~ 17"%' 
 
 6th Ring 
 
 W 16-18-Plates h'^ 62;f "x 182x' 
 
 All ^^'liivets 
 
 -'/S-Spaces® about 2Jf = 177%- 
 
 1 
 
 -72-Spaces@abont 2J^ = 11S% 
 
 3rd Ring 
 W 13-18-PIates V^^ y^ 62X'x-185X' 
 
 5^"KiTetS'''~ 
 
 -68-Spaces®about 2^"= nsH"- 
 
 -78-Spaces@ about 2Jf "= 177% 
 
 4th Ring 
 W 14-lS-Plates %'x 62%'x 182js' 
 
 ■^X'Kivets 
 
 72-Spaces® about 2)4 = 177%- 
 
 — C8-Spaces®about 2%°= ITS)^"- 
 
 68-Spaces@ about 2%'= m'Vi,- — 
 
 l.Pl. uitb Manhole ■■.i", l-Pl. with Mimhole "B" « iH" ^^ I '*-j 
 
 ^» 
 
 i 
 
 
 3nd Ring 
 
 W 12-18-Plates Ji'x 625i"x 185K 
 All ;«'KiTeta 
 
 CS-SpacesQ-about 25^''- 177%' 
 
 NOTE: .\11 Plates are to be Bevel Sheared for Outside Caulking 
 Outside of Plates shown 
 
 FIG. 2. — DEVELOPMENT OF SHELL PLATES OF STEEL TANK 85' BY 30'. 
 
 For the fourth ring, the pressure is that due to a head of 
 15 feet of water, or 15 X -433 = 6.459 pounds per square inch. 
 As the pressure on this ring is only half of that at the bottom 
 of the tank, the vertical seams may be double instead of treble 
 riveted. The efficiency of the joint will then drop to about 
 65 p&raent; therefore, 
 
 6-459 X 1,020 X 4 
 
 t = = .339 inch. 
 
 60,000 X -65 X 2 
 
 Use J^-inch plate for this course. 
 
 For the fifth ring, the pressure is that due to a head of 10 
 feet of water, or 10 X -433 = 4.33; therefore. 
 
 This pressure is, therefore, small compared with the stress in 
 the plates, due to the internal fluid pressure, so that the shell 
 which has been figured to withstand the fluid pressure with a 
 fairly large factor of safety will, be sufficiently strong to sup- 
 port the weight of the tank. The force due to the weight of 
 the tank acts in a vertical direction, while the force due to the 
 fluid pressure acts in a horizontal direction. Therefore, the 
 lesultant of the two forces will be slightly larger than the 
 force due to fluid pressure. 
 
 Make the width of plates in the five upper rings 60 inches 
 between rivet lines. As the tank is to be 30 feet high over all, 
 the width of the bottom ring will be something less than 6o' 
 
MISCELLANEOUS PROBLEMS IN LAYING CUT 
 
 169 
 
 inches, depending on the width of laps at the top and bottom 
 of the tank. These will be determined when the size of rivets 
 is determined. The length of plates between rivet lines may 
 be made about 15 feet, as plates much larger would be difficult 
 to handle in the shops, and small ones would necessitate an 
 unnecessary number of vertical seams. As our tank is 85 feet 
 in diameter, the circumference is about 267 feet; therefore, if 
 each ring is made of eighteen plates, each plate will be about 
 14 or 15 feet long between rivet lines. Make the bottom ring 
 an outside ring, then the mean diameter of the ring measured 
 to the center of the thickness of the plate will be 85 feet 5^ 
 inch. The circumference corresponding to this will be 85.052 
 X 12 X 3-l4i6 = 3206.41 inches. Dividing by 18 the length of 
 one plate is found to be 178% inches. 
 
 The second ring will be an inside ring, and since the plates 
 are I2 inch in thickness, the mean diameter will be 84 feet 
 llj^ inches. The circumference corresponding to this will be 
 3202.86 inches. Dividing by eighteen we find the length of 
 one plate between rivet lines to be 177 iS/16 inches. 
 
 The third ring will be an outside ring, and as the mer.n 
 diameter is only slightly smaller than the mean diameter 
 of the first ring, the length of the plates may be made the 
 same as for the first ring. Similarly the length of the plates 
 in the fourth ring may be made the same as the length of 
 plates in the second ring. The mean diameter of the fifth ring 
 is 85 feet % inch, making the length of one plate equal 
 178 1/16 inches. The mean diameter for the sixth ring is 84 
 feet 11^ inches, making the length of one plate 17731/32 
 inches. 
 
 For the vertical seams in the first ring, use i-inch rivets. 
 The pitch of the rivets may then be determined by making 
 the strength of the net section of the plate equal to the 
 strength of the rivets. The strength of the plate will be 
 t (_p — d) Ts. Calling 5" the shearing strength of rivets in 
 pounds per square inch, the strength of rivets for a treble 
 riveted lap joint will be J4 X 3-i4l6 d' 5'. Assuming S equals 
 42,000 pounds per square inch or .7 Ts, and equating the 
 strength of plate to strength of rivets we have 
 
 t {l>-d) XTs = V4X 3.i4i6<f (.7 Ts). 
 
 ■75 X 3-1416 X .7 d- 
 p = d + - — 
 
 t 
 
 1.65 d' 
 
 d + 
 
 p = 3.64 inches, or 3 11/16 inches. The pitch of rivets for the 
 vertical seams in the second and third rings will be found in 
 a similar manner, using % rivets in each case. 
 
 As the vertical seams in the fourth ring are double riveted, 
 the strength of rivets will be equal to J4 X 31416 d' X -7 Ts. 
 
 I.I d" 
 
 Therefore, p z= d -\ 
 
 t 
 Using J4 rivets for the fourth ring, we find the pitch equals 
 2.4 inches. A slightly larger pitch might just as well be used 
 and still have a perfectly tight joint. Increasing the pitch of 
 the rivets simply means that the strength of the rivets is 
 
 r.iade less than the strength of the plate and that the joint 
 will fail by the shearing of the rivets. Therefore, use 2j4 
 inch pitch for the fourth ring. 
 
 .\ similar calculation for the fifth and sixth rings, using 
 ^■^-inch rivets gives 2.34 inches pitch. Use 25^ for these 
 seams. 
 
 As the stress in the shell in a vertical direction, due to the 
 weight of the tank, has been found to be small, all circular 
 seams may be single riveted except the lower edge of the first 
 ring, which should be double riveted. By using the size of 
 rivets ordinarily used with given thicknesses of plate and a 
 sufficiently small pitch to insure a perfectly tight joint, suffi- 
 cient strength will be obtained for these seams. As the thick- 
 ness of the first ring is 5^, use ^ rivets in the circular seams, 
 using a 3-inch pitch in the lower double-riveted seam and a 
 25^ pitch in the upper single-riveted seam; ^^-inch rivets with 
 a 2i/% pitch may be used for the second ring. The diameter 
 of rivets for the top seam of the third ring may be reduced 
 to 34 inch, and the pitch to about 2^^ inches. Beginning with 
 the top seam of the fourth ring, 5^-inch rivets spaced about 
 2^/4. inches may be used in the remaining seams. 
 
 As the bottom of the tank is well supported, j4-inch plate 
 may be used with single-riveted seams, %-'mzh rivets. The 
 plating will be laid in parallel rows using plates of as large 
 size as possible, say, approximately, 6 feet wide by 15 feet 
 long. This will give thirteen rows of plating, eleven of which 
 are 7854 inches wide between rivet lines, the two outer ones 
 being 7454 inches wide. A plan of the bottom may be laid 
 out to a small scale, and the lengths of the seams scaled of? 
 the drawing, or the length of each seam may be calculated, 
 since it is the chord of a circle whose distance from the cente! 
 of the circle is known. For if R is the radius of the circle 
 and 5" the distance of chord from the center of the circle, and 
 L the length of the chord, then 
 
 {Y, LY = {R Jr S) {R - S) 
 
 L = 2VR' 
 
 -S' 
 
 A template made to fit the arc of a circle 85 feet in diameter 
 may be used to obtain the shape of the ends of the outside 
 plates, two points in the curve having been found, viz., the 
 ends of the seams. The butt joints of adjacent plates should 
 never come together. The plan. Fig. i, shows the arrange- 
 ment of these plates. 
 
 It siill remains to lay out the angle-bars which join the 
 shell and bouuin, and also the angle-bars which are placed 
 around the top edge of the tanks as stiffentrs. As there is to 
 be a double row of J^-inch rivets in each leg of the bottom 
 angle, at least a 6-inch angle should be used, and as the lower 
 shell plates are % inch, the angle should be at least ^ inch 
 thick. The length of a 6 inch by 6 inch by f^ inch inside 
 angle bent to an outside diameter of 85 feet, may be found 
 as follows : 
 
 If Z? = outside diameter of ring, 
 {•F^ width of angle, 
 f^ thickness of angle, 
 
 then the length of the ring before bending will be 3.1416 
 [D — (1/3 W + t)]. Therefore, the length of the bar will be 
 
I/O 
 
 LAYING OUT FOR BOILER MAKERS 
 
 3.1416 [8s X 12 — (6/3 + .625)] = 3196.18" or 266.4'. The 
 ring may be made of nine bars, each bar 29.6 feet long. 
 
 Using a 4-inch by 4-inch by ^■^-inch bar around the top edge 
 of the tank the length of the ring before bending, since it is 
 an outside ring, will be 3.1416 [85 X 12 + 4/3 + -625], which 
 equals 3211.58" or 267.63'. This ring may also be made of nine 
 bars, making the length of each bar 29.74 feet- 
 Having determined the sizes of the plates and angles for 
 the tank, the bill of material may be tabulated as follows : 
 
 BILL OF MATERIAL FOR I-TANK. 
 No. 
 
 Mark. 
 
 Required. 
 
 
 Description. 
 
 W I 
 
 39 
 
 Plates, 
 
 J"xSi".\i9iJ". 
 
 W 2 
 
 2 
 
 " 
 
 J"x Sketch. 
 
 W3 
 
 2 
 
 " 
 
 i"x " 
 
 W 4 
 
 4 
 
 " 
 
 i"x « 
 
 W5 
 
 2 
 
 " 
 
 i"x " 
 
 W 6 
 
 2 
 
 " 
 
 i"x « 
 
 W7 
 
 4 
 
 " 
 
 i"x " 
 
 W 8 
 
 4 
 
 " 
 
 i"x " 
 
 W 9 
 
 4 
 
 " 
 
 i"x " 
 
 Wio 
 
 4 
 
 " 
 
 i"x « 
 
 Wn 
 
 18 
 
 " 
 
 |"x58J"xi86|". 
 
 W12 
 
 18 
 
 " 
 
 4"x62j"xi85i". 
 
 W13 
 
 18 
 
 " 
 
 i'j".x62|"xi85i". 
 
 W14 
 
 18 
 
 " 
 
 f"x62|"xi82|". 
 
 W15 
 
 18 
 
 " 
 
 J"x621"xi82t\". 
 
 W16 
 
 18 
 
 « 
 
 i".x62i"xi82i". 
 
 W17 
 
 9 
 
 Angles, 
 
 6" X 6" x|"x3o' 0". 
 
 W18 
 
 9 
 
 " 
 
 4" X 4" x|".x3o' 0". 
 
 W19 
 
 .9 
 
 Plates, 
 
 X\"XI2/J"X2' 0". 
 
 W20 
 
 9 
 
 " 
 
 f "x 6J" X2' 0". 
 
 W21 
 
 2 
 
 30' Sections of std. ladder. 
 
 W22 
 
 2 
 
 I2"xi8 
 
 ' Saddle Plates, Manheads 
 
 
 
 arches, bolts, cranes, etc., complete 
 
 C I 
 
 I 
 
 20' C. 
 
 I. Gland and calking strip. 
 
 C 2 
 
 I 
 
 16" C. 
 
 I. Gland and calking strip. 
 
 C3 
 
 2 
 
 8" C. 
 
 I. Gland and calking strip. 
 
 Mark. 
 
 Required 
 
 R23 
 
 1000 
 
 R24 
 
 75 
 
 R2S 
 
 300 
 
 R26 
 
 15° 
 
 R27 
 
 2300 
 
 R28 
 
 1200 
 
 R29 
 
 1250 
 
 R30 
 
 4600 
 
 R31 
 
 15° 
 
 R32 
 
 145° 
 
 R33 
 
 800 
 
 R34 
 
 5° 
 
 -^iS 
 
 100 
 
 R36 
 
 800 
 
 R37 
 
 250 
 
 R38 
 
 1500 
 
 R39 
 
 95°° 
 
 BILL OF RIVETS FOR 1-TANK. 
 No. 
 
 Rivets, I " 
 
 v 
 
 Description. 
 
 
 
 diam. 
 
 X 
 
 2^" 
 
 Cone Heads 
 
 a 
 
 X 
 
 si' 
 
 ' 
 
 « 
 
 • 
 
 X 
 
 3" 
 
 ' 
 
 « 
 
 « 
 
 X 
 
 2j' 
 
 " 
 
 " 
 
 a 
 
 X 
 
 2i" 
 
 « 
 
 « 
 
 ' 
 
 X 
 
 = i' 
 
 « 
 
 " 
 
 It 
 
 X 
 
 24' 
 
 " 
 
 " 
 
 « 
 
 X 
 
 2" 
 
 " 
 
 " 
 
 « 
 
 X 
 
 2j" 
 
 « 
 
 " 
 
 " 
 
 X 
 
 li" 
 
 « 
 
 « 
 
 " 
 
 X 
 
 If" 
 
 a 
 
 a 
 
 " 
 
 X 
 
 2i" 
 
 « 
 
 ' 
 
 " t" " == li" • 
 
 The outside edges of the shell and the inside edges of the 
 bottom should be marked for calking, and the corners of the 
 plates, which come between two other plates, should be marked 
 for scarfing; also the manholes and locntion of pipe flanges 
 should be indicated, as shown on the drawing. Fig. i. 
 
 The capacity of the tank in gallons may be found as follows: 
 Find the area of the bottom of the tank in square feet, multiply 
 it by the height of the tank in feet, and multiply the product by 
 7.481, the number of gallons in a cubic foot. 
 
 3.1416 X (8s)= X 30 X 7-481 
 = 1,273,530 gallons. 
 
 The Layout of an Offset from a Round to an Oblong 
 Pipe. 
 
 The plan and elevation of the offset are shown in Fig. I. 
 It will be seen that this problem requires three separate pat- 
 terns, and that while two of them may easily be obtained by 
 
 orthographic projection, the third must be developed by tri- 
 angulation. 
 
 In Ffg. 2 is shown the method of solving this problem when 
 both halves are symmetrical. First draw the elevation of the 
 offset as shown by ABC. On C, place the half-section of 
 the round pipe, as shown in E, and on A the half section of 
 the oblong pipe, as shown by D. Divide the semi-circles in 
 both half-sections into equal spaces, and number E from i to 
 5, and D from 6 to 12. From these figures in E and D draw 
 lines parallel to the lines of the pipes intersecting the miter 
 lines in C and A, respectively, as shown from i to 5 and 6 to 
 12 in B. Connect these figures with solid and dotted lines, as 
 shown, which represent the bases of sections which will be 
 constructed in K and M, whose altitudes are equal to the va- 
 rious heights in the semi-sections in D and E. 
 
 For example, to obtain the true length of the line 9-3 in 
 B, take this distance and place it on any line in K, as shown 
 by 9' 3'. from which points erect perpendiculars 9' 9 and 3' 3, 
 equal, respectively, to the distance measured from the line 12 
 6 to point 9 in i? and the distance measured from the line i 5 
 to point 3 in £ Then will the distance 9 3 in iC be the true 
 
MISCELLANEOUS PROBLEMS IX LAYING OUT 
 
 171 
 
 length of 9 3 in B. Proceed in this manner for all the true 
 solid lines shown in K, and the true dotted lines shown in M, 
 all indicated by similar numbers. 
 
 Before the pattern is developed for B, the half patterns for 
 A and c are developed as follows : Obtain the girth of the 
 half section D and place it on the line 6' 12, extended as 
 shown from 6' to 12'. Draw the usual measuring lines which 
 are intersected by lines drawn parallel to 6 12 from similar 
 
 tance of S 6 in B and place it on the horizontal line 5 C in 5. 
 Now, with 6 7 in the half section D as a radius and 6 in 5" as 
 a center, describe the arc 7, which is intersected by an arc 
 struck from S as a center and 5' 7 in i?' as a radius. As the 
 dotted line runs from 7 to 4 in B, then take the true lengths 
 of 7 4 in M, and with 7 in 5" as a center describe the arc 4, 
 which intersect by an arc struck from 5 as a center and 5 4 
 in the miter cut G F as radius. Now, with 7 8 in the miter 
 
 lit' 9' 8' ;• t 2' 3' «r 
 
 TRUE LENGTHS OF DOTTED LINES ' 
 IN "B'" 
 
 FULL PATTERN FOR 
 TRANSITION PIECE "B" 
 
 numbered intersections on the miter line between A and B. 
 Trace the miter cut H I; then will / 12' 6' H be the half 
 pattern for the oblong pipe A. For the half pattern for the 
 round pipe C, place the girth of the semi-section E upon the 
 line i' s' extended, as shown by i to 5, from which points the 
 usual measuring lines are drawn and intersected by lines 
 drawn parallel to l' 5' from similar numbered intersections on 
 the miter line between B and C. Through points thus ob- 
 tained trace the miter cut F G. Then will F G 5' i' be the re- 
 quired half pattern. 
 
 Now, having the true length in the sections K and M and 
 the true lengths along the miter cuts G F and H J, the pat- 
 tern for the transmission piece B is developed as follows : As- 
 suming that the seam will come on I 12 in B, take the dis- 
 
 cut H J zs radius and 7 in 5" as center, describe the arc 8, 
 which intersect by an arc, struck from 4 as center, with the 
 (rue length 4 8 in i<r as radius. Proceed in this manner using 
 alternately first the division in the miter cut, F G, then the 
 true length in M ; the division in the miter cut H J, then the 
 true length in K until the line I 11 in S has been obtained. 
 Then with II 12 in the half-section D, or the miter-cut H J 
 as radius, and II in 5 as center, draw the arc 12, which inter- 
 sect by another arc struck from i as center and i 12 in B as 
 radius. Trace a line through the points thus obtained in 5 
 as shown by I, s, 6, 12, which will be the half pattern. Trace 
 this half pattern opposite the line 5 6, as shown by 5, 1°, 12", 
 11°, 7°, 6. and the full pattern is completed. The laps and 
 other allowances must, of course, be added to this pattern. 
 
172 
 
 LAYING OUT FOR BOILER MAKERS 
 
 The Lay Out of a Four=Piece 90=Degree Elbow with 
 Large and Small Ends on Each Course. 
 
 Draw the lines EO and YO, Fig. i ; then with O as a center 
 and with the trammels set to a length of 12 inches, draw the 
 quarter circle FCZ. With the same center and with the tram- 
 mels set to a length of 24 inches, draw the quarter circle 
 EAY. Divide the quarter circles FCZ and BAY, respectively, 
 into six equal parts. Draw lines from C to D, ^ to O and B 
 to O. Also draw the line LO through the point H perpen- 
 
 of the iron locate a point G'. Then, with one leg of the 
 dividers on C" and a radius equal to C" G, draw the arc 
 intersecting XB" at A'. Then with one leg of the dividers 
 on B" and a radius equal to A" X draw an arc to the 
 point K. 
 
 Draw the line L' H' , Fig. 3, 38 inches long, and divide it 
 into sixteen equal parts. Draw lines through these points of 
 division at right angles to L' H'. Mark these lines with the 
 same numbers as were used for the corresponding points, Figs, 
 
 LAYOUT OF FOUR-PIECE 90-DEGREE ELBOW. 
 
 dicular to CD. Where the line CD intersects LO, lay off a 
 distance of 12 inches to the point L. Draw the line AB 
 through the point L parallel with CD. 
 
 The course ABCD is all that is required for the pattern. 
 Therefore transfer ABCD, Fig. i, to A" B" C" D" , Fig. 2. 
 Describe a semi-circle on the line YZ and divide it into eight 
 equal parts. Draw horizontal lines from the points i, 2, 3, 4, 
 5, 6, 7, 8 and 9, Fig. i, extending them until they intersect the 
 line B" D" , Fig. 2. On the line B" A" mark K i inch from B. 
 Draw the line KD" , and then lay off from A" the distance 
 A" X equal to I inch. Draw the line XC" ; then the measure- 
 ments for the development, Fig. 3, should be taken from these 
 lines KD" and XC" , Fig. 2. 
 
 To obtain the distance XA" run the line C" A" some 
 distance above the line XB" and then set the dividers with 
 one leg on A" and with a radius equal to twice the thickness 
 
 I and 2. Aleasure the distance from l-l", Fig. 2, and transfer 
 it to i-i". Fig. 3. In a like manner transfer the distances 
 2-2", yz" 4-4", etc., to Fig. 3. Having completed the pattern 
 on one side of L' H', transfer the distances i-l', 2-2' 3-3', 4-4', 
 etc., Fig. 2, to the corresponding lines in Fig. 3. The points 
 thus located are to be punched for rivets. Add the lap outside 
 these points and the pattern is completed. 
 
 The development shows that the line A' B', Fig. 3, is longer 
 than the line C D' , thus showing how the large and small ends 
 are obtained. Two pieces of stock will, therefore, be needed 
 for the pattern A' B' C D' , one piece for A' B' L' H' and one 
 piece for C D' U H'. The figures given for this layout are 
 for 14-gage iron. A sheet 30 inches by 39 inches will make the 
 elbow without waste. An elbow of any size can be laid out 
 for any size iron by making the necessary allowance at B" K 
 and A" X, Fig. 2. 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 173 
 
 Layout of the Bottom Course of a Stack. 
 
 It will be seen from the plan and elevation, Fig. I, that 
 the course is round at the top and rectangular at the bot- 
 tom. First draw the line ST, Fig. 2, and at any convenient 
 point, as E, draw the line ED at right angles to it. With 
 £ as the center, and a radius equal to the radius of the stack, 
 draw the quarter circle and divide it into as many equal 
 spaces as there are in the quarter circumference of the stack, 
 marking each point as shown by the figures I, 2, 3, 4, etc. Lay 
 off from the points E and D half the width of the base of the 
 stack, locating the line AC. Make ED and AC equal in length 
 
 strike the arcs 2. 2 intersecting those which were made from 
 the points M and D. Do the same with the rest of the points 
 until point 4 is reached ; then the lines A^4 and M4 would locate 
 the rivet lines for the sides of this sheet. As the plate is bent, 
 however, on the lines lAT and iM, it will be seen that this 
 would bring a rivet hole on the sharp corner ; to avoid this, 
 draw the rivet lines as shown about 54 inch in toward the 
 center line but parallel respectively to the lines 4A^ and 4A/. 
 
 For the side patterns, shown in Fig. 4, set the trams to the 
 distance DC, Fig. 2, and with D', Fig. 4, as a center locate the 
 points C C. Center punch these points and with the trams 
 
 / ,' ,- 4 -- ^-,". 
 
 FiD. I 
 
 Fig Z. 
 
 PATTERNS FOR BOTTOM COURSE OF ST.^CK. 
 
 to half the length of the base ; thus making the figure EDC\ a 
 quarter plan. Lay a straight edge on the points C and D, 
 and draw the line CD, extending it indefinitely, as shown, then 
 with the trams set from the point C to the points i, 2, 3, 4, 
 etc., on the quarter circle describes the arcs shown dotted until 
 they interesect the line CD at points i, 2, 3, 4, etc. Extend 
 the line AC to B, making CB equal to XY, Fig. i, the height 
 of the course. Connect the point B with the points i, 2, 3, 4, 
 5, 6 and 7 ; then the lines Bi, B2, B3, etc., will be the true 
 lengths of the lines drawn from C to the points i, 2, 3, 4, etc., 
 in the plan view. 
 
 As the course is to be made in four sections, lay out first 
 the front or back section, shown in Fig. 3. Draw a line on the 
 sheet at a distance from the edge equal to the distance at which 
 the rivet holes are to be located from the edge of the plate ; 
 then set the trams to the distance AC, Fig. 2, and with F as a 
 center locate the joints M and A''. Center punch these points 
 and set the trams to the line Bl, Fig. 2, and with the points M 
 and A'', Fig. 3, as centers, strike the arcs intersecting at i. 
 The center line may then be drawn from i to P. Again, set 
 the trams to the line B2, Fig. 2, and with M and N, as cen- 
 ters, strike the arcs 2, 2. With the dividers set to the distance 
 1-2 on the quarter circle. Fig. 2, and with I (Fig. 3) as a center 
 
 set to the distance B 7, Fig. 2, and the points C C, Fig. 4, as 
 centers, strike arcs intersecting at 7. Then reset the trams to 
 the distance B6, Fig. 2, and with the points C C, Fig. 4, as 
 centers strike the arcs 6, 6. Also with the dividers set to the 
 space 6-7 on the quarter circle. Fig. 2, and with point 7, Fig. 4, 
 as a center, strike the arcs 6, 6 interesecting the arcs pre- 
 viously drawn. In a similar way locate the points s and 4, 
 Fig. 4 ; then the lines C'4 would be the rivet lines for these 
 two sets of patterns. Since, however, the rivet holes in Fig. 3 
 were located J4 inch in towards the center from the lines M4 
 and A'4, in order to match, the rivet lines in the side patterns. 
 Fig. 4, should be located J^ inch outside the lines C'4, as shown 
 by the solid lines parallel to the lines 4C'. 
 
 It seems to the writer that the diagram. Fig. 2, for develop- 
 ing the parts of the patterns which must be laid out by triangu- 
 lation saves considerable time, as the whole thing is laid down 
 together and cannot easily be lost sight of. 
 
 Any problem in triangulation is simple if care is taken to 
 avoid confusing the various construction lines used in the 
 solution of the problem, and that has been the special object 
 in each step of the preceding problem. The patterns might 
 have been divided in a different way, bringing the seams in a 
 different position, without changing the method of solution. 
 
174 
 
 LAYING OUT FOR BOILER MAKERS 
 
 Explanation of a Simple A\ethod of Laying Out Ship 
 Ventilating Cowls. 
 
 In desigr.ing a group of cowls for a vessel, the visual effect 
 should be taken into consideration, as vieW as utility, as it 
 costs no more to make a well-shaped cowl than- it does to 
 make a poor one. 
 
 In the annexed sketches are presented a group of six cowls, 
 and a very simple method of determining their outlines from 
 the diameters of their bases, and the development of the 
 patterns for their construction. In Fig. 3. the group of cowls 
 is shown, ranging from 4 inches to 14 inches diameter of 
 
 the center line of the cowl will be found, and an equal dis- 
 tance between the points H and A, will give the centers for 
 a corresponding curve below the center line. Extending the 
 line of the axial plane through the cowl, the points of inter- 
 section with the perpendicular line through the center of the 
 base will give the base line of the cowl, with a proportional 
 amount of straight part to receive the usual fittings. In Fig. 
 3 the line of the axial plane cuts the center of the base of 
 each cowl. 
 
 In laying out a group of cowls for a ship, first establish 
 the axial plane from the largest cowl in the series. From this 
 
 -SIDE VIEW OF COWL, SHOWING METHOD OF OBT.MNING THE 
 SIDE PATTERNS. 
 
 -FRONT VIEW OF COWL, SHOWING THE WORKING POINTS IN 
 THE PATTERN SHEET. 
 
 base. It can be readily seen that their curves and diameters 
 have a relative proportion to each other. In Fig. 4 is shown 
 the method of obtaining the outlines from the diameter of 
 the base. The throat line is first determined, its radius be- 
 ing taken as one-fourth the diameter of the base. Thus the cowl 
 in Fig. 5 is 14 inches in diameter at the base, and the radius 
 of the throat is 3^ inches. This is the largest cowl of the 
 group shown in Fig. 3. In developing the further outline, 
 draw in the throat and project a line parallel to the base, as 
 from E to C. With ^ as a center, draw an arc tangent to the 
 perpendicular line through the center of the base and cutting 
 the horizontal line at C. This point of intersection is the 
 center for the curve of the back or crown. Draw a line from 
 A to C, which forms the axial plane, upon which will be 
 found the centers of the different radii required in developing 
 the outlines, or the patterns of the sheets to form them. 
 Bisect the axial plane and you obtain the point H ; this is 
 the center of radius for a curve that will pass through 
 the center of the cowl from the base to the mouth. Between 
 the points H and C the centers for all the curves used above 
 
 plane the others can be developed, and so they w'ill have a 
 relative proportion. In developing the patterns for an axial 
 seamed cowl, as represented in Figs. 8 and 9, mark off on the 
 base and mouth of the cowl the points // and EG, Fig. i, 
 which should equal one-fourth of the circumference of their 
 respective diameters. Draw the curved lines from E to /, 
 and from G to /; this gives the pattern for the sides. The 
 center of radius for these curves is found on the axial plane. 
 To obtain the pattern for the back and throat pieces, divide 
 the center line through the side pattern into any number of 
 equal parts, and from the center of radius of throat, draw the 
 cross-sectional lines through the side pattern, which will give 
 one-fourth of the circumference of the cowl at these points. 
 Extend these lines until they cut the curve of the back, and 
 the curved working line at the throat numbered i. 2, 3, 4 and 
 5. Transfer these divisions as they occur to the straight lines 
 SU and TV, Figs. 5 and 6. Draw lines through these points 
 of divisions at right-angles to the lines SU and TV, and make 
 them correspond to the length of the cross-sectional lines in 
 the side pattern. With a light wooden batten sprung along 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 175 
 
 
176 
 
 LAYING OUT FOR BOILER MAKERS 
 
 the extremities of these lines, draw the outHnes of the 
 patterns for throat and back. In Fig. 2, the dotted lines give 
 the front view of the cowl. The solid lines show the edges 
 of the pattern sheets in the flat before being worked into 
 shape, and on the working lines. 
 
 In making the cowls of planished iron or steel, the back 
 
 PATTERN FOR BACK. 
 
 FIG. 5. 
 
 and side sheets are worked down in the center on a hollow 
 block between the points LL, MM and 00. In working down 
 the centers, tht edges of the sweep will rise to the sweep. 
 The edges of the throat-piece are peened to the sweep of the 
 curve and the center filled out afterwards. The four pieces 
 are then roui dcd up and planished on suitable heads, fitted 
 together, riveted, and a finishing bead put on the edge. 
 
 Fig. 7 shows the front view of the throat piece worked into 
 shape. This is the most difficult to make, and care is re- 
 quired in its manipulation. In making the cowls of sheet 
 copper, very little work is is performed before brazing. The 
 pattern sheets of the throat and back are bent to the work- 
 ing lines, as shown in Fig. 3, the edges are worked over about 
 
 I inch to meet the side pattern and then scarfed. The edges 
 of the side patterns are then scarfed and cramps cut to receive 
 the back and throat pieces, as shown in Fig. g. They are 
 then fitted together and brazed. After the seams are dressed 
 the cowl is then rounded up and planished on suitable man- 
 drels and heads. 
 
 The finishing bead on the edge of the mouth of the cowl 
 is made of a split tube, and is bent to shape around a wooden 
 sweep, the radius of the mouth, with a strip of metal in the 
 slit to keep it from closing and also to keep the slit in the 
 center. 
 
 This method of making cowls is very flexible. The cowls 
 
 6;v 
 
 FIG. 6. — PATTERN FOR THROAT. 
 
 FIG. 7. — FRONT VIEW OF THROAT WORKED TO SHAPE. 
 
 may be proportioned to suit the judgment of the designer, or 
 the requirements of a case, by simply altering the pitch of 
 the axial plane. The principal features in this method, which 
 will recommend its use, are: The simplicity of development 
 of the outlines and patterns, the absence of cross-sectional 
 seams, a uniform thickness of metal throughout the cowl, 
 and the saving of time, labor and material. A cowl made 
 from this method does not look as though it had been con- 
 structed from the scrap heap, but gives a finished appearance 
 well worth trying for in an up-to-date steam vessel. 
 
 Developing a Cylinder Intersecting an Elbow by the 
 Method of Projection. 
 
 Though this method involves a large amovmt of work, the 
 result gained more than compensates for the time taken to 
 execute the drawing, for it shows step by step how and why 
 the plan is divided into equal spaces, which in turn by extend- 
 ing lines develops the pattern. If you take some particular 
 numbered point on the plan and follow the line from that 
 point up to the miter line of the elbow, thence out to the de- 
 velopment to the same numbered line, you will readily see 
 how that particular point is secured on the development, but 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 177 
 
 for the benefit of the uninitiated we will proceed to explain 
 step by step. First, erect the perpendicular line 6 from the 
 bottom plan to 6 on the top plan, then draw center line of 
 the angle you wish to make the elbow, in the drawing it is 
 120 degrees from the horizontal line Ri-R:-Rj to Ru, ex- 
 tend the dotted lines Ri and i?ii until they intersect at .V, 
 these lines being at right angles to the center lines of the el- 
 how, with A' as a center draw arc R, to Rn also arcs on 
 center line and inside line of the elbow. Space the arc R, to 
 R,t into ?ix equal spaces, set off on the arc one-half of a 
 single space, and from that point step off five full spaces and 
 
 Ra, y of the bottom plan as radius, set this distance from 
 ^ to C on B', and with C as a center, swing the arc A, B, C, 
 D, E, F, G, and with 1/2 of the top plan of H, 6 to 11, draw this 
 Yi circle to the left of the line i to C, space this into equal 
 spaces same as top plan and number i to 6; drop hues parallel 
 to I, C down to arc which gives you points on arc of A, B, 
 C, D, E, F, from these points extend lines parallel to A to 
 Sec. B, then draw lines from top plan of H down to where 
 they intersect lines from B', as you will see by the drawing 
 the lines 5 and 6 of // do not run into Sec. B, but drop on to 
 Sec. C, likewise lines from E, F, of B' are not extended 
 
 FIG. 8. — FINISHED COWL IN FOUR PIECES, STEEL. 
 
 FIG. 9. — FINISHED COWL IN FOUR PIECES, COPPER. 
 
 from the last point spaced, the distance to i?ii should be the 
 other half of the single space, this makes a seven-pieced elbow, 
 but virtually comprised of six fvdl sections, as Sec. A and 
 Sec. G are one-half sections, from these points secured on 
 the arc draw lines to the common radial center X, these lines 
 constitute the miter lines of the seven pieces of the elbow 
 viz., A, B, C, D, E, F, then draw bottom line of Sec. A par- 
 allel to 7?i, Ri ; directly below this draw a one-half plan of 
 the elbow and divide into equal spaces ; from these points 
 draw lines up to miter line of Sec. A and B, extend these 
 lines through the several sections B, C, D, E, F, G, making 
 Sec. G the same length as Sec. A, the points /, /, K, L, show- 
 ing a half section of a full section. Now draw the side lines 
 (i and II) of the cylinder H, with line 6 being the center of 
 the cylinder, also draw directly above the half plan of H and 
 space into equal parts ; in order to get the true intersection of 
 the cylinder H with the elbow, it is necessary to have a cross- 
 section, which is shown as B" , C and Z)^ We will first pro- 
 ceed with B' \ extend the outside line 11 of S any suitable dis- 
 tance clear of the elevation, then draw the line i to C of 
 B" at right angles to the extension of line 11 oi B. then with 
 
 through to B. It is not necessary to make as many of the 
 cross-sections as shown, but was done, as it gives a better 
 understanding, for by so doing you can more easily see what 
 points require extending to meet the corresponding numbered 
 lines from H. For instance, line 6 does not fall on Sec. D^ 
 therefore it is useless to extend it from F of D2. The cross- 
 sections C and D' are shown in the same manner ; always 
 make the line to point A an extension of line 11 of the elbow 
 As will be seen by the drawings, all developments are one- 
 half of the circumference ; B', C and Z?" showing the full half 
 with the line of intersection of H shown thereon as marked 
 by the numbers corresponding to the cross-section. 
 
 The section A is secured by drawing the line i to 11, (A') 
 at right angles to line 11 of A, the spacing on A' being the 
 same as on bottom plan, the several points from i to 11 on 
 miter line of Sec. A to B are drawn parallel to the base line 
 and produced to meet the perpendiculars from the corre- 
 spondingly numbered spacing line on A', then drawing a line 
 through these several points gives you ^ the development 
 of A. 
 
 To secure B' draw lines at right angles to the lines i to 11 
 
1/8 
 
 LAYING OUT FOR BOILER :\IAKERS 
 
 ^. 
 
 -5^-v 
 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 •79' 
 
 of B, where those cross the miter hues of Sees. A to B and 
 B to C, extend these hnes until they meet the correspondingly 
 numbered spacing lines i to ii of B', then draw a free hand 
 line through the several points and that development is "^ the 
 circumference of B. To secure the intersection of the cylin- 
 der H oil B, first take the distance on B', from A to B, B to 
 C and C to D, set off and draw lines parallel to line ii of B', 
 then extend lines from the points on B of i, 2, 3, 4, that in- 
 tersect lines from B° of A, B, C, D, until they meet lines on 
 S' of A, B, C, D. You will notice that line of intersection of 
 H on B crosses the miter line between 8 and 9; to secure this 
 point on B' draw a line from that point on miter line up to 
 B', which comes on the developed line between 8 and 9, draw 
 a line from that point through the intersections of D, C, B, A 
 and you have the intersection line of cylinder H on Sec. B. 
 Proceed in same manner with Sec. C and D. 
 
 The cylinder H' is secured similarly to A', the points O and 
 P being the points where the cylinder comes on miter lines of 
 B to C and C to D. 
 
 By taking a smgle point on plan such as s, and following it 
 up to the miter line on B, thence out to 5 on B' you will see 
 that all points and lines are relative to each other; likewise 
 take 8 from plan of cylinder H, follow it down to D, thence 
 out to D^, then go back to D', point 8 down to the arc point 
 D and on to D, thence out to W and it brings you out on line 
 8, {W). 
 
 Developing the Pattern for a Copper Converter Hood 
 Having a Round Top and an Irregular Base. 
 
 First draw the end elevation Fig. i, then draw the side 
 elevation Fig. 2 ; from these two elevations you will be able to 
 obtain the dimensions of the plan Fig. 3. In this plan all 
 measurements of circles are taken from the center of the iron. 
 On the elevations Fig. i and Fig. 2, let the center line of Fig. 
 I extend downward indefinitely, and at right angles to this line 
 draw the line ABC, Fig. 3, and on this line lay oS. the points 
 a and b. Fig. i, holding B as center. As the top of the hood 
 is to be round, take o S as radius, and B as center, and strike 
 the semi-circle a D b, which will give the plan of the top. 
 
 Next in order will be to lay down the lines on the plan 
 which will form the base of the top plates which lap over the 
 lower sections of the hood. This will not be a true circle, as 
 will be seen. Transfer the points c and d, Fig. i, to the line 
 ABC, Fig. 3 ; also transfer the length of the line E F, Fig. 2, 
 and mark it on the center line of the plan from B to E, Fig. 2, 
 this being one-half the elevation of the side view of the hood. 
 Draw in to find the length of the major axis of the portions cf 
 the eclipses used in this work. It will be seen that the half of 
 this article to the left of the center line (Fig. 3) is made ellip- 
 tical in shape at the base ; therefore all intermediate points be- 
 tween the round top and the base would also be elliptical. The 
 length of the major axis is taken from Fig. 2, and the minor 
 axis from Fig. i, while the portion to the right is circular in 
 all respects. Each circular division being struck from a dif- 
 ferent center, B is only the center of the semicircle a D h, 
 while the arc E d oi the plan is struck from another center; E 
 c is a portion of an eclipse made by arcs of different circles. 
 
 Next in order will be to lay down the plan of the top and 
 bottom of the lower sections of the hood which can be done 
 in the same way that the plan was done for the top plates. 
 
 Transferring the points c f. Fig. i, to the line ABC, Fig. 3, 
 also transfer the length of the line G H, Fig. 2, and mark the 
 length from B to G, Fig. 3. The points c G will be the two 
 points on which to construct the portion of the ellipse, while 
 G f will be the two points on which to construct the portion 
 of a circle or arc, whose center will be located on the line A 
 B C, which will complete the plan of the top of the lower 
 section. 
 
 The plan of the base will be constructed in the very same 
 manner, and needs no further explanation. 
 
 Now that we have the plan and elevation, all that remains to 
 be done is to construct the triangles, the bases of which will be 
 found on the plan Fig. 3, and the altitude of the different tri- 
 angles will be found in the elevation. To construct these 
 triangles it will be necessary to divide the line g I h oi the 
 plan into a number of parts, these parts can be equal or un- 
 equal, as it makes no difference ; so in this case we will di- 
 vide it into equal spaces, because a sketch so small can be 
 better worked out that way. Divide g I into five spaces, and 
 / h into six spaces; from these points, I, 2, 3, etc., draw solid 
 lines to the point B or center of the semicircle at the top. 
 These solid lines will be the true length of the bases of the dif- 
 ferent triangles to be constructed, that is, the distance on each 
 from the line c E d io the semi-circle a D b will be the bases of 
 the triangles for the lower part of the hood. The distance 
 from the line c E d to the semicircle a D b will be the basis of 
 the triangles on the solid lines for the top part of the hood. 
 
 In order to complete the bases of the triangles it will be 
 necessary to construct another set of bases which are dis- 
 tinguished by dotted lines and lettered a, b, c, etc., in italic 
 letters. These bases, it will be seen, run diagonally across the 
 spaces made by the solid lines and join No. i, solid line, to- 
 No. 2, solid line, also No. 2 to No. 3, etc., which completes the 
 bases of the triangles. Now it will be necessary to construct 
 the altitude of the triangles. In the top plate the altitude is- 
 the same for all. In the lower plate they will all be different 
 lengths, and may be obtained in this way. From the points 
 established on the line g I h, Fig. 3, draw lines parallel to the 
 center line / B, up till they cut the base of the hood or the 
 shell of the converter. Fig. i ; at these points draw lines at 
 right angles to the center line / B indefinitely to the right 
 and left and number them according to the point drawn 
 from in Fig. 3. — I, 2, 3, etc. The distances from / to the dif- 
 ferent lines en the center line. Fig. 4, will be the altitude of 
 the triangles to be constructed. Then transfer the solid base 
 lines No. i, Fig. 3, to the same lines on the elevation, Fig. i, 
 using the junction of the base lines and the center line as the 
 right angle corner cf the triangles. A line drawn from this 
 point to / will b,e the hypotenuse of that triangle; then trans- 
 fer the solid lines No. 2, of Fig. 3, to the same number on Fig. 
 I, also on this same line, transfer the length of the dotted line 
 a. A line drawn in from these points to 7 will be the 
 hypotenuse of these triangles and the true length on the lines 
 for the pattern. All the rest of the lines in the lower part of 
 
i8o 
 
 LAYING OUT FOR BOILER MAKERS 
 
 PATTERNS FOR A COPPER CONVERTER HOOD. 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 the hood will be obtained in the same way, and need no fur- 
 ther explanation. 
 
 The triangles in the top plate which form Fig. 6 and Fig. 8 
 on the pattern are somewhat easier to obtain, as the altitudes 
 of these triangles are all of one length, that of L K, Fig. i. 
 
 Transfer the solid lines No. i between the lines a D b and 
 c E d to the line M N, and mark them to the right and left 
 of K, in Fig. i, and by this system set up a series of triangles 
 of both solid and dotted lines No. i, 2, 3, etc., and a, b, c, etc. 
 Now the triangles are complete. All the triangles at the right 
 go to make up the plates Fig. 5 and Fig. 6, while those to the 
 left will make up Fig. 7 and Fig. 8. 
 
 You will notice that the spaces between the points on line 
 g I h, Fig. 3, are not the correct spaces to be used in develop- 
 ing the pattern, as they are much too short, on account of the 
 hood setting on a convexed surface, therefore, it will be neces- 
 sary to draw an extended view of the base of the hood. 
 
 In other words lay out the hole, which will be cut or 
 punched in the top section of the shell, and to which the hood 
 joins. From the edge of this take the spaces which form the 
 lower edge of the plates or the flange line. This will give the 
 correct spacing between the solid and dotted lines at that part 
 of the hood. 
 
 To lay out the hole, a correct stretch-out of the line from 
 g to h, Fig. I, at the center of the shell must be obtained and 
 laid ofif on line O P, Fig. 4. Take the distance from the point 
 where the center line of the hood intersects the center line of 
 the shell to the point where the line at the left intersects the 
 center line of the shell. Mark it to the right of the center 
 line on Fig. 4, which is marked 5, the center line being 6 and 7 
 on the right side ; transfer the rest of these points in the 
 same manner. From these points on the line O P, Fig. 4, draw 
 lines at right angles from the points i, 2, 3, etc., right and left, 
 and upon these lines transfer the length of the vertical lines 
 in Fig. 3, from where they intersect the line A B C to where 
 they intersect the circular line g I h, which is the base line of 
 the plan. Whatever the distance is from B I, Fig. 3, mark it on 
 the line 6 and 7, Fig. 4, which establishes the point U , and the 
 center line of the hole. Also transfer the rest in like manner. 
 This done, join the joints together by straight lines. These 
 lines or distances will be the true length of the bases of the tri- 
 angles used to lay out Fig. 5 and Fig. 7, or the lower plates of 
 the hood. They will also give the cut-out of the hole, or one- 
 half of the hole in the top of the convertor. The other half 
 will be a duplicate of it, and from the cut-out the proper al- 
 lowance can be made for the rivet holes in the plate by which 
 the flange will be marked of? after being fitted to the shell. 
 
 To lay out the plate, Fig. 5, take the length of the hypote- 
 nuse line No. 1, at the right on Fig. i, the lower part of the 
 hood, and place this line at any convenient place on the plate 
 Fig. 5 and mark its length ; then set the trammels with dis- 
 tance from No. i, Fig. 4, to R, and with this distance as radius, 
 and with the lower end of the No. i line. Fig. S, as center, 
 make an arc cutting the arcs made by the dotted line A, and 
 from the intersecting points of the arcs draw lines to the 
 lower end of the No. i line, and from the intersecting points 
 draw the dotted line to the top of the solid line No. i. This will 
 
 give two of the triangles used in the plate. To obtain the 
 next triangle, set the trammels with the distance between the 
 solid lines i and 2, which will be found on the line c G f 3.t the 
 right of Fig. 3, and with this distance as radius, and the upper 
 end of the No. I line. Fig. 5, as center, cut arcs to the right and 
 left of the line No. i ; then take the length of the solid hypote- 
 nuse line No. 2, Fig. i, and with this as radius, and the lower 
 end of the lines a, Fig. 5, as center, draw arcs cutting the arcs 
 at the right and left of line i ; this will give four of the tri- 
 angles used in this plate, and the remainder need no further 
 explanation. Fig. 7 will be made in the same way by using 
 the line at the left of the center line in Figs. I, 3 and 4. Next 
 we will take up Fig. 6, which is the top piece of the hood and 
 must lap over the top of Fig. 5, and for which we must use 
 the hypotenuse line at the right, also in Fig. i, but in the 
 uppper part of the figure : first take the length of the solid line 
 No. 1, Fig. I, and place it on the plate Fig. 6, which is the 
 center line and is the altitude of two triangles whose bases 
 are taken from the plan Fig. 3, between the lines i and 2, on 
 the line c E d; with this distance as radius, and the lower end 
 of No. I line, Fig. 6, as center, scribe an arc at the right and 
 left of the No. 1 line, then take the length of the dotted line 
 a, top of Fig. I, and with this distance as radius, and with the 
 top of the No. I line, Fig. 6, as center, scribe arcs cutting the 
 arcs made by the radius struck from the other end of the line ; 
 joining these points will give two of the triangles in this 
 plate. To obtain the next, take the distance between the lines 
 I and 2, Fig. 3, on the circular line a D b, at the right, and 
 with this distance as a radius, scribe arcs to the right and 
 left of line l, Fig. 6, at the upper end of line. Then take the 
 length of the solid line 2, Fig. i, and with that distance as 
 radius, and the lower end of the dotted line a, Fig. 6, as center, 
 scribe arcs cutting the arcs to the right and left of line i ; this 
 will give four of the triangles in plate 6; the rest can be ob- 
 tained in the same way. 
 
 Fig. 8 can be constructed bj' using the hypotenuse of the 
 triangles at the left in Fig. i as altitudes, and the spaces on 
 the line a D b and c E d. Fig. 3, as bases outside of the line 
 given here. Allowances must be made for flange at the base of 
 hood, also rivet holes for laps and butt straps. 
 
 By making more spaces in the plan you will of course make 
 more triangles, and in this way you will be able to overcome 
 the irregularities on the pattern, such as the corners left by 
 the different angles of the triangles. 
 
 Laying Out a Hopper for a Coal Chute by the Method 
 of Triangulation. 
 
 The hopper and chute to be laid ou*" are shown shaded in 
 Fig. I. The conditions are : that the mouth of the hopper shall 
 be round, 4 feet 6 inches diameter, that the distance on the 
 side where the chute joins it should be 12 inches from the 
 edge of the hopper to the chute, that the angle formed by this 
 intersection should be go°, and that the after side of the hopper 
 should lay parallel with the chute, the chute to be round, 12 
 inches in diameter. 
 
 The practical considerations are how to lay out the hopper 
 so as to make the least work in connecting the chute to it 
 
LAYIi\G OUT FOR BOILER MAKERS 
 
 FlG.l 
 
 LAYOUT OF A HOPPER FOR A COAL CHUTE. 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 This may be done in several ways, but we shall make it as 
 shown in the drawing with the joint parallel to the short side 
 of the hopper, so that the end of the chute which joins the 
 hopper should be only a straight cut. By this method very 
 little flanging will be required, and it can be easily riveted. 
 
 In the accompanying illustrations it will be noted that similar 
 figures and letters denote similar joints or lines. 
 Fig. I is a shaded view of the hopper and chute. 
 Fig. 2 is a side view of same. 
 Fig. 3 is a top or plan view of half the hopper. 
 Fig. 4 is a view of half the end of the chute. 
 Fig. 5 is a set of triangles, of which the lines a2, b3, C4, ds, 
 e6, fy, g8, hp, Fig. 3, are the bases ; these lines or distances are 
 taken from Fig. 3 and set off on the line P. R., Fig. 5, from the 
 point P. The verticals of these triangles are taken from Fig. 
 2, from the line M N (which is the upper edge of the hopper), 
 downward to the line of the joint, as I, 2, 3, etc. They are set 
 off upward, on the line P K, Fig. 5, as from P to 2, 3, 4, etc., 
 the lines P R and P K form a right angle, and the points 
 2, 3, 4, etc., on P R are connected to the joints a, b, c, etc., on 
 the line PR. We now have right angle triangles, the slant 
 side or hypotenuses of which we desire to obtain. 
 
 It will be noticed that there are two sets of lines on Fig. 3, 
 one set running from the letters on the edge or rim of the hop- 
 per inward to the edge of hole, as a2, b3, c4, etc., and another 
 from the edge of the hole outward to the edge of the hopper, 
 as 2b, 3c, 4d, etc. ; for this second set of lines we must also have 
 a set of triangles; these are shown in Fig. 6; these were also 
 constructed for the purpose of obtaining their hypotenuses, 
 using the same heights as in Fig. 5. 
 
 Now to determine the points, i, 2, 3, 4, 5, 6, 7, 8, 9 on Figs. 
 2 and 3 : make the drawing as shown in Figs. 2, 3 and 4, divide 
 the circles into an equal number of spaces and mark them 
 as a, b, c, d. e, f, g, h, j. Fig. 3, and i, 2, 3, 4, 5, 6, 7, 8, 9, 
 Fig. 4, the number in this case is eight, but when the experi- 
 mental pattern to determine the correctness of the rule was 
 made only four were used. 
 
 Having done this, transfer these points from the half circle 
 in the direction of the dotted lines from Fig. 4 to the joint line, 
 Fig. 2, and from there vertically upward to Fig. 3, making a 
 solid line on Fig. 3 as a continuation of the dotted lines (in 
 reality the dotted lines are not needed in laying out the work, 
 they were put here only for the purpose of showing the direc- 
 tion in which the points are to be transferred.) 
 
 The points i and 9 are established on Fig. 3 by the inter- 
 section of the lines i and 9 with the line A J, but the points 
 2, 3, 4, 5, 6, 7, 8 are taken from Fig. 4, as, for instance, we take 
 the length of the solid line 2 from Fig. 4, and set it off on the 
 solid line 2 on Fig. 3 from the line A J, and the line 3, Fig. 4, 
 to the line 3, Fig. 3, from A J, and so on, until they are all 
 taken off from Fig. 4 and set on their corresponding lines on 
 Fig. 3, and the points so established when connected with a 
 curved line form the edge of the hole for the chute. Now 
 connect these points with the points b, c, d, e, f, g, h on the 
 ■edge of the hopper, forming triangles as shown. 
 
 Having completed these operations we are now ready to lay 
 out the pattern of the hopper, the half of which is shown in 
 
 Fig. 7. Draw a line, any length, long enough on which to lay off 
 the distance ai, take this distance, which is from AI i. Fig. 2, 
 then from Fig. 4, on the circle, take the distance 1-2, and 
 from the point i, on ai. Fig. 7, and at right angles to ai, 
 describe an arc, then take the distance a, b. Fig. 3, and from 
 the points a, on line ai, Fig. 7, describe an arc. Then from 
 Fig. 5 take the hypotenuse a2, and from the point a on ai, 
 Fig, 7, cut the arc 2, establishing the point 2. Then from Fig. 
 6 take the hypotenuse 2b, and from the point 2, F'ig. 7, de- 
 scribe an arc cutting the arc b, connect these points with lines, 
 and it will be seen that we have laid out a section of the pat- 
 tern composed of two triangles, formed by the points la2 and 
 a2b. Then we start over again and lay out the adjoining sec- 
 tion 2C3 and C3d.- Take from Fig. 4 the distance 2 3 on the 
 circle and set it off on Fig. 7 from the point 2, describing an 
 arc, then take the distance b c from Fig. 3 and set it off from 
 the point b. Fig. 7, describing an arc. Now, from Fig. 5 take 
 the hypotenuse b3 and set it off from the point b. Fig. 7, 
 cutting the arc 3, and from Fig. 6 take the hypotenuse 3c 
 and set it off from the point 3, Fig. 7, cutting the arc C. Con- 
 nect these points with lines and we have another section. 
 Continue this process until the point 9 is established and the 
 distance h J has been set off, then from the point 9, Fig. 7, cut 
 the arc J. Connect 9J with a line and also connect all the 
 points a, b, c, d, e, f, g, h, and i, 2, 3, 4, 5, 6, 7, 8, 9 with curved 
 lines, and we have half the pattern but without laps, and the 
 lines 9j and la are the center lines. 
 
 Now, if it is desired to make the hopper in one piece, and 
 you are laying it out directly on the sheet you are going to 
 use, it will only be necessary to work the laying out of the 
 other half backwards. Allow half the lap on the outside of 
 ai on each end. If it is desired to flange the hopper into the 
 pipe, the flange must be allowed ; if the pipe goes into the 
 hopper, then allow the flange on the pipe. 
 
 By this method it will be seen that it is not necessary to 
 lay out a special pattern for the pipe, as it would be if the 
 joint was made at an angle to the side. 
 
 Pattern of a 90=Degree Tapering Elbow. 
 
 As will be seen, the patterns of this elbow have been de- 
 veloped by the method known as triangulation, as it requires 
 less room to work it than it does by the method of conic sec- 
 tions; as, for instance, if the large end were 36 inches diameter 
 and the small 30 inches, and each half section 10 inches long, 
 from the center line making the whole length 80 inches, 
 the radius would be a little over 40 feet, and if the taper was 
 less than 6 inches, the radius would be proportionately larger, 
 and in either case not very easy to handle ; whereas, in the 
 case of triangulation, all the preliminary work can be done 
 on the drawing board, making the drawings to a scale, ?.nd 
 when taking off the different leneths to lay down the pattern, 
 multiply their lengths by the scale. 
 
 Fig, I is a side elevation and is constructed as patterns. 
 Lay off a right angle ECD, and from the point C as a center, 
 strike a quarter of a circle AB , with a radius required for the 
 center of the elbow. Determine the number of sections you 
 want in the elbow and multiply by two. This elbow is made 
 
i84 
 
 LAYING OUT FOR BOILER MAKERS 
 
 in four sections, tliree whole and two half, and is known as a 
 four-section elbow. There should always be a half section at 
 each end, otherwise you would have to miter the end of the 
 connecting pipe to the end section. 
 
 As above stated, this is a four-section elbow and 4X2 = 8; 
 then divide the quarter circle into eight equal parts, as i, 2, 
 3. 4, etc. After having done this, draw lines from C through 
 the points 2, 4, 6. On these points, at right angles to the radial 
 lines and tangent to the circle, draw straight lines of an in- 
 definite length, intersecting each other at MNPQ. Then on 
 the line CE, set off the half diameter of the large end on each 
 
 joints of the intersection of these lines at the back and in 
 the throat with lines, the different sections of the elbow are 
 defined. The side elevation is complete and the final shape 
 and correct dimensions are determined. 
 
 Now, prepare for the development of the pattern of the 
 large end, but in order not to get too many lines piled on top 
 of one another, make a separate drawing of this end section, 
 as shown in Fig. 2. Within the points i, 0, h, 9, continue the 
 center line far enough above and below the figure so as to be 
 able to lay Figs. 3 and 4 on it. Then below Fig. 2, draw a 
 horizontal line I, 9, Fig. 3, and from its intersection with the 
 
 PATTERN FOR END SECTION OF 
 
 side of the center A, and on the line CD, set off the half di- 
 ameter of the small end on each side of the center B. 
 
 Now, in order to get a regular taper it is necessary to have 
 the diameters of the ends of the different sections at the miter 
 or joint lines. To determine these, set off on the line AE 
 from A, the half diameter of the small end, which leaves the 
 distance JK as the difference of half the diameters of the 
 two ends. This difference must be divided into four equal 
 parts, consisting of three whole and two half parts, just as 
 the elbow is divided into three whole and two half sections, 
 and the half parts should be at the end as shown. Then the 
 distance Aq' is the half diameter on the joint line 7; the dis- 
 tance Ap' is the half diameter on the joint line 5; the distance 
 An' is the half diameter on joint line 3, and Am' is the half di- 
 ameter on the joint line i. 
 
 Take these half diameters as radii, and from the intersections 
 q. p, n, m as centers, strike arcs of circles at the back and in 
 the throat ; then by drawing straight lines tangent to these 
 arcs, the back and throat are produced ; then by connecting the 
 
 s 
 f/C 3 
 
 A 90-DEGKEE TAPERING ELBOW. 
 
 vertical center line as a center and a radius .IE, Fig. i, strikt 
 a half circle i, S, 9 and divide it into eight equal parts and pro- 
 ject the points 2, 3, 4, 5, 6, 7, 8 upward onto the horizontal line 
 
 1, 9, Fig. 2, locating the points 2-8, Fig. 2. 
 
 Above Fig. 2 erect Fig. 4, by drawing horizontal line i, 9, 
 and with a radius A)ii', Fig. i, strike a half circle and divide it 
 into eight equal parts ; then through Fig. 2, draw the hori- 
 zontal line FC the same height from the base line i, 9 as the 
 point m, Fig. i, is above A. Then project the points i, 2, 3, 
 etc.. Fig. 4, down onto the line FG, Fig. 2. From the points 
 
 2, 3, 4, etc., on line i, 9, Fig. 2, draw lines through the points 
 on the line FG, cutting the miter line Oh and establishing the 
 points a, b, c, d, etc. Then project these points down onto 
 Fig. 3, making the vertical dotted lines : also from these points 
 draw lines at right angles, as in Fig. 5 ; then through these 
 poii:ts draw the horizontal dotted lines to the surface lines, 
 having extended the line 9/t up far enough so that, the line 
 drawn from d will intersect it. 
 
 Then with the compasses take the distance from the center 
 
:\IISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 185 
 
 line to tile surface line lO. which cuts through tlie point a and and on these verticals, set off these chfferent licights in ';uc- 
 
 use it as a radius, and from the center of Fig. 3, cuf the verti- cession as shown, marking each set with tlie corresponding 
 
 cal dotted line in a. Again, take the distance from center to letter at the top. Then, from Fig. 3, take the distance 20, and 
 
 surface on dotted line, which cuts through the point b, and as set it ofT on the horizontal line, Fig. 7, from the vertical a, es- 
 
 before, using the center of Fig. 3, cut the vertical dotted line tablishing the point 2; connect the points 2a. This, you will 
 
 in b. Continue this until you reach the point d, Fig. 2. Then notice, forms a triangle, of which 20 is the hypotenuse. Tlien 
 
 work from the other side, that is, from the center line out to from Fig. 3, take the distance 3ft and set it off on tlie liori- 
 
 r.MTERN FOR MIDDLE SECTION OF .\ gO-DEGREE T.\PERIXG ELBOW. 
 
 the line 9/1 and continue cutting the vertical dotted lines suc- 
 cessively until all the points on Fig. 3 are established. 
 
 Then connect these points with the points on the base 
 circle I, 5, 9, Fig. 3, as 10, 02,' 2b, 63, 3c, C4, etc., until all are 
 connected. Take the distance from the line i, 9 to a, Fig. 3, 
 and set it ofif on the line a, Fig. 5, establishing the point /; 
 then take the distance from the line I, 9 to b, Fig. 3, and set it 
 ofif on the line b. Fig. 5, establishing the point k ; continue 
 until all the distances are set off ; then on the continuation of 
 the line i, 9, Fig. 2, erect a perpendicular. Fig. 9. Onto this 
 perpendicular project the points a, b, c, d, c, f, g from Fig. 2. 
 These points mark the vertical heights from the base line i, 
 9 at the different points on the miter line Oh. 
 
 Now, we are ready to erect the triangles. Draw two hori- 
 zontal lines as in Figs. 6 and 7. On these, draw vertical lines 
 
 zontal line. Fig. 7. from the line h; connect the points jb and 
 we have another triangle, of which 3b is the hypotenuse. Con- 
 tinue this until you have taken all the distances from Fig. 3 
 and form triangles. 
 
 Then take the distance ai, Fig. 3, and set it off on the hori- 
 zontal line. Fig. 6, from vertical a establishing the point i ; 
 connect la and another triangle is formed. Continue this pro- 
 cess until all these distances are taken from Fig. 3 and the 
 triangles in Fig. 6 are formed. Now, the object of this opera- 
 tion, and, in fact, all the operations gone through with in 
 Figs. 2, 3, 4, 5, 6 and 7, is for the purpose of obtaining true 
 distances. Since all the distances shown in Fig. 2, except lO 
 and 9/1, and the distances 1, 2, 3, 4, S, 6, 7, 8, 9, in Fig. 3, are 
 in perspective you will see that the surface of the section Fig. 
 2, is cut up into triangles, and what we must do is to get the 
 
i86 
 
 LAYING OUT FOR BOILER MAKERS 
 
 distances or lines necessary to construct these triangles of 
 their true size and lay them together in their proper places to 
 form the pattern as shown in Fig. 8. 
 
 Now, let us lay out the pattern. Draw a vertical line as 
 
 10, Fig. 8; then take the distance lO, Fig. 2, and set it off on 
 the vertical line, Fig. 8. Then take I, 2, Fig. 3, and with I, 
 Fig. 8, as a center, describe the arc 2. Take the distance O; 
 Fig. 5, and from O, Fig. 8, as a center describe the arc a. 
 Then take the hj-potenuse of the triangle la. Fig. 6, and from 
 the point i, Fig. 8, as a center, strike an arc cutting the arc 
 a. Take the hypotenuse 2a, Fig. 7, and from the point a, Fig. 
 8, as a center, strike an arc cutting the arc 2. Now, if you 
 will connect all these points with lines you will see that the two 
 triangles have been formed, and laid down in correct relation 
 to each other, forming the section of the envelope shown in 
 Fig. 2 enclosed within the points lO, a, 2. 
 
 To continue, take the distance 2, 3, Fig. 3, and from the 
 point 2, Fig. 8, strike an arc 3 ; then take the distance jk. Fig. 
 S, and from the point a strike an arc b; then take the hypot- 
 enuse 2b, Fig. 6, and from the point 2, Fig. 8, as a center, 
 strike an arc cutting the arc b; then take the hypotenuse &3, 
 Fig. 7, and from Z? as a center, strike an arc cutting the arc 3. 
 Continue this process until you have fixed the point h, Fig. 8 ; 
 then with distance gli, Fig. 2, and with /; as a center, strike 
 an arc cutting arc 9, thus completing half of the pattern of 
 the first section or large end. To this you will have to add 
 the necessary laps. 
 
 Now proceed to lay out the ne.xt section. Draw a vertical 
 line QR, running through all the figures from 11 to 12. Across 
 this draw a horizontal line, as CS, Fig. 10, which represents 
 the line CS, Fig. i. On the line QR, from the line CS, step 
 off the distances 1112 and 2n, Fig. i, and through these pomts 
 draw the horizontal lines // and KL. Then on the vertical 
 line QR, as in Fig. II, describe a half circle, which is the 
 same diameter as the circle struck from the center m, Fig. i. 
 Again, as in Fig. 12, describe another half circle the same 
 diameter as that struck from center n. Fig. i. Divide both 
 these circles into eight equal parts, as you did in Fig. 3. 
 
 Project the points i to 9 on Fig. 11, upward onto the line 
 
 11, and the points i to 9 on Fig. 12 down onto the line KL. 
 Then draw the lines Oi and hg by connecting the outside 
 points on the lines // and KL, and on these slanting lines set 
 off the following distances: From the line CS, Fig. i, take 
 the distance SO, Fig. i, and set downward from the line CS, 
 Fig. 10. Then take the distance 5'i', Fig. i, and set it up- 
 ward from the line CS, Fig. 10. Take the distance ch, Fig. i, 
 and set it downward from CS, Fig. 10. Then take the dis- 
 tance cP, Fig. I, and set it upward from CS. Fig. 10. Con- 
 nect the points Oil and i 9 with slanting lines, thus producing 
 the miter or joint lines. 
 
 Now project the points from the lines II and KL down- 
 ward and upward by connecting lines onto the lines 
 I 9 and Oh, establishing the points a. b, c, b, e, f, g on 
 Oh, and v, s, t, u, v, zv, x on the line i g. From 
 these points draw lines at right angles to the lines i 
 9 and Oh, on which to construct Figs. 14 and 15. Then 
 as in Fig. 13, draw a horizontal line i 9, project the 
 
 points a, b, c, d, c, f, g, h, and at the same time draw the 
 vertical lines from these points as shown. Again, on Fig. lO, 
 draw the horizontal dotted lines through the points a, b, c, d, 
 ^, fi S> «^"d V, s, t, u, V, w, X, to the surface lines 0\ and hg. 
 Then with compasses take the length of the dotted line which 
 runs through the point a, and with the intersection of the 
 lines QR and i 9 as a center, cut the line a in ;'. Again, take 
 the length of the dotted line which runs through the point b, 
 and from the same center cut the line b in k; continue this 
 until you have got around to g. 
 
 Then take the length of the dotted line which runs through 
 the point r, and from the same center, cut the line v in 2. 
 Then take the length of the dotted line which runs through 
 point .f and from the same center cut the line i in 3. Con- 
 tinue this until you get around to .r. Then connect these 
 points with lines as follows : O2, 2j, 2], 3k, k^, 4t, t$, sm, »"6, 
 611, n~, yp, p8, Sq, qg. These distances are the bases of the 
 triangles in Figs. 17 and 18. Then transfer the lengths of the 
 vertical lines on Fig. 13 to their corresponding lines on Figs. 
 14 and 15, as r2, s^, i4, on Fig. 14, and aj, bk, cj, etc., on 
 Fig. 15. Connect the points i, 2, 3, 4, 5, 6, 7, 8, 9, also a, b, c, 
 d. c, f, g, h, with lines, and you have the profile of each end 
 of the section. Next take out the vertical heights between 
 the points Ox, ar, bs, ct, du, ev, fiv, gx. Fig. 10, by erecting 
 on the line CS" a perpendicular for each pair of points as 
 shown in Fig. 16, and onto these project the points from 
 Fig. 10. 
 
 Now we are again ready to form the triangles. Figs. 17 and 
 18. Draw two horizontal lines, and on these lines erect per- 
 pendiculars as shown, and on these set off the vertical heights 
 taken from Fig. 16. Then take the distance O2, Fig. 13, and 
 from the line 2, Fig. 17, set it off on the horizontal line. 
 Take the distance js, Fig. 13, and from the line 3, Fig. 17, set 
 it off on the horizontal line. Do this with all the large bases 
 on Fig. 13, and connect the points O2, /3, A'4, and so on, thus 
 forming all the large triangles. Then on the horizontal line, 
 Fig. 18, set off the lengths of the short bases, 2J, 3k, 46, etc. 
 Connect the points with the lines thus forming the other set of 
 triangles, Fig. 18. Now we are ready to lay out the pattern. 
 Fig. 19. Draw a vertical, Oi. On this set off the distance 
 Oi, taken from Fig. 10. Then take the distance Oj, Fig. 15, 
 and from O, Fig. 19, strike an arc ;'. Take the distance i 2, 
 Fig. 14, and from i. Fig. 19, as a center, strike the arc 2. 
 
 Then take the hypotenuse O2, Fig. 17, and from O, Fig. 19, 
 as a center, cut the arc 2 ; then take the hypotenuse and from 
 2, Fig. 19, as a center, cut the arc /, and connect the points so 
 established with lines. Then take the distance 2, 3, Fig. 14, 
 and from the point 2, Fig. 19, strike the arc 3 : then take the 
 distance //:, Fig. 15, and from the point /, Fig. 19, strike the 
 arc k. Take the hypotenuse J3, Fig. 17, and from ;', Fig. 19, 
 cut the arc 3. Then take the hypotenuse ks, Fig. 16, and from 
 the point 3, Fig. 19, cut the arc k. Connect these points with 
 lines as before. Continue this process until you have estab- 
 lished the point 9, Fig. 19, and described the arc li. Then 
 take the distance hg. Fig. 10, and from the point 9, cut the 
 arc h. Connect hg with a line, and half of the pattern of the 
 section is completed, with the exception of adding the laos 
 
JMISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 187 
 
 £ X 
 
 3 g 
 
 pBa4 0i pawAjj aimj/ 
 
1 88 
 
 LAYING OUT FOR BOILER MAKERS 
 
 A Flue and Return Tubular Marine Boiler. 
 
 The flue and return tubular t>-pe of marine boiler is little 
 used to-day, having been superseded by Scotch and water tube 
 boilers, which are much better able to carry the high pres- 
 sures now used in marine work. In proportion to the space 
 occupied, the flue and return tubular boiler has, however, a 
 large grate area and for a low working pressure it is difficult 
 to design a boiler which will be more efKcient. 
 
 The furnaces, which are three in number, are surrounded by 
 water legs SJ4 inches wide. At the rear of the furnaces is a 
 combustion chamber from which ten large flues, ranging 
 
 ai'i Is'SlnnhoIo 
 Elog )4'j 2!i'; 
 
 the front shell and side sheets 19/32 inch; of the furnaces 
 and steam chimney shell 4^ inch. Double riveting is used 
 throughout the boiler, the rivets being Ji inch and i inch in 
 diameter. All seams on the boiler are thoroughly calked both 
 inside and outside. The 130 4-inch tubes are all number 10 
 B. W. G. seamless drawn tubes and are each tested to a hydro- 
 static pressure of 500 pounds per square inch. 
 
 This type of boiler, due to the low steam pressure carried, 
 is very durable and reliable, its weakest feature being that, 
 owing to poor circulation and inaccessibility for cleaning, the 
 water legs are apt to deteriorate rapidly. 
 
 I 1b"s]iUd Steam \ 
 
 ! 
 
 n'ilj"MaDhole 
 
 Steel Nozdo 
 l4"CaBt 
 iSleel Noixle 
 
 Center L i ne of Bo i ler /lvi~S 
 
 Plan "" 
 
 Showing Position of Noiiles 
 'Single Riveted Seaiai 
 H"Rivet 
 11/,; Hole 
 l?g"Pitcb' 
 
 Double Riveted Seami 
 H"Rlvet 
 Il/ieHoIe 
 
 21i"ilJ4"Pitch ^ 
 l>6"Lap 
 
 Braces 
 ■ Body IJ^'Round 
 ■^'Toea S'l.W' | 
 RlvetB 94'^ B^. 
 Spaced on a Base of 
 6^<:^6^1'CenterB 
 
 
 -J ±— fefj F lTl 
 
 DETAILS OF LOBSTER BACK BOILER. SHOWING METHOD OF ARRANGING BATTERY. 
 
 from 10 to 18 inches in diameter, lead to two large combustion 
 chambers in the rear of the boiler. The return tubes, 130 in 
 number, 4 inches in diameter, lead from the rear combustion 
 chambers to the front tube sheet and smoke-box. The up- 
 takes instead of being outside of the boiler, as in the Scotch 
 marine type, lead up through a large steam dome or super- 
 heater 7 feet 3 inches in diameter by 7 feet high. The total 
 grate area of the boiler is 73.5 square feet, and the total heat- 
 ing surface 2,205 square feet, giving a ratio of heating surface 
 to grate area of 30. The working pressure is only 60 pounds 
 per square inch. 
 
 The principal dimensions of the particular boiler illustrated 
 are as follows : 
 
 Length of base 15 feet 9 inches. 
 
 Length over all, including steam chimney.. 17 feet. 
 
 Width of boiler front 12 feet 9 inches. 
 
 Diameter of boiler shell 11 feet S inches. 
 
 Height of boiler from bottom of leg to 
 
 top of shell II feet 6 inches. 
 
 Height of steam chimney above shell of 
 
 boiler 7 feet. 
 
 Diameter of steam chimney 7 feet 3 inches. 
 
 The plates in the boiler are worked as large as possible to 
 avoid numerous riveted joints which would otherwise be neces- 
 sary. The thickness of the cylindrical shell is 9-16 inch ; of 
 
 A Lobster Back Boiler. 
 
 The lobster back boiler is a type which is little used except 
 for marine purposes where only a low pressure is needed, as 
 in the case of a slow-speed long-stroke beam engine. From 
 its external appearance (see page 164), the boiler is apparently 
 a plain tubular boiler with a modified form of locomotive fire- 
 box. Looking at the detailed drawings, however, it will be 
 seen that its construction is much more complicated. The 
 gases from the drop leg furnaces are led over a water leg arch 
 to a small combustion chamber just beyond the furnaces and 
 then through four large flues to a second combustion chamber 
 in the rear of the boiler. From here they make a return pass 
 through a number of small tubes to a third combustion cham- 
 ber or smoke-box placed directly over the first one, whence 
 the products of combustion are directed out of the boiler 
 through an opening in the side. This opening is not seen in 
 the photograph but is shown clearly in the detailed drawings. 
 The exit of the gases from the boiler is made through the 
 side, for the reason that two of the boilers are installed in a 
 battery in connection with a common superheater. 
 
 The superheater consists of a vertical cylindrical shell con- 
 taining an inner concentric corrugated flue through which the 
 gases from the two boilers are led to the stack. In the par- 
 ticular boiler of which plans are shown herewith, the super- 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 heater is g feet in diameter by i8 feet in heiglit, with an inner 
 flue 56 inches in diameter. From the plan view it will be 
 seen that steam pipes are connected directly from the dry pipes 
 in each boiler to the lower part of the superheater, while the 
 main steam outlet is placed at the top of the superheater. 
 
 The details of the staying or bracing of this boiler combine 
 the methods used in both a Scotch and locomotive boiler. All 
 flat surfaces are stayed with screw stays % inch diameter, 
 spaced 6^ by 6]/^ inches between centers. The through stay 
 rods for the boiler heads are l}4 inches in diameter. 
 
 The shell and heads of the boiler are 5^16 inch thick, the 
 shell being made in four courses. All girth seams are single 
 riveted and all longitudinal seams double riveted lap joints. 
 The steam pressure is only 55 pounds per square inch. 
 
 A Dog=House Boiler. 
 
 Replace the cylindrical shell and furnaces of a Scotch marine 
 boiler by a shell and furnaces which have cylindrical tops and 
 fiat sides, and the resulting type of boiler is what is commonly 
 known as a dog house boiler. The particular boiler of which 
 a photograph and detailed drawings are shown on this page i>. 
 7 feet 6 inches long and 7 feet 6 inches high, with a steam 
 dome 26 inches in diameter by 32 inches high. It is designeil 
 to carry no pounds steam pressure. There are two furnaces, 
 each 26 inches wide and 70 inches long, made of 3^ inch steel 
 plate. The gases from both furnaces enter a common com- 
 bustion chamber at the back of the boiler and from there are 
 led back to the up-takes through 124 2><-inch tubes. 
 
 ThF lower edges of the furnaces and the combustion cham- 
 ber are joined to the shell plate by a 7-16-inch S-shaped 
 flanged plate, leaving a 4-inch water leg all around the lower 
 part of the furnaces and combustion chamber. The flat plates 
 throughout this water leg are stayed with ordinary screw 
 staybolts. The tops of the furnaces and combustion chamber 
 are stayed from the shell of the boiler by means of long sling 
 stays attached to the plates with crowfeet. The segment of 
 the boiler head above the tubes is braced by means of direct 
 
 through stays, 1% inches in diameter, pitched 6 inches between 
 centers, the ends being secured by inside and outside nuts 
 and washers in the same way as in an ordinary Scotch boiler. 
 
 ^fttttft«t 
 
 •••••§••• 
 
 tfttttttt 
 
 • ••• 
 
 • #•• 
 •••• 
 
 • ••• 
 
 • ••• 
 
 • ••# w 
 
 • §••• 
 
 \ 
 
 A TWO-FURNACE DOG-HOUSE BOILER. 
 
 The shell of the boiler is made of ^-inch steel plate, with 
 heads and steam dome of the same thickness. 
 
 This boiler presents no unusual features as a problem of 
 laying out if the layout of a Scotch boiler is well understood. 
 
 LONGITUDINAL AND TRANSVERSE SECTIONS OF DOG-HOUSE BOILER. 
 
1 90 
 
 LAYING OUT FOR BOILER AIAKERS 
 
 Layout of an Exhaust Elbow. 
 
 The introduction of the steam turbine in modern power- 
 plant construction has made it necessary to provide much 
 larger exhaust passages from the engine to the condenser than 
 was formerly the case with a reciprocating engine. Commercial 
 sizes of steam pipe are not manufactured of sufficient area to 
 be used for this purpose. So the job of building an exhaust 
 connection between the turbine casing and the condenser has 
 passed from the hands of the pipe smith and steam fitter into 
 the hands of the boiler rriaker. Such a connection is now made 
 of steel plates of sufficient thickness riveted together and 
 
 rivets. The elbow is to be made of 7/16-inch steel plate, 
 therefore for steam-tight work the layer out will use J's-inch 
 rivets, spaced 25^ inches between centers with a lap of i->^ 
 inches. Since the difference between the pressure of the at- 
 mosphere outside the connection and the exhaust steam inside 
 is less than 14.7 pounds per square inch, the connection will 
 be sufficiently strong if single-riveted seams are used through- 
 out. It will be noted from the side elevation, Fig. i, that 
 while the distance between the center lines of the two ends 
 of the connection is 321/3 inches, the center of the lower end of 
 the circular section is 3 inches below the center of the rec- 
 
 r. M"o--o-^^-o-r-.-.-o-o---,-^-o-o^-o-o--Z-7\i 
 
 FIG. I. — BLUE PRINT AS SENT FKOM DRAFTING ROOM TO LAYING-OUT BENCH. 
 
 calked to prevent leakage. The exhaust elbow shown in Fig. 
 I is 8 feet loys inches long over all, 36 inches in diameter at 
 one end and rectangular at the other end, the opening being 
 7 feet 11-)^ inches long by 12^^ inches wide, while the distance 
 between the center lines of the two ends is 32^^ inches. 
 
 Fig. I shows the blue print of this connection as it comes 
 from the draftsman to the laying-out bench. Only the gen- 
 eral shape and dimensions of the elbow are given, and it is 
 left to the layer out to build it in any way he thinks best, so 
 long as it conforms to these general dimensions. He must 
 decide the size of the sections into which the connection shall 
 be divided according to the size of plates he can handle most 
 conveniently, using as large plates as possible in order to re- 
 duce the number of riveted joints to a minimum. Where the 
 plates are very irregular in shape, with outlines which are re- 
 versed curves, it is frequently desirable to make the sections 
 of small plates in order to avoid., waste in cutting the ma- 
 terial. Each end of the connection is to fit into a cast-iron 
 flange in which cored holes have been provided for J/^-inch 
 
 tangular end. This is necessary in order to bring the con- 
 nection around the 13-inch pipe shown dotted. 
 
 Since the connection is to form a reverse curve, the easiest 
 method of laying it out, which immediately suggests itself, is 
 to divide the connection into sections which form a regular 
 elbow. To do this, lay down the side view of the connection 
 as shown by the dotted lines (Fig. 2). Then from the centers 
 a and b, divide the two curved portions of the connection into 
 equal sections of regular elbows. It will be found that it is 
 impossible to make these two sections meet in a smooth jomt, 
 and therefore a connecting piece, shown as section D, must be 
 inserted, which has an irregular shape and must be laid out by 
 triangulation. The part of the connection joining the last 
 regular elbow section G to the rectangular flanged casting will 
 consist of four irregular shaped plates, which must also be 
 laid out by triangulation. 
 
 Since the sections A, B and C form a three-piece regular 
 elbow, the layout of these sections is easily accomplished by 
 dividing the base of the section A, a half view of which is 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 191 
 
 shown dotted at the end of the section, into any number of laid out in the pattern. A half pattern of each section is shown 
 equal parts and extending these lines to the lines of intersec- in each case. Referring to the diagram of the finished 
 tion between the sections. Then by drawing the center lines section (Fig. 2), it will be found that section A is an inside 
 
 -DIVISION OF ELBOW INTO SECTIONS AND DEVELOPMENT OF H.ALF PATTERNS FOR REGUL.\R SECTIONS. 
 
 of the various sections and extending them beyond the elbow, 
 the pattern for each section may be laid out directly by pro- 
 jecting the points of intersection between these dotted lines 
 and the ends of the section to the corresponding parallel lines 
 
 section ; section B an outside piece, etc. Thus the length of 
 the center lines of the three patterns must be made such that 
 when the sections are rolled to shape, section A must be 
 small enough to fit inside section B. Since the mean di- 
 
192 
 
 LAYING OUT FOR BOILER MAKERS 
 
 ameter of the elbow is 36 inches, and the thickness of plate equal parts, and not a section taken along the edge of section 
 
 7/16 inch, the length of the plate A will be the circumference G, as was the case with section A. Half patterns are shown 
 
 of a circle 36-7/16 inches in diameter, or 1 11.72 inches. The for these sections as before, and the proper lengths for the 
 
 length of the half pattern, or one-half of 11 1.72 inches, is in- plates are indicated on them. These patterns, of course, show 
 
 12 11 in 
 
 4 5 
 
 Elevation 
 
 6 5 6 5 4 3 
 True Lengths 
 
 -L.W'OUT OF SECTION D. 
 
 dicated in the sketch. The length of the section B will be the 
 circumference of a circle 36 -f- 7/16 inches in diameter, or 
 114.47. One-half of this is S7% inches as indicated on the 
 half pattern. The length of section C should be the same as 
 that of section A. 
 
 the layout of the plate to the center line of the rivets. The 
 lap of ij^ inches must be added outside of this, and each 
 section should be laid out so that the longitudinal seam comes 
 on the side of the elbow and not on the top or bottom. 
 
 Section D must be laid out by triangulation, since it is an 
 irregular section. The details of this work are shown in Fig. 
 3, the horizontal line 1-9 of the side elevation is made equal to 
 the length oi c d (Fig. 2). The outline of the rest of the sec- 
 tion is then drawn in, giving i, 18, 10, 9 as the side elevation. 
 Before constructing the plan view it should be noted that the 
 lines c d and e f (Fig. 2) are not equal in length to the di- 
 
 ne. 4. — TRI.^NCULATION OF SECTIONS H, J AND K. 
 
 FIG. 5. — PATTERN FOR 
 SECTION J. 
 
 Sections E, F and G also form a regular elbow and are laid ameter of the elbow, 36 inches, and that a section of the el- 
 out in the same way as sections A, B and C. Care should be bow through these lines is not a true circle, since the sections 
 taken in this instance, however, to divide a section of the pipe are inclined at an angle with the axis of the pipe. Therefore 
 along the center line of section G into the required number of in constructing the plan view (Fig, 3), lay out the line 1-9 as 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 193 
 
 stated and divide it into the same divisions as indicated on 
 the line c d (Fig. 2). From these points lay off the width of 
 the section as measured on corresponding points of the semi- 
 circle shown dotted on one side of section G (Fig. 2). In the 
 same manner on the line 18-10, lay off the divisions indicated by 
 
 1-2 in the plan, and with i as a center, strike an arc through 
 point 2. Set the dividers to the true length of the line 18-2, 
 and with 18 as a center, strike an arc intersecting the one pre- 
 viously drawn at the point 2. Proceed in similar manner to 
 complete the half pattern. This locates the lines through the 
 
 FIG. 6. — TRUE LENGTH OF DOTTED LINES IN FIG. $. 
 
 the intersection of the dotted lines with e f (Fig. 2). Draw 
 lines at right angles to 18-10 at these points and lay off the 
 off-sets measured from the corresponding lines in the semi- 
 circle shown dotted at the left of section A (Fig. 2). Project 
 the points 10, II, 12, 13, etc., from the elevation (Fig. 3) to 
 the plan, and lay off the corresponding off-sets at points 11, 
 12, 13, etc., in the plan. 
 
 Having constructed the half plan and elevation of section 
 D, divide the surface into trianges as shown. Find the true 
 length of the lines which form these triangles bv construct- 
 
 centers of the rivets, and of course the laps should be added 
 outside this. 
 
 Since this is an outside section, the allowance to be made 
 in the length of the plate so that it will fit outside sections 
 C and E should be made by laying down lines i-g, 18-10, each 
 7/16 inch longer than the corresponding lines c d and e f in 
 Fig. 2. 
 
 To obtain the layout of plates H, K and /, which form the 
 connection from the round section of the pipe to the rec- 
 
 
 
 4 3 
 
 2 
 
 , 
 
 
 / / 
 
 •y 
 
 r 
 
 
 
 / / ^ 
 
 
 / 
 
 
 
 / ' / 
 
 ^^ 
 
 
 
 
 //'/>' 
 
 
 
 
 
 / ' / '' 
 
 
 
 
 
 / / / -' 
 
 
 
 
 
 / ^ / '' 
 
 
 
 
 
 //''/ 
 
 
 
 
 
 '/ // 
 
 
 
 
 / 
 
 '// 
 
 
 
 
 / / 
 
 / / 
 
 
 
 
 / / '■ 
 
 '/ 
 
 
 
 
 
 
 
 
 
 ///^' 
 
 H 
 
 
 
 
 //^^ 
 
 
 
 
 
 /^/ ^ 
 
 
 
 
 
 //// 
 
 
 
 
 
 ///y 
 
 
 
 
 
 V/^ 
 
 
 
 
 / 
 
 V^ 
 
 
 
 
 fi'i' 
 
 
 
 
 
 
 
 
 
 
 •/^- 
 
 _y__ 
 
 __Flange_Iiine 
 
 
 ^. 
 
 
 
 
 — . 
 
 «.» 
 
 i;c." 
 
 FIG. 7. — HALF PATTERN OF SECTION H. 
 
 ing right-angle triangles, the height of which is taken as the 
 height of the lines in the elevation, and the base the horizontal 
 length of the lines as measured from the plan. The hypothe- 
 nuse or third side of these triangles is the true length of the 
 lines as they should be laid down in the pattern. This work 
 raay be easily followed through, since all lines and points are 
 numbered similarly throughout the work shown in Fig. 4. 
 The true length of the lines 1-18 and 10-9 is shown at once 
 ■on the side elevation. Therefore, when laying out the pattern, 
 first lay down the line 1-18. Set the dividers to the distance 
 
 FIG. 8. — HALF SECTION OF SECTION" K. 
 
 tangular flanged casting, draw a half plan and elevation of 
 this part of the elbow, as shown in Fig. 4. This section is to 
 be made of four plates, two of which are of exactly the same 
 shape, therefore only three patterns need be laid out. 
 
 Divide the semi-circle which represents the half plan of the 
 round section of pipe into twelve equal parts. Draw lines from 
 points 14 and 21, which locate the ends of the straight section 
 on the rectangular cast-iron flange, to the points 10 and 4- 
 These represent the center lines of the rivets for the seams be- 
 tween the side and end plates. Also draw lines from the 
 
194 
 
 LAYING OUT FOR BOILER MAKERS 
 
 point 14 to the points 12 and 11 and from 21 to 2 and 3. Di- 
 vide the quarter circle in the corners of the rectangular cast- 
 ing each into three equal parts. From these points of di- 
 vision draw lines to the point 7. The entire surface of the 
 half section is now divided into triangles, and it is only neces- 
 sary to find the true length of these lines in order to lay out 
 tlie pattern. The line 18-22 in the elevation of this section 
 represents the flange line or the line at the top of the flanged 
 casting marked g h in Fig. 2. As the patterns are laid out 
 from this line the required depth of flange must be added so 
 that the plates will fit into the cast-iron ring. 
 
 It should be noted that the height of all lines of which the 
 true length must be found is the same. Therefore, lay off 
 this height, which is equal to 1-22, at O Z (Fig. 6). Then on 
 either side of O on a line at right angles to O X, lay ofif 
 the horizontal lengths of all the dotted lines shown in the 
 plan (Fig. 4). Connect these points with X, and the result- 
 ing lines are the true lengths, which are to be used in laying 
 out the patterns of these plates. Each of these lines is care- 
 fully marked with the numbers corresponding with the posi- 
 tion of the line in Fig. 4. 
 
 The pattern for plate H is shown in Fig. 7. The flange 
 line 21-22 is laid off equal in length to the flange line 21-22 
 Fig. 4. 1-22 is laid off at right angles to this, equal ii^ length 
 to the line 1-22, Fig. 6. Then with the dividers set to the equal 
 spaces 1-2, 2-3, 3-4, shown in the plan view of the semi-circle 
 (Fig. 4) strike an arc from the point I (Fig. 7) as a center. 
 Set the trammels to the line 21-2 (Fig. 6), and with 21 (Fig. 7) 
 as a center strike an arc, cutting the one previously drawn and 
 locating the point 2. In the same manner locate points 3 and 
 4, which complete the outline of the half pattern of the plate 
 with the exception of the flange below the line 21-22. 
 
 The depth of this flange may be found by first referring to 
 Fig. I, where it will be noted the center of the rivet hole in the 
 flange is ij4 inches from the top of the flange. Since, how- 
 ever this section is riveted to the front or longest side of the 
 casting, the plate need be flanged only to a small angle. 
 
 Furthermore, the direction of this flange is such that the out- 
 side of the plate or the side upon which the pattern should be 
 laid down is bent up in a reverse direction, so that the fiber 
 on this side of the plate will be slightly shortened in the pro- 
 cess of flanging. For this reason the depth of flange from the 
 flange line to the rivet line may be laid off slightly less than the 
 measured distance, 114 inches. This allowance should be 1/16, 
 or perhaps 3/32, of an inch, making the depth of the flange 
 from flange line to rivet line i 7/16 inches. At the corners of 
 the plate, as at point 21, a little extra material should be left 
 when shearing the plate, as indicated by the dotted line, in 
 order to compensate for the material which is drawn in in the 
 process of flanging. After these allowances have been made 
 the plate should fit accurately in place. 
 
 The layout of plate K is similar to the layout of plate //, 
 except that the length of the lines is different, since the center 
 lines of the top of the upper and lower bases of this section 
 are 3 inches apart. The same allowances should be made for 
 the flange as in section H. The pattern is shown in detail in 
 Fig. 8. 
 
 In the layout of plate /, or the end of the section, as shown 
 in Fig. 5, the flange line 17-18 is laid down equal in length to 
 
 17-18 in the plan (Fig. 4). Dith the trammels set to the line 
 18-7 (Fig. 6), and with 18 (Fig. 5) as a center, strike an arc. 
 Reset trammels to the length of the line 17-7 (Fig. 6), and 
 with 17 (Fig. 5) as a center strike another arc intersecting 
 the one previously drawn locating the point 7. Since the 
 corners of the flanged casting are circular, with an appreciable 
 radius, in order to make an accurate job, the portion of the 
 flange line included between the points 14-17 and 18-21 should 
 be located by triangulation in the same way as the upper edge 
 of the pattern. The triangles which were used in accomplish- 
 ing this are clearly numbered, and corresponding lines in Figs. 
 4, 5 and 6 may be easily found and the work followed 
 through. Since this section is to be riveted to the end of the 
 flanged casting, the angle which it makes with the flange of the 
 casting will be large, and since the plate should be flanged 
 downward from the side on which it is laid out, it will be 
 necessary to add an allowance for this flanging to the distance 
 between the flange line and rivet line as measured from Fig. 2. 
 In this case this allowance should be approximately >i of an 
 inch, making the total distance between the flange line and 
 rivet line 1^4 inches. The corners of the flange should be 
 sheared, as shown by the dotted lines, to allow for the stretch- 
 ing of the metal when it is flanged. 
 
 To Develop Regular and Irregular Y^Pipe Connections. 
 
 The forms of Y-connections or breechings generally en- 
 countered in sheet metal work are shown in Figs. 1, 2, 3 and 
 4. Figs. I and 2 are irregular and require a more extensive 
 and complicated method of development than is required for 
 Figs. 3 and 4. The general arrangement of Figs, i and 2 
 shows that all lines assumed on the drawings are foreshort- 
 ened, which is due to the irregular taper in Fig. 2 and the 
 irregular taper and shape of the leg openings in Fig. I. Owing 
 to the above conditions the practical method of laying out the 
 constructions for Figs, i and 2 is by the triangulation system. 
 
 Fig. 3 is regular in outline and is introduced for the pur- 
 pose of showing the principles involved in obtaining correct 
 mitre lines and patterns by the parallel method for intersec- 
 tions between cylinders which are shown in their true length 
 in elevation. There are numerous varied modifications of 
 this construction in pipe work, but the development remains 
 practically the same if the arrangement of the pipes is regu- 
 lar. The term "regular" in this case means that all construc- 
 tion lines assumed on the surface to be developed are shown 
 in their true length. 
 
 Fig. 4 involves the radial and parallel method of develop- 
 ment for its solution. Fig. 2 is a modification of this con- 
 struction. 
 
 CONSTRUCTION OF FIG. I. 
 
 The first operation is to draw the plan and elevation in 
 their relative positions and to the required dimensions. In 
 this construction a flat surface is shown from a to x, and h to 
 .r in the elevation. The major diameter of the oval openings 
 is usually made equal to the diameter of the large pipe. 
 
 Divide the semi-circle o to rf of the plan view (Fig. i) into 
 any number of equal spaces, in this case three, as shown, 
 from a to &, b to c, and c to d. Project these points of divi- 
 sion to the line ^ to rf of the elevation. Parallel to the out- 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 195 
 
 side border lines of the V-legs and from the points just lo- 
 cated on the line f to d draw solid lines until they intersect 
 the line of intersection between the large pipe and the Y-Iegs. 
 These points are then dropped to the plan view. In order 
 to avoid confusion alternate dotted and solid lines sliould be 
 drawn. Solid lines connect the points a to a, b to b, c to c, etc. 
 Dotted lines connect the points from o to fc, 6 to c, etc., cor- 
 responding dotted lines can be shown in the elevation if de- 
 sired ; this, however, is not essential, as these lines serve no 
 purpose other than they may aid in checking up the drawing. 
 Having drawn in all the construction lines, the next oper- 
 ation will be to obtain their true length. This is done in the 
 usual manner by constructing triangles, the bases of which 
 are obtained from the plan view and the corresponding 
 
 it locate the distance d to d. Then with the dividers set equal 
 the space d to c of the oval opening plan view and, using d 
 as a center, shown at the bottom of the pattern, draw an arc. 
 Set the dividers equal to the space d to c of the large circle 
 plan view, and with point d, shown at the top of the pattern, 
 as a center, draw an arc. The corresponding true length of 
 line c to d \s then transferred to the pattern. Continue in 
 this manner, using alternately the true spaces solid and dotted 
 construction lines until the pattern is complete. 
 
 The vertical or throat connection between the two branches 
 of the Y is determined in the manner as set forth in the pat- 
 tern. The distances between the points h to i, /; to 2, g to 3, 
 and g to 4, etc., art transferred from triangles shown to the 
 left of elevation to the pattern. 
 
 FIG. I. — PLAN, ELEVATION .AND PATTERN FOR AN ELLIPTICAL V-PIPE CONNECTION. 
 
 heights from the elevation. The diagram of triangles shown 
 to the right of the elevation is used for developing the 
 whole leg of the Y shown within the limits of the boundary 
 lines e to (?, ^ to d, d to d, and d to e. To obtain the throat 
 connection, or the line of intersection between the two 
 branches of the Y, it is necessary to determine the true length 
 of lines shown within the section e to x to 7 of the elevation. 
 The true lengths of lines are constructed as drawn to the le''t 
 of the elevation. The bases are equal to the distances e to 7, 
 / to 6, / to 5, o- to 4, etc., of the plan view. Their heights are 
 obtained from the elevation. The line connecting the base 
 with the height is the hypotenuse, or the required true length 
 of line. 
 
 Having now sufficient information for developing the pat- 
 tern it can readily be constructed as follows : 
 
 Set the dividers equal in length to the distance rf to d in 
 the elevation, then draw a line of indefinite length and upon 
 
 This problem and the one shown in Fig. 2 embody condi- 
 tions which necessitate the principles of triangulation draw- 
 ing for their proper solution. The errors which are notice- 
 able in this method of development are not very great, unless 
 the curvature 06 the surface is large. The system, as a whole, 
 can be relied upon, and if very accurate construction is re- 
 quired a greater number of triangles can be drawn, which will 
 reduce the errors to a minimum. 
 
 Fig. 4 is a construction in the form of an intersection be- 
 tween two right cones and a cylinder. The cones are tilted, 
 so to speak, until their axes make the required angle with the 
 axis of the cylinder. The development of this connection is 
 as follows : 
 
 First draw the center lines or axes of the three connec- 
 tions to the required angles between them. Through the 
 apex R, virhich is the point where the axes meet, and at right 
 angles to the center lines of the respective sections, draw the 
 
196 
 
 LAYING OUT FOR BOILER MAKERS 
 
 required diameters of the bases. The bases of the cones are 
 made slightly larger than the diameter of the cylinder, as 
 -will be noted. After the bases of the cones have been prop- 
 erly located on the drawing, their extremities are then con- 
 nected with points and O'. Using point i? as a center, and 
 with a radius equal to one-half the diameter of the cone 
 iase, draw a semi-circle. Divide its periphery into any num- 
 ier of equal divisions and extend these points to the base line 
 of the cone. The points located on the base line are then 
 connected with the apices O and O'. These lines are termed 
 the elements of the cone. 
 
 in all radial developments that the measurements of points 
 and lines are determined by means of their elements. The 
 true lengths of the elements b and c are obtained in the man- 
 ner as set forth in the elevation, where the points 6 and c are 
 found by projecting lines at right angles to the axis of the 
 cone through the point of intersections between the elements 
 and mitre line to the outer edge line of the cone. 
 
 To develop the patterns for sections A and B, first draw 
 a circular sector with a radius that equals the slant side of the 
 cone ; the arc is equal to the circumference of the base of the 
 cone. Divide the sector into halves, and on either side of 
 
 The next operation is to determine the proper mitre lines 
 between the three sections. In this case the lines of inter- 
 section between them center at point R. The mitre connec- 
 tion between the two cones is established through the inter- 
 section of their outer elements, as shown at T, and the inter- 
 section between the cones and cylinder is fixed where the 
 outer ordinates intersect the lower element of the cone, as 
 shown at u. Points u and T are then connected with R, which 
 gives the line of connection between the intersections. 
 
 Before the patterns can be obtained for the conic sections, 
 it will be necessary to find the true length of the elements 
 within the outer boundaries of the cones, as it is understood 
 
 the point 7 on the arc of the sector step off the same number 
 of equal spaces as contained in the semi-circle, which repre- 
 sents one-half the base of the cone. Radial lines are then 
 drawn connecting the points of division with 0', as shown 
 from I to 0', 2 to O', 3 to O', etc. To establish the line of 
 connection simply revolve the points a, h, c and d around to 
 the pattern until they intersect their corresponding lines. A 
 line traced through the intersection of these lines gives the 
 required mitre line. " 
 
 An explanation for laying out the pattern for section C 
 will not be given, as the drawing is sufficient to make clear 
 the requirements. 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 197 
 
 CONSTRUCTION OF FIG. 3. 
 
 Draw the elevation and profiles in their relative positions. 
 The location of the mitre lines between the upper throat and 
 the connections between the section B to C and D are to be 
 made to suit the requirements. Divide the profile into any 
 number of equal spaces. Drop these points of division to 
 the line of connection between the large pipe and the Y- 
 
 permit. There are also "rules of thumb" which are close 
 approximates and answer the purpose just as well as the 
 theoretical method in same constructions. These, however, 
 are simply modifications of the parallel method and require 
 careful attention in their application. 
 
 Fig. 3 brings out very clearly the principles used in devel- 
 oping regular surfaces by orthographic projection (parallel 
 
 LL^J^LimJ^ 
 
 htm 
 
 '■•J-.1J 
 
 V- 
 
 I I I I I 
 
 Profile I |j 
 
 W I i/ 
 
 FIG. 3. — Y-PIPE CONNECTION DEVELOPED BY THE PARALLEL METHOD. 
 
 branch. In a like manner divide the remaining profiles and 
 draw the construction lines as shown within the sections 
 B, C and D. These projections are the true lengths of the 
 required lines, which are used for developing the patterns. 
 
 Having determined these lines, the patterns are very easily 
 constructed in the following way: 
 
 A stretch-out line, m to m, is first drawn, and which is 
 equal in length to the distance around the pipes ; this dis- 
 tance is obtained by multiplying the diameter by the constant 
 3.1416. Divide this stretch-out into quarters, and these divi- 
 sions into the same number of corresponding equal spaces as 
 contained in one quarter of the profiles. Projections from the 
 pipe sections are then drawn to the corresponding lines in the 
 pattern. 
 
 The allowances for laps and spacing of rivet holes were 
 not taken into consideration in these problems, as these will 
 be governed according to the requirements and thickness of 
 material. 
 
 Fig. 2 is a modification of the work shown in Fig. i, and 
 the same method of development is applicable for its solution. 
 
 It is the best practice to use the parallel or radial method in 
 all construction drawing if the conditions and the problems 
 
 method). This character of work may be very well under- 
 stood by the average and advanced layer outs, but we know 
 from experience that many of the apprentice boiler makers 
 know little or nothing in laying out along this line, and since 
 this subject is the basis of the layer-outs' profession it is ob- 
 vious that simple problems should be treated in detail for 
 their information. Everyday examples explained in a simple 
 way would be of interest to the young men of the trade, 
 where the more complicated ones would effectually scare them' 
 from any attempts to study the underlying principles. 
 
 Layout of a Horizontal Return Tubular Boiler 
 18 Feet Long by 72 Inches Diameter. 
 
 In many shops, part of the layer-out's work is to order the 
 material, so the following list is given of what is needed to 
 lay out a horizontal tubular boiler l8 feet long by 72 inches 
 diameter. 
 
 MATERIAL 
 
 Two plates, .47 inch by ,72^^ inches by 228 inches, for fronf 
 and rear courses. 
 
 One plate, .47 inch by 71^ inches by 225 inches, for middle 
 course. 
 
LAYING OUT FOR BOILER MAKERS 
 
 PATTERN FOR SECTION C 
 
 FOR EXPLANATION OF ABOVE FIGURE SEE PAGES I94, IpS, I96 AND I97. 
 
 One plate, .47 inch by 45 inches by 121 inches, dome plate. 
 
 Two plates, J-^ inch by 15^:4 inches by 68 inches, inside cov- 
 ering straps for front and rear courses. 
 
 One plate, yi inch by lS}i inches by 72 inches, inside cov- 
 ering strap for middle course. 
 
 Two plates, ^ inch by I0J4 inches by 72 inches, outside 
 covering straps for front and rear courses. 
 
 One plate, fg inch by 1014 inches by 68 inches, outside cov- 
 ering strap for middle course. 
 
 Two flanged heads, 72 inches outside diameter by % inch 
 thick, 2 inches internal radius on turn of flange, 3j4 inches 
 straight flange. One of these heads to have two manholes 11 
 inches by 15 inches flanged inwards from face to head; same 
 to be provided with patent pressed steel manheads, bolt, yoke 
 and gasket. Center of upper manhole to be 20'A inches from 
 center of head, and the lower manhole to be 27 inches from 
 center of head to center of manhole. 
 
 One flanged and dished head, 36 inches outside diameter by 
 14 inch thick, to be dished to a radius of 36 inches; 2 inches 
 internal radius on turn of flange and 3 inches of straight 
 flange. 
 
 The quality of steel to be homogeneous flange steel, and a 
 certificate of test to be furnished. Steel to meet the require- 
 ments of any reliable insurance company. All other material 
 needed to complete the boiler is, of course, added to this ; 
 such as flanges for pipe connections, brackets, etc., after the 
 list is handed in to whoever might have charge of that part 
 of the work in the office. 
 
 On receiving the material, we will proceed to lay out the 
 boiler. Fig. i shows the heads, shell and dome of the boiler 
 assembled, giving all the necessary dimensions. This, with 
 the specifications, is all the layer-out gets with his order; in 
 fact, it is all that is necessary. Figs. 2 and 3 show both heads 
 laid out, and give correct figures showing the distance the 
 braces will come on the shell of the boiler from the top and 
 bottom center line. Fig. 2 also shows the location of the 
 holes for the feed pipe and water column. 
 
 It is always necessary in laying out the boiler to find the 
 exact circumference of the head, as it will be found in nearly 
 every case that the head runs small or large. In this case 
 it will be seen that the heads are a fraction over 72 inches in 
 diameter, for by measuring around we find the circumference 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 199 
 
 to be 226H inches. The writer finds the wheel to be the most 
 convenient tool to measure a circle, as in measuring a head 
 it can be done much quicker and without any assistance. 
 However, some layer-outs prefer a steel tape line, and one is 
 used about as much as the other. 
 
 manufacturer from whom they are ordered, in case tlicy are 
 not at hand when you are ready for them. 
 
 Fig. s gives the layout of the first course. This is the same 
 as Fig. 4, or the rear course, and can be marked off from it, 
 leaving out all the brace holes and the 4-inch pipe hole. The 
 
 FIG. I. — SHELL^ HEADS AND DOME ASSEMBLED, SHOWIXC PRINCIPAL DIMENSIONS. 
 
 Maving the heads laid out, we next take up the rear course. 
 The layout for this is shown in Fig. 4, which shows the neces- 
 sary allowance in the length of the plate, which is called the 
 take-up in rolling. This sketch also shows the location of the 
 braces, with measurements corresponding with same taken 
 from the rear head, Fig. 3. It should also be noted that there 
 
 holes for the braces in tliis plate can very quickly be put in 
 by the layer-out after the plate is marked ofif. 
 
 Fig. 6 gives the layout for the middle course, or small 
 course, of the boiler. It shows the correct total length of the 
 plate so as to make a good fit. It will be noticed that in this 
 la^'out there is H inch allowed on each end of the plates. This 
 
 FRONT HEAD 
 FIG. 2. 
 
 is an allowance made in these measurements. Very little at- 
 tention is paid to this allowance by most layer-outs, and it 
 hardly amounts to anything. However, it is correct. 
 
 The correct location of the brackets is also shown in this 
 sketch. The centers for the rivet holes are not given, for the 
 reason that nearly always these castings come from the foun- 
 dry with the holes cored, and it is better to make a template 
 for each casting in order to get fair holes. The layout for 
 the blow-off connection is also shown. These dimensions can 
 nearlv always be secured bv referring to the catalogue of the 
 
 Note;- 9B Rivets, 2!4 PitcK 
 
 REAR HEAD 
 FIG. 3. 
 
 is to be taken off with the planer, and makes a perfect butt 
 joint when the plates are rolled. 
 
 In Fig. 6 we also show the location of the opening for the 
 dome, the two long braces from each head and the holes for 
 the braces from the shell of the boiler to the shell of the 
 dome. In the layout for the middle course it will be seen that 
 the proper amount of lap is given, as it is not necessary to 
 bevel this plate, while on each end course an allowance is 
 made for the planer or bevel shear. 
 
 Fig. 7 gives a detail of the dome connection on a larger 
 
200 
 
 LAYING OUT FOR BOILER MAKERS 
 
 scale, showing the development of the hole in the plate and 
 the layout of rivet holes. 
 
 Fig. 8 shows the development of the dome plate, location of 
 holes for braces and the layout for the safety-valve connec- 
 
 courses. Dotted lines on the inside strap show how the plates 
 are to be scarfed. The marks G, B, R and W are to show 
 where braces will come on the straps. Figs. 1 1 and 12 show 
 the butt straps for the middle course, while details of the 
 
 tion. It will be seen that this plate is marked to be laid out braces required for the boiler are not shown. 
 
 Toward Front of BoUei 
 
 FIG. 4. — LAYOUT OF REAR COURSE. 
 
 Toward Front of Boiler 
 
 One Quarter of Circumference 
 £3 holes to the Quarter 
 
 FIG. 5. — LAYOUT OF FRONT COURSE. 
 Toward Front ofBoiler 
 
 ' One Quarter of Circumference : 
 25 holes to the Quarter 
 
 FIG. 6. — LAYOUT OF MIDDLE COURSE. 
 
 on the opposite side from the stamp. This is done so as to 
 have the center for the flange line on the inside when the plate 
 is rolled, and saves the trouble of back-marking the flange 
 line for the flange turner. It will also be noticed that an al- 
 lowance is made on the outside lap for the stretch of material 
 in flanging. If this allowance is not made, it would be found 
 that there would be quite a large opening at the toe of the 
 flange when the dome was finished. 
 
 Figs. 9 and ic show the butt straps laid out for the end 
 
 SPECIFICATIONS. 
 
 Dimensions. — To be 72 inches in diameter by 18 feet long 
 from face to face of heads. 
 
 Steel. — Boiler to be constructed of the best open-hearth 
 homogeneous flange steel plates, same to meet the require- 
 ments of any reliable insurance company. 
 
 Shell and dome plates to be .47 inch thick. 
 
 Heads to be ^ inch thick. 
 
 Dome head to be yi inch thick, dished to a radius of 36 
 inches. 
 
AlISCELLANEOUS PROBLEAIS IN LAYING OUT 
 
 201 
 
 Tubes. — To contain seventy best American lap-welded tubes 
 of standard gage, 4 inches in diameter and 18 feet '2 inch 
 long. 
 
 Dome. — To be 36 inches in diameter and 42 inches high. 
 Shell of dome to be braced to shell of boiler with six crow- 
 
 riG. 7. — DOME CONNECTION. 
 
 foot braces. Pad of braces to be J4 inch by 214 inches ; flat 
 bar iron. Rod of braces to be i J^ inches diameter ; round 
 iron. Braces to be about 24 inches long. 
 
 Rh'eting. — Boiler to be riveted throughout with steel rivets 
 Js-inch diameter. Girth seams to be lapped and single riv- 
 eted, with pitch of about 2]4 inches. Longitudinal seams to 
 
 convenient low section for l^-inch pipe. Pressed steel flanges 
 to be used. 
 
 Pressure. — Boiler to be constructed for a working pressure- 
 of 125 pounds per square inch, and to be tested to a hydro- 
 static pressure of 188 pounds per square inch. 
 
 Feed Pipe. — Feed pipe to be 2 inches in diameter and about 
 12 inches long, perforated. 
 
 Lugs. — To have four lugs or brackets, two on each side. 
 
 Manholes. — To have two improved-type manholes, 11 inches- 
 by 15 inches, located one above the tubes and one below the 
 tubes in front head. 
 
 Braces. — Heads to be stayed with thirty crow-foot braces, 
 placed ten above and two below the tubes on front head, and 
 fourteen above and four below the tubes on back head ; also- 
 six inside the dome running from shell of boiler. Shortest 
 brace in boiler to be not less than 42 inches in length. Braces 
 in dome can be about 24 inches long. 
 
 The shell of the boiler shall be made in three equal rings, 
 of one plate to the ring, with longitudinal seams coming well 
 above the fire line, and to break joints in the usual manner. 
 
 Heads to be flanged to an internal radius of not less than 
 two inches. 
 
 Construction. — Tubes will be set in vertical and horizontal 
 rows, carefully expanded in place with a straight roller ex- 
 pander. No self-feed or taper-roller expander to be used. If 
 necessary, to cut tubes to proper length, same must be done 
 in a neat and workmanlike manner : each end of tubes to be 
 neatly turned over. Holes for tubes in heads to be drilled 
 and chamfered. All rivets must be of the best quality open- 
 hearth steel, with tensile strength of not less than 50,000 nor 
 
 FIG. e. — DEVELOPMENT OF DOME SHEET. 
 
 be triple-riveted butt joint, with double covering straps, hav- 
 ing a rivet pitch of 3^ inches by 7]4. inches. 
 
 Head of dome to be single riveted to shell of dome. Pitch 
 of rivets, 2j4 inches. Straight or vertical seams of shell of 
 dome to be double riveted with rivet pitch of 3% inches. 
 Flange of dome to be double riveted to shell of boiler. Pitch 
 of rivets, 3^ inches. 
 
 Ofienings. — Main steam openings on top of dome to be for 
 7-inch pipe. Safety valve opening on shell of dome towards 
 front end of boiler to be for S-inch pipe. Blow-off opening 
 in bottom to be for 4-inch pipe. Opening in front head above 
 tubes for feed pipe to be for 2-inch pipe. One opening to be 
 provided in top of boiler near front end and another in a 
 
 more than 62,000 pounds per square inch, elongation of 30 
 percent in 8 inches, and elastic limit equal to at least one- 
 half the ultimate tensile strength. Heads of rivets must be 
 of equal strength with the shanks. All rivet holes to be 
 punched 1/16 inch smaller than required, shell plates to be 
 rolled to a perfect circle, the work assembled and rivet holes 
 reamed to full size. Rivet holes, when ready for riveting, to 
 be 1/16 inch larger in diameter than the diameter of the 
 rivet to be used. 
 
 All rivets, whenever possible, to be driven with strictly 
 modern hydraulic riveters, allowing the rivets to cool and 
 shrink under standard pressure adopted by the American 
 Boiler Makers' Association. 
 
LAYING OUT FOR BOILER MAKERS 
 
 Braces to be so set and spaced as to bear uniform tension. 
 The working strain on the braces not to exceed 7,500 pounds 
 per square inch, making the usual allowance for the flat sur- 
 face cared for by the surrounding shell, tubes and manholes. 
 Where braces are placed below the tubes, they will be led well 
 up on the shell of boiler to prevent obstructing the flow of 
 sediment to the blowolY. 
 
 Lugs will be of cast iron, with a projection of about 15 
 inches from boiler, measuring 16 inches on boiler and 12 
 inches in width. Lugs to be 1% inches thick and to be heavily 
 ribbed and securely fastened to the boiler. 
 
 Feed pipe will be approximately 12 feet long, securely 
 braced and located 3 inches above the upper row of tubes, 
 
 Construction of Ninety=Degree Elbow. 
 
 Fig. I shows a cross sectional elevation of the tapering pipe 
 connection which is lap riveted and made up of seven heavy 
 plate rings. The upper ring, /, is a section of a true cylinder 
 and does not require a development for securing its pattern. 
 The other sections are tapering, the connecting sections over- 
 lap each other, the difiference in diameter, therefore, between 
 the small and large ends of all sections, excepting ring /, is 
 equal to two times the plate thickness. This is evident from 
 the cross sectional drawing (Fig. l). Section I could be made 
 like section /', but this would require some additional work 
 in making the elbow. It is better to consider the ring / as a 
 part of a horizontal pipe to which the elbow joins. 
 
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 entering through the front head. Feed pipe to be perforated 
 with 5/16-inch holes on each side, of sufficient number to 
 equal the area of pipe. Inner end of pipe to be left open. 
 
 All tests of steel for tensile strength, elongation and re- 
 duction of area will be made at the place of manufacture. 
 Shell will also stand customary bending tests without frac- 
 ture, and in all respects will conform to the Association of 
 American Steel Manufacturers' Standard Specification. Each 
 plate to be plainly stamped with the name of maker, brand 
 and tensile strength. 
 
 Plates to be properly beveled for calking and boiler thor- 
 oughly calked with round-nose calking tool. The above men- 
 tioned hydrostatic test to be applied and boiler to be tight at 
 said pressure. 
 
 Proceed with the development of this problem by drawing 
 a right-angle triangle A B C. Upon line A B locate the center, 
 •);;, of the elbow, and with B m as a radius draw the arc ;;/ n- 
 Divide the arc 111 n into one less than the desired number of 
 sections ; therefore, in this case, divide it into six equal parts. 
 Then take one-half of one of these divisions and set off this 
 distance from points ;;; and n on the arc in n as at I and i', 
 thus determining the centers of two half sections. It is the 
 usual practice to use half sections at the respective ends of a 
 90-degree elbow, because their use will produce a uniform or 
 more symmetrical elbow. 
 
 Next divide the distance between l and i' into the required 
 number of divisions to produce five whole sections, as //, 
 ///, IF, V and VI. Through the points i, 2, 3, 4, etc.. on the 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 203 
 
 arc 111 It draw radial lines connecting with point B, as B D, 
 B E, B F 3.nd B G. The lines D D', E E', F F', etc., taken on 
 these radial lines, are the lines of intersection or miter lines 
 between the joining sections; for instance, the line D D' is the 
 miter line between sections / and //. 
 
 To arrange the different sections so that they will be sym- 
 metrical about the arc in », simply divide the arc distances 
 between points I and 2, 2 and 3, etc., into two equal parts and 
 tangent to the points of division draw the respective center 
 
 and F F' draw lines from the points a b c, etc., until they in- 
 tersect the miter lines, as shown. Connect the points a' a', 
 b' b' and c' c', etc. These construction lines will be used in 
 laying off the pattern. 
 
 Referring to Fig. 2, lay off the stretchout line m n. Upon 
 this line two stretchouts must be laid off; one for the small 
 end equal in length to the neutral circumference, the other 
 equal to the neutral circumference of the large end. It is best 
 to use the neutral dimensions in laying off the stretchout, be- 
 
 /' tf' / 
 
 lines. About these lines and the miter lines the sectional 
 views can be constructed. 
 
 It is not necessary to draw in all of the sections shown in 
 the drawing of Fig. i, as enough information can be had from 
 one section in order to lay oft' the necessary patterns. Con- 
 sider ring /// in this development. It is divided into two 
 equal parts by line O P. Tangent to point r draw the center 
 line d' d' : about this line the sectional view of ring /// is 
 drawn. From points d' d' at the small and large end lay off 
 the required diameters, considering the thickness of plate. As 
 mentioned previously, the difference in the two ends is equal 
 to two times the plate thickness. Now with d' as a center, and 
 with the neutral radius, draw a semi-circle for the small end ; 
 do the same for the large end. Divide these arcs into equal 
 spaces. Then at right angles to the respective miter lines E E' 
 
 cause at that point the plate neither gains nor loses in length 
 during the operation of rolling. Divide the stretchout be- 
 tween r r into two times the number of spaces contained in 
 the semi-circle of the large end : divide the small end in a 
 like manner. From the points on the stretchout lines erect 
 perpendiculars thereto. In laying off the pattern consideration 
 of the location of the seam lines must be made. In light work 
 it does not matter so much, but in heavy plate work no two 
 seam lines should come together ; the3' should alternate on 
 opposite sides if possible. The seam should come on line 
 d' d' for this section, and the seams for the adjoining sections 
 should come diametrically opposite. Fig. 2 shows the develop- 
 ment of the pattern as required to meet this condition. 
 
 The solution of this problem as given herewith is not mathe- 
 matically correct, as, owing to the taper of the respective 
 
204 
 
 LAYING OUT FOR BOILER MAKERS 
 
 sections, the lines produced, as shown on the drawing — that 
 is, the lines b' b', c' c', etc. — are foreshortened, owing to the 
 difference between the diameters of the two ends. For prac- 
 tical purposes, however, the solution is sufficient. Allow for 
 laps. Ordinarily the points d' e' f g', etc., are used as centers 
 for the rivet holes. To connect the sections together it will 
 be necessary to scarf opposite ends of the pattern. For in- 
 stance, the outer point d' on the small end must be scarfed in 
 order that the connecting sections will set up snug. The inner 
 point d' on the large end must also be scarfed; otherwise there 
 will be a gap between the sections on account of the additional 
 thickness of metal at the joints. 
 
 spirally formed ; that is, the pipe runs around another of a 
 larger size, as a helix, and where the rise or fall is sometimes 
 equal for each section or irregular as required. Pipe elbows 
 of this kind are usually used in blast furnace work, as in a 
 downcomer. Each section in such a construction is oblique 
 to all planes of projection. 
 
 In all cases of this character where the patterns are re- 
 quired, each section must be revolved around into a plane 
 which will show the pipe section in its true length. It is also 
 apparent that to obtain the required twist and the required rise 
 or fall of each section, the miter lines between each section 
 must be carefully determined, otherwise the result would be 
 
 Development of an Irregular Elbow. 
 
 One of the problems met with quite frequently in the shop 
 is the layout of elbows of one form or another. The regular 
 elbows are probably the ones used the most. In developing 
 these regular forms no difficulty is encountered unless the 
 elbow is oblique to the principal planes of projection. But in 
 such a case the problem can be readily solved by simple steps 
 of projection. 
 
 Elbows of an irregular shape and tapering from one profile 
 of one kind into that of another require sometimes a lengthy 
 series of operations in developing the required patterns. This 
 is especially evident in constructions where the elbow is 
 
 that when the pieces are assembled the elbow would be straight. 
 
 Other conditions enter into elbow problems, various forms 
 and irregularities in profiles are met with. Some taper from 
 a round to a square, rectangular, elliptical and wash-boiler 
 sections, but any combination of these profiles can be used. 
 The developments of any arrangement that might be made are 
 practically alike, and the layerout who has a practical knowl- 
 edge of the application of the "triangulation development" will 
 find it to his advantage that he does understand the system, as 
 Httle trouble will be found in securing layouts which are ap- 
 proximately correct and practical. 
 
 Fig. I of this article represents an elbow tapering from a 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 round section into an elliptical one. The major diameter of 
 the ellipse is greater than the diameter of the circle. The 
 minor diameter is equal to the diameter of the circle. The 
 elbow in this case is made up of four sections — A, B, C and D. 
 Each section is irregular and requires a separate layout, as the 
 profiles through the planes d d, c c, b b, etc., are of different 
 form, owing to the taper and shape of the profiles. 
 
 Before entering into the discussion of Fig. 2 a method for 
 ■constructing an approximate ellipse will be given, which is 
 of value, since ellipses must be drawn for each profile through 
 the planes c c, d d, etc. 
 
 CONSTRUCTION OF FIG. 3. 
 
 A-B equals the major diameter of the ellipse. C-D equals 
 the minor diameter. From A and B set off distances A-0 and 
 B-0 equal to less than one-half A B. With 0-0 as centers 
 and with the dividers or trammels equal to the distance be- 
 tween them, draw arcs intersecting as at P and R, respec- 
 tively. Draw lines from P and R to 0-0. If the work has 
 been accurately done, sides O P, O and O R should be equal. 
 With P as a center and the dividers set to a radius P C, draw 
 an arc of an indefinite length, and from i? as a center and with 
 the same radius draw an arc through D. With O and O as 
 •centers complete the ellipse by drawing arcs through A and B. 
 
 CONSTRUCTION OF FIG. 2. 
 
 This figure shows the development of section D. The re- 
 maining sections, A, B and C, are developed in a like manner. 
 Transfer the section D, Fig. i to Fig. 2, as shown in the ele- 
 vation. Bisect the top and bottom lines of the elevation, as at 
 points 4. Erect perpendiculars therefrom, then at right angles 
 to either perpendicular draw a horizontal line. Upon these 
 lines as axes construct the plan. Some preliminary drawing 
 must now be done in order to show correctly how the top of 
 the section will appear, since the plan is inclined to the hori- 
 zontal plane. Owing to the inclination the top through its 
 major axis will appear foreshortened in the plan. The minor 
 width, however, will appear in its true length. 
 
 To the left of the plan view at a convenient distance, con- 
 struct a profile through the plane taken on line d d hy the 
 method explained for constructing Fig. 3. Divide its circum- 
 ference into any number of equal parts, and from these points 
 ■draw horizontal lines of an indefinite length. Then on the 
 elevation locate the points 2, 3, S. 6, etc. This is done by 
 transferring from the profile the distances located on the 
 major axis. An inspection of this figure will show how these 
 points were found. From the points i, 2, 3, 4, 5, 6 and 7 draw 
 vertical lines until they intersect the horizontal ones previously 
 •drawn in the plan. Their points of intersection determine the 
 points through which the foreshortened curve of the ellipse is 
 to pass. 
 
 The ellipse for the base of the section is then drawn in full 
 size according to previous directions. Divide its circumfer- 
 ence into the same number of equal spaces as contained in 
 the profile. Solid and dotted construction lines are then 
 •drawn between the points of division on the ellipses. Solid 
 lines join the points i-i, 2-2, z-2 to 7-7, inclusive. Dotted 
 lines are drawn from i to 2, 2 to 3, 3 to 4, etc. The corre- 
 sponding construction lines are then drawn in in the elevation. 
 This is the best practice, even though it does involve extra 
 
 labor, because it aids the layerout to check up his work after 
 he has laid ofli the pattern. The triangles at the right and 
 left are drawn for the purpose of finding the true lengths of 
 the dotted and solid construction lines. The bases for the 
 solid lines are equal to the distances i-i to 7-7, inclusive ; those 
 for the dotted are equal to the dotted distances of the plan. 
 The relative heights are shown projected from the elevation. 
 The lines joining the bases with heights are the true lengths 
 of the lines required. 
 
 DEVELOP.MENT OF PATTERN. 
 
 One-half of the pattern for section D is shown developed. 
 The triangles are assembled in their relative positions ac- 
 cording to the numeral notations placed on the drawing. The 
 distances between the triangles at the top of the pattern are 
 equal to the chord distances between the spaces of the profile ; 
 those at the bottom are equal to those of the profile on the 
 large ellipse. 
 
 Layout of Gusset Plates. 
 
 Arrangements of this kind are used to strengthen a pipe 
 laterally, and to prevent the entire weight of a stack from 
 resting upon a small area of the boiler or pipe ; that is, the 
 gussets distribute the weight of the stack upon a larger area 
 of the object to which it connects. 
 
 Figs. I (a) and (&) show an end and side view with the 
 gusset C in position. The edge ah of C makes an angle of 
 60 degrees with the horizontal plane. The edge be 45 degrees. 
 Before the patterns of C can be laid out it is necessary to find 
 first the line of intersection between the gusset C and pipe B. 
 This miter line is produced by passing a number of planes , 
 through each other. Those which are passed through pipe B 
 are parallel to its axis, and lie in a horizontal position ; those 
 passed through the gusset C are parallel with its outer edge 
 be. Where these planes intersect locates the required points 
 on the line of connection between the two objects. Before 
 planes are passed through the gusset C the section at right 
 angles to the edge be is produced. This section will appear, as 
 shown, below the side elevation when viewed in the direction 
 of the arrow indicated on the drawing. It will be noted that 
 section taken on line aed is one-half of an ellipse, the minor 
 diameter of which is equal to the diameter of the pipe to which 
 it connects. The one-half major axis is equal to the distance 
 ad through the elevation of C. The one-half elliptical section 
 is produced by drawing arcs on the respective axes. Each 
 quadrant is then divided into the same number of equal spaces 
 as contained in each quadrant of the circle end view; 45 
 degree planes parallel to the side be are then imagined to 
 pass through the gusset C. These planes are not seen, but we 
 do see each edge of the planes, which are termed traces of the 
 planes. They are represented on the drawing by lines drawn 
 through the elevation as I'l, 2'2, 3'3, etc. The horizontal 
 planes parallel to the axis of pipe B are then imagined to be 
 passed through the pipe. Where the horizontal planes inter- 
 sect the inclined ones determines the lines of intersection be- 
 tween pipe B and gusset C. 
 
 Fig. 2 shows clearly how the pattern is produced for the 
 gussets C. The line aa' is equal to the theoretical circumfer- 
 ence around the one-half elliptical section taken on line aed. 
 
206 
 
 LAYING OUT FOR BOILER MAKERS 
 
 plus an allowance to take care of the "take up" in rolling. 
 Usually if light material is used no allowance is made, as in 
 such cases the layerout would simply transfer the chord dis- 
 tances on section aed and locate them on the stretchout line 
 
 pendicular lines in the pattern. Add for laps and space off 
 rivet holes, thus completing pattern for C. 
 
 The side view. Fig. i, shows clearly how the intersection 
 between two cylinders of equal diameters intersecting at right 
 
 Ml 2 3 a" 3 2 1 nTo 
 
 F'IG.2(a^CON6TRUCriOM FOR FINDWQ 
 TRUE LENGTH OF STRETCH-OUT OF C 
 
 DEVELOPMENT OF GUSSET PL.\TES JOINING PIPES INTERSECTING ,^T RIGHT ANGLES. 
 
 iia' according to their relative positions ; but when heavy plate 
 is used the chord distances cannot be used in determining the 
 stretchout. The length of their arcs must be found, also the 
 required allowance for "take up" between each arc must be 
 added. To determine the required lengths involves a con- 
 struction shown in Fig. 2 (a), which is drawn as follows: 
 Draw a line M N, and upon it set off the arc distances be- 
 tween the points a, I, 2, 3 and d of the section aed. Erect per- 
 pendiculars therefrom, then from A'' set off a distance equal to 
 the result of si.x and one-half times the thickness of plate 
 divided by 2. In the form of a formula we have as follows : 
 
 Where ?== thickness of plate. 
 6% = constant. 
 ^ := allowance of material to be added. 
 
 With the trammels or dividers set equal to M O draw the 
 arc intersecting the perpendicular drawn from M at O'. Con- 
 nect O' with M, thus completing a right-angled triangle. The 
 distances on lines M O', determined by the intersection of the 
 perpendiculars drawn from the line M N, give the required 
 distances for laying off the stretchout in Fig. 2. After the 
 stretchout line aa' has been drawn, draw at right angles to be 
 lines from the points a'a. I'l, 2'2, etc., intersecting the per- 
 
 angles to each is produced. The miter line is straight on 
 either side in viewing the object from the side, but in the 
 pattern the corresponding lines are curved, in order to con- 
 form to the curved surface of the cylinder to which it joins. 
 The miter line is indicated by the dotted line ad, and the pat- 
 tern of the pipe is shown to the right of the elevation. Above 
 the side view a drawing of the development of the hole in pipe 
 B is shown on the flat; that is, before the pattern has been 
 rolled up. 
 
 Layout of a Conical Elbow. 
 
 Sometimes in sheet metal work a conical elbow must be 
 built and the layouts must be made. This is simple work if 
 the elbow is well constructed, but it might be difficult if the 
 method of laying out was not understood. Fig. i shows a 
 conical elbow and its construction, and as can be seen both 
 the construction and layout are very simple, saving time and 
 money. It is stated that the elbow sections always must be 
 circular. If properly constructed the two ends / and I'l 
 should be cylinders intersecting the cones // and V, these 
 cones intersecting the cones /// and II', which intersect each 
 other. 
 
 For constructing the elbow, first divide the arc 2-6 into any 
 number of equal parts, the greater the length of the arc the 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 207 
 
 greater should be the number ; 1-2 and 6-7 are the axes of cylin- 
 ders and may be short if the parts / and // and V and I'l 
 are made of one sheet. Having divided the arc 2-6 and located 
 the points 3, 4 and 5, draw straight lines through 2 and 3, 3 
 and 4, 4 and 5, 5 and 6. On the line passing through 2 
 measure from 3 to 6' the whole length of the divisions 3-4, 
 
 intersecting points are found. After connecting the corre- 
 sponding points, the intersecting lines and the conical parts 
 //, ///, !!' and /' are found. 
 
 The layout of each of the parts is found in the usual man- 
 ner and will not be described. Figs. 2 and 3 show the method 
 clearly. The parts / and // are each made of one piece of 
 
 SIMPLE METHOD OF L.4YING OUT A CONICAL ELBOW. 
 
 4-5 and 5-6. Erect perpendiculars at 2 and 6, and on the 
 perpendicular going through 2 measure the major diameter, 
 thus locating .1' and B', and on the square going through 6' 
 measure the minor diameter, thus locating D' and C After 
 having drawn the lines A'-C and B'-D' the first cone is found. 
 On the line going' through 3 and 4 measure from 3 to 2" one 
 division, equal to 3-2, and from 4 to 6" two divisions equal 
 to 4-5 and 5-6. After squaring on the ends at 2" and 6" 
 measuring the diameters and having drawn the lines A"-C" 
 and B"-D" , the second cone is completed. 
 
 In the same manner the other two cones are found. These 
 cones and the two end cylinders are intersecting each other, 
 and all the intersecting lines are straight lines, but none of 
 these lines passes through the points 2, 3, 4, 5 or 6. If such 
 construction is made, the layout of the conical parts is very 
 easily found. For this purpose draw Fig. 2. First draw 
 the cylinder / and the cone //, so that the points a. b, c and rf 
 are found, and also the first intersecting line from c to d. 
 With c as a center draw an arc with c-e from Fig. i as a 
 radius and locate the point c. With d as a center draw an 
 arc with d-f from Fig. i as a radius for finding /. Now with 
 <? as a center draw an arc with /-/; from Fig. i as a radius, 
 thus finding /( and e, c becoming also the point /. With / as 
 a center draw an arc with e-g from Fig. I as a radius, find- 
 ing g and /, / becoming the point c. This can be done till all 
 
 sheet ; the cylindrical part must be flanged out for the cone 
 and the necessary layout is found simple. Take c-a in Fig. I 
 and draw an arc with c in Fig. 3 as a center. Continue with 
 all other points and lay a curve, which is tangent to all these 
 arcs, and the layout is found. By the same method the lay- 
 out of the cone and cylinder V and VI is made. 
 
 That the parts // and /// and IV and V in Fig. 2 are the 
 same as in Fig. i is shown by drawing these parts on tracing 
 paper and superimposing the corresponding parts, therefore // 
 from Fig. I coincides with // in Fig. 2, etc. The allowances 
 for lap joints are not shown. 
 
 Unusual Layout for an Irregular Elbow. 
 
 The following is a description of the methods used in de- 
 veloping patterns for an irregular elbow. The elbow, as 
 shown, is a section of a large pipe order, and the elbow is a 
 transition piece connecting the oblong portion of the pipe 
 with the round. The drawings as received by the layerout 
 gave no radius for the center line of the elbow, so it was 
 decided to hold the figures for the ofifsets and the overall 
 length of the elbow exact and find arcs for the center line 
 of the elbow so as to make the ogee as gradual as possible. 
 An angle-iron joint was needed at a point about 7 feet from 
 the oblong end of the elbow, and it was decided to make the 
 
208 
 
 LAYING OUT FOR BOILER MAKERS 
 
 pipe round at that point. The transformer part of the elbow 
 "was made in three courses, as shown in the elevation, and in 
 order to simplify the layout the seams were placed horizon- 
 tally where it was possible to do so. 
 
 To lay out the different courses in this piece of work it is 
 Tiecessary to draw a side and end elevation, full size if pos- 
 sible, and locate the circumferential seams so as to make the 
 job as uniform as po.ssible. In this case the transformer sec- 
 tion of the elbow has been divided into three courses, the 
 ■cylindrical section in four courses, with one course of oblong 
 .pipe at the bottom. 
 
 To lay out section A draw the plan view as shown in Fig. i. 
 Draw center line R-R, and on this line draw an oblong i8H 
 inches by 48 inches, also draw center line A''-A'' parallel to 
 R-R, and at a distance from R-R equal to distance R in the 
 end elevation also draw center line 6'-.? bisecting the oblong. 
 At a distance from .S"-5, equal to distance O in the side eleva- 
 tion, draw center line M-M. The intersection of center line 
 M-M and N-N will be the center of the upper end of course 
 A. From this point as a center draw an oblong whose major 
 axis is equal to distance C (Fig. A, side elevation) and minor 
 axis equal to distance F (Fig. B, end elevation). Note that 
 the outline of the upper end of course A was assumed to be 
 a true oblong, and the half circles were described with a 
 radius equal to half the distance B (Fig. B, end elevation). 
 This was done to avoid a lot of unnecessary developing to find 
 the true outline, and it answered the purpose just as well. 
 
 Divide the semi-circle. Fig. i, into the same number of equal 
 spaces, and connect points thus located with full lines, as 
 i-i', 2-2', 3-3', etc. Also draw dotted lines from 1-2' to 2 to 
 .3', 3 to 4', etc. Also draw full lines from A to A', B to B', 
 C to C, etc., and dotted lines from i' to A, A' to B, B' to C, 
 etc. Then take distances i-i', 2-2', 3-3' etc., and set off to the 
 right of the vertical line 0-0' in Fig. 2. Also take the lengths 
 of dotted lines 1-2', 2-3', 3-4', 4-5', and set them off to the left 
 as shown in Fig. 2. Draw lines from these points to the 
 apex 0. The height H is made equal to distance H (Fig. A, 
 side elevation). This gives the true lengths of triangles. 
 
 To lay out the pattern, set trams to the distance i-O, Fig. 2, 
 and strike an arc from any point i on a straight line, locating 
 point i', then with dividers set to the distance i'-2' on the 
 semi-circle, Fig. i, and with i' as a center strike an arc, then 
 -with trams set to distance i-O, Fig. 2, and with point i as a 
 ■center strike an arc, intersecting the first arc and locating 
 point 2'. Next, with trams set to the distance 2-O, Fig. 2, 
 and with 2' as a center strike an arc; then with dividers set 
 ■to the distance A-i, and with i as a center strike an arc in- 
 tersecting the previous arc, locating point 2. The other points 
 are located in the same manner, taking the numbers in rotation 
 until we come to points 5-5'. Then with distance s-6. Fig. i, 
 as radius, and point 5, Fig. 3, as a center strike an arc, then 
 with the trams set to distance 6-0, Fig. 2, and with point 5', 
 Fig. 3, as a center, strike an arc intersecting the previous arc 
 and locating point 6. Next set the trams to the distance 5-7, 
 Fig. I, and with point s'. Fig. 3, as a center, strike an arc. 
 Then with trams set to distance 7-O, Fig. 2, and with 6, Fig. 
 3, as a center, strike an arc intersecting the previous arc, locat- 
 
 ing point 7. Connect 5-7-6-7 and 5-6 with straight lines, also 
 connect points 1-2-3-4-5, drawing the lines with a steel 
 flexible strip, bending it to the proper curvature. Points 1-2-3, 
 etc., are found in the same manner, and the other half of the 
 pattern is developed in the same manner. Note that the points 
 are marked with letters instead of figures. This was done to 
 avoid confusion. This completes the pattern for one-half of 
 course A. The other is developed in the same manner. It 
 should be remembered that the pattern is developed to rivet 
 lines, and that the lap must be added for J4-inch rivets. The 
 upper part of the pattern is rolled to a diameter equal to B, 
 end elevation. The lower part is rolled to iSj^ inches di- 
 ameter. 
 
 The next course, B, is developed in the same manner, so 
 no further description is needed. To lay out the pattern for 
 course C it is necessary to develop three different views before 
 working lines can be obtained. The lower end is an oblong, 
 whose major axis is equal to distance E in the side elevation, 
 and the minor axis is equal to distance F in the end eleva- 
 tion. At the upper end a 3-inch by 3-inch by ^-inch angle- 
 ring, 32 inches diameter, is wanted, and the upper end of 
 course C must be laid out so that the face of the angle-ring 
 will be at right angles to the center line in the side elevation 
 and also in the end elevation ; in other words, the regular 
 elbow comprising the four top courses must follow the center 
 line, as shown in the side and end elevations. 
 
 It will be noted that the upper end of course C, as shown 
 in side and end elevation, is not a true view, and it must be 
 developed to obtain the true outline. Draw Fig. 4 exactly as 
 shown at C, side elevation. Also draw Fig. S as shown at C, 
 end elevation. Draw a semi-circle from centers O in Figs. 
 4 and 5, and divide into the same number of equal spaces, in 
 this case eight. Project points thus located through center 
 line R-R, Fig. 4, also project the points on the semi-circle 
 through center line S-S, Fig. 5. This gives us points to de- 
 velop the elliptical outline shown in both views. Project 
 points from center line, Fig. 4, horizontally to vertical line, as 
 at B. Project points from center line. Fig. 5, to vertical line 
 A; then mark points on vertical line A, on a strip, and project 
 these points as shown at A, Fig. 4, intersecting the parallel 
 lines previously drawn, thus locating points for the ellipse in 
 Fig. 4. Take the points from vertical line B, Fig. 4, and pro- 
 ject in the same manner as shown at B, Fig. 5, thus locating 
 points for ellipse in Fig. 5. Draw the ellipse as shown, and 
 number the points as 1-2-3, etc., to 16, Fig. 4. Now it will be 
 noted that course C, as shown in Fig. S, is turned a quarter 
 way around from its position as shown in Fig. 4, and the 
 figures as 1-2-3, etc., remain in the same positions. 
 
 Now draw Fig. 6, which is a plan view, directly under Fig. 
 4. First draw the center line m~m, and on this center line 
 draw an oblong with a major axis equal to distance E and 
 minor axis equal to distance F. The semi-circles are drawn 
 with a radius equal to half of distance F. Now project lines 
 downward of indefinite length from points 1-2-3-4-5, etc.. Fig. 
 
 4. Also project lines downward from points 1-2-3-4, etc., Fig. 
 
 5. to a horizontal line as shown in Fig. 5. Now transfer these 
 points on a strip, and project horizontally as shown in Fig. 6, 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 209 
 
 taking care that the intersecting point of the vertical center points are located for the ellipse. Next divide the semi-circle 
 line Ill-lit, Fig. 5, is placed on horizontal line m-m. Fig. 6. into eight equal spaces and number as shown at Fig. 6, as 
 Now the intersection of these lines with tlie lines previously i'-2'-3'. etc. Connect points I'-i, 2'-2. 3'-^, etc., with full 
 
 projected from Fig. "4 locates the points for the ellipse in lines and 2'-i, 3'-2, 4'-2, etc., with dotted lines. Also connect 
 
 Fig. 6, taking care that the corresponding lines intersect each i6'-i6, I5'-I5, etc., with full lines and i'-l6, l6'-i7, i/'-iS with 
 
 other; that is. horizontal line i must intersect vertical line i, dotted lines, 
 
 horizontal line 2 must intersect vertical line 2, etc., until all Next erect a perpendicular line as shown in Fig. 7. Take 
 
210 
 
 LAYING OUT FOR BOILER MAKERS 
 
 the lengths of full lines I'-i, 2-2, etc., from the plan view, 
 Fig. 6, and set them off to the right of the perpendicular line. 
 Take the lengths of dotted lines 2'-i, 3'-2, etc., and set them 
 off to the left of the perpendicular line in Fig. 7, then project 
 points on the ellipse, Fig. 4, to the perpendicular line, locating 
 the heights of the different triangles, as shown at Fig. 7. 
 Connect points I'-i, 2'-2, 3'-3, etc., with full lines. The points 
 2'-3'-4', etc., on the left of Fig. 7 and points 1-2-3, etc., on rae 
 perpendicular line are connected with dotted lines, which 
 form the true lengths of the third sides of the triangles. 
 
 To lay out the pattern, set the trams to the distance I'-i, 
 Fig. 7, and with any point i' on a straight line as a center 
 strike an arc, locating point i. With point i as a center, and 
 with trams set to the length of the dotted line 2'-i, Fig. 7, 
 scribe an arc near point i'. Then with dividers set to equal 
 spaces i'-2'-3', etc.. Fig. 6, and with point i' as a center scribe 
 an arc intersecting previous arc, locating point 2'. 
 
 With trams set to distance 2'-2 and point 2' as a center 
 scribe an arc near point i, then with dividers set to equal 
 spaces on the semi-circle. Fig. 4, and point i as a center, scribe 
 an arc intersecting the previous arc, thus locating point 2. 
 Locate the other points in the same manner until points s'-s 
 are located, then with trams set to distance 6'-5, Fig. 7, and 
 with point S, Fig. 8, as a center scribe an arc near point 5'. 
 Then with trams set to distance 5'-6', Fig. 6, and point 5' as a 
 center scribe an arc intersecting the previous arc, thus locating 
 point 6'. Draw straight lines connecting points S'-6'-5 ; also 
 draw lines with a flexible strip connecting points i'-2'-3', etc., 
 at the bottom of the pattern end 1-2-3, etc., at the top of the 
 pattern; this completes half of the pattern shown at Fig. 8 
 to rivet lines. Lap must be added for ^-inch rivets. The 
 other half of the pattern is developed in the same manner, so 
 no further explanation is necessary. 
 
 The elbow in four sections, as shown in the side elevation, 
 is 32 inches diameter and is laid out by parallel lines in the 
 usual way. It will be noted that the view of the elbow at the 
 side elevation is a foreshortened view, and it will be necessary 
 to get the true length of the center line of each section. To 
 find the true length, draw a vertical line from any point on the 
 center line of the end elevation and let the distance A' equal 
 the length of center line A. Square over as shown, and the 
 hypotenuse of the triangle forms the true length of center 
 line A. 
 
 Pipe With a Compound Curve. 
 
 The plan is shown in Fig. 3, and the elevation in Fig. i. 
 The first step in this problem is to delineate the plan and 
 elevation. After this is done draw the semi-circles, g-io-ir, 
 as shown in Figs, i and 3 ; divide these arcs into any number 
 of equal spaces (in this case six) and from these points draw 
 lines at right angles to the base line, X-Y , and cutting it, as 
 shown. From these points on the base line (Fig. i), usin.g 
 X as a renter, draw arcs, as shown, until they cut the line 
 X-Z, and from these points, using Z as a center, draw lines 
 as shown. Then from the points on the base line in Fig. 3, 
 draw arcs, as shown. 
 
 The next step will be to find the true length of the center 
 line, 12-13, the shape of which must be such that, when it is 
 divided into equal spaces, lines can be projected from these 
 points parallel to the base line, cutting the center line. This 
 can be done as shown in Figs. 2 and 4; the line 14-15, Fig. 2, 
 is the center line, as shown in Fig. I ; the line 12-16 is the 
 center line as shown in Fig. 3 ; line 14-15 is to be divided 
 into equal spaces as far as the line iV-4'-4-A'', which is the 
 center line between the points Z, O, Fig. i ; then from 4' to 15, 
 on line 14-15, mark off the same number of equal spaces. 
 Then, from these points, draw lines parallel to the base line, 
 cutting the center line, 12-16 ; then from point 14, perpendicu- 
 lar to base line X-Y , draw a line cutting the line above, and 
 from point I draw to the line above, and so on until you 
 reach the point /;. The line 12-16 is straightened out as shown 
 in Fig. 4, and all the points, I, 2, 3, etc., are the same ; from 
 these points, draw lines perpendicular to line 12-16, and, in 
 length, equal to the distances I'-o, 2'-&, 2!-c, 4'-d, etc., in Fig. 
 2; then if the lines 12-0', i-b', 2-c', etc.. Fig. 4, were added 
 together they would make the true length of the center line, 
 but this line must have some shape to it before we can use it. 
 As shown in Fig. 2, line 12-13, this shape is developed as 
 follows : 
 
 The spaces 12-0', a'-b', b'-c', etc., in Fig. 2, are, in length, 
 equal to those in Fig. 4, lines 12-a', i-b' , 2-c', etc. Using 12 
 as a center. Fig. 2, and 12-0' as a radius, cut the line I'-i ; using 
 a' as a center and a'-b' as a radius, cut the line 2'-2, etc., until 
 we reach the point 13, then connect these points with a number 
 of arcs. This line just developed should be divided into as 
 many spaces as you want sections in the pipe; in this case 
 I would suggest that we divide into four equal spaces, from 
 12 to d', and four equal spaces from d' to 13 ; from these 
 points draw lines parallel to the base line, X-Y, cutting the 
 center lines in Figs, i and 3, as shown. Then from these 
 points. Fig. i, draw lines in the direction of X, cutting both 
 sides of the pipe and the upper half of the center line, draw 
 lines from the points, in the direction of Z, cutting both sides 
 of the pipe ; then from these points, on the sides, draw lines 
 parallel to the base line, cutting the center line in Fig. 3; the 
 points on the side {G-C , A-A') are found the same as in 
 Fig. I, with the exception that all the lines are drawn in the 
 direction of one point, as shown; from the points just found, 
 on the sides, draw lines parallel to the base line; cutting the 
 center line in Fig. i, this gives four points at each intersection ; 
 now draw an ellipse at each intersection through these four 
 points ; this will give the complete lines of intersection. 
 
 You will notice, the circumference of each section is divided 
 into twelve equal spaces ; the next step will be to find the 
 lengths of the lines forming these spaces. In Fig. 3, draw 
 lines perpendicular to the base line from each point on the 
 lines of intersection as high as the corresponding points above, 
 as shown ; the perpendicular line A'-a is as high as the point 
 A; the lines a^A, b-B, c-C, etc., are the altitude of a number 
 of right angle triangles, whose bases are equal to the cor- 
 responding space lines in Fig. i, A'-A, B'-B, C'-C, etc. In 
 Fig. s, spaces A-'L', B'-A' , C'-B', etc., are equal to the spaces 
 A'-A, B'-B. C'-C, etc., in Fig. i, and A'-B, B'-C, C'-D, etc.. 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 211 
 
LAYING OUT FOR BOILER MAKERS 
 
 Fig. 5, are equal to d-B, c-C, h-D, etc., in Fig. 3, the lines 
 A'-A, B'-B, C'-C, D'-D, etc., Fig. 5, are the true lengths of the 
 space lines A'-A, B'-B, C'-C, D'-D, etc., in Fig. i, section .3. 
 Each section of this pipe must be developed separately, as 
 they are of different shapes. However, we will develop sec- 
 tion 3, the other sections can be developed tlie same way. Find 
 the circumference of this pipe by multiplying the diameter by 
 3.1416. Stretch out this circumference, as shown in Fig. 6 
 at A'-.V, divide it into the same number of spaces as each 
 section is divided in Figs, i and 3, then, from these points, 
 draw lines perpendicular to this line A'-.V, of indefinite length, 
 each side; now take the lengths A'-A, B'-B, C'-C, D'-D, etc.. 
 Fig. 5, and place them in their proper places, equal distance 
 each side the line X-X, Fig. 6; through these points draw a 
 number of arcs, and this will complete the section 3. 
 
 Construction of a 90" Elbow Running From a Round 
 Into a Rectangular Section. 
 
 This particular problem requires a separate development of 
 each section in order to obtain the respective patterns. All of 
 the sections with the exception of the two outer ones are 
 irregular and in the form of transition pieces. The two outer 
 sections, A and F, are different in form according to their 
 respective profiles, as shown in the elevation. The parallel 
 system of development is the method suitable for their con- 
 struction. Triangulation is the method used for the develop- 
 ment of the remaining sections. 
 
 Owing to the irregularity in shape of the dift'erent sections, 
 a great amount of time and labor must be expended to secure 
 the correct patterns. As a rule, in order to overcome these 
 complicated conditions it is the practice to construct a tran- 
 sition piece at the irregular end, the shape of which in this 
 case would be from a round to a rectangular section. A 
 regular 90-degree round elbow can then be used, which will 
 answer the purpose as well and obviate the necessity of 
 making so many different layouts. However, to demonstrate 
 the principles involved in constructing this problem, a draw- 
 ing and an explanation of same is given, which may be of 
 some interest. 
 
 It should be borne in mind, when designing work of this 
 character, that the important feature consists of providing 
 ample air space for the conveyance of the gases. It is a well- 
 known rule that governs both liquids and gases that the dis- 
 charge through any line of pipe is governed according to its 
 area. 
 
 Owing to the flat sides running into a round section a 
 change of profile in each section will result. To obtain these 
 different profiles means must be provided to show to what 
 extent these changes in form are in evidence in the different 
 sections. Referring to Fig. i, it will be understood from the 
 drawing that there are in each section subjected to this change 
 in shape four flat sides, one of which is on the outer curve of 
 the elbow, one on the inner curve and the other two along the 
 outer sides. The length and width of these flat sections will, 
 of course, depend upon the number of sections in the elbow 
 and the size of the profiles. The curved portion connecting 
 the flat section will naturally be elliptical in shape. The ques- 
 
 tion as to how many sections will compose the elbow is a 
 matter to be decided by the designer. In this instance the 
 problem is made up of six sections. 
 
 CONSTRUCTION. 
 
 As the principal dimensions of the elbow are shown in the 
 elevation and profiles, these views should be drawn first. The 
 preliminary drawing of the elevation is done in the usual way 
 as for an ordinary round 90-degree elbow. The outside and 
 inside arcs are drawn to their required radii, using point W 
 as a center. Divide either arc into the required number of 
 divisions, in this case si.x. From these ponts lines are drawn 
 through the elbow to the apex W, which locates in the ele- 
 vation the miter lines between the sections. 
 
 Section E of this problem is developed, and the explanation 
 relating thereto will be sufficient to make clear the require- 
 ments involved for laying out the remaining sections. Before 
 the plan view of this section can be constructed some pre- 
 liminary drawing must be done to secure the proper profile 
 through the plane c c , Fig. i. These auxiliary views are 
 shown at Figs. 4, 5 and 6. Fig. 4 is a view showing the re- 
 spective heights of the sections on the center line P \' ; that 
 is, the length of the line P P' , Q Q', R R', etc., shows the 
 relative distances of the flat surfaces from the center line 
 of the profile. This view is constructed as follows : 
 
 A horizontal line is drawn indefinite in length, and upon it 
 are set off the distances P, Q, R, S, T, U and V, taken from 
 the center line of the elevation. Perpendiculars are then 
 drawn from these points. From P and Q set off a distance 
 equal to the radius of the circle. From (7 and J' set off the dis- 
 tance equal to H i of the rectangle. Connect Q' U' as shown, 
 thus determining the required heights for the profiles. 
 
 The next operation will be to show in the elevation to what 
 extent the flat side H K is in evidence in each section. This 
 is done by dividing u f and u f into the same number of 
 divisions as there are sections subjected to the change in 
 shape; in this case four. Set off on either side of T the dis- 
 tances T 4 and T 4' equal to the distances « 4 and u 4', re- 
 spectively. Connect 4 4' to / and /', as shown. 
 
 In a like manner continue the operation for the remaining 
 sections, using the distances u 3 and « 2, respectively. As 
 stated previously, the flat sides are also on the outer and 
 inner curve, running from the length of the side H j of the 
 rectangular profile to nothing at the intersection between sec- 
 tions F and E. The view showing the construction on the 
 outer curve o g is shown in Fig. 6, and Fig. S represents the 
 shape of flat surface on the inner curve a' g'. 
 
 To accomplish the results as shown in Figs, s and 6 proceed 
 as follows : 
 
 Draw stretch-out lines, as a' g', Fig. 5, and a g. Fig. 6. 
 On line a g' set off the distances a' b', b' c', etc., which are 
 taken from the inner curve. Erect perpendiculars, as shown, 
 through the points g' , /', e', etc. A distance equal to H i of 
 the rectangular profile is then set off from /' and g'. Connect 
 line /' with point b', which completes the figure and shows 
 the shape of the flat surface. The same construction is ap- 
 plicable to Fig. 6. It is, of course, necessary to use the spaces 
 on the outer curve a g in order to secure the correct view. 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 213 
 
 CONSTRUCTION OF SECTION E. 
 
 Since the different sections require a separate construction 
 for their proper development a detail explanation therefore 
 will be given for the layout of section E. The principles as 
 explained are applicable to the remaining sections. Fig. 2 
 gives the complete construction of this section. 
 
 The first requrement essential in this construction is to 
 erect an elevation corresponding exactly in form to the view 
 as shown in the elevation, Fig. i. A correct profile must then 
 be drawn, showing the shape of the connection through the 
 
 sides with elliptical curves. One-half of this same profile is 
 drawn above the elevation. 
 
 The foreshortened view of the plan will now be obtained 
 and in the usual way. Divide the curves of the profiles into 
 the same number of equal spaces; project these points of 
 division as shown to the plan view ; through the point of in- 
 tersection between the projectors draw the required curve and 
 the relative flat portions which complete the view. Divide the 
 true circle plan view into the same number of divisions as 
 there are in the profile. On the circle they are numbered as 
 
 View showiing the respfectlve helgbC 
 of aeoUons on center line P-v j 
 
 Q |r Is 1t_ 
 
 Tig. 6 
 
 Fig. 5 
 
 DIAGRAMS AND PATTERNS FOR THE LAYOUT OF AN IRREGULAR gO° ELBOW. 
 
 plane c c' of the elevation. Since the connecting plane be- 
 tween sections F and £ is a true circle, the plan view of this 
 portion will be represented by a circle, which is drawn with 
 a radius equal to b b' of the elevation. Fig. 2. Proceeding 
 further with the construction of the plan view it will be un- 
 derstood that the plane through c c' of the elevation will be 
 shown foreshortened in the plan, owing to the angle the plane 
 makes with the horizontal plane of projection. To obtain this 
 result a true profile of the plane must be drawn to the right 
 of the plan view and also at right angles to the elevation as 
 shown. The construction of the profile is as follows : 
 
 At right angles to the horizontal axis of the profile erect 
 the perpendiculars R' R equal in length to the distance R R' 
 of Fig. 4. The width of the flat section is equal to the dis- 
 tance 2 2' of the elevation, Fig. i. The flat portion c of the 
 profile is equal to the distance c of Fig. 6, and the opposite 
 flat section is equal to the distance c' of Fig. 5. Join the flat 
 
 follows: b' I, I 3, 3 5, 5 &, & 7, 7 9, 9 10 and 10 b". On the 
 irregular view they are 2, 2 4, 4 R', etc. Alternate dotted 
 and solid construction lines are then drawn, as shown in both 
 plan and elevation, Fig. 2. 
 
 The construction of this problem so far is complete, the 
 remaining work necessary is to secure the pattern ; in order to 
 do so the first requirement is to find the true length of the 
 solid and dotted construction lines shown in the plan view, 
 Fig. 2. The drawing in the production of these lines is shown 
 to the right and left of the elevation, and is termed the "Dia- 
 gram of Triangles." 
 
 The reproduction of these triangles in the pattern is a 
 simple matter. A study of the pattern will show how the 
 operation of transferring the triangles was done. The stretch- 
 out spaces for the connection to section F are taken from the 
 true circle plan view, and those for the irregular connection 
 from the profile shown to the right of the plan. 
 
214 
 
 LAYING OUT FOR BOILER MAKERS 
 
 Development For a Y Pipe Connection. 
 
 The conditions entering into this construction cover a va- 
 riety of pipe arrangements. Fig. i shows the axes of the 
 pipes in question, and in both views, plan and elevation the 
 axes are shown foreshortened. For convenience in the matter 
 of drawing it was deemed sufficient to show the construction 
 or arrangement in this manner. 
 
 The elevation. Fig. i, shows that the Y branch and the pipe 
 I B lie in the same plane, which is 45 degrees to either the 
 vertical or horizontal plane or projection. 
 
 Vertical pipes intersect the Y at its extremities. The angle 
 between the vertical pipes and the legs of the Y branch is 
 not 13s degrees, as one may suppose. A further study and a 
 correct solution of the problem will prove conclusively that 
 
 Fig. 1 
 
 SHOWING AXES OF PIPES 
 IN THEIR RELATIVE POSITIONS 
 
 DEVELOPMENT OF THE CONNECTION, GRAPHICAL METHOD. 
 
 The requirements of this problem are to lay out all pat- 
 terns for the pipe connections, consequently it is necessary to 
 draw Fig. 2. It may appear at first that the drawing calls for 
 a 45 degree Y connection; that is, the two branch pipes form 
 a Y in a full view at an angle of 45 degrees with the axis of 
 the pipe 1 B. A further study of the problem, however, will 
 disclose that in the plan the projectors of the Y axis show an 
 inclination of 45 degrees with the axis of the pipe i B. Unless 
 the conditions are clearly understood, difficulty in securing the 
 correct construction may ensue. 
 
 the angle of inclination changes between the limits of 135 and 
 go degrees, depending upon the angle the legs of the Y make 
 with the axis of the pipe i B. In order to make this point 
 clearer. Fig. 3 is drawn. The solid lines of a and b represent 
 a front and side view of the connection in question. The 
 dotted lines are for demonstrating purposes, to show how the 
 pipes are revolved in different positions. Within these bounds 
 the angle changes according to the amount the pipe is raised 
 or lowered. 
 Referring to a, Fig. 3, supposing one of the legs of the Y 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 215 
 
 branch is revolved around to the vertical dotted position V. 5 the tangent of the angle BAD will equal the ratio of the side 
 
 The axis of the branch is then in the same position as the axis BD 
 
 , ., . n -ri. i.- 1 ■ iU 1 „i„ „f opposite to the side adjacent; hence the tangent == . 
 
 of the pipe I B. The vertical pipe then makes an angle of ^*^ ' ' jr 
 
 135 degrees with the pipe i B. Referring to Fig. 3, c repre- 
 sents a side view of this connection and d the front or plan 
 view. 
 
 Revolving the pipes around to the dotted position W, the 
 construction will then be entirely different, as the vertical pipe 
 
 For calculation we will assume the following 
 BD = i 
 AB = 1.414 
 BD I 
 
 = .70721. 
 
 AB 
 
 AB 
 
 1-414 
 
 
 
 1C 
 
 IC 
 
 IC 
 
 
 IC 
 
 > 
 
 
 
 
 1 
 
 
 10 
 
 
 
 
 
 / 
 
 \ 
 
 1> 
 lAJg / 
 
 
 
 
 
 
 
 
 IC 
 
 \ 1A 
 
 ^A 
 
 
 1A\ 
 
 \ 
 
 1A 
 
 Itfs. 
 
 ^ 
 
 
 
 Position W 
 
 
 
 
 
 
 
 
 
 
 
 
 
 a 
 
 
 
 \1B 
 
 d 
 
 
 ^yC 
 
 
 
 FRONT 
 
 VIEW 
 
 
 
 ^^ 
 
 IB 
 
 
 
 \1B 
 
 
 
 
 
 
 
 
 elevation\ 
 
 
 
 
 \ 
 
 makes a connection at an angle of 90 degrees with the branch 
 of the Y. From the above it is obvious that in raising or low- 
 ering, the Y, which is simply turning the pipe upon the a-xis O, 
 governs the angle between the two connections i C and i A. 
 Any position of the pipes within the bounds of V and W will 
 necessitate the drawing of a full view for its correct solution, 
 as the pipes within this limit are not shown in their true 
 length. There are three methods which can be used for ob- 
 
 The next operation is to find the angle whose tangent equals 
 .70721. Referring to a table of natural sines, cosines, tan- 
 gents, etc., we find that there is no angle given for this tan- 
 gent ; consequently we will have to find the angle between the 
 next less and next greater tangent. From the table we find 
 the tangent of the next less angle is .70717 = tangent 35° 16'. 
 The tangent of next greater angle is .70760 = tangent 35° 17'- 
 
 Their difference is equal to .70760 — .70717 = .00043; 
 
 DIAGRAM INDICATING M.\THEM.^TICAL SOLUTION. 
 
 taining the correct angles between the pipes, two of which are 
 graphical, while the other involves the principles of trigo- 
 nometry. 
 
 Figs. 2 and 4 represent the graphical solution, and Fig. 5 
 the principles of mathematics. Fig. 4 is practically the same 
 in principle as Fig. 2, the difference being wholly in the mat- 
 ter of determining the true length of line or axis of the Y 
 branch i A. In construction, Fig. 4 is simpler, as it does 
 not involve the drawing of so many lines. It is also more 
 practical, as in some instances the dimensions of the pipe 
 arrangement may be so great that it would be impossible to 
 lay the problem out on the plate. 
 
 To calculate the exact angle between the vertical pipe and 
 the 45 degree branch, proceed as follows : Referring to Fig. 
 
 .70721 — .70717 = .00004 equals the dift'erence between the 
 tangents of the two small angles. Then 
 
 ■ X 60 = 5.5". 
 
 43 
 
 The angle of the tangent .70721 will then equal 35° 16' 5-5". 
 which is for angle A. 
 
 Angle £1 = 90° — 35° 16' 5-5" = 54° 43' 54-5". 
 
 The angle the vertical makes with the Y is then equal to 
 180° — 54° 43' 54-5" = I2S° 26' S-S". 
 
 For most purposes encountered in the boiler shop it will not 
 be necessary to work as close as the above. 
 
 A shorter method of calculation which will answer for this 
 purpose is as follows : Given the vertical and horizontal pro- 
 
2l6 
 
 LAYING OUT FOR BOILER MAKERS 
 
 jection of the V, which is equal In either case, and assuming it 
 
 equal to I, we have, according to formula, V I -(- i =: 1.414. 
 approximately. 
 
 Referring to a table of tangents, 1.414 is given as equal to 
 the tangent of 50° 44' approximately ; 180° — 54° 44' ^= 55° 16' 
 approximate angle in full view between branch of Y and the 
 pipe I B. 
 
 Angle between vertical pipe and Y will then equal 180° — 
 55° 16' = 124° 44', which is approximately 125°. 
 
 CONSTRUCTION OF FIGS. I AND 2. 
 
 Proceed as follows : First draw the axes of the pipe i B 
 and I ^ in the elevation to the required dimensions, project 
 these respective sections to the plan view. At right angles to 
 the line AB plan view draw the auxiliary planes or traces of 
 an indefinite length. Parallel to the elevation and at any con- 
 venient distance to the left, draw the vertical trace. Where 
 the lower horizontal trace and vertical trace intersect deter- 
 mines the axes of the traces which will be used for revolving 
 the axes of the pipes l A and i C around until they are in a 
 plane at right angles to the line of sight, and which will show 
 the pipes in their true length and at the required angle. Re- 
 ferring to the drawing it will show how this view is projected. 
 Upon the axes of the pipes draw the outer ordinates of the 
 pipes parallel to their respective axes. Where these ordinates 
 intersect determines the connection between the pipes. -A. line 
 connecting them will be the miter line. 
 
 The connection between the vertical pipe a, Fig. 2, and the 
 branch is not shown in its true position ; that is, with respect 
 to the other connections, as the pipe a must be swung up until 
 the end view shows a true circle, in order to be shown in its 
 relative position. However, for the purpose of laying out the 
 patterns so that their connections will be correct, the pipes 
 have been arranged so that very little confusion in their draw- 
 ing will arise. 
 
 It will be noted at the pipe connections that elliptical sec- 
 tions are shown ; these views represent the pipe in this manner 
 when viewed from above, across the bevel. To obtain such 
 a view simply revolve the connection around until one of the 
 outer ordinates will be shown upon the axis of the pipe. This 
 is done by projecting from the bevel or miter line at right 
 angles to the axis either outside ordinate until it intersects the 
 center line. The intermediate construction lines are then pro- 
 jected to their corresponding positions. It is not essential 
 that these views should be drawn, but for bringing out the 
 proper relationship it was thought advisable to install the fore- 
 shortened sections. 
 
 DEVELOPMENT OF P.^TTERNS. 
 
 At right angles to the axis of the pipes draw a stretch-out 
 line of an indefinite length. Locate upon it the same number 
 of equal spaces as contained in the profiles shown in Fig. 2. 
 
 Through these points draw lines at right angles to the 
 stretch-out line m-m. Draw the full view parallel to the 
 stretch-out line and project to ordinates of the pipe to their 
 corresponding lines in the pattern. A line traced through 
 these points of intersection determines the camber or miter 
 line for the connection. Add for laps and space off for rivets, 
 thus completing the layout. 
 
 Fig. 4 is simple in its construction. Draw a right-angled 
 triangle, making the base equal to AB plan view, the height 
 equal to -V of the elevation, the hypotenuse will be the true 
 length of one of the legs of the Y. The angle between i C 
 and I A is the required angle between the vertical and Y pipe, 
 and the angle between AB and I A is the required one be- 
 tween the Y connection and the axis of the pipe i B. 
 
 Layout of an Irregular Pipe Intersecting a Large Cylinder 
 at Right Angles. 
 
 The conditions that are covered by this problem are met 
 with quite frequently in sheet metal work, and it is given 
 here for the purpose of showing how the principles of pro- 
 jection and triangulation drawing are applied to irregular 
 pipe intersections. There are innumerable forms of connec- 
 tions encountered, but the same general principles enter into 
 similar constructions which are found in the every-day work- 
 shop practice. 
 
 It will be noted, by referring to the respective views, es- 
 pecially the side elevation, how this connection is made, but 
 before going into the details of its construction it may be 
 well to explain the form or shape of the connecting pipe ; 
 this may be well understood by referring to Fig. i, side ele- 
 vation, and to Fig. 2, designated "plan view of pipe connec- 
 tion." The portion of the problem as shown at (a) Fig. I, 
 side elevation is a regular development, which means that the 
 developers used for its construction are shown in their true 
 length in either an end or side elevation, or an elevation 
 which is at right angles to the line of sight. The plan view 
 for this portion of the object is shown to the left of the line 
 i-l, and can very readily be developed by projection drawing. 
 The portion as shown at (b), however, is a construction 
 which will necessitate the drawing of an elevation and plan 
 in order to determine the correct length of lines for the de- 
 velopment of the pattern ; hence, the drawing of the plan 
 view. The part as shown at (6) and the portion shown to 
 the right of the line l-l shows how the irregular portion of 
 this connection is determined. 
 
 CONSTRUCTION. 
 
 The first essential requirement in any drawing, whether in 
 laying out or drafting, is to locate the respective center lines. 
 This forms the foundation of our development upon which 
 the remainder of the drawing is determined : Consequently, 
 in this case we draw the lines A A, B B and B' B' convenient 
 in length and at right angles to each other. Upon these center 
 lines locate the front and side elevations to the required di- 
 mensions as shown at C, D, E. P, R, S, T and l'. Fig. i. 
 Below the front view upon the line B' B' draw a profile equal 
 in diameter to the top of the small connecting pipe, which is 
 equal to the distance R and S. Divide one-quarter of its cir- 
 cumference into any number of equal spaces : in this case four, 
 numbered from i to 5, inclusive. Project these points of 
 division parallel with the line B' B' until they intersect the 
 line R S. The lines for R S to the respective points c, d, e, f, 
 and «, are the true lengths of lines for the development of 
 the pattern as shown at Fig. 5. The next requirement is to 
 complete the side elevation, but in order to do so it is neces- 
 
MISCELLANEOUS PROBLEMS Ii\ LAYING OUT 
 
 217 
 
 sary to draw the plan view for the pipe connection, Fig. 2. 
 This is done in the following manner : Below the side ele- 
 vation upon the line B B, draw the small circle with a radius 
 equal to one-half the diameter of the top of the small cyl- 
 inder; then locate the profile below this circle Fig. 2, which is 
 drawn with a radius equal to the distance i to 5 of the side 
 elevation. Divide this arc into the same number of equal 
 spaces as are shown in the profile below the front elevation. 
 Extend these points of division to the line C D, side elevation. 
 
 traced through the intersection of these lines determines a 
 foreshortened view for the plane of connection, between the 
 small and the large pipe. Dotted construction lines are then 
 drawn in as shown from i to 2', to 2 to ,V. 3 to 4', etc., in 
 both the plan and elevation. 
 
 The next procedure necessary for the completion of the 
 problem is the drawing of Fig, 3 and the diagram of triangles. 
 Fig. 3 represents the hole in the pattern for the large cylinder 
 sheet; and its development is determined in the usual manner 
 
 Ll-Ll 
 
 ONE HALF PATTERN 
 FOR SECTION 
 
 L 
 
 I I I; 
 
 PROFILE) 1/ 
 
 ' ! / 
 
 (6) 
 
 At right angles to the line B' B' project the points of divi- by projection drawing. First locate the center Ime (c'), and 
 sion from the profile front elevation until they intersect the on either side locate the distance c' to d', d' to e' . e' to f and 
 corresponding lines or projectors which were extended to the f to u. These distances are obtained from the end eleva- 
 line C-D. A line traced through these respective points com- tion taken on the circumference of the large cylmder between 
 pletes the plan view for the small pipe. Projections from the the points c' and u. At right angles to the hne u u. Fig. 3, 
 small circle plan view are then drawn through the side ele- draw the horizontal lines from the points d', e', f and it. 
 vation imtil they intersect the line which represents the cutting 
 plane for the top of the pipe. 
 
 Referring to the portion (6), connect the points 2 to 2', 3 to 
 3', 4 to 4', with solid lines of an indefinite length. It is then 
 required to ascertain the connecting plane or miter line be- 
 tween the two pipes. This operation is done in the following 
 manner. At right angles to the line B' B', and through the 
 points c' d' e' f and n, projectors are drawn until they in- 
 tersect the corresponding solid lines which were drawn 
 through the points to I to i', 2 to 2', 3 to 3' and 4 to 4'. A line 
 
 indefinite in length. Corresponding lines are then projected 
 from the side elevation until they intersect the horizontal 
 lines c\ d', e' , f and u. A line traced through these points 
 completes the development for the hole. This layout is very 
 essential, as the spaces for the development of the pattern for 
 the portion shown at (6) are taken from this view. It is 
 the general rule, when taking the distances or transferring 
 the spaces, to use the chord distances. The chord distances 
 are not the true lengths, but are close enough to answer. 
 The construction of the diagram of triangles is the next 
 
2l8 
 
 LAYING OUT FOR BOILER MAKERS 
 
 procedure. The heights for each respective triangle which are 
 shown at a, b, c and d, are taken from the elevation ; the true 
 lengths of solid lines are shown to the left of the heights a, b, 
 c and d, and the dotted lines are located to the right. The 
 bases for these required lines are taken from the plan view. 
 A line connecting the height and base is the required line. 
 
 DEVELOPMENT OF PATTERN. 
 
 The pattern for the part of the pipe shown at (b) will be 
 developed first and in this manner : Draw the line i to i equal 
 in length to the distance i to u' of the side elevation, or to 
 the distance i? to T of the front elevation. Set the dividers 
 equal to the space i to 2', Fig. 3, and using i' in the pattern 
 as a center, draw an arc. Then with the trammel points set 
 equal in length to the dotted line of the triangle (o), and 
 using (i) in the pattern, draw an arc through the arc pre- 
 viously drawn. Continue in this manner, using alternately the 
 true dotted and solid required lines until the pattern is com- 
 plete. The spaces for the top of the connection are taken 
 from the small circle or profile of either the front elevation or 
 plan view. 
 
 The pattern for (a), as shown in Fig. 5, is obtained by 
 projection drawing. Since all data for its development have 
 been determined, it will only require the laying out of Fig. 
 5 to complete the entire problem. It is first necessary to 
 draw a stretch-out line equal in length to one-half the cir- 
 cumference of the profile, as shown in the front elevation. 
 Divide its length into the same number of equal spaces ; 
 through these points and at right angles to the stretch-out line 
 draw lines of an indefinite length. The camber line for the 
 connection is obtained by transferring the true length of lines 
 from the front elevation as shown. 
 
 The pattern for the entire connection can be made in one 
 piece, or the patterns for (a) and (b) can be made and then 
 riveted together. 
 
 The construction of the different triangles required in this 
 development is determined exactly in the same way as ex- 
 plained for similar triangulation problems. The method, 
 therefore, should not prove complicated. 
 
 Development of an Irregular Pipe Connection. 
 
 There are many cases that arise in the course of a boiler 
 maker's experience where he is required to make irregular 
 pipe connections. One such instance is shown in Fig. i, which 
 represents a pipe connecting to an irregular tapering form, 
 which is commonly called a transition piece. In this case the 
 pipe makes a connection at an angle of 40 degrees to the hori- 
 zontal ; however, the principles of development, as applied to 
 this problem, are applicable to a connection at any angle. The 
 principles entering into the development of this layout are 
 very simple if the elementary elements of triangulation are 
 thoroughly understood. 
 
 In order to make the desired connection it will be necessary 
 to construct a transition piece, which must taper from a round 
 base to an elliptical top; the major axis of the ellipse being 
 equal to the diameter of the base, and the minor axis equal in 
 diameter to the pipe connection. The development for the 
 
 ellipse can be very readily determined by projection drawing; 
 the explanation of this operation is shown in the construc- 
 tion of Fig. I. 
 
 CONSTRUCTION OF PLAN AND ELEVATION. 
 
 First draw the center lines A-A and B-B of a convenient 
 length and at right angles to each other. Upon the line A-A 
 draw the base or lower portion of the elevation to the re- 
 quired dimensions, then make the desired pipe connection by 
 drawing the line x-x to the required angle; in this layout the 
 angle is 40 degrees to the horizontal. The line x-x represents 
 the axis of the connecting pipe. At right angles to the axis 
 and through point D, draw the line a-G, and make it equal 
 in length to the diameter of the pipe; connect the points a 
 and G to the horizontal line l-i. On the line x-x locate the 
 profile which represents the opening of the pipe ; draw it to a 
 radius equal to one-half the diameter of the required pipe. 
 Divide one-half of its circumference into any number of equal 
 spaces, in this case six. Project these points parallel to the 
 line x-x until they intersect the line i-i, or the top of the 
 transition piece. 
 
 The next procedure will be the development of the plan 
 view. Upon the lines B-B and A-A, and using the intersection 
 between these lines as an apex, draw a circle equal in diam- 
 eter to the base of the transition piece. Divide its outline 
 into the same number of equal spaces as are shown divided 
 in the profile in elevation. Through these points of division 
 and parallel to the line A-A, or at right angles to the line B-B, 
 draw projectors to the elevation. It is then required to de- 
 velop the plan view for the pipe connection. Upon the line 
 B-B locate the profile for the opening in the pipe at a con- 
 venient distance from the plan; divide one-half of its periphery 
 into the same number of equal spaces as are shown in the 
 profile side elevation. Project these points of division parallel 
 to line B-B until they intersect the corresponding projectors 
 drawn through the points of division on the large circle. A 
 line traced through the intersection of these respective lines 
 represents the top of the transition piece, and which is shown 
 elliptical. It will be seen that the opening in the pipe is also 
 shown elliptical in the plan view. This is due to the fact that 
 in viewing this part from above it will be seen foreshortened, 
 or as shown in the drawing. The development for this por- 
 tion is determined in identically the same way as explained 
 for the large ellipse. Projectors are dropped from the ele- 
 vation to the plan until they intersect the corresponding lines 
 which run parallel to the line B-B. A line traced through the 
 intersection of these lines represents a foreshortened view of 
 the opening in the connecting pipe. Number the points of 
 intersection on the large ellipse from i to 4, inclusive, and on 
 the small ellipse letter the points a, B, C, D, E, F and G. Con- 
 nect these points with dotted and solid construction lines as 
 shown. From 4 to A 3 to E, 2 to F and i to G connect with 
 solid lines; from 4 to £, 3 to F and 2 to G connect with 
 dotted lines. Draw in the remaining construction lines in a 
 like manner. 
 
 We now have sufficient data in order to determine the true 
 length of lines for the development of the pattern. Referring 
 to Figs. 2 and 3 it will be seen how these lines are obtained. 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 219 
 
 The bases of the triangles are taken from the plan and the 
 heights from the elevation. The hypothenuse is the required 
 or true length of line. 
 
 Fig. 2 represents the true length of lines for the pipe con- 
 nection, and Fig. 3 represents those for the transition piece or 
 the base connection. An illustration for the development of 
 
 B. With I as an apex and the dividers set equal to the dis- 
 tance 1-2 of the profile, draw an arc, then set the trammel 
 points equal to the solid line 2-S of the triangles, and using B 
 in the pattern as an apex, draw an arc through the arc just 
 drawn. Continue in a like manner, using alternately the true 
 length of dotted and solid lines until the pattern is complete. 
 
 CONSTRUCTION. 
 
 one of these triangles will be given ; then it will not be neces- 
 sary to go into detail and describe the various operations for 
 each respective diagram. Set the trammel points or dividers 
 equal in length to the distance 4-D, plan view, and upon the 
 base of the diagram of triangles locate this distance. The 
 height for this base line is D, which is shown projected from 
 the elevation to the vertical line of the triangles. A line con- 
 necting these points is the true length of line. The remaining 
 triangles are determined in the same manner. 
 
 TO LAY OUT THE PATTERNS. 
 
 The pattern for the pipe will be developed first. It will be 
 seen by referring to Fig. 4 that only one-half the pattern is 
 shown developed. As the other half is laid out in the same 
 manner, a complete layout was not deemed necessary. 
 
 First draw the vertical line A-i equal in length to the dis- 
 tance o to I of the elevation, then with the dividers set equal 
 in length from i to 2 of the large ellipse plan view, and using 
 A in the pattern as an apex, draw an arc. Then set the tram- 
 mel points equal in length to the dotted line i-B of the dia- 
 gram of triangles, and using i in the pattern as an apex, draw 
 an arc through the arc previously drawn which locates point 
 
 In the development of the pattern for the base connection 
 one-quarter of the pattern is shown developed; as all four 
 quarters are equal it would not be necessary to involve the 
 extra time in a complete construction, when sufficient data can 
 be obtained from one quarter. - The solid line 4-4' is first 
 drawn, and which is equal to the height of the object. The 
 spaces for the top, or for the elliptical connection, are ob- 
 tained from large ellipse, plan view, and the spaces for the 
 
220 
 
 LAYING OUT FOR BOILER MAKERS 
 
 base are taken from the large circle. The true length of lines 
 for its development are shown in Fig. 3. As the operation 
 of constructing this portion of the layout is comparatively 
 easy, it will need no further explanation. It should always 
 be borne in mind that accuracy is the main requisite in prob- 
 lems of this character, and if care is not e-xercised, especially 
 where so many lines are involved, the pattern will be wrong, 
 which will involve an unnecessary cost in both material and 
 labor. 
 
 Through the intersecting points of these irregular curves 
 with the radial lines. Fig. 2, draw the irregular curve repre- 
 senting the intersection of the smaller cone with the larger 
 cone, as it appears from a plan view. From these intersecting 
 points project parallels intersecting the same radial lines of 
 the small cone, Fig. i. Through the intersecting points so 
 made, draw the irregular curve representing the intersection 
 of the two cones as they appear from a side elevation. 
 
 To develop the pattern of the smaller cone. Fig. 3, draw an 
 
 , ■ \ \ \ y 
 _- 1-— -^ 
 
 Fig- 1 
 PLAN, ELEV.'VTION AND DEVELOPMENT OF INTER.SECTING CONES. 
 
 Layout of Intersecting Cones. 
 
 In Fig. I is shown the intersection of two cones, the axis of 
 the smaller cone being at an angle of 45 degrees to the larger 
 cone. To develop the pattern, first draw the plan and side 
 elevation as shown in Figs, i and 2. Divide the smaller cone 
 into any number of equal spaces (in this case twelve have 
 been used), and draw lines radial from its apex. Reproduce 
 these same lines on the plan by projecting lines from the side 
 elevation. 
 
 On that portion of the plan. Fig. I, where the smaller cone 
 intersects, divide off a number of equal spaces on each side of 
 the center line of the smaller cone. Project these lines, cut- 
 ting the circumference of the plan, to the side elevation, and 
 erect radial lines to the apex of the larger cone. Lay off 
 points on the division lines made on the plan view equal to 
 the distance from the center line. Fig. i, to the intersecting 
 points made by the radial lines of the two cones. Through 
 these points construct the irregular curves as shown. 
 
 arc having a radius equal to the line a' b', Fig. i, the length 
 & c of the arc should be equal to the circumference of a circle 
 having a diameter equal to the line b' c' , Fig. i. Divide the 
 arc b c. Fig. 3, into the same number of spaces as the cone in 
 Fig. I is divided, through which division points draw radial 
 lines to the point o. With a pair of dividers lay off points on 
 these radial lines, from the line h c, equal to the distance on 
 the same radial lines in Fig. i, from the line b' c' at the point 
 b' to the intersection points made in the hypotenuse of the 
 small cone by projecting lines at right angles to the axis of 
 the small cone from the intersection points made by the ir- 
 regular curve d' e', with the radial lines. 
 
 Through these points draw the irregular curve d e. From 
 the point a. draw another arc. / g, having a radius equal to 
 the line a' /', Fig. i. Connect the arc / g, and the irregular 
 curve d e hy the solid lines / d and g e, thereby finishing the 
 development of the small cone. 
 
 To develop the large cone, Fig. 4, draw arcs in a similar 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 221 
 
 way, the length of the arcs being equal to the circumference 
 of the upper and lower base of the cone, and having a radius 
 equal to the hypotenuse of the cone. 
 
 To develop the opening for the intersection of the small 
 cone, draw a series of arcs through the center of the sheet, 
 
 used as conveyors to the tanks or vats. The development 
 of this problem can very readily be determined by projection 
 drawing. 
 
 CONSTRUCTION. 
 
 First draw the elevation, plan and profies to the required 
 
 their radius being equal to the distance from the apex of the dimensions and construct the respective views, as shown 
 
 LAYOUT OF OBLIQUE INTKRSECTION. 
 
 large cone. Fig. i, to points on the hypotenuse of the cone by 
 projecting parallel lines from the points of intersection of 
 the irregular curve d e, with the radial lines as shown. 
 
 On the arcs so drawn, lay ofif points on each side of the 
 center line equal to the length of the curves representing the 
 same arcs in the plan view. Fig. 2. Through these points draw 
 the irregular curve forming the opening for the intersection of 
 the small cone, thus finishing the development of the cones. 
 
 Layout of a Rectangular Pipe Intersecting a Cylinder 
 Obliquely. 
 
 It is frequently required of the layerout to develop cylinder 
 and irregular pipe connections, as shown in the accompanying 
 drawings. This form of construction is generally found in 
 hot-air heating, and it is also found in brewery-pipe work 
 
 the drawing. Divide the profiles in the plan view into any 
 number of equal spaces, in this case eight; extend these points 
 of division parallel to the center line A-A until they intersect 
 the large cylinder, as shown at the respective points num- 
 bered I, 2, 3, 4 and S. 
 
 The next procedure is to project these points to the side 
 elevation and at right angles to the line A-A until they inter- 
 sect the upper and lower portions of the rectangular pipe. 
 Number these points i, 2, 3, 4 and 5 for the upper portion, and 
 i', 2', 3', 4' and 5' for the lower; these lines are the required 
 lines, or the true length of lines to be used in developing the 
 pattern. 
 
 TO LAY OUT THE PATTERN. 
 
 Draw the horizontal line 5-5 equal in length to the distance 
 around the profile, and then divide this stretchout line into 
 
222 
 
 LAYING OUT FOR BOILER MAKERS 
 
 four divisions, making the distances 5' to 5' and 5 to 5 equal 
 in length to the widest portion of the profile, and the distances 
 5 to 3', respectively, equal to the narrow portion. In this case 
 the seam line is located on the line 5-5. However, this is 
 immaterial, and it can be located at the discretion of the 
 layerout; the best practice would be to locate the seam on 
 either the line I'-b or i-c, as this will aid the work for the 
 mechanic who rivets up the piece to do his work more handily. 
 After the stretchout has been determined and divided into 
 the respective divisions, as shown, divide the distances 5' to 5' 
 and 5 to 5 into the same number of equal spaces as there are 
 
 Layout for the Intersection of Two Right Cones. 
 
 In order to convey to the reader this layout clearly. Fig. 3 
 and Fig. 4 have been drawn, although in practice Fig. i and 
 Fig. 2 are all that is necessary, since points and lines having 
 served their purpose may be erased. Also the division lines 
 are elements of the small cone and are got by dividing the 
 profile of the small cone as shown at A, B. However, in prac- 
 tice, to be more exact, these lines are best determined by 
 drawing, adjacent to the base a half plan and then proceed in 
 the usual way. Hence the clearness of Fig. 2. 
 
 Commence by drawing the plan for the large cone in Fig. I. 
 
 INTERSECTING CONES FOK L.\YING-OUT PROBLEM. 
 
 in the profile plan view; through these points and at right 
 angles to the line 5-5 draw lines of an indefinite length. The 
 next procedure is to determine the camber line for the con- 
 nection. This is obtained in the usual manner, the true length 
 of lines having previously been pointed out and determined ; 
 hence the method of transferring these respective distances 
 will not necessitate an explanation. After the camber line 
 has been determined, add for laps to complete the pattern. 
 
 DEVELOPMENT FOR OPENING IN CYLINDER SHEET. 
 
 First lay out the cylinder sheet equal in length to the cir- 
 cumference around the cylinder, then locate the center lines 
 for the opening. The spaces for the development of the hole 
 are taken from the circle in the plan view and are located on 
 both sides of the center line, as shown from I to 5, inclusive. 
 The width of the opening is obtained from the elevation, and 
 these respective points are shown projected to the cylinder 
 sheet. 
 
 Then draw the side elevation for the large and small cones in 
 Fig. 2. On line A, B in the top plan of the small cone draw 
 the profile and divide this circle into eight equal divisions, as 
 shown, S-i-2-3 and A. Project these points to the center 
 line A, B, locating points i', 2' and 3'. Now from point S, the 
 apex, draw the division lines through the points i', 2' and 3', 
 and extend them until they meet the center line of the large 
 cone at e and /, and the base line at k and 0. Next divide one- 
 fourth of the circumference of the plan. Fig. i, into four equal 
 spaces, as shown from 4 to 8. From these points draw division 
 lines to the center W. Also project these points to the base of 
 the large cone, Fig. 2, and draw division lines to the apex W, 
 intersecting the division lines from the small cone as shown 
 by the letters b, c and d; also g, h, i and m, n. Next project 
 points e and / from the center line, Fig. 2, to the side, locating 
 points e*, f, and from these points drop perpendicular lines 
 to the plan. Fig. i, as shown by the points e', f. Now, with 
 a radius equal to W , e", and using point W as a center, cut 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 the line !F', 4 at e'. In the same manner locate point /'. The 
 next step is to locate points on the division lines in plan. Fig. 
 I, to represent the horizontal cutting plans in elevation. To 
 do this, drop perpendicular lines from points a, b, c and d, 
 Fig. 2, to similar letters in the plan, Fig. i, as shown, a, b, c, 
 d and e. A curved line drawn through these points represents 
 one-half the horizontal plan on line a, e in Fig. 2. In the same 
 manner irregular curves / and / may be obtained. Since the 
 lines B-E and A-F on the smaller cone intersect the large 
 cone at points E and F, it is necessary to locate their true 
 points of intersection. These points are shown in plan, Fig. 
 I, at points E' and F', respectively, and no horizontal sections 
 are needed on these two plans. The next move is to obtain 
 the intersections where the division lines of the small cone 
 will intersect these irregular curves in plan, Fig. i. To do 
 this with clearness, Fig. 3 and Fig. 4 have been drawn, which 
 is an exact reproduction of Fig. i and Fig. 2, omitting all 
 unnecessary letters and figures, as shown in Fig. 3 and Fig. 4. 
 The plan view of the small cone, Fig. 3, is obtained by the 
 intersections of the projectors from the side elevation. Fig. 4, 
 with similar projectors in the plan view. Fig. 3, as shown 
 ^-3-2-1 and B. Now from points S, the apex in the plan view, 
 draw the division lines through the points 3-2 and i, and 
 extend them, cutting irregular curves at points 3°, 2° and 1°. 
 Trace a curve through the points F', 3°, 2°, 1° and B' will 
 represent one-half the intersection between the two bodies 
 
 
 ^ .1 
 
 / /// 1 WW 
 
 / / / I ^ \ \l/ 
 
 .' 1 * ^ X 
 
 3A r« 3" 
 
 PATTERN FOR SMALL CONE. 
 
 as they would appear viewed from above. Now project the 
 points 3°, 2° and 1°, Fig. 3, to the side elevation. Fig. 4, 
 cutting division lines at points 3^^, 2^ and 1=^. A curved line 
 drawn through the points E, V^, 2^, 3^ and F will represent the 
 line of intersection between the two bodies viewed from the 
 side. The next step is to project the points i^, 2^ and 3=^ at 
 right angles to the axis of the smaller cone to the side, as 
 shown by points i*, 3* and 2*. To lay out the pattern for the 
 small cone, as shown at Fig. S, with the radius equal in length 
 to S, A, Fig. 4, and using point 6", Fig. S, as a center, draw an 
 arc B-B and equal in length to the circumference on A, B, 
 Fig. 4. Divide the arc into the same number of spaces as the 
 profile. Fig. 4, in which eight are used, as shown, B, I, 2, 3, A, 
 3, 2, I and B. Through these points draw the radial lines in- 
 
 definitely and number them as shown, B, 1,2, 3, A, 3, 2, i and 
 B. Then using 5", E, Fig. 4, as a radius and point S of the 
 pattern as a center, cut the radial lines S, B and E, A and E, A. 
 Continue this way, using S, i*, S, F, S, 3^ and S, 2*, Fig. 4, 
 as radii until the several points in the pattern are located. 
 Then by joining these points as sliown you complete the pat- 
 tern for the small cone. 
 
 To develop the pattern for the large cone, including the 
 opening, proceed as follows : First draw the outline of the 
 large cone U, V and .Y, Y, and erect the center line ]V, F^, as 
 
 
 P.A.TTERN FOR LARGE CONE. 
 
 shown in Fig. 6. Then from the intersections £, i-"^, 2-\ 3=^ 
 and F, Fig. 4, draw lines at right angles to the axis, cutting the 
 side of the cone at points E^, 1", 2', 3^ and F^. Then, in the 
 plan view. Fig. 3, with the straight edge resting on points W 
 and 2°, cut the base line at 2V. Do the same with points 1° 
 and 3°, locating points i^ and 3^. Then, with a thin strip or 
 batten, lift the spaces in plan view O 3^, O 1^ and O 2V, and 
 transfer to the pattern on both sides of the center line W, F^, 
 as shown, F^, 3V iv and 2V, etc. Through these points draw 
 radial lines to the apex W. Now, with the radius equal to the 
 distance from apex W, Fig. 4, to the points £^ I^ 2', 3' and 
 F^, and using point W, Fig. 6, as a center, draw the several 
 arcs intersecting the radial lines with similar numbers by 
 joining the points so found with an irregular curve, complet- 
 ing the opening in the large cone. 
 
 Layout of a Hopper for a Concrete Mixer. 
 
 CONSTRUCTION. 
 
 Fig. I. This figure shows three views of the hopper desig- 
 nated part A. Fig. 2 shows the pattern of A. Figs. 3 and 4 
 are the respective views and pattern of the part marked B. 
 
 The main portion of the hopper, as at A, is an irregular 
 tapering form, running from a wash-boiler opening into a 
 round one. The wash-boiler opening lies in a vertical plane, 
 and the round in a plane at an angle of 45 degrees to the 
 horizontal. This will be better understood by referring to Fig. 
 I in the side elevation, which shows the relative positions of 
 the two openings. The front view shows how the sides taper 
 from the irregular opening to the circular one. In this con- 
 struction it is necessary to work up first the top and front 
 views before the triangles can be found for developing the 
 pattern. 
 
 After the side elevation or view has been drawn according 
 
224 
 
 LAYING OUT FOR BOILER MAKERS 
 
 to dimensions, show the position of the part B relative to the 
 cide view by drawing an end view of this chute. Then to the 
 left of the side view draw the profile of the wash-boiler open- 
 ing. Below the side view locate the top view. The hole in the 
 hopper will appear elliptical or foreshortened in this view. 
 Its true form is found by development and as follows : 
 
 Divide the small circle which represents an end view of the 
 hole in the elevation into a desired number of spaces. Project 
 the divisions on the circle to the inclined side of the hopper 
 
 bottom is shown in llie top view from a' to /', /' to b', b' to a'. 
 The portion around the triangle sections is irregular and runs 
 from the circular section of the wash-boiler end into the hole 
 of the end of chute. Consequently the semi-circular ends of 
 the large profile are divided into the same number of equal 
 spaces as contained in the profile shown in the top view. 
 Solid and dotted construction lines are then drawn in both 
 top and front views, as indicated by the Figs, i, 2, 3, 4, 5, etc. 
 The diagrams of triangles are then drawn. The heights are 
 
 I ■^op|vidwl| 
 
 ;i I I I ' 
 
 5J 
 
 FIG I. — THKEE VIEWS OF THE HOPPER, WITH DIAGRAM OF TRIANGLES. 
 
 as shown. On the axis of the top view locate a profile equal 
 in diameter to the hole in the hopper, and divide it into the 
 same number of spaces as contained in the end view. Parallel 
 to the axis of the top view draw the parallel lines as shown. 
 From the side elevation drop the corresponding lines to the 
 top view until they intersect the horizontal projectors. 
 Through the points of intersection between these lines draw 
 the ellipse. 
 
 The ellipse of the front view is now found very easily. 
 With X-X' as a base line and A'' as a center, swing the spaces 
 of the profile of the top view around to the line X-X. The 
 spaces of the profile must, of course, be first located on the 
 vertical base line. In this case it is the edge which represents 
 the edge line of the wash-boiler end. At right-angles to line 
 X-X' these points are then projected up through the front view 
 an indefinite distance. Corresponding projectors are then 
 drawn from the side view intersecting the vertical ones. 
 Through their points of intersection draw the ellipse. 
 
 In view of the straight portion on the large opening it will 
 be best to make a triangular section at both top and bottom 
 of the hopper. In this problem the top triangle section is 
 shown from o to r, ^ to b and b to o in the front view. The 
 
 equal to the distances . /. B. C, D, etc., of the top view, and the 
 bases are obtained from the front view. 
 
 The pattern will need no explanation, as the triangles are 
 numbered to correspond to those given in the front view. 
 
 It will be noted that the pattern for the hopper is made in 
 two sections, one section for the part designated M and an- 
 other for A^, shown in the front view. By this arrangement 
 the seam lines will come on the side, through the line A"-/v. 
 The seam should not be placed on the bottom, as the rivets 
 and edge of the plate would affect the flow of concrete. Suf- 
 ficient material must be allowed at the small end for making 
 the connection between the chute and hopper. 
 
 DEVELOPMENT OF CHUTE E. 
 
 Figs. .3 and 4 show the respective views of this connection, 
 including its pattern. The views of the object were made 
 larger than in Fig. 2 lor the purpose of showing more clearly 
 its construction. It will be seen from the plan and elevation 
 that the connection is the frustum of an oblique cone. The 
 taper is on one side only, as shown at D B, Fig. 3, The op- 
 posite side is straight and at right-angles to the line C D. 
 The sides of the oblique cone is this case, if extended, inter- 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 22 = 
 
 sect at point M, as indicated on the drawing. If the sides 
 were prolonged and did not intersect within a distance con- 
 venient for development of the object, it would then be neces- 
 
 PATTERN FOR SECTION N. 
 
 FIG. 2. — P.\TTERN FOR SECTION A. 
 
 sary to lay it out by other methods. The application of the 
 triangulation system in such a case would prove satisfactory. 
 In order to find the shape of a fiat plate to form the frustum 
 of such a cone, proceed as follows : Draw the elevation as at 
 A, B, C and D. Extend the lines A C and B D till they inter- 
 
 To obtain the data for laying of? the camber line at both top 
 and bottom of the pattern, it will first be necessary to set off 
 on the line M D of the elevation a distance equal to M to A 
 and M to C, as shown from M to a and M to o. From a 
 draw the line a' A; from a draw the line a C. Now, if the 
 elevation is turned in such a way that the axis .1/ 4 is at right 
 angles to the line of sight, the line a C will be the base of a 
 right cone. The portion lying within the line a c, C D will be 
 the part to be added to the cone. Parallel to the line a C 
 draw from the points 2, 3, 4, 5 and 6 the lines 2 to 6, 3 to c, 
 4 to rf, 5 to (? and 6 to /. The portion above within the tri- 
 angle B A a' is to be treated in a similar manner. 
 
 DEVELOPMENT OF P.^TTERN. 
 
 Fig. 4 shows the development of the pattern. Draw the 
 center line M a equal to M a of the elevation of Fig. 3. With 
 
 
 FIG. 3. PLAN AND ELEVA- 
 TION OF B. 
 
 sect at the apex M. Below the elevation draw the circles 
 which represent the large and small ends of the oblique cone. 
 These circles represent views of the object when viewed di- 
 rectly down upon the elevation. 
 
 Divide the large circle into any number of equal parts, as 
 shown from C to 2, 2 to 3, 3 to 4. etc. Then from each of 
 these points erect perpendiculars intersecting the base of the 
 elevation, as indicated at points 2, 3, 4. 5 and 6 on that view. 
 Connect the apex M with these points. 
 
 
 ^-9 
 
 "1^ 
 
 FIG. 4. — PATTERN FOR CONNECTION B. 
 
 two sets of dividers set one equal to the spaces of the large 
 circle of the plan view, Fig. 3. Then use the other to set off 
 the true radial lengths of lines. The radial length M to a of 
 the pattern is equal to M to a of the elevation. Fig. 3. A to b 
 of Fig. 4 equals the space distance C to 2 of the plan. M to 
 f. Fig. 4, is equal to M to c. Fig. 3 ; b c, Fig. 4, equals C to 2, 
 Fig. 3 ; M to d. Fig. 4, equals M to d, Fig. 3 ; c to d equals 
 c to 2, Fig. 3. The remainder of the pattern for the large end 
 is determined in a similar way by transferring the true radial 
 distance from the elevation to the pattern. The small end is 
 developed by setting off from point M of Fig. 4 the true radial 
 distances M to a', M to b', M to c', etc., of Fig. 3 on their cor- 
 responding radial lines of Fig. 4. A curve drawn through the 
 points of intersection will give the shape of the plate required 
 to form the oblique cone. Laps are to be allowed in addition 
 to the plate developed. 
 
 Layout of a Transition Piece. 
 
 As will be seen this is an irregular piece, which connects a 
 rectangular opening over the boilers to a round flue that enters 
 into the brick chimney. Fig. I is the side view, as the piece 
 is set in its position. Fig. 2 shows the narrow side, or a view 
 looking down ; this figure is not really necessary for the lay- 
 out, as the dimensions can be taken direct from the drawing 
 and applied to Fig. 3. 
 
 CONSTRUCTION. 
 
 First erect Fig. i. Draw the line M-M ; set off the diameter 
 from 7 to 19; draw line C and line D at right angles to line 
 
226 
 
 LAYING OUT FOR BOILER MAKERS 
 
 M-M. Next locate point a. supposing the dimensions 7 b and 
 b a are given on the drawing. Take the distance a b from the 
 drawing on the dividers, and with one point on line C, as at b, 
 strike an arc at a : on this arc draw line E. With the trams 
 set to the distance iia. set one point on ii, scribe a line E. 
 
 line a b, line c d and line M M, Fig. i. Draw lines tangent to 
 those circles and parallel to line C, Fig. I. On line N N , Fig. 
 2, set the distance 7-19, Fig. i. From i and 13, Fig. 2, draw 
 lines to Fig. 3. This gives four points on the round end. Now 
 take the distance a b from the drawing; set off from o to ii 
 
 This gives point a. Ne.xt set the trams to the length of line 
 a c, with one point on a strike arc at c. Again take length c 
 19 on the trams, and with one point on 19 strike an arc 
 intersecting the one just drawn at c ; this completes the out- 
 line of Fig. I. Draw line F from point c. Now line E and 
 line F will form the height of the rectangle, and line C and 
 line D give the upper and lower points on the round end. 
 Fig. 3- 
 
 To construct Fig. 2, draw a vertical line from o through 
 b and line c d, and with <? as a center describe the circles on 
 
 and from d I0 c ; draw a line,, which is now the slant line a c. 
 Fig. I. Extend line i d a through Fig. 3, which makes the 
 fourth side in the rectangle, with center lines drawn from 
 Figs. I and 2 intersecting in Fig. 3. On this, as center, de- 
 scribe the circle. 
 
 Now divide the circle into a number of equal si!>aces, in this 
 case 24, and draw lines as shown. Beginning at point a draw 
 a I, a 2, a 3, o 4, a 5, o 6, 7. Step over to 6, and with & as a 
 center draw b 7. Now proceed the same as in section A. 
 When number 13 is taken step to c, draw c 13-19; then step 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 227 
 
 over to d and draw d ig-i. Next erect the triangles, Figs. 4 
 and 5. Distance between line N jV and line d c is the vertical 
 height of the short side ; extend line d c. Draw vertical line 
 x. To avoid confusion, the circle and triangles are in four 
 sections — A, B, C and D. 
 
 For good reason Fig. 5 is placed lower down on this draw- 
 ing instead of on line a b, Fig. 2, which is the proper place. 
 Draw the base line H H, Fig. 5. Now take the distance / 1,3, 
 Fig, 2, on the trams, and set this off from to x, Fig. 5. 
 With the dividers take the distance a i, Fig. 3, and on point 
 as a center strike an arc as at i on line H H. Using o as a 
 center for section A take all numbers to 7 ; set them down on 
 the base line H H, and number them as shown. Now step 
 over to the point b^ section B. Take the distances b 7 ; set 
 them off to the right from to 7 ; continue in that way till 
 13 is taken, completing the triangles for the long side. 
 
 We will now go back to Fig. 4 to finish the bases for our 
 triangles. First step to Fig. 3, and using c for a center, sec- 
 tion C, take distance c 13, set this off from to 13, Fig. 4. 
 Proceed the same as in the preceding sections, then step over 
 to d, section D. Set this off on left from 0, and draw lines 
 from .r to all points on base line. 
 
 DEVELOPMENT OF PATTERN. 
 
 At first make calculations for the seam. In the position of 
 Fig. I the straight side is shown, and as the flat part here gives 
 the true length line c 13 can be taken for the seam, point 
 being the center on line a c. Now locate point a, Fig. 6, 
 distance x I, Fig. 5, on the trams. Set one point on a, Fig. 6,' 
 strike an arc at i with the dividers already set one spacing. 
 Fig. 3. Strike a small arc at 2, again with the trams on line x 
 2, Fig. 5, step to a, strike an arc intersecting the small arc. 
 With the dividers on 2 strike another arc for the ne.xt line. 
 Continue that way with numbers 3, 4, S, 6 and 7. Draw lines 
 and section A is drawn. Next take distances a b. Fig. 2. Set 
 off from a to b, Fig. 6. Take the distance x t, section B, Fig. 
 S. With one point of the trams on 7, Fig. 6, strike an arc, 
 cutting the one struck from a. Draw the line o b, also line 
 b 7. Next take the distance .r 8, and on 6 as a center for sec- 
 tion B strike an arc at 8, and with the dividers from 7 to 8 
 now proceed the same as in section A to 13. Draw the line. 
 Next take the distance a c, slant line. Fig. i ; set on b. Fig. 6 ; 
 strike an arc at c. Next take the line x 13, Fig. 4, and on 13, 
 Fig. 6, scribe an arc as at c. Now take line x 14; step to c, 
 which is the center for section C, and strike an arc at 14, with 
 the dividers lay down 13, 14 ; when ig is taken step over to a 
 on the pattern, and distance a b is set off from c to d going 
 over to Fig. 4. Line x 20; step to d, Fig. 6; strike arc at 20 
 space 19, 20 on dividers. Continue the same as in the preced- 
 ing sections and draw line d i'. Now take distance c. Fig. 
 I. Set on d; strike arc at 0' ; step over to a at the left ; scribe 
 arc 0. Next take lap line 13, Fig. I ; step to i, Fig. 6, inter- 
 sect the arc just drawn at 0. Again step to i' on the right; 
 strike point 0' and draw lines through those points. For the 
 round end take a thin lath, lay it down on the points and 
 draw a curved line, touching all points, completing the pat- 
 tern. The lap and flange must be added. 
 
 Layout of Special Transition Piece. 
 
 The illustration shown in connection with this article repre- 
 sents an object which is encountered very frequently in sheet 
 metal work when wishing to make a connection to a pipe 
 having an opening along its longitudinal plane. The develop- 
 ment of the pattern for this object is obtained in the usual 
 manner as applied in developments for conical connections. 
 An examination of the drawing shows that the object con- 
 issts of one-half the frustum of a cone at each end, as shown 
 at A and B, plan view, connected together by two rectangular 
 surfaces C and D. 
 
 CONSTRUCTION. 
 
 It will be noted that in this development a full plan view is 
 shown. This, moreover, is not necessary, as in shop practice 
 the only requirements needed in obtaining the necessary data 
 for determining the true length of lines to be used in develop- 
 ing the pattern are the elevation and the semi-circle in the 
 plan view. In this case the full plan view is constructed in 
 order to give a clearer idea as to the nature of the problem 
 and to show how the object appears when viewed from above. 
 
 To construct the problem, draw the center line x-x, con- 
 venient in length, then locate the respective dimensions for 
 the height and base ; connect the points r-r of the base with 
 the vertex in. The center for the connecting cylinder is then 
 located in its required position ; in this instance it is shown at 
 O. Set the dividers or trammel points equal in length to the 
 radius of the pipe, and using the apex O as a center, describe 
 an arc, cutting the outside elements of the cone as shown. 
 It will now be necessary, in order to complete the elevation, 
 to draw the plan view ; hence, at a convenient distance from 
 the base of the elevation locate the point y on the center line 
 x-x; set the dividers equal in length to one-half the base 
 of the elevation, and using the point y as a center draw a 
 semi-circle ; divide the semi-circle into any number of equal 
 spaces, in this case eleven, numbered from one to twelve, in- 
 clusive. At right angles to the base of the elevation extend 
 these respective points of division up until they intersect the 
 base ; connect these points with the vertex in by radial con- 
 struction lines, thus creating what is termed the elements of 
 the cone. These intermediate lines are all shown foreshort- 
 ened, with the exception of the outer boundary lines, which 
 are shown in their true length. Where these intermediate 
 lines intersect with the connecting plane of the cylinder de- 
 termines the points from which the required or true length 
 of lines to be used in the development of the pattern are 
 obtained. This is accomplished by projecting these points of 
 intersection over at right angles to the center line x-x until 
 they intersect the outer elements of the cone, as shown at 
 i', 2', 3', 4', 5', etc., and designated on the drawing as "true 
 length of lines." 
 
 If it is desired to develop the full plan view it can be very 
 readily done in this manner, viz. : Connect the points i, 2, 3, 
 4, 5, etc., in the plan to the apex y; hence these lines represent 
 the corresponding radial lines of the end elevation, and appear 
 in this manner when viewing the object from above. The 
 elliptical or irregular curved portion is also a foreshortened 
 view of the cutting plane of the connecting cylinder. By pro- 
 
228 
 
 LAYING OUT FOR BOILER MAKERS 
 
 jecting the points of intersection between the elements of the 
 cone and the cutting plane of the cylinder down to the cor- 
 responding lines in the plan view, at the intersection of these 
 points, the ellipse is determined. The rectangular surfaces C 
 and D are then drawn. The irregular-shaped portion B is 
 drawn in the same manner as explained for the development 
 of A. 
 
 DEVELOl'MENT OF THE PATTERN. 
 
 Draw the center line .r'-.r' of an indefinite length, then 
 locate the points m' ; set the trammel points equal in length to 
 the distance m to r of the elevation, and using ;;;' in the pat- 
 tern as a center, draw an arc equal in length to the distance 
 around the semi-circle in the plan view, as shown, from one 
 
 Pattern for a Hood for a Semi-Portable Forge. 
 
 A C D B (Fig. i) represents the front elevation of a hood, 
 such as is frequently used for a portable forge ; E G H F (Fig. 
 2) its side view and 1 J K L (Fig. 3) the plan. As the top is 
 round, divide the quarter circle of the top A'' into any con- 
 venient number of spaces, using the "neutral diameter,'' also 
 divide the outer curve of the plan M K into the same number 
 of equal spaces. Connect points of similar numbers in the two 
 cur\'es by solid lines, as shown I to i', 2 to 2' and 3 to 3', etc. 
 .■\lso connect points in the plan of the top with points of the 
 next highest number in the plan of the base by dotted lines, as 
 6 to 5', s to 4', 4 to 3', etc. 
 
 Before the pattern can be begun it will first be necessary to 
 
 
 //'■ 
 '/ 
 
 PLAN, ELEVATION AND PATTERN OF IRREGULAR TRANSITION PIECE. 
 
 to twelve, inclusive. This distance can also be found by 
 calculation : Multiply the distance r-r, or the diameter of the 
 base, by the constant 3.1416. and divide by two; this will give 
 the required stretch-out of one-half of the base. Space the 
 stretch-out into the same number of equal spaces as the plan 
 view ; connect the center m' and these respective points with 
 radial construction lines. The camber line for the top con- 
 nection is obtained by transferring the true length of lines 
 shown in the elevation to the corresponding lines in the 
 pattern. Add for laps, and the pattern for A and B is 
 complete. 
 
 The patterns for C and D are not shown, as their develop- 
 ment only requires straight-line drawing; hence, further com- 
 ment is not necessary, other than that the heights for the re- 
 spective patterns are different. The height for C is equal to 
 the distance l, and for D it is equal to the distance 12, which 
 .are the two outer boundary lines of the frustum. 
 
 obtain the correct distances represented by the solid and dotted 
 lines across the plan. This is accomplished by means of two 
 diagrams of triangles, as shown in Fig. 4. Draw the vertical 
 line F-H in length corresponding to the height of the hood, as 
 shown by F-H in the side view ; at right angles to F-H draw 
 F-6 equal to 0-K or 6-6' of the solid lines of the plan. From 
 F set off also the spaces F-S, F-4, F-3, etc., corresponding to 
 the solid lines I l', 2 2', 3 3', etc., of the plan; then connect 
 these points to H with solid lines. Then on the other side of 
 F-H construct the second diagram of triangles in similar 
 manner. F-s' is set off in length equal to the dotted line 6-5' : 
 then set off the distances F-4', F-3', F-2', F-l' corresponding 
 to the dotted lines 5-4', 4-3', 3-2', 2-1' in the plan. 
 
 To develop the pattern, first draw vertical line 6'-5 (Fig. 
 5), representing the center line of the back, and make this 
 equal to the solid line 6 H (Fig. 4), or E-G in side view (Fig. 
 2). Then with the dividers used in spacing off the outer curve 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 229 
 
 of the plan and from point 6' as a center describe arcs, and 
 with trams set to the distance s'-H dotted, and with 6 as a 
 center, describe arcs intersecting the arcs previously made 
 with the dividers, which will give points s', s' in the bottom. 
 Draw dotted lines to these points, then with the dividers used 
 in spacing N-0 and with 6 as a center describe arcs. Set 
 trams to the distance 5-H solid, and with 5' as centers describe 
 arcs, intersecting the arcs just made with the dividers, which 
 
 with distance P-R, Fig. 2, and with i as a center describe an- 
 other arc, intersecting the arc just made; from this point 
 draw lines to i' and i, which will give the rivet lines. Then 
 lines drawn through points I, 2, 3, 4, 5 and 6 at the top and 
 bottom will complete the pattern ; material must be added for 
 the lap and flange as required. 
 
 It will be seen that Fig. 6 is the same pattern as Fig. 5, but 
 with measurements noted. 
 
 LAYOUT OF A CONICAL HOOD FOR A SEMI-PORTABLE FORGE. 
 
 will give points 5, 5 in the top. Connect 5' and 5 with solid 
 lines, then with the large dividers, and with points 5', 5' as 
 centers describe arcs, and with trams set to 4'-H, Fig. 4, and 
 from S as a center describe arcs intersecting the arcs just made 
 with the large tlividers, which will give points 4'-4' in the 
 bottom. Proceed in this manner, using alternately the dis- 
 tances shown in the solid and dotted lines in the diagrams of 
 triangles. Fig. 4, until points i, i' are reached. Then with dis- 
 tance J-M, Fig. 3, and from i' as a center strike an arc, and 
 
 There is no need to lay out the front plate by triangulation, 
 as there is an easier way. First draw line G C in the pattern 
 for the front plate equal to 5 T, Fig. 3, which is the straight 
 part of the plate at the base, 2 feet 6 inches long. Bisect this 
 at B; then from G and C, respectively, strike arcs with a con- 
 venient radius, then from B, through the points where the arcs 
 intersect, draw a line of indefinite length. Set the trams to 
 the distance F H (Fig. 2), and from B, G and C strike arcs at 
 /, A and E. The intersection of the arc at A with the line 
 
230 
 
 LAYIXG OUT FOR BOILER AIAKERS 
 
 B K will give point A. Set the trams to distance B C, and 
 with A as center strike arcs intersecting arcs made from G 
 and C. This will give points E and /. From £ as a center, 
 and with f.-C as a radius, strike an arc, and from / as a cen- 
 
 Fig. 7 is the band, developed 12 inches diameter outside 14- 
 gage plate, giving a length of 3 feet i}i inches. It is best to 
 punch the band and mark the holes off from it on to the hood, 
 and punch them with a screw punch. 
 
 PLAN, ELEVATION AND PATTERN OF TAPERING SPOUT. 
 
 ter, with the same radius, strike an arc. Then measure off on 
 these arcs one-quarter of 12 inches circumference, which will 
 give points / and F. Without changing the trams strike an arc 
 from A as a center, cutting line A B, giving K. Then from K 
 strike an arc and measure off on the arc each side from A a 
 length equal to one-quarter of 12 inches circumference, which 
 will give points D and H. Draw lines from H to J and from 
 D to F, which will be the rivet lines. Draw lines from A to 
 G and C. Inside of these lines the plate must remain flat, out- 
 side of them it is rolled to a 6-inch radius. Add a lap to the 
 sides and a flange to the top arc D H, then the pattern will be 
 completed. 
 
 Layout of a Spout Intersecting a Conical Body. 
 
 There is a certain class of patterns that is always trouble- 
 some to the sheet metal workers. This is owing to the fact 
 that the curves formed by the intersection of some kinds of 
 surfaces cannot be laid out except by making several inter- 
 mediate constructions that are not required in ordinary work. 
 A good example showing the extra work necessary to make 
 the pattern is the layout of a spout intersecting a conical body. 
 As the same principle is used in other important constructions, 
 the following illustration and description of the work will 
 make clear the parts that cause the pattern maker the most 
 trouble. The difficult part of this problem is to find the curve 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 231 
 
 on the pattern of the spout that is to fit the body. This curve 
 is found first in the projection of the plan, and from this the 
 projection in the elevation is made, and finally the curve on 
 the pattern is made from the elevation. It is advisable in a 
 case of this kind to make an actual layout of the pattern 
 from the beginning, performing each step in the process, and 
 also to make the drawing to a large scale, so that the different 
 projections will not become confused. 
 
 In the sketch, the first thing that is made is the plan, and 
 the elevation of the frustum of the cone used for the body. 
 Also, in the elevation, the side view and the section of the 
 spout are made to any desired size and form. The side view 
 of the spout is shown at A, and a section of the spout along 
 the line ab is shown at (a). In making the section at (a), 
 draw a line cd at right angles to the edge of the spout, and at 
 the point c draw an arc of a circle of any desired size. Then 
 draw a tangent gh to this arc, making the width dli the same 
 as the half width of the spout at b, or equal to jn as shown in 
 the plan." The angle of the spout is usually 45 degrees, and 
 is laid out at F j K in the plan. 
 
 The curve for the top of the pattern is very easily made, 
 and is shown at B. In order to get this curve, divide the line 
 c d into any number of parts desired, and draw lines parallel 
 with the edge of the spout e f. Where these lines cut the 
 curve e x b of the top of the spout, draw lines parallel to 
 c d to the left an indefinite distance. From the point a to 
 the left, lay off distances equal to the sections h-6 6-7. 7-8. 
 etc., along the edge of the spout as shown at (o) and erect 
 perpendiculars at these points to intersect the horizontal lines 
 previously drawn. These intersections will give the points 
 in the curve B for the top of the pattern of the spout. 
 
 To get the curve C for the bottom of the pattern where the 
 spout joins the body, is more difficult, as two or three inter- 
 mediate steps must be taken. In the first place, divide the arc 
 / A', shown in the plan, which includes the width of one-half 
 the spout, into any number of equal divisions, and draw radial 
 lines from the center ;' to each of these. Also, draw the pro- 
 jections of these lines in the elevation through the vertex m 
 of the cone. Five divisions are made in the drawing. The 
 next thing to do is to get the horizontal projections of a series 
 of curves that are cut from the cone by the several planes 
 passing through the line cd. Thus, the plane through the 
 point 2 on f rf crosses the several lines drawn on the cone 
 through the vertex m at the points O, i, 2, 3 and 4. By pro- 
 jecting these points down to the plan on the corresponding 
 lines of the cone, we get the points O, i, 2, 3 and 4. Then 
 draw the curve D E through these points. This curve is not 
 a circle, but is of irregular form and may be laid out by the 
 use of a special curve that will pass through the points. In 
 the same manner the several other curves H. I, I and L are 
 obtained in the plan by the use of the lines through the other 
 point's on the line c d. After getting these irregular curves on 
 the plan, the next step is to lay out the distances on the ver- 
 tical line j n, making / n equal in length to the line d h of (a). 
 Then make the other heights / 0, j p, j g. etc., equal in length 
 to the lines 5-6, 4-7, 3-8, etc., of (a). Draw horizontal lines 
 through the points on / n intersecting the different irregular 
 curves on the plan. The irregular curves show the form of 
 
 the spout at the section where the respective planes were 
 passed, and the distances on / 11 give the width of the spout 
 at each of these locations, so the points of intersection of 
 these horizontal lines and the irregular curves are points on 
 the horizontal projection of the curve where the spout unites 
 with the body. This curve has been drawn through the points 
 and is shown at f N. 
 
 The next step is to get the vertical projection of this curve 
 on the body. This is done by drawing vertical lines through 
 the points that determine the curve in the plan to the corre- 
 sponding lines in the elevation drawn from the line c d in 
 (a). Thus, the point / in the plan is projected to the point u 
 in the elevation ; the point 7' in the plan to the point w in the 
 elevation, etc. After getting the several points in the eleva- 
 tion, the vertical projection of the curve where the spout 
 unites with the body is drawn as shown at / b. Ne.xt, through 
 the several points u w, etc., on the vertical projection of this 
 curve, draw lines parallel to the line a b, extending them in- 
 definitely to the left across the ordinates on the pattern al- 
 ready drawn for the curve B. The points obtained by the 
 intersection of these lines, with the ordinates of the pattern, 
 will locate the curve C for the lower edge of the pattern. 
 
 Layout of Tapered Transition Piece. 
 
 A transition piece, tapering from round to square and 
 setting other than at right angles to the surface it connects, 
 is met with quite frequently in sheet metal work. It is used 
 for conveyors and in many fan connections in blast-pipe work. 
 The problem can be very readily solved by triangulation. 
 
 CONSTRUCTION. 
 
 First draw the plan and elevation, as shown in Fig. i, to 
 the required dimensions of the transition piece. It will be 
 seen from the drawing that it will be necessary to make a 
 development of the circle for the plan view. This is due to 
 the fact that in looking directly down upon the object, the 
 round portion of the transition piece will be seen foreshort- 
 ened, or elliptical in shape. To develop this foreshortened 
 view the same principles are applied as are used in projection 
 drawing. On the line A-A, which is the axis of the transi- 
 tion piece, and at a convenient distance from the object, draw 
 a circle equal in diameter to the circular portion of the ob- 
 ject. Divide the circle into any number of equal spaces, in 
 this case six. At right angles to the line 4 4' extend these 
 points of division until they intersect the line 0-0. On the 
 line B-B, and at a convenient distance from the plan, draw a 
 circle equal in diameter to the circle drawn in the elevation, 
 and divide it into the same number of equal spaces. Extend 
 these points of division parallel with the line B-B to the plan 
 view. Then at right angles to the line B-B drop the cor- 
 responding points from the side elevation until they intersect 
 the lines just drawn in the plan. The intersections of these 
 respective lines determine the development of the foreshort- 
 ened view of the transition piece. 
 
 In both plan and elevation, draw in the dotted construction 
 lines from the points, as shown from C to 4-3-2-1 and C to 
 i-2'-3' and 4' in the side elevation, and from D to 4-3-2-1 and 
 D' to i-2'-3'-4' in the plan. 
 
232 
 
 LAYING OUT FOR BOILER MAKERS 
 
 The next procedure is to determine the true length of lines set equal to the distance 4-4 of the triangles, and using 4 in 
 
 for the development of the pattern. This is done in the usual 
 way, by constructing triangles, obtaining the heights from the 
 elevation and the base from the plan. The hypothenuses of 
 these respective triangles are the required lines, or the true 
 
 the pattern as an apex draw an arc, cutting the arc just drawn, 
 thus locating the point C. The spaces for the stretchout at 
 the top will be taken either from the circle in the side eleva- 
 tion or from the circle on the line B-B. This is immaterial, 
 
 length of lines, used in developing the pattern. As the opera- 
 tion of constructing these triangles is so simple a description 
 of the various operations involved will not be necessary. 
 
 LAYOUT OF THE PATTERN. 
 
 First, draw the vertical line c, making it equal in length to 
 the line C to O of the side elvation. Then set the dividers, or 
 trammel points, equal to the distance from Z? to B of the plan 
 view, and using 4 as a center, draw an arc. With the dividers 
 
 as both are of the same diameter, and are divided into the 
 same number of equal spaces. It is good practice when de- 
 veloping patterns for pieces of this kind, where the spaces 
 are equal, to use two pairs of dividers, or trammels, setting 
 one pair for the spaces and using the other for the construc- 
 tion lines. 
 
 With 4 as an apex and using the spacing dividers, draw an 
 arc ; then set the trammels equal to the distance 3-3 of the 
 triangles, and using C as an apex draw an arc, cutting the 
 arc just drawn, as shown at 3. Continue in this manner, using 
 alternately the spacing dividers and the distances from 2 to 2 
 and I to I of the triangles, thus constructing the large portion 
 of the transition piece, as shown within the points C-1-4-C. 
 To construct the remaining portion of the half pattern, set 
 the trammels equal to the distance D-D' of the plan, and with 
 C as an apex draw an arc. Then with the dividers set to the 
 distance from i' to i of the triangles, and with i in the pattern 
 as an apex, draw an arc, cutting the arc just drawn, thus de- 
 termining the distance in the base from the point C to C. 
 The remainder of the pattern is now developed in the same 
 manner as given for developing the larger portion. The 
 placing of the seams, amount of lap and spacing of rivet holes 
 are to be made at the discretion of the mechanic when laying 
 out the pattern. 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 233 
 
 Triangulation Applied to the Layout of a Transition 
 Piece. 
 
 The following plan is a convenient one for getting out a 
 pipe with an elliptical base and round top : In Fig. i the ele- 
 vation of the article is shown by A B D C. In the plan, 
 E H F G represents the elliptical base and i H j G the circular 
 top. An inspection of the plan will show that the part repre- 
 sented hy F j G is similar to the other parts, consequently the 
 
 the same height as B R, Fig. i, represented by O, Fig. 2, in 
 the drawing. Measuring in each instance from iV on N M, 
 set of? the length of solid lines drawn between F G and ; G 
 in the plan, thus making N M equal to i i' in the plan, N 2 
 equal to 2 2' in the plan. A' 3 equal to 3 3'. in the plan, etc. 
 Having established the various points, lines can be drawn, as 
 shown, from the points to O (but it is not absolutely neces- 
 sary if the points are well defined) ; then the hypotenuses of 
 
 ll 
 I III 
 I II 
 
 ' ;/',' 
 
 / ll 
 
 I ll 
 
 I In 
 
 iln 
 
 2 3|4'>5 
 OF SOLID LINES DIAGRAM OF DOTrED 
 
 LINES 
 
 DIAGR.^MS FOR L.^YOUT OF TR.ANSITION PIECE BY TRI.4NCUL.\TI0N. 
 
 pattern for one of these parts, as F j G, will answer for the 
 others. 
 
 The method most convenient to employ for obtaining the 
 proper shape is that of triangulation. For this purpose divide 
 F G into any convenient number of equal parts, as shown by 
 the small figures on F G. In the same manner divide ;' G of 
 the top into the same number of spaces as indicated. Connect 
 the points by solid and dotted lines, as shown. 
 
 The next step preparatory to obtaining the pattern will be 
 to construct triangles whose bases are equal to the lengths of 
 lines drawn between points on F G and / G, whose altitudes 
 are equal to the straight heights of the article and whose 
 hypotenuses will give the correct distance from the points 
 on F G to the points on j G. The diagram of triangles repre- 
 sented by the solid lines is shown in Fig. 2. To obtain these 
 triangles, draw a horizontal line any convenient place, and 
 from A^, as shown, erect a perpendicular line, and make it 
 
 the triangles in the diagram give the true distances between 
 the points on F G of the base and the points on / G of the 
 top as indicated by the solid lines in the plan. 
 
 The triangles shown in Fig. 3 are constructed in the same 
 manner, and are derived from the dotted lines in the plan. 
 K P represents the straight height of the article. Then on 
 K L, Fig. 3, measuring in each instance from K^ set ofT the 
 lengths of the dotted lines; thus make K 2 oi the diagram 
 equal to i' 2 of the plan, K ^ oi the diagram equal 2' 3 of the 
 plan, etc. Having established the various points on K L, draw 
 lines to P, as shown. The hypotenuses of the various tri- 
 angles in Fig. 3 are equal to the correct distances measured 
 on the finished article between the points F G and / G of the 
 plan, as indicated by the dotted lines. 
 
 In working this or any other article by triangulation it will 
 be found very convenient to have two pairs of dividers, one 
 pair for large spaces on F G, and the other for the smaller 
 
234 
 
 LAYING OUT FOR BOILER MAKERS 
 
 spaces on ; G, thereby avoiding chances of error in resetting, 
 and if two sets of trams were used, one for the solid lines and 
 one for dotted lines, it would save time. For the pattern, 
 begin by drawing a line as i l', Fig. 4, on which set off a 
 distance equal to ^1/ 0, Fig. 2, which equals B D in the ele- 
 vation, or I O in the diagram of solid lines. Fig. 2. Then with 
 the dividers set to the large spaces on F G, scribe arcs on 
 each side of i, as shown at 2 2, using the point i as a center 
 with the trams set from P to 2, Fig. 3. Carry to Fig. 4, and 
 tising i' as a center scribe arcs, cutting those just made, which 
 establish the points 2 2 in the pattern at the bottom. Now set 
 the trams from O to 2, Fig. 2, and using 2 2 as centers scribe 
 arcs at the top. Then use the dividers set to the small spaces 
 on / G, and using i' as a center scribe arcs, cutting the arcs 
 made with the trams, and establish the points 2' 2' as shown 
 at the top. Then using the dividers, set to the large spaces, 
 scribe an arc from the point 2 to 3 ; set the trams from P to 3, 
 Fig. 3, and with 2' and 2' as centers scribe arcs, cutting the 
 arcs just made, and establish the points 3 3. Now, using the 
 small dividers and 2' and 2' as centers scribe arcs. Set the 
 trams from O to 3, Fig. 2, and with 3 and 3 on the pattern as 
 centers scribe arcs, cutting these just made from 2' and 2', 
 and we have the points 3' 3'. Continue in this manner until 
 the various points on M N and L K are located. Connect 
 these points, and the pattern for part of the envelope as shown 
 in Fig, 4 will be made. 
 
 Fig. s shows an easy plan to get an ellipse. Draw the 
 diametrical lines at right angles to each other, intersecting at 
 o. Set out the length and breadth of the figure on these lines 
 equally from the center o ; set off the length r, or d, with 
 the compasses on the longer diameter from b to e, and with 
 as a center, with the radius e describe the quadrant e f. 
 Draw the line or chord e f; set off half of it from e to /, 
 and with 7 as a radius scribe arcs on the diametrical lines 
 as at y h i k. Then / and i are the centers for the segmental 
 arcs at a and b, and h and k are the centers for the lateral arcs 
 at c and d. This is a very convenient way to get out an 
 elliptical base, although it is, of course, not a new method. 
 
 Layout of an Irregular Offset Piece. 
 
 Figures 3, 4 and 5 show the plan and side views of the up- 
 take from a battery of boilers and its connection through an 
 irregular offset piece to the stack. The opening in the stack 
 is out of line with the breeching, and the boilers are placed 
 so close to the stack that there is no room to use an elbow 
 or any regular form of connection between the breeching and 
 the stack. Therefore it becomes necessary to use an irregular 
 section, which must be laid out by triangulation. End and 
 side views of this piece are shown in Figs, i and 2. The end 
 which joins the breeching is circular, while the end which 
 joins the stack is oblong, with circular ends. The latter is 
 also inclined on a miter line. 
 
 To lay out this article, first draw Fig, 6, which is an end 
 view of the piece drawn to dimensions taken at the center of 
 the thickness of the iron, that is, the mean or neutral dimen- 
 sions. Before drawing Fig. 6, however, it is necessary to 
 draw Fig. 7. the side view, and construct the section ilf-.Y, 
 
 which is a section taken along the miter line R and shows the 
 true shape of the opening in this end of the offset piece. This 
 is an oblong opening with semi-circular ends. Divide the 
 semi-circles into a number of equal parts. In this case each 
 semi-circle has been divided into six equal parts. Project 
 these points to the miter line R and from the miter line pro- 
 ject them across to the end view. Fig. 6, where by laying 
 off the proper widths on each line the end view of the sec- 
 tion M-N, as it would appear inclined at the same angle as 
 the miter line R, will be shown. Of course, it is evident that 
 the ends of the oblong section in Fig. 6 are not true semi- 
 circles, since this is a foreshortened view of the section M-N, 
 where the ends are shown as true semi-circles. Divide the 
 large circle. Fig. 6, into twelve equal parts, or double the 
 number of spaces into which the small semi-circles were 
 divided. Number these points i, 2, 3, 4, 5, etc, up to 11. ■ Also 
 number and letter the points in the oblong end as shown. 
 Connect the corresponding numbers in each semi-circle with 
 a full line and connect the odd numbers, as i to 2, 2 to 3, etc., 
 with dotted lines. Some of these points have been lettered 
 instead of numbered in order to avoid confusion in the draw- 
 ing, as points thus indicated can be more readily distinguished. 
 Draw similar solid and dotted lines in the side view. Fig. 7, 
 being careful to number or letter each point with the same 
 figure which was used in Fig. 6. To obtain the length of the 
 offset for each point on the small semi-circle of the oblong 
 end, draw vertical lines from each point in the miter line R 
 to intersect the horizontal X K. Then the distance from ,Y to 
 each of these lines will represent the amount to be laid off 
 when constructing the triangles for the pattern. 
 
 We are now ready to draw diagram No. i of the triangles 
 Fig. 8. In diagrams No. i and No. 3, the full lines are shown, 
 while in No. 2 and No, 4 the dotted lines are shown. All 
 the distances on the horizontal line of diagram No. i are 
 taken from the end view. Fig, 6, All the distances on the 
 vertical lines of the diagram are taken from the side view. 
 Fig. 7, along the line .Y K from the point X to the point of 
 intersection of the vertical lines drawn from the points on 
 the miter line R. For example, take the length of line 4-4, 
 Fig. 6: mark it off on the horizontal line from the point O. 
 diagram No. i. Fig. 8. Now take the distance from X, Fig. 
 7, along the line .V K to the point where the line 4 inter- 
 sects the line A' K and lay it off on the vertical line O H, 
 diagram No, i. Fig, 8. Then the length of the hypoteneuse 
 4-4 in diagram No. i will be the length of the line 4-4 in the 
 pattern. Proceed in this manner until the true length of each 
 of the lines shown in Figs. 6 and 7 has been determined. 
 
 The method of triangulation is easier to study from the 
 sketches than from an explanation, and so the explanation is 
 given of how only one line, that is the line 4-4. is obtained, 
 and it is left to the reader to trace out by means of the 
 sketches how the other lines are obtained. As the method is 
 exactly the same for every line, there should be no difficulty 
 in following out this work. 
 
 Having completed all four diagrams in Fig. 8, we now pro- 
 ceed to lay out the pattern. Fig. 9. Determine the length of 
 the sheet at the round end. by figuring out the circumference 
 of a circle corresponding to this diameter. Set the dividers 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 235 
 
 to step off the same number of spaces on this distance as are 
 spaced on the circle, Fig, 6. Do hl-cevvise with the small semi- 
 circles.. Assuming that 5'-6'-5'-6' is the plate from which the 
 pattern is to be cut, draw the line 4-4 at about the same angle 
 as 4-4, Fig. 6. The length of the line 4-4 will, of course, be 
 equal to the length of the hypotenuse 4-4 in diagram No. i. 
 With the dividers set to the same length as the equal spaces 
 in the large circle, Fig. 6, draw the arcs s and 3. Also with 
 another pair of dividers set to the length of the equal spaces 
 on the small semi-circle, describe the arcs 3 and 5 in the 
 upper edge of the pattern. Take the length of dotted lines 
 
 The Layout of a Taper Course. 
 
 The first thing in this layout is to find the neutral diameter 
 at each end of Fig. i. This course is 70'A inches outside di- 
 ameter at the big end, 54 inches inside diameter at the little 
 end, 48 inches between the flange lines and 23/32 inch thick. 
 The neutral diameter of the big end therefore equals 7014 
 inches— 23/32 inch, or 6925/32 inches. The neutral diam- 
 eter of the little end equals 54 inches -j- 23/32 inch, or 54 23/32 
 inches. Now draw two circles as shown in Fig. 2 one 
 6925/32 inches diameter and the other 5423/32 inches diam- 
 eter: setting your trammel points at 3457/64 inches for the 
 
 4-3 and 4-5 from diagram No. 2, Fig. 8, and with point 4 as 
 a center, draw arcs cutting the arcs previously drawn with 
 the dividers at points 4 and 5. This locates the points 3 and 
 5 in the upper edge of the pattern. Points 3 and 5 in the 
 lower edge of the pattern may now be located by laying off 
 the lines 3-3 and 5-5 as taken from diagram No. I, Fig. 8, to 
 intersect the arcs previouslj' drawn from point 4 through the 
 points 3 and 5. Proceed in this manner with the other lines 
 until the pattern is completed. 
 
 The height of the flat portion P is taken directly from the 
 miter line R, Fig. 7. 
 
 In case any of the lines are confused, refer to Fig. 6, which 
 will show the termination of each full and dotted line. A 
 curve drawn through all the points located in the manner just 
 described will be the flange line of the pattern. Add the 
 necessary amount outside of this for the flange and space in 
 the rivet holes in the seams, also allow for the laps. 
 
 The portion of the elbow marked X, in Fig. 5, which con- 
 nects directly with the stack, needs no special explanation, as 
 it is a common job of laying out. 
 
 radius of the large circle and at 27 23/64 inches for the radius 
 of the small circle. 
 
 Divide one-half of the circle representing the big end of 
 the course into any convenient number of spaces as shown in 
 Fig. 2. In like manner divide the inner circle, which repre- 
 sents the small end, into the same number of spaces as shown. 
 These points are called the points of intersection. Draw a 
 solid line from the large circle to the corresponding point on 
 the small circle as indicated by the letters A, B, A', B' ; also 
 connect the points on the inner circle with the next letter on 
 the outer circle as indicated by the dotted lines. Thus connect 
 A' with B and so on, as shown. These lines just drawn are 
 the bases of a number of right-angle triangles whose alti- 
 tudes are equal to the distance between the flange lines. A A 
 and i? B in Fig. i, and whose hypothenuses, when drawn, will 
 give the correct distances across the pattern, or the envelope 
 of the article, between the points in the big end and those in 
 the small end in the direction indicated in Fig. 2. 
 
 The triangles having solid lines are shown in Fig. 4, while 
 those having the dotted lines are shown in Fig. 5. At any 
 
236 
 
 LAYING OUT FOR BOILER :\IAKERS 
 
 convenient point erect a perpendicular A' B' , Fig. 4, whose 
 length is equal to the distance between the flange lines, Fig. i, 
 which is 48 inches. On the base line C D, measuring from 
 A' set off the lengths equal to the solid lines in Fig. 2, as at i, 
 3- 5. 7. 9i etc. From the points thus established on the base 
 line, draw lines to the point 5'. The triangles thus con- 
 structed will represent sections through the article on the solid 
 lines in Fig. 2. In like manner construct the triangles shown 
 in Fig. 5, using the dotted lines instead of the solid lines. 
 
 In developing the pattern draw a solid line as shown at 
 E E', Fig. 6, equal in length to the distance between the flange 
 
 the lines of intersection G C. Then using / as a center and 
 / // as a radius, strike an arc cutting the outside rivet line at 
 H. Do this until all the holes in the outside rivet line are 
 placed. Then using L as a center, and L K as a radius, strike 
 an arc cutting the inside rivet line at 7s.'. This completes Fig_. 
 6. The reason all these measurements have been taken is to 
 show the reader how to allow for the thickness of material, 
 or, in other words, how to lay out a taper course for a boiler 
 and make it fit. If this method is carried out properly, every 
 hole will be exactly in its right place and it will be exact in 
 circumference and fit the shell of the boiler to perfection. A 
 
 Tig. 1 Fig. 2 Fig. 3 
 
 SIDE AND END VIEWS OF THE COURSE, WITH DETAILS OF TRIANGULATION AND DEVELOPMENT OF PATTERNS. 
 
 lines in Fig. i. Then take two pairs of dividers and set one to 
 the length of the spaces on the big circle and the other to the 
 length of the spaces on the little circle. Fig. 2. Using E' as a 
 center, Fig. 6, and the dividers just set to the small spaces, 
 strike an arc toward F'. Then taking the distance S-16 of 
 Fig. 5, with the trammel points, and with £ as a center, in 
 Fig. 6, intersect the small arc just made at F'. Now, using E 
 as a center, and the dividers set to the large spaces, strike an 
 arc toward F. Then using F' as a center and S'-iS as a 
 radius, Fig. 4, cut the small arc at F, and so on until the 
 whole pattern is complete. 
 
 After the article as shown in Figs. 2 and 3 is complete, 
 Fig. 3 being the elevation of the article, add to this pattern the 
 amount of flange called for, which is 5 inches at the small 
 end and 5 7/16 inches at the large end. Then draw the rivet 
 lines as called for. After having the rivet lines and the 
 amount of flange added, space the number of holes wanted on 
 
 great many people, in putting holes in a taper course, find that 
 when it is fitted up the holes are very bad, but with this 
 method it is not so. You can put a i^-inch bolt in a i 9/32- 
 inch hole. 
 
 Method of Laying Out the True Camber of a Taper 
 Course. 
 
 The following is a rule for laying out the true camber of a 
 regular tapering course whose radii are very large. This rule 
 is quite simple, and will be found to be very accurate, more 
 so than most other methods, except when the camber has been 
 drawn from a center or apex. 
 
 For an illustration, V, W, X, Y (Fig. l) represents a very 
 large sketch plate, as it is ordered from the mill. We know 
 the radius R B and the chord C A. Rules for calculating 
 these are described on page 258, 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 237 
 
 Use the chord C .-J as a radius and scribe an arc, A H and 
 H A, using A and H as centers, preferably at the small end 
 of the sheet, as it allows the diagram of radial lines to be 
 constructed on the sheet; whereas, if the larger camber is 
 drawn bj' this method the diagram will extend beyond the 
 extremes of the sheet, which will be quite unhandy for the 
 
 to same. Mark the degrees off on the arcs and draw radial 
 lines to A and H. Space the same off in equal lines to A and 
 /-/ ; letter the same so that corresponding letters will not be 
 opposite each other, as noted on the sketch. The points at 
 which each line of corresponding letters cross will be a point 
 through which the camber will pass, as noted by PPP. 
 
 no. 2. 
 
 layer-out. We will then find the degrees in the arc H A and 
 
 A H, which are the same. 
 
 y2CA 
 
 The sine of the angle is . 
 
 RB 
 
 Having determined the sine of the angle, refer to a table of 
 
 natural sines and find the degrees and minutes corresponding 
 
 Draw radial lines L L, on which lay ofT the distance from 
 P to Pi, equal to the slant height of the course. Passing a 
 curve through the points P, P from O, as a center, will con- 
 vince the reader that this is a very accurate method. 
 
 The Development of an Irregular Connection by 
 Triangulation. 
 
 This problem is a good exercise for the student on the 
 drawing board, also it is a practical method of laying out a 
 smokestack base, connecting directly on to a return tube or 
 locomotive type of boiler. The "sketch showing stack base 
 connection to a cylinder" gives a good idea of its practicability. 
 It will be noticed that Fig. i is only one-half of the elevation, 
 and that Fig. 2 is only one-quarter of the plan view; this is 
 all that is necessary in the development, as all the other parts 
 are similar, thus reducing the working lines and saving a 
 large amount of space and unnecessary work. 
 
 Having determined the smoke outlet required for the size of 
 the boiler, first draw an indefinite line A A, and at right angles 
 to this line draw line B B. then draw the quarter secticn plan 
 
238 
 
 LAYING OUT FOR BOILER MAKERS 
 
 view of the oblong end as shown in Fig. 2, making it the 
 same area as one-quarter of the area of the circle. (The ob- 
 long is the size of the opening in the cylinder on line D, look- 
 
 SKETCH OF THE COMPLETED CONNECllON. 
 
 ing up or down through elevation, Fig. i.) Then with R as 
 a center, draw the arc C of indefinite length. Make the dis- 
 tance 7 to no, Fig. I, any required height, and at point 7 
 extend an indefinite line X at right angles to A A, from the 
 
 Now space the quarter circles of the plan view, Fig. 2, into the 
 same number of squal spaces. Extend dotted lines from the 
 points 2, 3, 4, 5, 6, Fig. 2, up to the line X, Fig. i, also draw 
 dotted lines from 22, 33, 44, 55, 66 and 77, Fig. 2, up to the arc 
 C, Fig. I. From the point 77, Fig. i, space off on arc C equal 
 spaces as at points 8, 9, 10, no, and from these points drop 
 dotted lines down to line \\ Fig. 2. 
 
 On the plan view. Fig. 2, connect the points 2 to 22, 3 to a, 
 4 to 44, 5 to 55, 6 to 66 and 7 to 77, also 7 to 8, 7 to 9, 7 to 10. 
 The lines i to 11 and 7 to iia have already been drawn. These 
 lines constitute the base lines for the direct triangles as shown 
 in Figs. 4 and 6. Then from point I, Fig. 2, draw a dotted 
 line to 22, also from 2 to 33, 3 to 44, 4 to 55, 5 to 66 and 6 to 
 77 ; these make the base lines for the diagonal triangles, Fig. 5. 
 
 To secure the actual distance to step off on the layout of 
 the intersection on the arc C, it is necessary to draw another 
 set of triangles, as shown in Fig. 3. To secure the- different 
 sets of triangles, extend lines of indefinite length at right 
 angles to line A A from the points 11, 22, 33, 44, 55, 66, 77, 8, 
 9, 10, no. To complete the triangles, Fig. 3, first draw two 
 perpendicular lines, making the distance between them equal 
 
 1,2.3,4,5,6. 
 
 DETAILS OF L.WOUT OF IRREGULAR CONNECTION. 
 
 points I to II, Fig. 2, on line B B extend dotted lines until to the distance from 11 to 22, Fig. 2. Then draw lines from 
 
 they intersect arc C, also extend a line from 7, Fig. 2, up to 11 to 22, 22 to 33, 33 to 44, 44 to 55, 55 to 66 and 66 to 77 ; the 
 
 the line X. From point i draw a line to point 11, Fig. i. length of the lines is the true spacing in laying out the de- 
 
 This gives you the outline of one-half of the elevation. Fig. i. velopment of Fig. 7, 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 239 
 
 To secure the triangles in Fig. 4, first erect the perpendicu- 
 lar line E E. Set off on line 11 from line E E a distance 
 equal to i-ii, Fig. 2. Likewise take from Fig. 2 the distances 
 2 to 22, 3 to 33, 4 to 44, 5 to 55, 6 to 66 and 7 to 77 and set 
 them ofif from line E E. Then the lines drawn from the inter- 
 section of £ £ and X to the several points set off from the 
 hypothenuses of the triangles are the true lengths of the lines 
 with corresponding numbers on Fig. i (note, the lines on the 
 elevation of Fig. i are not the true lengths. They are only 
 filled in to show more clearly the different points of the plan, 
 Fig. 2). 
 
 To secure the true length of the dotted lines of Fig. i, pro- 
 ceed in same manner. Erect the line F F, Fig. 5, and with 
 distances i to 22, 2 to 33, 3 to 44, 4 to 55, 5 to 66 and 6 to 77 
 from Fig. 2, set off on lines 22, 33, 44, 55, 66 and 77, and with 
 these points connected with ihe intersection of line F F on 
 A' you have the true length of the dotted lines on Fig. i. 
 
 The length of lines 7 to 8, 8 to 9, 9 to 10 and 10 to iiu. Fig. 
 6, are secured from Fig. 2 and set off in the same manner as 
 in Figs. 4 and 5. 
 
 To develop the layout. Fig. 7, first erect the perpendicular 
 line I to II equal to i-ii. Fig. 4. Draw a short arc equal 
 to 11-22, Fig. 3, from 11, Fig. 7. Then set off from I, Fig. 7, 
 a distance equal-to 1-22, Fig. 5. Draw another short arc from 
 I, Fig. 7, equal to the space 1-2, Fig. 2, and with a distance 
 equal to 2-22, Fig. 4, lay off an arc from 22, Fig. 7, cutting the 
 short arc previously drawn at point 2, Fig. 7. Proceed in like 
 manner on both sides until you have laid down all the lines 
 up to 7-77, then with a short arc from yj, Fig. 7, equal to 
 77-8, Fig. I, set off from 7, Fig, 7, a distance equal to 7-8, Fig. 
 6, cutting the short arc at point 8, Fig. 7. Proceed in the 
 same manner with all the triangles of Fig. 6, using the same 
 spacing on points 8 to 9, 9 to 10, 10 to 11 a, as in Fig. i. 
 
 Draw straight lines from points 7 to iia, and a smooth curve 
 through all other points and you have one-half the develop- 
 ment of the irregular surface as shown in _the sketch. AH 
 allowances must be made for material, laps and flanges. 
 
 Layout of a Taper Course with a Flat Side. 
 
 In order to lay out the pattern as shown in Fig. 5, the re- 
 spective side and end views must be drawn up. Fig. i rep- 
 resents the side view of the taper course as it will appear 
 when rolled up into its true shape or position. Fig. 2 repre- 
 sents' the relation of the respective ends. The dimensions 
 given in Figs, i and 2 show the small diameter to be 16 inches, 
 the length of the course to be 20 inches, and the large end to 
 be drawn with a 20-inch radius with the flat side extending 
 8 inches bej'ond the center line. 
 
 Having drawn up the outline of Figs, i and 2, divide the 
 semi-circle of the small end into any number of equal spaces ; 
 in this problem eight equal spaces have been taken. Now di- 
 vide the curved surface of the large end into the same 
 number of equal spaces as the small end. Number the spaces 
 from I to 9, inclusive, and connect together the spaces as 
 shown. It is common practice to connect the spaces together 
 with dotted and solid lines, as this permits the layer-out to 
 keep the layout from getting confused, as will be the case 
 when the lengths of the various lines are nearly equal. It 
 
 is well to connect together figures of equal value with solid 
 lines, and figures of unequal values with dotted lines. 
 
 The value of this method will be more fully brought out in 
 Figs. 3 and 4. It is not really necessary to draw up the side 
 
 elevation, Fig. i, as about all the information required is the 
 length, 20 inches. Fig. 2 is practically the whole foundation 
 of the problem. 
 
 After connecting the lines as shown in Fig. 2, turn to Figs. 
 3 and 4. Draw the vertical lines Y-X in Figs. 3 and 4, 20 
 
 X X 
 
 
 
 /> 
 
 
 Fig. 4 
 
 9 8 16 54 32 
 
 12345 6 7 8 9 
 
 inches long, which is equal to the height of the course, as 
 shown in Fig. i. Now draw the horizontal lines Y-T, Figs. 
 3 and 4, at right angles to the vertical lines A'-i'. Step off 
 from Fig. 2, on the horizontal line of Fig. 4, the length of 
 the dotted lines. Likewise take the length of the solid lines 
 of Fig. 2 and step them off on the horizontal line of Fig. 3. 
 Draw the connecting solid and dotted lines to the apex X. 
 These slant lines just drawn give the true length of the lines 
 for the pattern, Fig. 5. 
 
240 
 
 LAYING OUT FOR BOILER MAKERS 
 
 In order to lay out the work rapidly, as well as to avoid 
 «rror, it is well to use two pairs of dividers : setting one pair 
 equal to the spaces of the large end and the other pair to the 
 spaces of the small end. Draw the vertical line, Fig. 5, from 
 I to I. equal to the full line i from the base to point X, Fig. 3. 
 Step off one large space at the top and one small space at 
 the bottom. 
 
 Take the length of the dotted line 2 from the base to the 
 point A', Fig. 4 ; using i as a center. Fig. 5, draw an arc cutting 
 
 the arc previously drawn at the bottom. Then take the length 
 ■of the solid line 2, Fig. 3 ; using 2 as a center, Fig. 5, draw an 
 arc cutting the arc previously drawn at the top. The balance 
 ■of the layout is carried out in a like manner, exercising care 
 not to use the wrong line. It will be understood that the 
 plate is worked from the neutral diameter of the taper course. 
 The wedge-shaped piece is merely iSH inches at the bottom, 
 tapering off to nothing at the top. Assuming that this is a 
 Ijutt-joint, the pattern is complete. 
 
 Layout of a Qranet or Hood for an Oval Smokestack. 
 
 A new style of funnel or smokestack is gradually supplant- 
 ing the old round smokestack on the steam trawl vessels 
 around the British coast. The stack is of an oval shape and 
 has an outer casing with an air space between the outer and 
 inner stack to carry oft' the hot air from the stokehold and 
 ■engine room. A granet or hood is riveted to the inner stack 
 at the top. Fig. i shows the arrangement of smokestack and 
 .! ranet. 
 
 DEVELOPMENT BY TRIANGUL.\TI0N. 
 
 Assuming that the oval is of the shape shown in the plan. 
 Fig. 2, with the granet sloping at the angle shown in the ele- 
 vation, Fig. 2, first divide one-quarter of the inner ellipse 
 ■of the plan into as many parts as convenient, numbering each 
 point ; in this case we have eight spaces. Keep the dividers 
 set at this size. Take another pair of dividers and step off 
 the same number of spaces on the outer ellipse, then connect 
 the points with solid ar.d dotted lines, as shown in Fig. 2. 
 
 Next draw a straight line as at M-N, Figs. 3 and 4, and 
 erect a perpendicular the same height as required for the 
 granet, namely, 8 inches. From the point of intersection on 
 the line M-N lay off a distance equal to the length of the 
 dotted line O-l in the plan ; do the same with each of the 
 dotted lines, numbering the points to correspond with the 
 plan. This gives us the length of the bases of a series of 
 triangles. Connect these points with the vertex O by dotted 
 lines. Do the same with the solid lines, numbering them as 
 before, but keeping to the right-hand side to avoid confusion. 
 See Figs. 3 and 4. 
 
 To lay out the pattern, lay out a line at Fig. 5 equal in 
 length to the line O'-O, Fig. 4. then from the point O', with 
 a radius equal to the length of the dotted line 0-0', Fig. 3, 
 strike an arc at the point O. With a radius equal to the 
 length as found on the dividers for the outer edge of the plan 
 strike an arc. Then from the point O', through the intersec- 
 tion of these arcs, draw a dotted line as O'-i, Fig. 5. 
 
 With I as a center and a radius equal to the length of the 
 solid line O-i, Fig. 4, strike an arc. With O' as a center and 
 a radius equal to the length as found on the dividers for the 
 inner curve of the plan, strike an arc. Then from the point 
 I through the intersection of these arcs draw a solid line as 
 I'-i, Fig. 5. 
 
 Do the same with the lines 2'-2, 3'-3 to 8'-8. Then draw a 
 smooth curve through the points so found ; this will give the 
 required pattern for one-quarter of the granet. The breadth 
 of the flange can easily be added to the inside edge, this de- 
 pending on the size of rivets used, as the plate may be 3/16 
 inch or % inch thick. 
 
 DEVELOPMENT BY THE METHOD OF RADIAL LINES. 
 
 This pattern may also be laid out by taking each diameter 
 and treating it as a separate cone and combining the two 
 figures to form one pattern. Fig. 6 is the plan of our granet. 
 Fig. 7 shows the elevation of the small diameter. Fig. 8 shows 
 the elevation of the large diameter. We vvfill take up first the 
 small diameter at the elevation, Fig. 7, and extend the sides 
 until they intersect, thus forming a cone with the vertex at O. 
 The required distance around the base of the cone may be 
 measured on an arc whose radius is equal to the length of 
 the elements of the cone. Such an arc may be drawn for 
 the stretch-out of the cone from the same vertex; this is 
 shown clearly in Fig. 7, where from the vertex O with the 
 radii 0-D and 0-A, the stretch-out is drawn. 
 
 We now turn to our plan, and from the center of the large 
 circle and through the center of the small circle draw a 
 straight line, extending it to the outer edge of the plan as 
 shown in Fig. 6 ; take a pair of dividers and divide this part 
 of the plan into any number of spaces. With the dividers set 
 to these spaces step off the same number of spaces on the 
 stretch-out. A straight line from the vertex through the 
 point thus found will give us the pattern A, D, E. F equal to 
 that part of the plan marked /, /, K, L. 
 
 Extend the lines of the elevation of the large figure. Fig. 8, 
 until they intersect at 0'. From the point of intersection with 
 radii equal to the length of the sides O'-E' and O'-F' describe 
 the stretch-out. Then step off the remaining portion of the 
 quarter plan and transfer as before to the stretch-out ; this 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 241 
 
 will give the pattern for the side piece of the granet To get 
 a pattern for one-quarter we must combine the two pieces. 
 
 Tal'ce a radius equal to the length of the side of the small 
 cone and transfer it to the line O' F', Fig. 8, giving the point 
 O". From O" as a center and with the trammels set to the 
 
 same curve on the stretch-out. They should be the same 
 length. 
 
 In actual practice this is a simple problem and can be laid 
 out with very little drawing. It may be done very quicl<ly and 
 accurately by the second method. 
 
 DETAILS OF STACK, GRANET AND LAYOUT BY TRIANGUL.\TI0X 
 
 Fig. 6 
 
 DETAILS OF LAYOUT BY METHOD OF RADI.\L LINES. 
 
 lengths 0" F' and 0" £', respectively, strike the arcs F' A' 
 and E' D', making F' A' equal in length to F A, Fig. 7. Then 
 draw a straight line from the vertex O" to A'. This will 
 give us the required stretch-out or pattern for one-quarter 
 similar to the pattern found by triangulation. 
 
 If the verte.x of the large cone extends too far to be laid 
 out with the trammels it may be laid out as an ordinary 
 tapered plate, with a square and compass. 
 
 The work may be proven by measuring the curved line of 
 the plan with a steel tape, or hoop, and then measuring the 
 
 Layout of a Double Angle Pipe from the Same Miter Line 
 
 First draw the plan with an angle of 38 degrees, 48 inches 
 off the center and 1165^ inches long. Now project the eleva- 
 tion with a rise of 30 inches, with the center of the miter line 
 in the same plane as the center of the miter line in the plan. 
 
 Place the miter line of the elevation A as at A' , so that the 
 points 1-9 are in the same line as 1-9 in the plan; then project 
 the lines up in the plan until i intersects I, 2 on 2, 3 on 3, etc. 
 Where these lines meet gives the line of intersection. Now 
 we can lay off the patterns for both end sections. 
 
242 
 
 LAYING OUT FOR BOILER MAKERS 
 
 DETAILS SHOWING CONSTRUCTION AND DEVELOPMENT OF THE PATTERNS FOR "A DOUBLE-ANGLE PIPE. 
 
 Space off the sheet into the same number of parts as the 
 circles. Draw lines from the line of intersection over to the 
 pattern. The other line of intersection B is found in the same 
 way as A. 
 
 Now we will find the true length between centers of the 
 miter lines, as both the plan and elevation are foreshortened 
 views. 
 
 (60)' + (48)' = 3,600 + 2,304 =5,904. 
 V5,904^ 76.81 inches. 
 This gives the length of the plan. 
 Now we will find the length of the elevation. 
 (76.81)=+ (30)2 = 5,904 + 900 = 6,804. 
 
 V6,8o4 = 82.5 inches as the length of the 
 center part between centers. 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 243 
 
 By reference to the drawing it will be seen that the numbers The first step is to draw the center line AB, shown in Figs, 
 
 have been moved around half way. This is done to bring the i and 2, then draw an end view (Fig. i) and a side view 
 high part in line with the lowest part, or so that they would (Fig. 2) of the cone and cylinder to which the spiral piece is 
 be in the same relative position as they were in the plan and to fit. Then draw a center line through the center of the end 
 elevation. The details of the remainder of the layout are view (Fig. i) and at right angles to the line AB, each end 
 clearly shown in the drawing. cutting the circumference of the large circle of the cone. 
 
 The main difficulty with this layout is the proper location Then divide this circumference into any number of equal 
 of the lines of intersection at each end of the plan view of spaces. We will take sixteen, and from these points carry 
 
 lines parallel to line AB until they cut the large end of the 
 cone (Fig. 2), and from these points extend lines in the 
 
 the pipe. After these lines are located the development is 
 carried out in the ordinary manner for cylindrical surfaces. 
 Care must be taken to keep each line numbered or lettered 
 with the same character in each view. 
 
 Layout of an Irregular Spiral Piece. 
 
 Before a pattern for any piece of sheet metal work can be 
 laid out, a working drawing is usually necessary. No pattern, 
 however simple or plain, can be produced until we have some- 
 thing definite to work from. We must make a working draw- 
 ing of the object as it will appear when completed. It should 
 
 direction of B until they cut the small end of the cone. Then 
 m Fig. r draw (from the points on the circumference) lines 
 in the direction of the center until they cut the small circle, 
 and from these points draw lines parallel to the line AB until 
 they cut the small end of the cone in Fig. 2. 
 
 Now we will draw the outline of the spiral piece. Measure 
 from C I, then from i measure off the pitch 1-34.' Then 
 draw the helix; the pitch i'-34' is the same as 1-34, except 
 that it is on the opposite side of the cylinder and should be 
 divided into the same number of equal spaces as the small 
 
 be made the exact size if possible, or if that is too large it circle in Fig. i, then draw the corresponding lines on the 
 
 can be made half size, or to any other scale. 
 
 The development of this surface appears complicated, but, if 
 the explanation is followed very closely, it will be found very 
 simple. 
 
 cylinder as 32-32', 30-30', etc. This will give the points of 
 the helix. Connect these points together with a number of 
 arcs and this will complete the helix, i, 3, 5, 7. 9, etc. 
 
 The spiral 2, 4, 6, 8, 10, etc., will come next, which is drawn 
 
 LAYOUT OF A SPIRAL CONNECTING A CONE TO A CYLINDER. 
 
244 
 
 LAYIXG OUT FOR BOILER MAKERS 
 
 the same as the helix, the pitch 2-33 is divided into the same 
 number of equal spaces, and from these points parallel to 2, 
 G and cutting the corresponding lines on the cone, connect 
 these points with a number of arcs. To draw the spiral in 
 Fig. I, draw lines parallel to AB from the points just located 
 (4, 6, 8, 10, etc.) in Fig. 2, cutting the lines that were drawn 
 ftom the circumference in the direction of the center, we find 
 we can get all the points of the spiral except 10 and 25, which 
 can be taken from Fig. 2, 25 and 26' are equal to 25 and 26 in 
 Fig. I, and 5' and 10, Fig. 2, are equal to 5 and 10 in Fig. I ; 
 then connect these points of the spiral with a number of arcs, 
 this completes the spiral in Fig. I. Then from these points on 
 the spiral draw the triangles, as shown by connecting the 
 points 2-3, 4-5, etc. Find the length of the helix and divide 
 this length into si.xteen equal spaces ; this is done as follows : 
 
 Let d ^= diameter of cylinder, 
 57 = 3.1416, 
 P=: pitch of helix, 
 C = length of heli.x. 
 D = diameter at big end of cone ; 
 
 Then /> = V (d 7r)= + P= h- 16 in Fig. 3. 
 H = d^, 
 p in Fig. 3 is equal to p in Fig. 4. 
 
 We will now find the lengths of the spaces A, B, C, etc., 
 in Fig. 4 ; first draw lines parallel to 2, G, Fig. 2, from the 
 points 4, 6, 8, 10, 12, etc., cutting the side of the cone Gh. 
 From S as a center and GB as a radius describe the arc 2, 0' , 
 Fig. 5. The length of arc, 2, o'=:Z?'r; divide this arc into 
 sixteen equal spaces and from these points draw lines in the 
 direction of B, cutting the stretch-out of the small end of the 
 cone ; then with 5 as a center, and B 4' as a radius, strike an 
 arc, cutting the corresponding line in Fig. 5, likewise with B 
 as a center and B& as a radius, and so on until we have got 
 all the spaces A, B, C, D, etc. These spaces in Fig. 5 are 
 equal to the spaces A, B, C, D, etc., in Fig. 4. Now we are 
 ready to find the true lengths of the lines in the several tri- 
 angles in Fig. I ; the length of the lines, as shown, 1-2, 2-3, 
 etc., are the bases of a number of right-angle triangles whose 
 altitude is projected from Fig. 2 to Fig. 6. The bases of 
 these right-angle triangles in Fig. i are transferred to Fig. 6, 
 as shown, i to 2, 3 to 4, etc., inclined lines drawn from the 
 ends of these base lines to the ape.x of these triangles are the 
 true lengths of lines to be used in Fig. 4 ; to make this more 
 clear, i, 2 is the base line, of which x is the apex, and so on. 
 
 To develop the spiral piece from the dimensions just ob- 
 tained, proceed as follows : At any convenient place draw 
 the straight line l, 2 (Fig. 4) ; in length equal to i, x (Fig. 6) ; 
 set the dividers to the space /> (Fig. 3) and strike an arc in 
 the direction of 3 (Fig. 4), using i as a center; strike another 
 arc with a radius equal to 3, x in Fig. 6, cutting the arc just 
 made, then, with 3 as a center and Y Z (Fig. 6) as a radius 
 strike an arc in the direction of 4. using 2 as a center and the 
 space ^ as a radius, cut the arc just made, and so on until the 
 spiral piece is complete. You will understand the inclined 
 lines in Fig. 6 are the length of the corresponding lines in 
 Fig. 4. and the space p in Figs. 3 and 4 is one-sixteenth of C 
 in Fig. 3. 
 
 The Spiral Pipe. 
 
 A much greater efficiency can be obtained by using the spiral 
 seam than can be obtained by using the longitudinal seam. 
 To lay out a pipe having a spiral s^m, however, without 
 allowing for the thickness of material we find to be very sim- 
 ple, but when allowing for this thickness we find it makes the 
 problem more complicated. 
 
 In laying out most problems the thickness of material must 
 be taken into consideration, and we find this changes the 
 method of developing considerably, therefore a student should 
 devote a great deal of his time to the thickness of material 
 rather than to develop his problems as if there were no thick- 
 ness. It is true, in many cases, we draw up the object as if 
 there was no thickness, and in the layout of the pattern we 
 allow for it, as on an elbow or a ball. 
 
 The first step in this problem, as in most any other, is to 
 draw the center line A'-A', then the plan, Fig. 3, which is two 
 circles, the smaller is the center line of material of the inside 
 edge of the plate and the larger the center of material of the 
 outside edge ; divide these circles into any number of equal 
 spaces, in this case sixteen, then carry lines down from these 
 points parallel to line A'-Aof indefinite length ; divide the cen- 
 ter line of the material 4' -4 (Fig. i) into the same number of 
 equal spaces, carrying the same spaces to the bottom of the 
 pipe as shown ; draw lines from these points perpendicular ti 
 X-X, cutting the corresponding lines as shown at c, e, 5', etc. : 
 these points form the center line of material of the outside 
 edge, and d, f, 5, etc., form the center line of the inside edge, 
 which is nothing more than constructing a helix. 
 
 It is not necessary to draw all the lines as shown in Fig. i, 
 the only lines needed in the general outline are the center lines 
 of material, the base line and line 4'-2'. 
 
 Now draw the triangles by drawing the lines s'-5, e-f, c-d, 
 etc. ; connect these by diagonal lines s'-f, e-d, etc. ; you will 
 notice there are only four lengths of lines used in constructing 
 the true triangles, they are H, h, I, 2; to find the length H 
 construct a right-angle triangle, one side equal to p and one 
 equal to A' (Fig. 3), the h.vpotenuse will equal H. To find 
 the length h construct a right-angle triangle, one side equal to 
 p and one equal to B' (Fig. 3), the hypotenuse will equal /(. 
 To find the length of line i construct a right-angle triangle, 
 one side equal to P and one equal to D (Fig. 3), the hypote- 
 nuse will equal line i. To find the length of line 2 construct a 
 right-angle triangle, one side equal to P-p and one equal to C 
 (Fig. 3), the hypotenuse will equal line 2. 
 
 A more accurate way to find the lengths H and /; is as 
 follows : 
 
 Let A'' = Number of turns the spiral makes (in this 
 case iH). 
 E = E, Fig. 3. 
 F^=P, Fig. 3. 
 
 M = Number of spaces into which each circle is di- 
 vided. 
 
 Then H — - 
 
 h — - 
 
 \/(E^Ny-+(.NPy 
 
 NM 
 
 v(P7rNy-+ (Npy 
 
 NM 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 245 
 
 LAYOUT OF A SPIRAL PIPE, ALLOWING FOR THICKNESS OF MATERIAL. 
 
 In Fig. 2 we find another way. A B is the length of the 
 pipe, A C ^ E ■^ N, B C is the length of the outside center 
 line, Fig. i, and is to be divided into as many spaces as the 
 spiral in Fig. l; this will give the length H; D E (Fig. 2) is 
 the length of the pipe, D C — F ■"■ N, E C is the length of the 
 inside center line, Fig. i, and is to be divided into the same 
 number of spaces as B C ; this gives the length /;. 
 
 In Fig. 4 you will notice that only one-fourth of a turn is 
 developed by the use of triangles and the rest is developed 
 from this by diagonal lines. 
 
 Draw line 4'-4, the length of which is equal to line I, Fig. i, 
 and line 2, Fig. I, is equal in length to line 4-a, b-c, d-c, fs' ; 
 4'-4 is equal to a-b, c-d, e-f, 5'-5, then using 4' as a center and 
 H as a radius strike an arc at a; using 4 as a center and 4-0 
 as a radius cut the small arc just struck; using 4 as a center 
 and h as a radius strike an arc at b; using a as a center and 
 a-b as a radius strike an arc at b, cutting the small arc just 
 struck, and so on until one-fourth turn is developed ; then 
 using 5 as a center and 5-4 as a radius, strike an arc at 6, using 
 5' as a center and 5'-4' as a radius strike an arc at 6' ; using 5' 
 as a center and 4'-$ as a radius strike an arc cutting the small 
 arc at 6; using 5 as a center and 5'-4 as a radius strike an arc 
 cutting the small arc at 6', this develops another fourth ; con- 
 tinue this operation until you have the required length pointed 
 off, then connect these points with an arc. 
 
 Now to get the end cuts o-i'-2'-3'-4' and 6-7-8-g-io; I'-i 
 equals one-fourth of i"-i, 2'-2 equals one-half of 2"-2, t,'-2 
 
 equals three-fourths of Ti"-i ; connect these points with arcs 
 and the pattern is completed. 
 
 The length 4'-5'-6'-7'-8'-9'-io' is equal to B C in Fig. 2; the 
 length 0-1-2-3-4-5-6 is equal to E C, Fig. 2. 
 
 Laying Out a Wrapper Sheet for a Locomoti\e Firebox 
 
 There are some types of locomotive fireboxes with the door 
 sheet lower than the flue sheet at the crown, and with the 
 door sheet inclined to the flue sheet at an angle, but of the 
 same width throughout. This problem may be laid out readily 
 by the method of projection. There are other types of loco- 
 motive fireboxes, with the door sheet lower than the flue 
 sheet at the crown, also with the door sheet inclined to the 
 flue sheet at an angle, but with the door sheet considerably 
 narrower, at the center line of the boiler than the flue sheet, 
 but of the same width at the foundation ring. This problem 
 may be laid out in various ways by the method of triangu- 
 lation. It is the latter type which will be described briefly iu 
 the following. To do this a smaller number of division points 
 have been taken than would actually be taken in order to 
 avoid confusion. In tracing out the boundary line for the 
 stretchout of the pattern, this should be the rivet line. With 
 this much information proceed as follows: 
 
 In the center of your sheet, from which you wish to make 
 your wrapper, draw up a full-size side elevation of the fire- 
 box, also a half-end view of the door and a half-end view of 
 
246 
 
 LAYING OUT FOR BOILER MAKERS 
 
 the flue sheet, vertical lines R-D and S-H of the side eleva- 
 tion representing the rivet lines and the curved lines in the 
 end views representing the neutral lines of the material used, 
 as shown at Fig. i. Care should be used in the construction 
 of the foregoing, since it is the foundation for all future 
 measurements. 
 
 Next divide the half view of the door and flue sheet into a 
 
 points /, / and K, then will the distances A-I, B-I and C-K be 
 the true lengths of the lines sought. Since the lines R-S and 
 D-H represent their true lengths, it will be observed that we 
 have obtained the true distance between the principal points 
 of intersection. In like manner any number of intermediate 
 points may be found. 
 
 Next, construct the diagonal right triangle S-A-L, and make 
 
 like number of equal parts (as small as possible). In this case 
 four have been taken. Project the points so found to the 
 center line or axis of the heads, as shown, z-A, 2-B, 4-C to 
 S-D on the door sheet, and 2-E, 3-F, 4-G, etc., to 5-H on the 
 flue sheet. These lines, A-E, B-F and C-G, represent the 
 horizontal distances between the door sheet and the flue sheet. 
 Since the door sheet is narrower at the center line of the 
 boiler, and yet inclined at an angle to the latter, it is very 
 evident that if a right triangle be constructed for each of the 
 
 A-L perpendicular to AS and equal in length to chord A-2, 
 make B-M perpendicular to B-E and equal in. length to w-3, 
 which is the difference in length of chord E-2 and chord B-3. 
 Make C-A'' perpendicular to C-F and equal in length to x-4, 
 which is the difference in length of chord F-s and chord C-4. 
 Also make D-0 perpendicular to D-G and equal in length to 
 y-5, which is the difference in length of chord G-4 and chord 
 D-S- Then will the sides L-S, M-E, N-F and 0-G be the true 
 lengths of the diagonal lines. 
 
 """^^^2 
 
 R 
 
 ^^-l\ 
 
 \ 
 
 
 
 / ^1 
 
 
 
 
 
 D 
 
 / ; 
 
 
 
 
 \ 
 
 
 ' ( 1 
 
 \ \ 
 
 
 1 
 
 \ \ 
 
 f / 
 
 
 
 
 
 \ \ 
 
 5 / 
 
 1 
 
 
 ,0 , 
 
 / 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 1 
 1 
 
 1 
 
 1 
 
 1 
 
 1 > 
 1 \ 
 1 \ 
 
 \ 
 
 1 
 1 
 1 
 1 
 
 1 
 
 1 
 1 
 1 
 1 
 
 1 
 
 following sets of division points, A-E, B-F and C-G, with a 
 base equal in length to the difference of the corresponding 
 chords, then will the hypothenuse be the true length of the 
 lines sought. To do this, with a radius equal in length to 
 chord A-2 on the door sheet, and using point £ as a center, 
 draw an arc locating point t on chord E-2 of the flue sheet. 
 In a similar manner transfer B-3 and C-4 to corresponding 
 chords on the flue sheet, locating points u and z'. Now, erect 
 perpendiculars to the horizontal lines from the points E, F 
 and G equal in length to t-2, 1/-3 and v-4, as shown by the 
 
 To lay out the pattern, first draw the center line R-S, Fig. 2, 
 make R-S equal in length to R-S, Fig. i. Then with one pair 
 of dividers, set equal to division space R-2 of the door sheet, 
 and using point R of the pattern as a center, draw arcs 2, 2. 
 Now, with a radius equal to the diagonal distance L-S, Fig. I, 
 and point S, Fig. 2, as a center, intersect the arcs 2, 2 pre- 
 viously drawn. Then with a second pair of dividers, set equal 
 to division space .^-2, Fig. I, of the flue sheet, and point S, 
 Fig. 2, as a center, draw the arcs A-A as shown. Then with 
 radius A-I, Fig. I, and using points 2-2, Fig. 2, as centers. 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 247 
 
 intersect the arcs A-A. Since the remaining points on the 
 pattern are located in a similar way no further explanation is 
 necessary. 
 
 The pattern should now be checked up from the center line; 
 it must be understood that this includes the relative positicn 
 of the four points 5-5 and D-D with respect to points R and 
 5' of the center line. Whence the contour for the rivet line 
 to suit extended flanges at the crown, also angular-shaped 
 corners at the mud-ring, may now be placed in. The rivet 
 holes are then properly spaced and punched 1/16 inch small, 
 and reamed to size in place. 
 
 Layout of a Smokestack Collar. 
 
 This collar, or rainshed, has the top cut parallel to the base 
 or roof line, and the distance between the stack and the base 
 of the collar is the same all around. 
 
 First, draw line A B in the plan. With O as a center de- 
 scribe two semi-circles representing the large and small bases. 
 Divide the semi-circles into a number of equal spaces, each 
 
 this line and from the intersections draw lines as shown. 
 Ne.xt take points 2, 3, 4, 5, 6, 7, 8, 9 and 10 in the plan and 
 project them to the roof line, and from the intersections in the 
 same line draw lines as before. 
 
 To construct the end elevation, first draw line E F, and 
 with the trams set on points 6 and O in the plan, set one point 
 of the trariis on O', line E F, which is the center of the large 
 base, and describe a small arc at 6. If a full view is wanted, 
 strike an arc on the other side ; next take distance 7 to line 
 A B in the plan. With one point of the trams on 7', line E F, 
 describe an arc, by stepping over to point 5' describe another 
 arc. Take the remaining numbers, 8, 9 and 10, using line A B 
 as a center in the plan ; transfer to points 8-4, 9-3, 10-2, line 
 E F ; draw a curve through those points. Next take the dis- 
 tance 6' O in the plan, and on O' line E F, which is center for 
 the small base, describe a small arc at 6'. Next take the dis- 
 tance 7' to the line A B in the plan ; set it oflf from point 7', 
 line E F, to 7". Step over to 5' ; scribe point 5" ; transfer 
 points 8', 9' and 10' in same order as before, and draw the 
 curved line, completing the end elevation. 
 
 METHOD OF TRIANGULATION AS APPLIED TO A SMOKESTACK COLL.AR. 
 
 circle having same number of spaces. Next draw the roof 
 line at the required angle, and set ofif the vertical height of 
 the collar. Draw line C D parallel to the roof line. From 
 points l', 11' in the plan draw perpendicular lines to line C D ; 
 and from points i, 11 in the plan draw lines to the roof line. 
 From the point of intersection of these lines draw slant lines 
 which form the side elevation. Now project points 2', 3', 4', 5', 
 6', 7', 8', 9' and 10' in the plan to line CD; at right angles to 
 
 Now divide one-half of the end elevation into a number of 
 equal parts, and draw solid and dotted lines as shown on the 
 drawing. It is advisable to use two pairs of dividers, one for 
 the small and another for the large oval, and to leave them 
 set for further use. To construct the triangles, draw any line 
 for a base line ; erect the perpendicular and take the vertical 
 height of ,the side elevation and set it ofif from x to x". Next 
 take the distance 11" from the end elevation, and from x in 
 
248 
 
 LAYING OUT FOR BOILER MAKERS 
 
 the base line of the diagram of triangles scribe point i for the 
 solid lines. Now take distance 2 2" and scribe point 2; trans- 
 fer all the solid lines in the end elevation in this order, setting 
 off each distance on the base line. From x" draw solid lines, 
 intersecting the small arcs on base line. 
 
 Now take the distance i to 2", shown by the dotted lines in 
 the end elevation, and set it oil on the left from x to i. 
 Similarly take the distances 2-3", 3-4", 4-5", etc., and draw 
 the dotted lines, completing the diagram of triangles. 
 
 To develop the pattern, take the distance shown by the 
 solid line .r" 11, draw a line on the pattern and set off points 
 II, 11". Next take the distance x" 10" (dotted line) and set 
 it off from 11" to 10 on the pattern. With the dividers al- 
 ready set from the large oval in the end elevation, from point 
 II describe an arc at 10, intersecting that made from 11". 
 Now take the next distance .r"-io (solid line) ; set the trams 
 on 10 and strike an arc at 10". With dividers set from the 
 small oval of the end elevation from point 11" strike an arc 
 at 10". Next take the distance .v"-g (dotted line), and from 
 10" scribe point 9; with the dividers set on 10 scribe point 9. 
 Proceed in this manner until all the lines in the diagram are 
 taken ; then draw a line through the points, which can easily 
 be done by bending a thin strip of wood on the points. Add 
 for the flange on top to clamp the collar on to the stack, com- 
 pleting one-half of pattern. 
 
 Layout of an Intersection Between a Dome and Slope 
 Sheet for a Locomotive Boiler. 
 
 m some construction of locomotive boilers it will be found 
 that the dome is located upon the slope sheet, although it is 
 the hest practice, when conditions permit, to locate the dome 
 on the firebox or cylinder connection. The development for 
 this problem may at first appear to the layer-out a very simple 
 matter, but looking further into the subject it will be found 
 that several difficult questions confront him, especially in the 
 case where the horizontal diameter of the boiler is less than 
 that of the firebox section. This will cause complicated con- 
 ditions if the layer-out does not keep his wits about him. 
 
 Referring to the plan of either Figs, i or 3, it will be seen 
 that the slope sheet tapers from a smaller to a large diameter ; 
 hence the layer-out will naturally come to the conclusion that 
 the same principles of development can be applied to this 
 object 'as are used in the development of frustums of cones, 
 and, to a certain extent, the construction is the same, with 
 one exception. Referring again to the plan view it will be 
 seen that the taper is irregular, due to the fact that the re- 
 spective diameters of the small and large ends do not lie in 
 the same plane. This is clearly shown at B and D, where B 
 represents the axis of the large end and D that of the smaller 
 end. If the axis of this object were neutral it could be very 
 readily developed by projection drawing; however, owing to 
 the irregularity it must necessarily be developed by triangu- 
 lation. 
 
 In the development for the dome connection the same 
 irregularity of elements is encountered. It will be noticed, 
 referring to the elevation, that where the dome intersects the 
 slope sheet it will require a development for all the elements, 
 in order to determine the connecting points of intersection 
 between the dome and slope sheet. 
 
 It might be well to point out that when drawing the profile 
 for the dome it must be drawn to the inside diameter, other- 
 wise the dome will be entirely out. If the profile is drawn 
 to the neutral a.xis of the material it will be seen that the 
 quadrant or semi-circle will be greater in circumference, con- 
 sequently causing a greater pitch of rivets. This will cause 
 the projectors to be too long, consequently throwing out the 
 flange centers. 
 
 In the development of these two problems, the thickness of 
 material, spacing of rivet holes, allowance for lap, etc., were 
 not taken into consideration, as these are to be made accord- 
 ing to requirements. 
 
 CONSTRUCTION OF FIG. I. 
 
 The layout for this condition can be easily obtained by pro- 
 jection drawing. It is first required to draw up the respective 
 
 R A s 
 
 4 3 2 12 3 13 2 12 3 4" 
 Fig. 2 
 DEVELOPMENT OF DOME CONNECTION. 
 
 views, as shown, to the required dimensions. In this case it 
 is good practice to draw the plan view first and then the 
 elevation. 
 
 First draw the line A-A ; locate upon it the center point D, 
 and with a radius of one-half the diameter of the small end, 
 and using point D as a center, draw a circle. This represents 
 the small end of the slope sheet. Then draw the center line 
 C C through point D and at right angles to line A-A. Lo- 
 cate upon this line C C point B, using B as an apex, and 
 with the trammels or compasses set equal to one-half the 
 diameter of the large end draw a circle as shown. Then locate 
 and draw the dome upon the line C C to the required di- 
 mensions. Locate the center of the profile at a convenient dis- 
 tance from the dome and draw the circle. Divide one of its 
 quadrants into any number of equal spaces, in this case three, 
 numbered from one to four, inclusive. Drop these points 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 249 
 
 parallel to the line C C and make the lines indefinite in 
 length. 
 
 The next procedure will be to develop the elevation. At 
 right angles to the line C C project the outer points of the 
 circles (that is, where the circles are tangent to the line C C, 
 to the elevation, as shown at R, S, T and U ; also project 
 the respective centers of these circles as shown at P and O. 
 Make the over-all length 5 to V equal to the required length 
 of the slope sheet. Connect the points R, S, T and U with 
 solid lines, as shown, which show the outer boundary lines of 
 the slope sheet in the elevation. Connect the points P arid O 
 with a construction line ; then locate the axis of the dome at 
 right angles to line S which is shown at C-C. Locate the 
 dome in its relative position to the plan view ; then draw the 
 profile and divide the circle into the same number of equal 
 spaces. Project these points parallel with the line C-C, and 
 
 neutral diameter, viz.: neutral diameter X 3.1416 = circum- 
 ference. Divide this stretch-out line into four equal quarters, 
 and space these quarters into three equal parts. At right 
 angles to the line draw the construction lines, indefinite in 
 length. The camber line for the connection is determined by 
 transferring the true lengths of lines from the elevation to the 
 corresponding stretch-out lines, thus producing the miter line 
 for the connection. In order to fasten the dome to the shell 
 sufficient material must be added for a flange, which must be 
 turned down by the operation of flanging until it sets uni- 
 formly upon the slope sheet. The allowance for flanging will 
 vary according to the thickness of material and diameter of 
 rivet holes. It is the best practice to flange the sheet before 
 punching the holes in the flange. After the allowance for the 
 flange has been determined add for laps, then space ofif the 
 rivet holes for the vertical and longitudinal connection. 
 
 DEVELOPMENT OF SLOPE SHEET CONNECTION. 
 
 extend them through the line T-R until they intersect the line 
 P-0. Where these projectors intersect the lines T-R and 
 P-0 determines the respective radii to be used in obtaining 
 the elements' and in determining the points of intersection 
 between the dome and slope sheet. 
 
 Project the points of intersection between the projectors 
 and the lines T-R and P-0 to the plan view as shown. Set 
 the trammels or dividers equal to the distance between points 
 4-4. 3-3, ---, i-i. plan view, and draw arcs, using the corre- 
 sponding points within the distance B-D as apexes. Where 
 the arcs intersect with the projectors dropped from the profile 
 plan view determines the cutting plane of the dome. These 
 points are then projected to the elevation until they intersect 
 the corresponding construction lines. Hence the lines from 
 4 to 4, 3 to 3, 2 to 2, I to I, etc., are the required or true 
 lengths of lines to be used in developing the pattern. 
 
 DEVELOPMENT OF THE PATTERN. 
 
 Draw the line X-X, as shown in Fig. 2, equal in length to 
 the circumference of the dome. This is figured from the 
 
 The longitudinal seam in this instance is the connection 
 between the dome and dome head. The line of rivet holes is 
 placed from i inch to iVz inches below the line A'-.Y, varymg 
 according to the thickness of material and diameter of rivet 
 holes. 
 
 LAYOUT FOR THE SLOPE SHEET CONNECTION. 
 
 As pointed out previously, the most applicable method of 
 development for this problem is by triangulation. First draw 
 the plan and elevation identically the same as explained for 
 the development of Fig. i. It will not be necessary, how- 
 ever, to locate the dome, as it will have no bearing upon the 
 subject, as sufficient data can be obtained from the plan and 
 elevation, Fig. i, to complete the development for the hole in 
 the pattern. 
 
 CONSTRUCTION. 
 
 Divide the circles in the plan view into any number of equal 
 spaces, in this instance eight ; numbered from one to nine, 
 inclusive. Connect the points with solid and dotted construc- 
 tion lines in order to avoid. confusion. Project the points on 
 
250 
 
 LAYING OUT FOR BOILER J^IAKERS 
 
 the large circle at right angles to the line C C until they in- 
 tersect the lower base of the line T-U of the elevation. Pro- 
 ject the points from the small circle in the same manner until 
 the\' intersect the top of the elevation, or the line R-S. Con- 
 nect these respective points with construction lines, as shown. 
 We now have sufficient data to obtain the true lengths of 
 lines for the development of the pattern. These required lines 
 are shown at the right and left of the elevation, and are 
 designated "diagrams of triangles." The diagram of triangles 
 shown to the left are the dotted and solid lines, or the true 
 lengths of lines, for the foreshortened lines shown on the 
 left of the line A-A and those on the right of the elevation 
 are those which are shown on the right of the line A-A. 
 
 TO L.\Y OUT THE PATTERN. 
 
 First draw the vertical line 1-9 equal in length to the line 
 R T shown in the elevation ; then set the dividers equal to the 
 space 1-2 of the large circle, plan view, and with i in the 
 
 elevations of a firebo.x wrapper sheet of this shape; Fig. i 
 representing an outline of both ends of the wrapper sheet, 
 and Fig. 2 representing a side view of the sheet. 
 
 At the very outset let it be understood that for developing 
 work of this character, triangulation is the best and safest 
 rule, yet with this particular shape of firebox the wrapper 
 sheet may be developed satisfactorily by an approximate rule, 
 which will be described. 
 
 First, draw up the outline of the respective views as shown 
 in Figs. I and 2. In Fig. i the points 3 and 4 represent the 
 points of intersection of the crown sheet with the side sheet 
 at the front and back ends respectively. Irrespective of the 
 fact that the firebox may be in one sheet, the curved part, 
 Fig. I, known as the crown sheet, and the straight part, or 
 distance, c, as the side sheet. It will be understood that all 
 following remarks in describing the layout will refer to the 
 parts of the sheet as outlined. 
 
 Extending horizontal lines from the points 3 and 4 in Fig. 
 
 Center Line 
 
 Fig. 2. 
 
 ■1 
 Rndius to Suit — */f' '1 
 
 I * 
 
 i 
 
 »—- Radii. 
 
 3 to Suit 
 
 
 Corner Shaped 
 to Suit 
 
 
 ^ 
 
 
 f 
 
 
 ^.-4-^ 
 
 OUTLINE OF FIREBOX WRAPPER SHEET. 
 
 pattern as a center draw an arc; then with the trammels set 
 equal in length to the dotted line 2 shown at the left of the 
 elevation, strike an arc, cutting the arc previously drawn. 
 Continue in this same manner, using alternately the true 
 dotted and solid construction lines until the pattern is com- 
 plete. It will be seen that only one-half the pattern is shown 
 developed. As the other half is developed in a like manner it 
 will not need any further explanation. 
 
 TO DEVELOP THE HOLE IN PATTERN. 
 
 Locate upon the line 1-9 the center for the hole as shown 
 at I ; then locate the points 2, 3 and 4 on both sides of this 
 center. These points are taken from the elevation, and are 
 also located upon the solid lines 2-8 and 7-3 in the pattern. 
 The remaining data for the development are obtained from 
 the plan view. As the operation is so simple it will not require 
 any further comment. Add for laps and locate the rivet 
 holes, then the pattern is complete. 
 
 Approximate Method of Developing a Sloping Firebox 
 Wrapper Sheet. 
 
 In many types of locomotive boilers the firebox wrapper 
 sheet is considerably higher at the flue-sheet end than at the 
 door-sheet end. In Figs, i and 2 are shown the end and side 
 
 I to Fig. 2 gives points,!, 3 and 4 in Fig. 2. Now draw con- 
 necting lines between points i and 3, i and 4. This gives the 
 true lengths of lines between the points, and since the center 
 line from O and 0' is its true length, it will be seen that we 
 have obtained the true length of three lines. 
 
 To develop the pattern, Fig. 3, draw the center line from 
 O to O' equal to the length, of center line in side elevation. 
 Fig. 2. Make the radius AA, Fig. 3, equal in length to the 
 distance from O' to 3, or O' to 4 in Fig. i, and then using 
 and C, Fig. 3, as center points, draw arcs as shown. Draw at 
 right angles to O O', Fig. 2, the line O 2, then make the 
 radius BB, Fig. 3. equal in length to the distance from i to 2, 
 Fig. 2, and using point 2, Fig. 3, as a center point, draw arcs 
 intersecting the arcs previously drawn, thus locating point i. 
 
 Make the radius AD. Fig. 3, equal in length to the distance 
 between l and 3, Fig. 2, and using point i, Fig. 3, as a center, 
 draw an arc locating point 3. With radius AC made equal to 
 distance a. Fig. i, and point 3, Fig. 3, as a center, draw an 
 arc. Then make the radius AE, Fig. 3, equal to the distance 
 between the points i and 4, Fig. 2, and using point i, Fig. 3, 
 as a center, di'aw an arc intersecting the arc previously drawn, 
 locating point 5. Thus the vital points of the crown sheet 
 have been developed. 
 
 It will be seen that if a line is drawn at right angles to the 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 251 
 
 center line at point O' , Fig. 3, tlie distances between points 3 
 and 8, and points 4 and 5, are equal to corresponding dis- 
 tances in Fig. 2, 
 
 Tlie camber line can ordinarily be placed in by holding a 
 flexible stick on the points i, O and i on the door-sheet end, 
 
 taken from the end elevation, Fig. i, so as to obtain their 
 respective true lengths. 
 
 Of late years, some builders are putting an extended flange 
 on the door and flue sheets, cutting the length of the crown 
 sheet as indicated by the dotted line in Fig. 2. When such is 
 
 O' 81 
 
 3. — LAYOUT OF FIREBOX WR.-\PPER SHEET. 
 
 and on the points 3, O' and 3, on the flue-sheet end, but it is 
 advisable, particularly at the door-sheet end, to locate some in- 
 termediate points, hence an intermediate point about midway 
 between O and 4, Fig. I, is located. From this point extend 
 over to Fig. 2, a horizontal line, locating points 6 and 7. 
 Then set off on the horizontal line, Fig. 3, between points 
 O and 2, a distance equal to that set off on the curved line 
 Fig. r. The distance between 6 and 7, Fig. 3, is made equal to 
 that between 6 and 7, Fig. 2. Any number of like intersect- 
 ing points can thus be located, but since the above demon- 
 
 the case the crown sheet is laid out as shown by dotted line, 
 Fig. 3. the distance being determined at the option of the 
 builder. 
 
 The Layout of an Arched Smoke=Box. 
 
 The general arrangement of an arched smoke-box connect- 
 ing three double-ended Scotch boilers to a single funnel is 
 shown in Figs. I and 2. 
 
 Draw a half-front elevation and a half-side elevation, as 
 
 FIG. 4. — DETAILS OF FIREBOX, L.AYOUT OF WHICH IS SHOWN IN FIG. 3. 
 
 strates thoroughly the principle no further demonstration is 
 necessary. 
 
 To develop the side sheet is only to reproduce what is 
 shown in the side elevation, Fig. 2, with the exception, how- 
 ever, that the vertical distances, b. c and d. Fig. 2, should be 
 
 shown in Fig. 3, and proceed to lay but the plates for the 
 fore-and-aft ends of the smoke casing. Divide the arc A B 
 (Fig. 3), side elevation, into any number of equal parts — say 
 four — and through each of the divisions or intersections draw 
 a line at right angles to the vertical center line and parallel to 
 
252 
 
 LAYING OUT FOR BOILER MAKERS 
 
 each other, and on the front elevation divide the arc C D into 
 any number of equal parts— say two— and again draw or strike 
 lines through the intersections of the arc. With these pre- 
 liminaries we have obtained all of the lines necessary for the 
 layout of all the plates of the front and ends. 
 
 Now place the plates in position on the trestles with the 
 required laps on each plate (for joints), and with a chalk line 
 strike the line i (Fig. 4) at the bottom side of plates. Then 
 with the trammels draw in the center line perpendicular to the 
 base line, and along the center line measure in points through 
 which lines 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11 will pass. Then draw 
 in these lines parallel to the base line, at distances correspond- 
 ing to those between i to 2, 2 to 3, 3 to 4, 4 to 5 (side eleva- 
 tion), and so on till line 11 is reached. Now take a narrow 
 strip of wood, a lath of wood, preferably the length of line i 
 
 With all the marks transferred from the front elevation to our 
 plates and all our points connected up thereon, we have now a 
 half-front pattern for either the "fore" or "aft" €nd, and it will 
 be necessary here after punching or shearing the plates to 
 mark one plate off each of the templets thus obtained, and 
 then two plates off each with the templet turned upside down, 
 thus securing "rights" and lefts." Note that the center line 
 on the plates is the center line of rivet holes for lap jointing. 
 Now remove all working lines from the drawing board, and 
 proceed with the laying out of the arch back, extending from 
 the "fore" to the "aft" end of the boilers. Divide arc E F, side 
 elevation. Fig. 5, into any number of equal parts, say two. 
 Then divide arc G H into any number of equal parts, say two, 
 and divide arc / / into any number of parts, in this case also 
 two. Now draw lines through all these points parallel to the 
 
 FRONT ELEVATION 
 Fig,l 
 THE ARCHED SMOKEBOX AS IT WILL APPEAR WHEN COMPLETED AND INSTALLED. 
 
 (front elevation). Fig. 3, and noting to keep your lath on the 
 center line, make the three points of intersection (1. e., points 
 marked 1,1, i) on the lath, and just where your mark occurs 
 on the wood carefully place the number of the line, in this 
 instance I. These numerals must be carefully inserted or con- 
 fusion would inevitably follow. Proceed to line 2, and holding 
 the lath at the center line, again mark the intersecting points 
 (this time marked by 2, 2, 2), and repeat this again on line 3, 
 and so on, till line ii-ii is reached, where there is only one 
 point to mark. Now proceed to transfer these points on to 
 their corresponding lines, as marked on your plates, commenc- 
 ing, naturally, with line i. The whole operation is simplicity 
 itself, for with the precise position of the lath, with its end to 
 the center line (on front elevation), mark the points numbered 
 I, and on line 2 at the corresponding number on the wood place 
 the mark 2. Similarly with lines 3 and 4 until line 11- 11 has 
 been reached, always taking care that the end of the lath is on 
 the center line. Now draw in arcs marked E and F on Fig. 3. 
 As can be seen, part of uptake between points i and 2 is di- 
 rectly perpendicular. It follows that its true shape will be 
 similar to the drawing. Join points i and 2, and then proceed 
 to join all the other points in the usual way. (Fig. 4.) All 
 rivet holes can now be marked in, and if it is desired to flange 
 all the plates throughout the uptake instead of using angle- 
 bars for corners, allowances for flanging should be made. 
 
 horizontal center line and extending from the arch back, side 
 elevation, across the front elevation. These are the lines 
 necessary for the layout of the arch back. 
 
 Layout the plates for one-quarter or one-fourth of the arch 
 in the same way as was done with the front ends, attention 
 being given to laps, etc. Draw a line along the bottom edge of 
 the plates and erect a perpendicular center line. Now strike a 
 line, distant from the base line, equal to the breadth of the 
 flange, which meets face of boiler, and proceed to lay down the 
 lines 2, 3, 4, 5, 6. 7, 8, 9, 10 and II, the pitches of which are 
 obtained from the side elevation, equal to the distance from 
 points I to 2, 2 to 3, 3 to 4, 5 to S, S to 6, 6 to 7, 7 to 8, 8 to 9, 
 9 to 10, 10 to II, the point represented by 11 being the center 
 of the arch. 
 
 Now take a lath of wood, and apply it as in the case of fore 
 ends, again noting to keep the wood just over at the center 
 line, and mark on it the points of intersection, three of which 
 occur on line i. Then proceed upwards to line 2. Mark the 
 points of intersection, and so on, 3, 4, s, 6, 7, 8, being treated 
 similarly (9, 10 and 11 have only one point of intersection), 10 
 and II being same length. 
 
 It is obvious that care must be taken in marking the lath 
 while lifting the various points, as the success or failure of the 
 whole thing depends on the care expended on these points. 
 
 Now proceed to transfer the points or marks just obtained 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 253 
 
 on to the corresponding line already placed on the plates (Fig. 
 6), commencing at line I and working upwards to line 2, then 
 lines 3-4, etc., marking the three points on each line. Lines 
 8, 9, 10 and 11 have only one point on each, while line 11 repre- 
 sents center of rivet holes. The arcs may now be drawn in. 
 The radius given on the drawing is the correct one, since the 
 part of uptake between lines I and 2 is perpendicular. The 
 true shape of the ciirve is that shown on the drawing. Join 
 the top of the arcs to line 2, and through all the points on 
 lines 2, 3, 4, 5, 6, etc., draw a line or lines as shown in Fig. 6. 
 
 The quarter pattern for the arch back is now complete, and 
 to secure "rights" and "lefts" it will be necessary to mark 
 one plate off each templet and two off the "other side up." 
 
 the lap joint, and line 7 is also the center of holes for joints 
 with side plates. Now, with a short lath of wood, keeping one 
 end of the lath on a line representing the face of the boiler 
 (side elevation), mark on the lengths of lines 1, 2, 3, 4, 5, 6 
 and 7 in their respective places. 
 
 Lay out these sizes on the plates at the lines i, 2, 3 and so 
 on (Fig. 8), and through the points on the respective lines 
 draw a line or a fair curve, which operation will complete 
 the templet for all the bottom plates— twelve in number — and 
 when punching and shearing of the templet has been per- 
 formed five plates will be marked "right side up," while the 
 other six will be marked from the templet turned upside dowri^ 
 or reversed, thus securing "rights" and "lefts." 
 
 As line 11 represents center. 
 
 of rivet holes allowance must 
 
 be made for laps. 
 
 Fig. 3 
 L.WOUT OF FRONT PLATES. 
 
 HALF FRONT AND HALF SIDE ELEVATIONS 
 Fig. 5 
 
 LAYOUT OF BACK PLATES. 
 
 Now remove all working lines from the drawing and pro- 
 ceed with the new lines for the development of the port and 
 starboard, outer and inner sides, as well as center sides and 
 bottom plates. Divide arc K, Fig. 8, at the bottom of the cen- 
 ter nest of tubes into two equal parts, and divide arc L into 
 any even number of equal parts, as it is necessary, or at least 
 desirable, to have a point at the top center of this arc ; in this 
 case we will make four equal divisions. Then divide arc O 
 (front elevation) into two equal parts and arc P (side ele- 
 vation) into two equal parts. Now draw lines through all 
 these points extending across the front and side elevations, as 
 shown in Fig. 8. 
 
 We will commence to layout the various plates, taking the 
 bottom plates first. First, square one end of the plate and 
 strike line I, say I inch from the edge of the plate. Then draw 
 in lines I, 2, 3, 4, 4, 5, 6, 5, 4, 4, 7 at pitches equal to the dis- 
 tances from I to I, 2 to 2, 2 to 3, 3 to 4, 4 to 4, 4 to 5, s to 6, 
 6 to 5, 5 to 4, 4 to 4, 4 to 7. Line I is the center of holes for 
 
 We will now lay out the plates for one-half of either the 
 port or starboard outer sides, allowance again being made for 
 lapping for joints. 
 
 Lay out the center line (Fig. 9), and commencing at the top 
 of the plates this time, draw line 21 at right angles to the 
 center line. Then draw lines 20, 19, 18, 17, 13, 12, 11, 10, 9, 8 
 and 7 (notice to omit lines 16, 15 and 14, as these are working 
 lines for the inner side and will be required later) . 
 
 The pitches of the lines along the plates are obtained by 
 measuring the distances from points 21 to 20, 20 to 19, 19 to 
 18, 18 to 17, 17 to 13 (center line, front elevation). Note line 
 7 represents the center line of the rivet holes for jointing the 
 bottom in a manner similar to that employed in transferring 
 lengths on other plates. Proceed to lift the true lengths of 
 lines on to the plates, beginning at line 21 at the top of the side 
 elevation. Fig. 8, keeping the end of the lath at the center linfe. 
 Mark 21 at the extreme length and similarly line 20. Lines 19, 
 18, 17 must now be marked, and these have two intersections 
 
254 
 
 LAYING OUT FOR BOILER :\IAKERS 
 
 each. Pass over lines i6, 15 and 14, meantime, and at lines 13, 
 12, II, 10, 9, 8 and 7 mark the lath at two different places on 
 each line, carefully noting to neatly insert the number of the 
 line on the lath immediately over the points representing the 
 lengths of lines. Line 7 is, again, the line for rivet holes for 
 the junction with the bottom plates. 
 
 Now transfer all these points to the lines on the plates, each 
 at its respective number, and when all the lengths have been 
 
 rTfnTTTim 
 
 laid out join the points as in the previous case. There being 
 four other sides it will be necessary to mark one plate off 
 similar to the templet and two with the templet reversed, thus 
 forming "rights" and "lefts." 
 
 Now proceed with the plates for the inner sides. Lay out 
 the plates as in the outer sides. Strike a center line and draw 
 line 16 at right angles to the center line at the top edge of the 
 plates. Now draw lines 15, 14, 13, 12, 11, 10, 9, S and 7 at 
 pitches equal to the distances between these lines on the "frjnt 
 elevation," Fig. 8, on a line representing the inner side. Take 
 the measuring lath again and mark on it the lengths of lines 
 15. 14, 13. etc. (side elevation). Now transfer these marks to 
 the corresponding lines on the plates, Fig. 11. Join all thes? 
 points as shown. To complete the inner side mark one plat; 
 off the templet, and two off the templet reversed, again secur- 
 ing "rights" and "lefts." 
 
 The developing of the eeni^r sides is practically a repetition 
 of the work done on the inner and outer sides. Fig. 10 shows 
 the developed plate, which was obtained in practically the same 
 manner as those previously described. 
 
 This completes the development of all the plates for our 
 
 up-take, as shown in Figs, i and 2, except the door plates, 
 which require little or no developing. Baffle plates will, of 
 course, be required for such a casing, and these can be quite 
 easily "lifted" from the templets of the smoke-casing, before 
 this has been spaced for riveting. Angle-bars, when these are 
 used, are sometimes developed, too ; that is, they are laid along 
 the edge of the plate to which they are finally to be attached 
 before the plates are bent, and then the bending is done in 
 practically one operation. The quality of the steel plates used 
 in this class of work has improved so much recently that the 
 practice of flanging the edges of the plates has become quite 
 common, and this method has many obvious advantages. 
 
 Layout of an Uptake for a Scotch Boiler. 
 
 The uptake for a Scotch boiler includes a covering for the 
 portion of the front head occupied by the tubes, and a smoke- 
 box leading to the stack. Fig. I shows a half view of the 
 front elevation for a single-furnace Scotch boiler. Fig. 2 
 shows the side elevation of the uptake ; while in Figs. 3, 4, 
 5, 6 and 7 the half patterns for the uptake are shown. 
 
 The uptake is divided into an upper and lower front plate, 
 a side plate, a bottom plate, which fits around the furnace and 
 the uptake proper. The two front plates are plain surfaces 
 and can easily be laid out from the drawing. 
 
 To lay out the upper front plate, shown in Fig. 3, it is only 
 necessary to strike the arc 17-10, corresponding to the arc 
 17-16-10 in the front elevation, and lay off the cord 17-9, so 
 that the height of the plate 10-9 is equal to 10-9 in the front 
 elevation. 
 
 Since the lower front plate intersects the side and furnace 
 plates at an angle, giving an irregular outline, it is necessary 
 to choose a number of points on the outline of the plate, as 
 shown in the front elevation, and project these over to the 
 sloping line, which represents the plate in the side elevation, 
 these parallel lines should then be projected to the pattern at 
 right angles to the sloping line in Fig. 2 ; then, having located 
 the center line 8-9, the distance 9-17 as measured from the 
 front elevation can be laid out, and, in a similar manner, the 
 other points 7, 6. 5 and so on up to 18 can be located. 
 
 Considering that the furnace plate, shown in Fig. 5, extends 
 from the center line of the boiler at 8 around the furnace and 
 across the bottom of the uptake to the point i, it will be seen 
 that the length of the plate must be made equal to the length 
 of the curved line 1-4-6-8, Fig. i. This is laid out on the 
 straight line A-B, Fig. 5, and parallel lines are drawn at 
 right angles to A-B at points i, 2, 3, 4. 5, etc. The length 
 of these parallel lines is then measured from the side eleva- 
 tion. Fig. 2, and laid off in the pattern ; a curved line through 
 these points locates the outer edge of the furnace plate. 
 
 The side sheet extends from point i. Fig. i, around the cut- 
 side edge of the boiler to a similar point on the opposite side. 
 Therefore, the length of the lower edge of the pattern for 
 the side sheet, shown in Fig. 6, should be made equal to the 
 length of the line 1-22-18-16-12-10. Parallel lines should be 
 laid out perpendicular to this line at the various points lo- 
 cated in the front elevation, the length of these lines being 
 determined upon the side elevation in the same manner as 
 the length of the lines in the furnace plate was determined. 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 255 
 
 The uptake opening in this sheet is made to accommodate an 
 oblong smoke-box with circular ends. The development of 
 the line of intersection between the side sheet and the smoke- 
 box or uptake is clearly indicated in Figs, i and 2. 
 
 From the projection of the uptake the half pattern for the 
 sheet to form the lower end of the smoke-box can readily be 
 
 tions forming the head. The greater number of sections you 
 have the better uniformity the finished head will present. 
 
 A circular head has been chosen for this problem ; the 
 same method can be applied where the height of head is the 
 same as the diameter. Strike up diameter of head as at E 
 and O ; erect center line, dividing into two parts A, B. Part 
 
 
 19^^ 
 
 Jr'"'^'^ 
 
 SIDE SHEET 
 Fig. 6 
 
 16/]l5 Il4 
 
 
 
 -..-S,,^ 
 
 1 
 1 
 
 UPTAKE 
 OPENING 
 
 1 St'S^ 
 
 III 
 ' 1 1 
 ' 1 ' 
 : 1 . 1 
 
 li 1 
 
 1 
 
 
 
 
 obtained. It will be noted that, while the points 13-14-15 and 
 16 are equally spaced, the points lo-ii and 12 are not equally 
 spaced, although they might very well be if so desired. 
 
 This problem is a very simple one in projection, and as the 
 various lines are numbered similarly throughout the work, 
 the location of the various points can readily be followed 
 through. No allowance is made on the half patterns for laps, 
 the lines indicating merely the outline of the sheets. 
 
 Layout for Hemisphere Head for Tank. 
 
 For laying out this piece of work much depends upon the 
 manner in which the different sections of the head are worked 
 up. Where the sections are heated and pressed to shape in 
 dies, a pattern can be struck out for the sections with a good 
 degree of accuracy. Where the sections are worked up by 
 hand it would be a difficult matter to bring out each section 
 alike. Another point to be considered is the number of sec- 
 
 A can be assumed as elevation of head. Divide the arc in 
 part A into equal parts, in this case six, and number as shown. 
 Strike lines from these poi-.ts to center line, as shown. Now, 
 with dividers, set to where these lines intersect center line, 
 
 5 ,__ 
 
 i4 . 
 
 42— i-— 
 ■2 / 
 
256 
 
 LAYING OUT FOR BOILER MAKERS 
 
 and at point D strike arcs to line O, E. Part B can now be 
 taken as a plan view of head. As the head is made up of eight 
 sections, divide B into two parts. Bisect the angle C, D, E 
 by the line F, D. C, D, E will give us the section from which 
 to develop the pattern. Set square to line F D at point F, and 
 strike line to base line as shown. Extend this line upward to 
 
 Layout of a Breeching for a Scotch Boiler. 
 
 Fig. I is a front view and Fig. 2 a side view of the breech- 
 ing or uptake for a three-furnace Scotch marine boiler. 12 
 feet long by 12 feet 6 inches diameter. The top view or plan 
 of the breeching is shown in Fig. 3, and in this the lines for 
 getting the true lengths of the sides of the triangles are 
 
 intersect center line at H. Now erect any line from I, as 
 shown ; then with trams set to points / and H strike an arc 
 across line /. Where arc intersects line step off the distances 
 6-5-4-3-2-1 from part A along line /. Now from point /, with 
 trams set to the different points, strike arcs as shown. Going 
 back to section C, D, E, measure the length of each arc and 
 transfer half of distance on each side of line / at their re- 
 spective numbers. A line traced through these points vi'ill 
 give the pattern, lap to be allowed. 
 
 The length of the different arcs can be verified by taking 
 ■the different radii in part B and figuring the circumference 
 of the circle of which they form part and dividing by eight; 
 this should give you the same distance as found on the arcs 
 in section C, D, E. 
 
 Care should be taken to strike up neutral diameter of head. 
 Quadrant G represents dished plate at top of tank. The al- 
 lowance for dished heads can be obtained easily without going 
 into figures. Erect right-angle A, B, C, as in Fig. 3, upon 
 A, B, set off half diameter of head desired ; on line B and C 
 set off depth of head required ; at center of head strike a line 
 intersecting points A and C. The length of this line will give 
 you the radius required for marking off the circular plate. 
 This rule has been figured to allow for shrinkage in shaping 
 plates to shape. 
 
 shown. Since this is an irregular piece, it is necessary to 
 lay it out by triangulation. The lengths of the lines, shown in 
 Fig. 3, form one side of the triangles, and the height of the 
 breeching, as shown in Fig. 2, forms the second side. The 
 third side of the triangles shows the true lengths of the lines 
 to be used in the pattern. These are shown in Fig. 4. Trans- 
 ferring these lines from Fig. 4 to their proper' place in the 
 stretch-out, we get the laj'out, shown in Fig. 6, for the front 
 plate. All the lines in this figure are taken from the side of 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 257 
 
 Fig. 4, marked "Front Lengths." The back plate is laid out 
 similarly, taking the lengths of the lines marked "Back 
 Lengths" in Fig. 4. This layout is shown in Fig. 7. 
 
 The layout of the box for the furnaces is shown in Fig. 5. 
 This shows the layout of only one-half of the box, since both 
 halves are alike, and when one is laid out the other can be 
 marked from it. This part of the work is very simple, and 
 the diagram needs no further explanation. 
 
 A Simple, Accurate and Positive Method for Securing 
 the Template for a Segment of a Sphere. 
 
 I have seen a number of different ways for getting such a 
 pattern, both by projection and triangulation, for a job of this 
 kind, where the plates have to be heated and dished and then 
 beaten out to shape, thereby changing any layout made on the 
 flat, but I have never yet come across' one that, to my mind, is 
 as simple and easy as the method I have the pleasure of pre- 
 senting here. 
 
 We will take, for example, a type of bell buoy known as the 
 Trinity House pattern, in use on our Canadian coast, a rough 
 sketch of which is shown in Fig. I. It is understood, of 
 course, that a full-size half-front elevation be drawn on the 
 blackboard. 
 
 It is required to get a mold or framework for segment 
 A, B, C, D in sketch. Fig. i, that will fit on the outside, each 
 
 B, C. Now lay the top and bottom pieces on a taljle at the 
 same distance from a center as their radii. Draw a line from 
 the center to the circumference, extending it outward to get 
 the miter or angle at H, F, Fig. 2. Divide the circumference 
 
 into the number of parts required to make the course, in this 
 case twelve being the number ; measure off the distance on 
 the circumference from H to K, Fig. 2, the length required 
 for one-twelfth the circumference. Draw the line E, G, cut- 
 ting the circumference at K, then G K and H F will be the 
 
 course consisting of twelve plates. We first cut out a sweep 
 from a board 54-inch or J.^-inch thick, with a radius from the 
 center of the buoy to the rivet line on the round-about at A, 
 using the concave piece, also one from the center to the rivet 
 line at D, again using the concave piece, these two forming the 
 top and bottom of the mold to mark the rivet lines at A, B 
 and C, D. Now cut two more pieces for the sides, both hav- 
 ing the same radius, being the same as that on which the curve 
 from /i to D is struck, marking the rivet lines at A, D and 
 
 angle at which the two side pieces will be fastened. Proceed 
 in the same way with the bottom piece. The angle or cut must 
 be carefully marked, as on it depends the important essential 
 —good holes. The angle or cut of the side pieces at O, D and 
 P, A, Fig. I, will be at right angles to the center line of the 
 buoy. The length of the curve at A, D, Fig. I, should be two 
 thicknesses of the j4-inch or ^-inch board used, less than the 
 actual length on the sketch, to allow the rivet line to be 
 marked all around outside of the mold, the top and bottom 
 
258 
 
 LAYING OUT FOR BOILER MAKERS 
 
 pieces being nailed to the side pieces. Allowance ought to be 
 made for inside and outside laps by extending the top and 
 bottom corners of the outside lap half the difference necessary 
 between the outside and inside laps. 
 
 After tracing the rivet line on the dished plate lay out the 
 holes required with dividers, then punch all holes. Take strips 
 of light material about 14 or 16 gage, 3 inches or so wide, 
 clamp them on the outside of the segment ; mark and punch 
 
 C D 
 
 FIG. 3. — FORM OR FRAME TO MARK SHEET 
 AFTER BEING DISHED. 
 
 same, then bolt them on in the original position. Fasten each 
 corner with four small rivets, also rivet cross pieces from side 
 to side and top to bottom, as shown in Fig. 4. You will then 
 have a template that will be true and fair for all time, and each 
 segment will be the same as the other, so that if a new plate 
 were needed no trouble would be encountered in replacing the 
 
 FIG. 4. — TEMPLATE READY FOR 
 MARKING NEXT SHEET 
 
 old one, each plate being interchangeable. The mold ought to 
 be beveled on the inside edge all around to allow the outside 
 to bear evenly on the plate. 
 
 I do not know whether this method has been used by anyone 
 previous to my using it, therefore I will not claim to be the 
 originator, but so far as I am concerned I never heard of it 
 prior to my first experience with it. 
 
 Calculations for Determining the Size of Plates for 
 a Self=Supporting Steel Stack Base. 
 
 Many articles have been written on stack design and the 
 development of plates for stacks, but as yet the subject has 
 not been treated in full detail. The following calculations are 
 essential in making the necessary estimates for ordering the 
 plates and laying them out. The layout of a self-supporting 
 steel stack base, with an outside diameter of 8 feet at the top 
 and an inside diameter of 13 feet at the bottom, is shown. 
 
 We wish to make the base bell shaped and in conical 
 courses; therefore, in outline, points at the horizontal seams 
 as well as at the top and bottom will be tangent to a certain 
 radius. See Fig. i. Suppose the base to be 15 feet high and 
 constructed of J^-inch material. The radius of the circle 
 which will be tangent to the four points on Fig. i is deter- 
 mined by the following formula ; 
 
 Z> = Difference- between top and bottom radius of 
 stack. 
 
 H-- 
 R-- 
 
 ■■ height of base. 
 ; radius desired. 
 
 H 
 
 XH + D 
 
 D 
 
 R = - 
 
 15 
 
 2.5 
 
 ■X IS + 2.5 
 
 -=46.25 
 
 We find the radius to be 46.25 feet. 
 
 We will now calculate the different diameters of the base 
 at the horizontal seams. This is done by first calculating the 
 different lengths of the half-chords of a circle whose diameter 
 is 92.5 feet. 
 
 R = radius of circle tangent to top and bottom of 
 
 base, 
 //^height of course. 
 C = chord No. i. 
 C = Vi?" — /f' = V 46.25' — sio^ = 45 feet iiM inches. 
 
 The radius of the base at the large end of the top course 
 will be 46 feet 3 inches + 4 feet o inches — 45 feet iij4 inches 
 = 4 feet 3^ inches, and the diameter 8 feet 6'A inches. 
 
 Chord No. 2=V(46 feet 3 inches)^ — (10 feet o inches)'' 
 = 45 feet i}i inches. 
 
 The radius of the large end of the center course will be 46 
 feet 3 inches + 4 feet — 45 feet iji inches = 5 feet lys inches, 
 and the diameter 10 feet 2;4 inches. 
 
 This completes the diameters of the different courses at the 
 horizontal seams between the laps on points of contact of the 
 two plates. The next step will be to calculate the slant height 
 of the different courses on a line through the center of the 
 thickness of the plate. The neutral diameter of the small 
 end of the top course equals 8 feet — ^ inch = 7 feet iif^ 
 inches. 
 
 The neutral diameter of the large end of the top course 
 equals 8 feet 65/2 inches + ^ inch =: 8 feet 6% inches 
 
 8 feet 6<s inches — 7 feet 11^ inches 7]4 inches 
 
 = = sVs 
 
 2 2 
 
 inches base of a right-angle triangle. (See Diagram I.) 
 
 B = base of triangle. 
 
 H = height of course. 
 
 5" = slant height of ring. 
 
 5-= V/f=H-S== V(5 ft.)=+ (3 ft. s/g iu.y = 5 ft. ^ in. 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 259 
 
 Thus the slant height of the top course is 5 feet % inch. The 
 slant heights of the remaining two courses are calculated in a 
 similar manner. By referring to Diagram 2 it will be seen that 
 the difference between the neutral diameter of the large and 
 small end is i foot Syi inches. One-half of this is io;4 inches 
 for the base of the triangle. (Diagram 2.) The slant height 
 
 Bottom course, 25 feet iJ4 inches. 
 
 Reinforcement, 23 feet 614 inches. 
 
 The radii of the different cambers are calculated from the 
 neutral diameter of the courses. This is essential in deter- 
 mining the exact camber. 
 
 We will now take up the development of one of the bottom 
 
 of the middle course is 5 feet 15/16 inch. Using the same plates and also the calculations necessary in ordering the 
 
 DIAGRAM SHOWING DIMENSIONS OF STACK BASE AND LAYOUT OF ONE OF THE PLATES. 
 
 calculations for determining the slant height of the bottom we 
 find it to be 5 feet 27/16 inches. (See Diagram 3.) 
 
 The next step will be to determine the radius of the camber 
 of the different sheets to make the courses. It is only neces- 
 sary to calculate the camber of the large end of each course. 
 D' = neutral diameter of small end. 
 Z)'^ neutral diameter of large end. 
 5' aslant height of the course through center of 
 
 thickness of plate. 
 R = radius of camber sheet. 
 
 R^ XS = 
 
 8 ft. 6% in. 
 
 D' — D" 
 X 5 ft. 
 
 in. = 71 ft. I s/i6 in. 
 
 8 ft. 6?^ in. — 7 ft. uYs in. 
 
 According to the above calculations we have a radius of 71 
 feet I 5/16 inches for the camber of the large end of the top 
 course. 
 
 The cambers are determined by the same formula for the 
 other sheets. It will be noted that if the thickness of the plate 
 is added to the large diameter, and if the thickness of plate 
 is subtracted from the diameter of the small end, the result is 
 the neutral diameter. 
 
 Referring to Fig. i will be seen that the radii of the cam- 
 bers are 
 
 Top course, 71 feet 1 5/16 inches. 
 
 Middle course, 30 feet 2^ inches. 
 
 sketch plates. The writer finds it good practice to mark the 
 results of the foregoing calculations on the blue print as well 
 as the circumference of each course at the large and small end. 
 There is but one calculation used in figuring the size of plates 
 that is not used in the development of same, and that is the 
 chord of the arc at the small end of the course. (See Fig. 2.) 
 As an illustration, we will consider the bottom course made 
 of three sheets to the course. The circumference of the bot- 
 tom of the base, whose neutral diameter is 13 feet f^ inch, 
 divided by 3, will give the length of one sheet at the rivet line. 
 
26o 
 
 LAYING OUT FOR BOILER MAKERS 
 
 13 ft H in. X 3-1416 
 
 : i63f4 inches length of one sheet at 
 
 large end at rivet line. To this add enough stock for laps, 
 making the sheet 167 inches around the camber. From the 
 latter dimensions we would determine the length of the chord 
 at the small end, so it will be necessary to find the number of 
 degrees there are in the arc whose radius is 25 feet i]4. inches 
 and length 167 inches. 
 
 A = length of arc. 
 
 C = circumference of circle of which the arc is a 
 
 part. 
 Z):^ degrees in arc. 
 360 ^degrees in circle. 
 A 167 
 
 D: 
 
 ■- X 360 = 
 
 C i8g2.8i 
 
 ■X 360 = 31.77 degrees. 
 
 Therefore, the degrees in arc are 31.77, or 31° 46' 20" 
 
 31° 46' 20" 
 
 ^15° S3' 10" = one-half the arc. 
 
 C:=the chord of arc at small end. 
 6" = sine of the angle of 15° 53' 10". 
 R = radius of the arc. 
 
 C = S X R X 2 = .27368 X 19 ft. 9^ in. X 2 = 
 10 ft. 9.86 inches ; therefore, the chord is 
 10 ft. 9.86 inches. 
 The next step will be to find the depth of the camber, which 
 is known as the versed sine. The versed sine is determined 
 by the following formula : 
 p' = versed sine. 
 R = radius of the arc. 
 C=: one-half the chord of the arc. 
 //^height of the angle. 
 
 i/=Vi?'— C= — H. 
 
 F=V(i9 ft. 9;4 in.)=— (5 ft. 4.83 in.y — H = 
 g 1/16 inches. 
 Thus the versed sine is 9 1/16 inches. This completes the cal- 
 culations for the article in question. 
 
 The plate, as we would order from the mill, would be A, 
 B, C, D, Fig. 2. There will be a saving of material if the 
 reinforcing straps are ordered on the sketch plate. Fig. 2, along 
 the large end. The size of the sheet is shown, Fig. 4, after the 
 reinforcing sheet has been added. Then A. B.C.D will be the 
 size sheet to order. The two different pieces can be laid out 
 at the same time, punched and sheared, and there will be no 
 extra labor added. 
 
 Layout of a Hemispherical Tank Head. 
 
 Fig. 2 shows both the plan and elevation of the end of a 
 cylindrical tank which is provided with a hemispherical head. 
 The hemispherical head is buih up of a number of plates 
 joined together with seams which are arcs of great circles on 
 the sphere. The end of the head is formed by a dished plate, 
 in order to do away with the awkward form of riveted joint 
 which would be necessary if the various sections were con- 
 tinued to the top of the head. 
 
 The dimensions of the various plates forming the head are 
 usuallv determined in the following way. Setting the trams at 
 
 a length equal to the radius of the tank, that is, Yz D, the ele- 
 vation of the head is divided into three equal parts, as at 
 points L and T. LT is then the diameter of the dished plate 
 which forms the end of the sphere. With the trams still set 
 at a length equal to Vi D, divide the circumference of the 
 
 4 
 
 3" — 
 
 12 22 32 42 52 
 
 92 102 112 122 132 
 
 tank shown in the plan into six equal parts. With the trams 
 set to a length equal to Yz LT, draw the plan of the dished 
 plate and divide its circumference into six equal parts corre- 
 sponding to the divisions in the circumference of the tank. 
 The head is now divided into seven sections, six of which are 
 
 / \ 
 
 / \ 
 
 / y^'^ 
 
 ****c. \ 
 
 / / 
 
 \ \ 
 
 
 /" \ , 1 
 
 \ \ 
 
 y / 
 
 \ \^ 
 
 y / 
 
 \ r^ 
 
 "^ / 
 
 exactly alike ; the seventh being the dished plate. If the di- 
 ameter of the tank is large, the head may be divided into a 
 greater number of sections, since the number of sections doe;s 
 not affect the method of laying them out. The head may be 
 made in seven sections for tanks up to 14 or 15 feet in di- 
 ameter, as then the plates would be only approximately 7 feet 
 wide and 7 feet long, but for tanks of greater diameter eight 
 or nine sections would be used. 
 
^MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 261 
 
 In Fig. 2 the dotted lines show the position of the rivet 
 lines, while the solid lines show the edges of the plates. It is 
 customary to make the dished plate, and also the first course 
 of the cylindrical part of the tank, outside plates. 
 
 To lay out the dished plate it is simply necessary to strike a 
 circle whose radius equals Vi LT plus a certain allowance 
 which must be made for the extra material required when the 
 head is dished. This allowance varies according to the di- 
 ameter of the plate. Approximately the proper allowance is 
 shown by the curve Fig. I, on which are plotted in inches the 
 necessary allowances for heads of different diameters. For 
 example, if it is necessary to lay out a head which is to have 
 the standard dish and be 72 inches outside diameter when 
 
 Having located the point F, next locate the point M , at a 
 distance from F equal to i^ times R. the radius of the dished 
 plate. With .1/ as a center, and with the trams set to the dis- 
 tance ij4 R, draw the arc A B, making the length of the arc 
 A B equal to 1/6 the circumference of the dished plate. 
 
 Having located the points A, B, C and D, it yet remains to 
 draw the curves AD and BC. These may be drawn as the 
 arcs of a circle whose radius is 1V2 D, or the same as that used 
 for the arc DEC. Setting the trams to a length ij^ D, with 
 points A and D as centers, strike arcs intersecting at the point 
 N. Then with the point iV as a center and the same radius, 
 draw the arc AD. In a similar manner locate the point 5 and 
 draw the arc BC. This completes the pattern, which, if suit- 
 
 %-X)^ 
 
 sv-- 
 
 ■^N 
 
 FIG. 3 
 
 finished, look on the curve for the diameter 72. The curve at 
 this point, as shown by the vertical scale, reads 2 inches. That 
 is, 2 inches should be added to the finished diameter of the 
 head for the size of the plate when it is laid out before dish- 
 ing. Therefore, when the plate is laid out it should be 74 and 
 not 72 inches in diameter. Instead of using the radius R and 
 making the above allowance, when laying out the head, a 
 radius equal to the length of the line LW may be used, which 
 will give at once the correct diameter of the plate. 
 
 The layout of one of the irregular sections is shown in Fig. 
 3. First draw the line OE of indefinite length, and then with 
 O as a center, with the trams set to a length equal to i^ D, 
 that is, Ij4 times the diameter of the tank, draw the arc DEC. 
 The length of this arc should be equal to the length of 1/6 of 
 the circumference of the tank. From E, lay out the distance 
 E F equal to the length of the curved line X T, which is also 
 equal to 1/6 of the circumference of the tank. Properly speak- 
 ing, if the sections are not to be dished, but simply rolled flat, 
 the line E F should be slightly shorter than 1/6 of the cir- 
 cumference. The allowance is so small, however, that it may 
 be neglected. 
 
 able allowances are made for inside and outside plates, will 
 answer for each of the six sections in the head. The arcs AB, 
 BC, CD and DA represent the location of the rivet lines, and 
 therefore the amount necessary for the laps should be added 
 outside this to obtain a complete pattern. 
 
 Layout and Construction of a Large Water Tank. 
 
 When water is wanted at an elevation of 50 feet or less 
 it is entirely a matter of personal choice whether it shall be 
 stored in an elevated tank or standpipe. If, however, it is 
 wanted at an average elevation of 100 feet, it will cost twice 
 as much to store it in the standpipe as in an elevated tank. 
 Should the water be wanted at an average elevation of 150 
 feet, it will cost three times as much to store it in a stand- 
 pipe as in an elevated tank. Similarly, at an elevation of 200 
 feet it will cost four times as much to use the standpipe as the 
 tower and tank. At 250 feet the standpipe will cost five times 
 as much as the tower and tank, and at 300 feet six times as 
 much. From this it is easily seen why towers and tanks have 
 come into general use for storage of water where its potential 
 energy is a matter of consideration. 
 
262 
 
 LAYIXG OUT FOR BOILER MAKERS 
 
 The tank shown in the illustrations has a capacity of 1,200,- ? 
 
 000 gallons of water, which is equal to a load of 10,000,000 : 
 
 pounds. It consists of a cylindrical steel tank 50 feet in ~J> 
 
 6/10 Plate 
 
 FIG. 2. OUTLINE OF THE TANK, SHOWING PRINCIPAL 
 
 DIMENSIONS. 
 
 diameter, extends from the center of the bottom of the tank 
 to the regular water mains about 12 feet below the ground. 
 Access is had to the tank by means of a steel ladder fastened 
 to one of the columns, and extending to a small balcony 
 built around the bottom of the tank; from this balcony 3 
 light ladder extends to the top of the tank, where a door 
 in the conical roof gives access to the inside of the tank. A 
 
 h"^2H'' 1«" 
 
 FIG. I. — THE COMPLETED TOWER AND TANK. 
 
 diameter, 65 feet 4 inches high, with a hemispherical bottom 
 24 feet iiJ4 inches deep, and a conical roof 18 feet 9 inches 
 high. It is supported at a height of 155 feet by eight riveted 
 steel columns. A vertical riveted steel pipe, 50 inches in 
 
 Inside Butt Strap Splice 
 
 FIG. 3. — DETAILS OF 
 
 Joint 3-( 
 RIVETING. 
 
MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 263 
 
 second ladder extends down into the tank on the inside from The vertical seams in the lower course of plating are fastened 
 this door. by triple riveted double butt strap joints, ^g-inch rivets being 
 The cylindrical part of the tank consists of eight horizontal used, spaced about 3}i inches center to center of holes, 
 courses of plates, alternate courses being inside and outside. Triple riveted butt joints are used for the vertical seams in 
 Each course contains eight plates, each plate being about 19 the four lower courses of plating, while in the fifth a quad- 
 feet 7}i inches long. This length varies slightly with each ruple riveted lap joint is used; in the si.xth, a triple riveted 
 
 ly " h« 43 Sjit.^6.608-=-JO_73'jfl forJtoof-Conn J^ j j.^" 
 
 " U- 180.Alt.-Bi«>^_l.a7'i:_a9Jl!ljoU!la(ilM -0=.- 
 
 L.W'OUT OF SHELL PLATES. 
 
 course of plating, as the length of the entire course is figured 
 from the diameter to the center of the thickness of the plate, 
 a quantity which varies with the thickness of the material. In 
 Fig. 4 details are shown of the layout of these plates, showing 
 the exact length, width, rivet spacing, etc. All of the hori- 
 zontal or girth seams are single riveted lap joints. The size 
 of rivets varies from % inch at the bottom to ^ inch at the 
 top ; the spacing for the ]4 rivets being about y/i inches and 
 for the 5^ rivets about 2% inches center to center of holes. 
 
 lap joint, and in the seventh and eighth double riveted lap 
 joints. 
 
 The thickness of the shell plates varies from i inch at the 
 bottom to s/i6 inch at the top. The bottom plates are re- 
 inforced by inside and outside cover plates, 30 inches wide 
 and 14 inch thick, riveted to the curved hemispherical bottom 
 plates. 
 
 The hemispherical bottom is made with two courses of 
 %-inch plate, fastened together with butt straps 161^ inches 
 
264 
 
 LAYING OUT FOR BOILER MAKERS 
 
 wide and IS inch thick. The bottom of the tank consists of a 
 dished plate 10 feet 9 inches in diameter and 54 inch thick. 
 Details of the riveting are shown in Fig. 3, the rivets all 
 being % inch in diameter, and spaced so that there are not 
 less than fifteen rivets per lineal foot.. 
 
 which each plate subtends, together with the versed sine or 
 distance from the center of the chord to the arc. In the de- 
 velopment, Fig. 4, the lengths of the tangents at points of 
 intersection of the courses are also shown, as well as the mag- 
 nitude of the angle which each plate subtends at the, center of 
 
 -24H'ir^ t—^' «0-SpojJ2.3D»_:,13.2i(,,oi,_2.1?53,Iua, 
 
 i , — rz-LfS 
 
 Or. Pi;~l.S! 
 
 © 
 
 ,, 2 U =„2)4"» 8)^' "W «■'/;;'"' " I>'^l7'7. 
 ~VJ— / 47-S[».(Sl-3J28^1118!(^for-La— J _ 
 
 _L 
 
 1 „ , — ;; 
 A 
 
 iV"- '^ 
 1 '16 
 
 ' Ctr. pC"1 
 
 ® ! 
 
 Ctx. PL' 
 
 Rivetfl = H Diam. i^g'f] ^;" 
 
 — 13-2/^9 C-to_C. 
 
 
 * 
 
 ~1 1.27 Si«.^2.0e^'= 6'-7-VK4ii 
 
 I .J*t.« 
 
 
 27 Spa.^2.U0M- 6-8^'^ 
 
 "I'/is" 
 
 ,.„ 2 Si 
 ia-4M— c.-to-o. ' 
 
 eg 
 ■It 
 
 FIG. S. — L.^YGUT OF VERTICAL PIPE. 
 
 The details of the method of laying out the hemispherical 
 part of this tank are shown in Figs. 7, 9 and 10. Fig. 7 is a 
 quarter section, showing the length of the plates measured 
 along the arc of the circle, and also the length of the chord 
 
 FIG. 6. — DETAILS OF ROOF TRUSS. 
 
 the tank. Knowing the radius and the chord, the length of the 
 plate measured along the arc of the circle can be figured. The 
 plate can then be divided into a number of equal parts, and 
 the offset or width of the plate at each of these sections can 
 be measured, the width in each case being a certain part of 
 the circumference of the tank at this point. These offsets 
 can then be laid out as shown in the patterns of Figs. 9 and 
 10, giving the true development of the curved plates. All 
 these dimensions are clearly indicated on the drawings and 
 can be readily verified by making these calculations. 
 
 The development of the plates for the vertical pipe con- 
 necting the tank with the inlet and outlet pipes below the 
 
 FIG. 7. — QUARTER SECTION OF HEMISPHERICAL BOTTOM. 
 
.MISCELLANEOUS PROBLEMS IN LAYING OUT 
 
 265 
 
 FIG. 8. — LAYOUT OF ROOF PLATES. 
 
 surface of the ground is shown in Fig. 5. This pipe is 50 
 inches in diameter and 135 feet 11^ inches high, and is made 
 of fifteen inside and outside courses of plating, the thickness 
 of each plate being 5/16 inch. All horizontal girth seams arq 
 single riveted lap joints, and the vertical seams double riveted 
 lap joints, the rivets being j4->nch diameter at the top. The 
 exact length of each of these plates is determined by finding 
 the circumference corresponding to the diameter of the plate 
 measured to the center of the thickness of the metal. 
 
 -mH-^ 
 
 I— 2T5i^^-»^25KM^25^^26>^- 
 
 ing, 28 inches in diameter, is left at the top of the roof, for 
 the purposes of ventilation. This opening is covered with a 
 conical cap, through which a flag pole extends for a height 
 of nearly 40 feet. The roof is supported by light, triangular 
 trusses, consisting of sixteen screw rods fastened to a circu- 
 lar ring at the top of the roof and extending to the foot of 
 angle struts normal to the roof, and riveted at the upper end 
 to a horizontal angle fastened to the joint between the second 
 and third courses of roof plates, and at the lower end to a 
 circular angle about 26 feet in diameter, which is held in 
 place by 5^-inch horizontal radial rods, the outer ends of 
 which pass through the upper edge of the cylindrical walls of 
 
 FIG. 9. — LAYOUT OF PLATES IN THIRD COURSE. 
 
 FIG. lO. — LAYOUT OF PLATES IN SECOND COURSE. 
 
 Details of the conical roof and the development of the 
 plates are shown in Figs. 7 and 8. The roof consists of three 
 courses of plates, % inch thick, the upper course being 6 
 feet 7% inches wide, and the middle and bottom courses 13 
 feet 6 inches wide. Four plates are required for the upper 
 course, sixteen for the middle and thirty-two for the lower. 
 The door, details of which are shown in the development, 
 Fig. 8, is located in the lower course. The lower edge of the 
 roof projects beyond the tank, forming a cornice. An open- 
 
 the tank. Forty-eight similar rods extend endways from the 
 circular angle, with their inner ends bolted between a pair of 
 3/16-inch spider plates, which constitute the base for the flag 
 pole. 
 
 The total weight of the structure is about 650 tons, and 
 when erecting it the lower course of the cylindrical part of 
 the tank and the hemispherical bottom should be completely 
 fitted up, pinned and bolted before any rivets are driven. All 
 the riveting is commonly done by pneumatic power. 
 
MISCELLANEOUS CALCULATIONS 
 
 Lap Joints. 
 
 Lap joints on longitudinal seams for shells are out of date, 
 so they say, j'et a little literature on the subject may be of in- 
 terest to many of the readers of this book. Fig. i represents 
 a plate K inch thick and large enough when laid out to roll 
 up 48 inches inside diameter. The stamp on the plate shows 
 the tensile strength to be 55,000 pounds per square inch. We 
 will figure on iron rivets to shear at 42,000 pounds per square 
 inch. In proportioning the joints for shells since the girth 
 seams must withstand one-half as great a force as the longi- 
 tudinal seams, it is necessary to design only the longitudinal 
 seams for the greatest possible strength of rivet and plate 
 section. 
 
 The Hartford Steam Boiler Inspection and Insurance Com- 
 pany allows for a plate Vx inch thick the following size rivets, 
 Vi inch, Yi inch, 11/16 inch. The corresponding efficiencies 
 
 D =; Diameter of hole and driven rivet, 
 
 T = Thickness of plate. 
 
 For steel plates and steel rivets : 
 
 23 X i?" X .7854 X I 
 
 P 
 
 + o 
 
 28 X T 
 To obtain equality of strength for rivets and net section of 
 
 plate divide the shearing strength of one rivet (for a single 
 
 seam) by the tensile strength of the plate. To the quotient, 
 
 add the diameter of the rivet hole, which sum will be the 
 
 pitch of rivets. 
 
 D-- X .7854 X S X N 
 
 P = 1- D 
 
 T X T S 
 P = Pitch of rivets, 
 
 D = Diameter of the hole and driven rivet, 
 
 S =^ Shearing strength of rivet per square inch, 
 
 jV:= Number of rows of rivets (in this case one), 
 
 — lli Spaces ® 1^ + = 151^ Inches — 
 
 LAYOUT OF PLATE FOR LAP-JOINT SHELL^ 48 INCHES INSIDE DIAMETER. 
 
 for a single riveted joint with rivets shearing at 38,000 pounds 
 and the tensile strength of the plate 60,000 pounds are 50, 57 
 and 60 percent. Thus the larger of these rivets gives the 
 greatest strength. 
 
 The maximum pitch for single riveted lap seams on marine 
 boilers consistent with steam tight joints is 1.31 X T -\- i^ 
 where T := thickness of plate. A rule for obtaining the di- 
 ameter of rivet holes for steel plates taken from W. S. Hut- 
 ton's Manual on Steam Boiler Construction, page 222, is Z) = 
 T X 5^ + .45 where D = diameter of rivet hole, T = thick- 
 ness of plate. Substituting figures we have .25 X /^ + -45 = 
 -575. or say 9/16 inch diameter of rivet hole. Thurston's Man- 
 ual on Steam Boilers, page 120, has this to say, "very thin 
 plates cannot be well calked and thick plates cannot be safely 
 riveted." The hydraulic riveter overcomes the latter, and close 
 spacing of rivets, snugly fitting plates and true holes over- 
 comes the former. The U. S. government rules for determin- 
 ing the pitch of rivets for the different grades of plates as 
 prescribed by the board of supervising inspectors are for iron 
 plates and iron rivets 
 
 D'- X .7854 X I 
 
 P = h D 
 
 T 
 Where 
 
 P = Pitch or rivets. 
 
 T = thickness of plate, 
 
 T S ^ Tensile strength of plate. 
 
 Substituting figures we have .5625 X .5625 X -7854 X 42,- 
 000 ^ 25 X 55,000 = .759 and .759 + -5625 = 1.321 pitch of 
 rivets. 
 
 The amount of lap from the edge of plate to the center of 
 rivet hole is generally taken as one and one half times the 
 diameter of the hole. This does not apply to seams in fire 
 boxes when the load is compression. Here a narrower lap 
 will obviate the sheets cracking from the rivet holes to the 
 
 3 1-6875 
 calking edge; ij^ X .5625 = — X .5625 = = .843, or 
 
 2 2 
 
 say %-inch lap. 
 
 Having ascertained the lap, pitch, etc., proceed to layout the 
 plate. Commence by drawing the line AB at a distance of li 
 inch from the edge of the plate, if the plate is beveled for calk- 
 ing ; if not, allow for what you take off. As previously stated 
 the plate is to roll up 48 inches inside diameter. The length 
 corresponding to this is 48 plus one thickness of plate {% inch) 
 times 3.1416 = 151.58 inches. If 48 were to be the outside 
 diameter, subtract one thickness of plate and multiply as 
 above. 
 
 Lay off on A B. 151.58 inches. Parallel to A B, and at a dis- 
 tance of 60 inches draw the line CD. Bisect line AB with 
 
MISCELLANEOUS CALCULATIONS 
 
 267 
 
 the tram points and draw the line E F perpendicular to .1 B. 
 then with radius E A and F as a center strike a small arc at C. 
 Do the same at D. To these points draw the lines A C and 
 B D and if the sheet is square the diagonal distance C B will 
 equal A D. 
 
 With our sheet squared up and ready for spacing let us 
 see how our spacing will come out. The width of our sheet 
 for the longitudinal seam is 60 inches, our pitch as figured 
 out above is 1.321 inches. Any change in this pitch will affect 
 the strength of the joint. Here is where practical knowledge 
 combined with theoretical knowledge is of no small impor- 
 tance to enable one to adjust in a correct manner any differ- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 < 
 
 > jo 1 
 
 
 
 
 
 
 
 
 
 
 
 -J l- 
 
 
 
 ■^ 
 
 ^^•t 
 
 
 
 ° 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Fig. 2 Fig. 3 
 
 L.AP-JOINT SHELL AFTER ROLLING UP. 
 
 ence that may arise. To determine the number of spaces di- 
 vide 60 inches, the distance A C, by 1.321, the pitch, 60 -H 
 1.321 ^ 45 -|- spaces, 60 -^ 45 = 1.33 inches pitch. As this 
 is a little above the original pitch this would give us a stronger 
 plate section and a weaker rivet strength. In practice it is 
 better to have a stronger rivet section in order to assure a 
 tight joint. Using 46 spaces, 60 -^ 46 = 1.30 inches pitch. Step 
 off the lines A C and D B into 46 equal spaces at 1.30 inches 
 -•)-. Next divide the girth seam by the pitch, which is 151.58 
 -f- 1.321 = 114 — spaces, 151.58 -f- 114 =: 1.32 inches pitch. 
 Step off the lines A B and C D into 114 equal spaces at 1.32 
 inches and the sheet is ready to punch. 
 
 In spacing up a large plate advantage may be taken of quar- 
 tering the sheet. Of course in this case the number of spaces 
 must be divisible by four. 
 
 Figs. 2 and 3 are a side and end elevation of the plate after 
 it is rolled up. 
 
 The efficiency of the joint may be found as follows: The 
 strength of a solid strip of plate equal in width to one pitch 
 as shown in Fig. 2 is F X T X T 5. 
 
 P = 1.30, pitch of rivets, 
 
 T = .25, thickness of plate, 
 
 T S ^ SSflOO pounds tensile strength of plate. 
 
 Substituting figures, we have 1.30 X .25 X SS.ooo =: 17,875 
 pounds. The shearing strength of a 9/16-inch rivet is D' 
 X .7854 X 42,000 =; 10,437 pounds. The strength of the net 
 section of plate is (F — D) T X T S. Substituting figures 
 we have (1.30— .5625) X .25 X 55,ooo = 10,136 pounds. It 
 will be seen that the net section of plate is the weakest, there- 
 fore 10,136 X 100 -^ 17,87s =: 56.6 percent. 
 
 To find the allowable pressure on this shell the rule is 
 
 T X r 5 X £ 
 
 Where 
 
 /-" = Working pressure in pounds per square inch, 
 
 T = Thickness of plate, 
 r 5' := Tensile strength of plate per square inch, 
 
 £ = Efficiency of joint, 
 
 R = Internal radius, 
 
 F = 5 (factor of safety). 
 Substituting figures we have .25 X S5,ooo X -56 -f- 24 X 5 = 
 64 pounds, allowable pressure with a factor of safety of 5. 
 
 The girth seams must withstand only one-half as great a 
 force as the longitudinal seams. Let us get the total shearing 
 strength of all the rivets around the head, and the tensile 
 strength of the net section of the plate, then, dividing the 
 weaker of the two by the total working pressure on the head, 
 we will get the factor of safety. Since there are 114, 9/16 
 inch rivets, the shearing strength of one of which is 10,437, 
 the total shearing strength of the rivets will be 114 X io,437 = 
 1,189,818 pounds, The net section of plate is (151 — 114 X 
 9/16) X .25 X 55,000 = 1,202,850 pounds. Therefore the rivets 
 are the weaker. The total pressure on the head is 48 X 48 X 
 .7854 X 64 = 115,811 pounds. 1,189,818 -f- 115,811 = 13. Thus 
 the girth seams have a factor of safety more than twice as 
 great as that for the longitudinal seams. 
 
 Diagram for Finding Efficiency of Riveted Joints. 
 
 This chart is based upon a tensile strength of 60,000 pounds 
 per sectional square inch for steel plates, and a shearing 
 strength of 40,000 pounds per sectional square inch for steel 
 rivets in single shear. Rivets in double shear are considered 
 as having 180 percent the strength of rivets in single shear. 
 The efficiency of the net section would not be changed if 
 sheets of 55,000 or 65.000 pounds tensile strength were used, 
 or if rivets having an ultimate shearing strength of 42,000 
 pounds were used, but changing the tensile strength of the 
 steel or the shearing strength of the rivets would change the 
 efficiency of the rivets as compared with the strength of the 
 solid plate. 
 
 If steel of 65,000 pounds tensile strength was used, the 
 efficiency of the rivets would decrease by 8 1/3 percent : or 
 if steel of S5,ooo pounds tensile strength was used, the effi- 
 ciency of the rivets will be increased by 8 1/3 percent. Should 
 rivets of 42,000 pounds shearing strength be used, the efficiency 
 of the rivets will be increased by 5 percent. 
 
 The efficiency of the rivets varies inversely as the thickness 
 of the steel, and also inversely as the pitch of the rivets. 
 
 The efficiency of the net section for any pitch is equal to 
 100, less than double the efficiency of the net section for twice 
 the pitch, or efficiency for (2 pitch X 2) — 100 ^ efficiency of 
 net section. 
 
 The efficiency of the net section for any pitch equals one- 
 half of the efficiency for net section for half the pitch plus 
 100, or efficiency for 
 Pitch 
 
 ^ efficiency of any net section. 
 
 R X F 
 
 Bearing these simple formulae in mind, with the aid of the 
 chart the reader will be able to determine the efficiency of 
 any riveted joint. 
 
268 
 
 LAYING OUT FOR BOILER MAKERS 
 
 DIAGKAM FOR FINDING THE EFFICIENCY OF RIVETED JOINTS 
 
 EXAMPLE NO. I. 
 
 We have a boiler constructed of steel of 60,000 pounds ten- 
 sile strength ^-inch thick. The horizontal seam is double- 
 lap riveted. The rivets are i inch in diameter, the rivet holes 
 I 1/16 inches in diameter, and the pitch of rivets 3'/2 inches, 
 find the efficiency of the joint. 
 
 The first step is to locate the pitch of the rivets on the left- 
 hand scale, marked greatest pitch. We find that 3^/2 inches is 
 not given on this scale, so we will take double the pitch, bear- 
 ing in mind that the efficiency of the rivets varies inversely as 
 the pitch. So the efficiency found using 7 inches pitch will be 
 one-half the actual efficiency. From the 7-inch mark on the 
 
MISCELLANEOUS CALCULATIONS 
 
 269 
 
 greatest pitch scale, follow the horizontal line to the left until 
 the line representing the diameter of the rivet hole is met. 
 This line is, in this case, the one marked i 1/16 inches. From 
 where we strike the rivet-hole line, proceed downward until 
 the diagonal line representing the thickness of the shell plates 
 is reached. This is the J^-inch line. From this point go 
 horizontally to the right until the line marked double-riveted 
 lap is met, going upward from this point and touching the 
 efficiency of rivets scale at 3354 percent. Doubling this effi- 
 ciency, as has been stated above, we find a rivet efficiency of 
 67.5 percent. 
 
 We will next consider the net section. Locate 3V2 inches 
 on the scale marked pitch of rivets in section considered. 
 Follow the horizontal line to the right until the line repre- 
 senting the diameter of rivet hole is met ; from this point 
 go downward, meeting the efficiency of net section scale at 
 the division 69.5 percent. This is the efficiency of the net 
 section as compared with 67.5 percent for the rivet shear. 
 
 If in the boiler considered above the steel had been of 
 55,000 pounds tensile strength, the efficiency of the rivets 
 would be increased by 8 1/3 percent of the efficiency, which 
 is 5.6 percent of the solid plate, making an efficiency of 
 67.5 + 5.6 = 73 percent. But should the tensile strength of 
 the steel be increased to 65,000 pounds, the efficiency of the 
 rivets in shear will be decreased to 62 percent. 
 
 E.XAMPLE NO. 2. 
 
 Consider the same boiler plate as in the previous example, 
 but assume a triple-lap riveted seam, using 7,8-inch rivets, 
 15/16-inch holes and pitch the centers 3^2 inches as in the 
 previous example. 
 
 We proceed as before by taking 7 inches as the pitch. Go 
 toward the left along the horizontal line, meeting the 15/16- 
 inch diameter of the rivet-hole line, then downward, meeting 
 the J^-inch plate line, then to the right to the line marked 
 triple-riveted lap, then up to the efficiency scale, which we 
 touch at 39.5 percent. This efficiency we double, on account 
 of doubling the pitch, and have an actual rivet efficiency 
 of 79 percent. 
 
 The net section is found, as previously explained, by going 
 from the rivet-pitch scale to the right, meeting the 15/16-inch 
 line, and then going downward to the scale marked efficiency 
 of net section, which we strike at the 73 percent mark, which, 
 heing the smallest efficiency, would determine the strength of 
 the seam. ' 
 
 We will next consider a triple-riveted butt joint: Rivets, 
 ^ inch in diameter; rivet holes, 15/16-inch diameter; pitch 
 of rivets, 7 inches ; thickness of shell plate, 7/16 inch ; tensile 
 strength of steel, 60,000 pounds. 
 
 From the 7-inch division on the pitch scale, pass horizon- 
 tally tovvfard the left to the line representing 15/16-inch di- 
 ameter of rivet hole, then downward to the 7/16-inch plate 
 line. From this point we should pass toward the right, but 
 it will be seen that the line marked triple-riveted butt passes 
 under the point where the plate line is met, so it will be 
 necessary to go toward the left. However, our rivet-efficiency 
 scale is graduated to but no percent, and we find that by 
 
 going horizontally to the left we do not touch our triple- 
 riveted butt line within the limits of the chart, so our rivet 
 efficiency is greater than no percent of the solid plate, and it 
 will not be necessary to know the exact efficiency. 
 
 The efficiency of the net section is found, as previously ex- 
 plained, by locating the 7-inch division of the right-hand scale. 
 From this point we pass to the right until the 15/16-inch di- 
 ameter of rivet hole line is met, then downward to the net 
 section-efficiency scale, where we find 86.5 percent, which is 
 the smallest efficiency and determines the strength of the seam. 
 
 We find the efficiency of quadruple-riveted butt joint in 
 very much the same manner as we find the efficiency of the 
 triple-riveted butt joint. Excepting when we find the efficiency 
 of the net section, one of our formula must be used. 
 
 We will find the efficiency of a quadruple-riveted butt-joint: 
 The shell plate 3-^-inch thick, of 60,000 pounds tensile strength, 
 diameter of rivets ^ inch, of rivet holes 13/16 inch, and pitch 
 of rivets 14 inches. 
 
 We find the same condition exists as with the triple-riveted 
 butt joint regarding the efficiency of the rivet shear. The 
 efficiency is greater than the no percent of the strength of the 
 solid plate, so the line representing quadruple-riveted butt 
 joints is not met within the limits of the chart. However, had 
 we taken 7/16 inch as the thickness of the shell plate, the effi- 
 ciency of the rivets would have been but 100 percent, and had 
 the thickness been taken as 14 inch, the rivet efficiency would 
 have been found by passing to right from the point where the 
 plate line is met, and the quadruple-riveted butt line would 
 have been crossed, and passing up the vertical line to the 
 rivet-efficiency scale 87.5 percent will be found to be the effi- 
 ciency of the rivets. However, to return to the consideration 
 of the ^-inch plate, quadruple butt-joint problem, we have 
 found that the efficiency of the rivets is more than no per- 
 cent of the strength of the solid plate. 
 
 We will next find the efficiency of the net section. The 
 pitch, 14 inches, is not given on the scale marked pitch of 
 rivets in section considered, so we will take one-half the pitch, 
 or 7 inches, and pass horizontally until the diameter of rivet- 
 hole line is met, then downward to the efficiency of net-section 
 scate, which we touch at about 86.5 percent. 
 
 We have taken one-half the pitch instead of the actual 
 pitch, so, remembering our formula, we have 
 P 
 
 \- ICO 
 
 6.5 + 100 
 
 = 93-25 percent, the least efficiency 
 
 of the quadruple butt joint just considered. 
 
 The efficiency of a quadruple butt joint as found above may 
 be taken as the smallest efficiency, so long as the diameter of 
 the rivet hole is double the thickness of the shell plate, but 
 when very thick plates are used it is not practical to use 
 rivet holes of a diameter twice the thickness of the steel, and 
 other modes of failure have to be considered. 
 
 For example, consider a case where ^-inch shell plates, 
 ij'^-inch rivets, i 3/16-inch diameter rivet holes, a pitch of 
 is;/ inches, and a quadruple butt joint are used. We find the 
 efficiency of the rivets to be slightly greater than no percent 
 
270 
 
 LAYING OUT FOR BOILER MAKERS 
 
 of the strength of the solid plate, and the efficiency of the 
 net section along the line of the outer row of rivets to be 92 
 percent of the strength of the solid plate. 
 
 Now we will determine the efficiency of the joint, consid- 
 ering the strength of the rivet "A" in shear, and the strength 
 of the net section "B-C" (see the drawing of the quadruple- 
 riveted butt joint on the chart). 
 
 First, find the efficiency of the rivet "A" by locating the 
 pitch of the rivets on left-hand scale and following the 
 method explained, until the thickness of plate line is met. 
 From this point follow the horizontal line until the diagonal 
 line marked rivet "A" in shear-net section "B-C" considered 
 is met. Then pass up the vertical line to the rivet-efficiency 
 scale, which we touch at 6.5 percent. This is the efficiency of 
 the rivet "A" in shear, to which we add the efficiency of the 
 net section along the line "B-C." The pitch of rivets along 
 this line is 7.75 inches, and the efficiency of the net section is 
 found to be 84.75 percent, making a total efficiency of 6.5 + 
 84.75 = 91 percent. 
 
 We will next determine the efficiency of rivets "A-B-C" in 
 shear and net section "D-C." Find the efficiency of the rivets 
 in same manner as used in the preceding case, except that we 
 pass vertically toward the rivet-efficiency scale from the point 
 where the diagonal line marked rivets "A-B-C" in shear-net 
 section D-E considered is met. We reach the rivet-efficiency 
 scale at the 19.5 percent division. The pitch of the rivets 
 along the line D-C is 3% inches, and we find the efficiency 
 of the net section to be nearly 69.5 percent. To this is added 
 the 19.5 percent efficiency of the rivets "A-B-C," making a 
 total efficiency of 89 percent, nearly, for this mode of fail- 
 ure. We have found that the efficiency of the rivets in shear 
 in this joint is over no percent; that the efficiency of the net 
 section, along the outer row of rivets, is 92 percent ; that the 
 efficiency of rivet "A" in shear and net section "B-C" is 91 
 percent; and that the efficiency of rivets "A-B-C" in shear 
 and net section "D-E" is but 89 percent. The latter efficiency 
 being the smallest, determines the strength of the joint. 
 
 The Area of Circular Segments. 
 
 In laying out a horizontal return tubular boiler it is neces- 
 sary to know how to figure out the area of a segment of a 
 circle. That part of the boiler head above the tubes must be 
 braced either by through or diagonal stays, and in order to 
 determine the size and pitch of these stays the area of this 
 portion of the head must be determined. 
 
 It may be safely assumed that the upper row of tubes in the 
 boiler will act as stays for a portion of the lower part of the 
 segment, and also that the flange of the head will serve to stay 
 the edge of the plate. There is no definite way of determining 
 just how much of the head is securely braced in this way, but 
 practice has shown that if 2 inches are allowed above the top 
 row of tubes and 3 inches from the edge of the flange, the 
 results will be well within the margin of safety. There is left, 
 then, as the area to be braced, the segment shown shaded in 
 Fig. I ; the diameter, length of chord and height of which can 
 be easily found. Since a strip 3 inches wide is considered to 
 be braced bv the flange of the head, the diameter of the circle 
 
 of which the shaded part is a segment, according to the dimen- 
 sions shown in Fig. I, is 72 — 6, or 66 inches. The height is 
 3S — (2-f 7), or 24 inches. One-half the length of the chord 
 is a mean proportional between the two parts of the diameter, 
 which it intersects at right angles, or 
 
 (chord \' 
 
 eight X (diameter — height). 
 
 The most direct way of finding the area of this segment 
 it to first obtain the area of the corresponding sector and 
 
 ^/W^M7M^,7^^ 
 
 OOOOOOT)OOOOOT 
 OQQQQQ -O QOOOQl 
 000000000000 
 000000000000 
 000000000000 
 0000000000 
 
 o 
 
 o 
 
 subtract from this the area of the triangle formed by the 
 chord of the sector and the radii to its extremities ; for in- 
 stance, in Fig. 2 the segment BCDE, whcih has a height of 18 
 inches, is equal to the area of the sector ABCD, minus the 
 area of the triangle ABED. It will first be necessary to find 
 the length of the chord BED. 
 
 Since BE is a mean proportional between CE and EF, (BE)' 
 = CE X EF; {BEY = 18 X 54 = 972; BE = 31.177, there- 
 fore, the length of the chord is 62.354 inches. 
 
 The area of a sector is equal to the length of the arc times 
 one-half the radius. If it were possible to measure directly 
 the length of the arc BCD this would be a simple calculation. 
 This, however, can seldom be done with any accuracy, and 
 therefore it is necessary to make use of trigonometry in order 
 to get the length of the arc. The length of the arc equals the 
 length of the cimcumference of the entire circle times the 
 number of degrees in the arc BCD (or in the angle BAD) 
 divided by 360. 
 
 Therefore, 
 
 circumference of circle X degrees in arc X radius 
 
 area segment 
 
 360 X 2 
 
 chord X (radius — height) 
 
 The number of degrees in the arc may be found by first 
 finding the angle BAC. The sine of this angle equals 
 BE 31-177 
 
 BA 
 
 36 
 
MISCELLANEOUS CALCULATIONS 
 
 271 
 
 Looking up the angle corresponding to this sine in a table of 
 natural sines and cosines, we find that the angle BAC is 60 
 degrees, and therefore the angle BAD, which is twice the angle 
 BAC, is 120 degrees, or the arc BCD equals 120 degrees. Of 
 course, in this particular case it will be seen at once that the 
 angle BAC is an angle of 60 degrees, since the side AB of the 
 triangle ABE is twice the length of the side AE. In nearly 
 every case, however, it will be necessary to make use of a table 
 of natural sines or natural tangents in order to determine the 
 number of degrees in this angle. 
 
 Having found these values, substitute them in the formula 
 for finding the area of a segment as follows : 
 
 3.1416 X 72 X 120 X 36 62.354 X 18 
 
 Height 
 
 Area 
 
 Area 
 
 360 X 2 2 
 
 Area = 1,357.171 — 561.186. 
 Area := 795.985 square inches. 
 While the above method is the exact method for finding the 
 area of a segment of a circle, it is by no means a simple and 
 convenient computation to make in practice, and it is prac- 
 tically useless unless a table of natural functions of an angle 
 
 iameter 
 
 
 .01 
 
 .001329 
 
 .02 
 
 .003749 
 
 •03 
 
 .006866 
 
 .04 
 
 .010538 
 
 ■05 
 
 .014681 
 
 .06 
 
 .019239 
 
 .07 
 
 .024168 
 
 .08 
 
 ■029435 
 
 .09 
 
 .035012 
 
 .10 
 
 .040875 
 
 .n 
 
 .047006 
 
 .12 
 
 .053385 
 
 • 13 
 
 ■OS9999 
 
 • 14 
 
 .066833 
 
 • IS 
 
 ■073875 
 
 .16 
 
 .081112 
 
 • 17 
 
 .088536 
 
 .18 
 
 .096135 
 
 .19 
 
 .103900 
 
 .20 
 
 .111824 
 
 .21 
 
 .119898 
 
 .22 
 
 .128114 
 
 ■23 
 
 .136465 
 
 •24 
 
 ■144945 
 
 ■25 
 
 .153546 
 
 Height 
 
 Area 
 
 Diameter 
 
 
 .26 
 
 162263 
 
 .27 
 
 171090 
 
 .28 
 
 180020 
 
 .29 
 
 189048 
 
 ■30 
 
 198168 
 
 .31 
 
 207376 
 
 ■32 
 
 216666 
 
 ■33 
 
 226034 
 
 ■34 
 
 .235473 
 
 •35 
 
 244980 
 
 .36 
 
 254551 
 
 .37 
 
 264179 
 
 .38 
 
 273861 
 
 ■39 
 
 283593 
 
 .40 
 
 293370 
 
 ■41 
 
 303187 
 
 .42 
 
 313042 
 
 .43 
 
 322928 
 
 ■44 
 
 332843 
 
 •45 
 
 342783 
 
 •46 
 
 352742 
 
 •47 
 
 362717 
 
 .48 
 
 372704 
 
 •49 
 
 382700 
 
 •50 
 
 •392699 
 
 There are a number of approximate rules for finding the area 
 of a segment which give results varying by only a few percent. 
 In the first place, the area of a segment may be computed by 
 Simpson's rule for finding the area of any irregular figure 
 bounded by curved lines. This rule is as follows : Given the 
 segment shown shaded in Fig. 3, first measure the length of 
 chord, 68 inches ; divide this chord into eight equal parts and 
 draw the vertical lines shown dotted at these points. Only 
 four of these lines are shown in the figure, as those on the 
 other side of the center line will have corresponding lengths. 
 
 is at hand. Therefore, it is necessary to use some more con- 
 venient, even if less accurate, method for finding this area. 
 
 Perhaps the simplest and most convenient method is to make 
 use of a table in which the area of the segment has been com- 
 puted for different ratios of height to diameter for a circle one 
 unit in diameter. Then multiplying this area by the square of 
 the diameter gives at once the required area of the segment. 
 The accuracy of this method depends upon the number of 
 decimal places to which the table is worked out. Such a table 
 is given below, and using the segment which is figured out 
 from Fig. 2, as an example, we find that the height of the 
 segment divided by diameter of circle = .25. Looking up .25 
 in the column of height divided by diameter, we find the cor- 
 responding area for a circle one unit in diameter ;= .153546; 
 • 153546 X (72)' = 795.983 square inches. 
 
 Measure the length of each of these vertical lines and then 
 multiply the length of the center line (25^^ inches) by i ; the 
 next one (24 inches) by 4: the next one (2024 inches) by 2, 
 and the last one (I4'4 inches) by 4. Add all of these products 
 together, multiply the sum by the base of the segment (68 
 inches) and divide the result by 12. This rule could be de- 
 pended upon for very good accuracy if the measurements could 
 be accurately made, but due to the difficulty of making ac- 
 curate measurements the rule is somewhat clumsy to use. 
 
 A modified form of the foregoing rule may be used, which 
 will give results with an accuracj' of 4 or 5 percent as against 
 an accurac}' of approximately i or 2 percent in the first case. 
 In this rule it is necessary to measure only the following dis- 
 tances : The chord (68 inches), the height (25^^ inches), and 
 the vertical line which divides the chord into quarters (20^ 
 
272 
 
 LAYING OUT FOR BOILER MAKERS 
 
 inches). Add the length (255^ inches) to 4 X 20^. Multiply 
 the sum by the base (68) and divide by 6. 
 
 A somewhat rougher approximation for the area of a seg- 
 ment may be obtained, as shown in Figs. 4, 5 and 6, where 
 the area of the entire semi-circle is first obtained, and then 
 an area equivalent to the difference between the entire semi- 
 circle and the segment is subtracted from this. The area of the 
 entire semi-circle is 5^ X 3.1416 X R'- The area to be sub- 
 tracted from this can be approximated in either of the foUow- 
 
 taken as a rectangle whose length is a mean between the 
 diameter of the circle and the length of the chord, the height 
 being the same as in the previous cases. The error due to 
 using either of the last three rules is likely to run up to 5 
 percent or over, and therefore they should be used only when 
 an approximate value is desired. 
 
 The following rule has been devised by the editor which 
 can be used with ease and accuracy whenever the height of the 
 segment is greater than one-half the radius of the circle. As 
 
 FIG. 5. 
 
 FIG. 9. 
 
 ing three ways : In Fig. 4 this area is considered as a rectangle 
 whose base is equal to the diameter of the circle, and whose 
 height is equal to the difference between the radius of the 
 circle and the height of the segment. This area is evidently 
 too large, and therefore the area of the segment will be too 
 small. In Fig. 5 the equivalent area is taken as a rectangle 
 whose base is equal to the length of the chord and whose 
 height is equal to the difference between the radius of the 
 circle and the height of the segment. This area is evidently 
 too small, and therefore the resulting area of the segment will 
 be too large. A closer approximation is shown in Fig. 6, where 
 the equivalent area to be subtracted from the semi-circle is 
 
 in the foregoing rule, first find the area of the semi-circle and 
 
 from this subtract the area of the rectangle, shown dotted in 
 
 Fig. 7. The width of this rectangle is equal to the difference 
 
 between the radius of the circle and the height of the segment. 
 
 Its length is equal to the length of the base or chord of the 
 
 segment plus .676 times the difference between the diameter 
 
 of the circle and the length of the chord. For the dimensions 
 
 shown in Fig. 7, the exact area of the segment, as given by the 
 
 table, is as follows : 
 
 height 
 
 = .3. Area of a segment of this ratio of height to 
 
 diameter 
 
 diameter in a circle one unit in diameter is given as .198168. 
 
MISCELLANEOUS CALCULATIONS 
 
 ■3 
 
 iMultiplying this by the diameter squared ,198168 X 60" = 
 713.4048 square inches. 
 
 The area of a segment, according to the rule just given, is 
 as follows: The area of the semi-circle equals 3.1416 X 30" = 
 1,413.72 square inches. One-half the length L is a mean pro- 
 portional between the height of the segment and the diameter 
 
 r L y L 
 
 minus this height. 1 herefore, I I ^ 18 X 42, or 
 
 ^= 27.49 and L = 54.98 inches. Therefore the length of the 
 equivalent rectangle is 54-98 + .676 X (60 — 54.98) = s8.37.35 
 inches. This length times the width of rectangle (12) equals 
 700.4822 square inches, the area of the rectangle. The area of 
 the semi-circle, which was found to be 1413.72, minus the area 
 of the rectangle, equals 713.2378 square inches. Comparing 
 this value with the exact area we find the error to be only 
 .023 percent. Calculating the area of the segment accurately 
 by means of a table and then by the method just given for 
 segments 6. 12, 18 and 24 inches in height for a circle 60 inches 
 in diameter, shows that where the height of the segment is 
 greater than one-half the radius, in this case greater than 15 
 inches, the percentage error from using this rule is very small 
 indeed, being only a few hundredths percent. For the smaller 
 segments the percentage rapidly increases, so that for the 
 segment only 6 inches high the percentage error is nearly 9. 
 These results, tabulated in the following table, have been 
 
 .-VREA OF SEGMENTS IN 60-INCH CII-iCLE 
 
 Height of Area Figured Area Figured by Percentage Error 
 
 Segment. from Table. Short Rule. of Short Rule. 
 
 6" 147-15 160.344 8.96 
 
 12" 402.5664 403704 .282 
 
 18" 713-4048 7^3-2378 -C26 
 
 24" 1056.132 IO56.0917 .CO26 
 
 plotted in Fig. 9 on the bases of the corresponding segments 
 and a smooth curve drawn through the points. This curve 
 shows then in a rough way the percentage of error which 
 might be expected from using this rule. The accuracy of the 
 rule where the height of a segment is greater than one-half the 
 radius is very apparent. Furthermore, the rule is very easy to 
 use, as it is simply necessary to remember or have noted down 
 in a convenient place the constant .676 used in finding the 
 length of the equivalent rectangle. 
 
 Two good rules for finding the area of a segment which are 
 not generally known were given in a recent issue of The 
 Locomotive. The first of these was devised by Mr. C. E. 
 Piatt, inspector of the Southeastern Department of the Hart- 
 ford Steam Boiler Inspection & Insurance Company, and 
 gives a sufficient degree of approximation for most practical 
 purposes, and furthermore is easy to use. It is as follows : 
 "Subtract the height of the given segment from the radius of 
 the circle and multiply the result by the diameter of the circle, 
 diminished by I inch. Subtract the product so found from the 
 area of the semi-circle of which the segment forms a part, and 
 the result is the approximate area of the segment. All meas- 
 urements are to be made in inches." It will be seen that this 
 rule is similar to the one last mentioned except that, instead of 
 taking the area of a rectangle whose length varies according to 
 the difference between the diameter of the circle and the base 
 
 of the segment, tlie length of the rectangle is in every case 
 taken I inch less than the diameter of the circle. 
 
 The other rule was devised by the editor of The Locomo- 
 tive, and although somewhat complicated, gives very accurate 
 results and can be solved by simple arithmetic. Quoting the 
 explanation of this rule as given by the author : 
 
 "The measurements that must be known in order to apply 
 this more accurate approximate formula are shown in Fig. 9. 
 The shaded area A here represents the segment whose area is 
 to be determined, and CD is a diameter of the circle to which 
 the segment belongs, CD being parallel to the base of the seg- 
 ment EF. The lengths denoted by the various letters in the 
 diagram will be apparent without explanation, with the possible 
 exception of M, which is the distance, measured in a straight 
 tine, from F, the extremity of the base of the segment, to D, 
 the corresponding extremity of the diameter CD. The lines 
 R. H, L and M can all be directly measured if desired, but it 
 is not necessary to measure more than two of them, since when 
 two are known the others can be calculated. For example, if 
 we measure R, the radius of the circle, and H, the perpen- 
 dicular distance from the center of the circle to the base of the 
 segment, then we may calculate L and M as follows : For 
 finding L we have the relation L' = {R -{■ H) (R — H) ; 
 and when L has been obtained in this manner, we may find M 
 from the relation M'' = 2R (R — L). 
 
 "When we know R, H, L and M, either by direct measure- 
 ment or otherwise, we may obtain a very accurate value of the 
 area A (except when the height of the segment is very small) 
 by means of the formula : 
 
 (R \ 4i?il/ 
 L I 
 
 "The first term to the right of the sign of equality represents 
 the area of the semi-circle, the number 1.5707693 being one-half, 
 of the familiar decimal number 3.1415926, by which the square 
 of the radius must be multiplied, in order to obtain the area of 
 the whole circle. 
 
 "The area of a segment 18 inches high, in a circle 72 inches in 
 diameter, is found, by this formula, to be 796.09 square inches, 
 whereas, the true area of such a segment was found to be 
 795.58 square inches. In this case, therefore, the approximate 
 formula last given is in error by only about o.ii square inches, 
 or by about one-eightieth part of i percent. The formula gives 
 results that are still more accurate, when the segment is more 
 nearly equal to a semi-circle." 
 
 Estimating the Cost of a Small Scotch Boiler. 
 
 In the following an estimate is made of the cost of building 
 a Scotch boiler capable of carrying 125 pounds working pres- 
 sure which is 42 inches in diameter, 84 inches long, containing 
 one furnace 22 inches in diameter and twenty-three 2!/-inch 
 tubes. The segment of the heads in the steam space is braced 
 by two 2j4-inch through stays. The top of the firebox is 
 stayed from the shell of the boiler by staj'bolts. 
 
 The first thing to do is to find the thickness of shell plate 
 necessary to withstand a working pressure of 125 pounds per 
 square inch. The British Board of Trade and the Canadian 
 
274 LAYING OUT FOR BOILER MAKERS 
 
 Marine Rules, which are ahnost identical, give the following will be 60,000. Using a plate 33/64 inch thick for the furnace, 
 
 formula for the strength of a cylindrical boiler shell: 60,000 X (33/64)- 
 
 ■.,., n • -J J- t c ^u u„ii • ■ !,„„ . , \ve find for the working pressure ::=ii6 
 
 uhere D = inside diameter of the shell in inches; t ^ ^^ ('^2<-l-i")V2^ 
 
 thickness of shell plate in inches : /t ^ tensile strength of the , . ,,. ,„ ,. ,. ..i,- • , ^ j 
 
 ^ '' ° pounds. Adding 10 percent to this gives 127.6 pounds as a 
 
 plate in pounds per square inch; P = safe working pressure ^^,^^^.^^ pressure. As we are building a boiler to withstand 
 
 of steam in pounds per square inch; E = efficiency of riveted ^^|^, ^^. ^^^^^^^ .^ ^^..^^ ^^ ^^^^ ^^^^ ^ ^^^^^^^ ^^ ^^.^ ^^^ 
 
 joints (the least to be taken) ; F = factor of safety. ^^/g^ .^^^ .^ thickness will be sufficiently strong. Other rules 
 
 -.., ^ will probably not require such a thick plate, and as it is de- 
 
 2/t X E sirable to have the furnace wall as thin as possible consistent 
 
 Assuming a double riveted lap joint with an efficiency of with strength, it would be better to use a 7/16-inch plate for 
 
 125 X 42 X S this purpose. 
 
 70 percent and a factor of safety of 5 ; then f = T,^^ ^-.^^ ^^ ^j^^ f^,^^^^^ pj^^^ ^^^1^ ^^ ^^ ^^ g. ^^ ^/jg_ 
 
 2 /\ 00,000 /\ ./O 
 
 __ J,,. ^^ ,/jg j^j.1, Therefore, its weight would be 72 X 65 X 4365 X 2833 = 
 
 If the holes are all punched small and afterwards reamed ■' 
 
 ^ r • .lu 1 I i. 1 ^ J 1 J 4.1 The back head before flanging is 47 inches in diameter by 
 
 out fair, the plates taken apart and burrs removed, then a sat/ j 
 
 .- ^ c c ^ t . X. J T »u- n 1 ■ 5/16 inch thick. Therefore, its weight would be (47)" X 
 
 factor of safety of 4.5 may be used. In this case the working -^ ' ° ^^' ' ^^ 
 
 2 X .3125 X 60,000 X .7 ''^^^^ ^ '•^'^^ ^ '^^^^ ~ ^^'^ pounds. The front head is also 
 
 pressure P^ =138.8 pounds. 47 inches in diameter, but would be Ys inch thick. Therefore, 
 
 '^^'^■^ its weight = (47)- X -7854 X .375 X .2833 = 185 pounds. 
 
 The boiler would be allowed 125 pounds pressure if ^-inch r^^^ ^^^^^ ^^^^^ .^ ^^ ^^ ^^ ^^ ^ ;^^^,^^ ^^^ ^^^^j^ ^^^^j^^ ^^^ 
 
 plate were used with double riveted butt straps; but in this ^^^^^^_ ^.^^ ^^^^ ^^ ^^^ ^^^^^^ i^ ^^ ^y 3^ by 5/16 inch, 
 
 estimate s/i6-inch plate will be used with a lap joint. ^„^ ^^^j^ ^^^^^ ^^g ^^^^^^_ ^j^^ ^i^^^ ^^^ ^^^^^ ^^ ^^^ 
 
 The size of the shell plate can now be determined. Its g^^^^^ ^^^,,j ^^ ^^^^^ ^^^^ ^ ^^^^^ ^^^ j^^^^^ j^^ ^^^ ^^ 
 
 width, of course, is equal to the length of the boiler, 84 inches. -^^^^^ ^-^^ ^^ ^/^g -^^^ ^^-^^^^ ^,,^5^^^ ^^^^^j^ ^^.^^ ^^^ ^^^^^^_ 
 
 Its length is equal to the circumference of a circle the diam- ^^^ ^^^^j ^^^-^^^ ^^ p,^^^ ^^^^^ -^ ^^^ ^^.^^^ ^^^^ ^^^^ ^^ 
 
 eter of which is measured to the center of the thickness of ^^^^^^ ^p ^^ follows: 
 
 the plate. The inside diameter of the boiler is 42 inches, 
 
 Pounds, 
 
 and the thickness of the plate is 5/16 inch. Therefore, the Shell ulate 
 
 mean diameter is 42 5/16 inches. The circumference, corre- Furnace 580 
 
 sponding to this 42 5/16 X 3-i4i6 = 132 15/16 inches. Allow- Back end of boiler 154 
 
 ing 454 inches for the lap and waste in trimming, the actual Front end of boiler 185 
 
 size of the shell plate is 1321.4 by 84^ by 5/16 inch. The . ^^^^ ^^^^ , ^^^ 
 
 Back of firebox 116 
 
 weight of a cubic inch of mild steel is .2833 poimd. There- gj^^^ ^„j ^^^^^„ ^^ ^^^^^^ j, ^ 
 
 fore, the weight of the shell plate equals 137.5 X 84.5 X ■3125 
 
 X .2833 = 1,029 pounds. '^°'^' -'354 
 
 Having determined the size and weight of the shell plate, j^ ^^,ijj ^^ ^^^^^ ^^^^ ^^^ illustration that in the original 
 
 the next item is the furnace and the main flue. The Canadian ^^j,^^ ^„ ^^.^^ ^^p^;^^ ^^^^ ^^^^ ^^_.^ ^^^^ ^^j^ ^^^^ 
 
 Marine Rules on furnaces and flues are as follows: *v,,„„„i, „,..,,,.- ,.„„„„,*• ,.i,„ 1, j • *t, ,. tu 
 
 through stays supporting the heads in the steam space. I he 
 
 \\r^^\.;„„ nno^o,,,-.. total area to be supported in each head is 220 square inches, 
 
 v\ orK.ing pressure — 
 
 (L-f-l) Xi? or lio square inches per stay. It is now necessary to find 
 
 Where t is the thickness of the furnace in inches; L the what working pressure these stays are capable of withstand- 
 
 length of the furnace; D the diameter of the furnace, and C ing. The formula for the working pressure of a flat surface 
 
 a constant determined as follows : stayed at regular intervals is : 
 
 C ^ 90,000, when the longitudinal seams are double riveted (7 (i6X t-\-i)^ 
 
 and fitted with single butt straps, or single riveted and fitted -^^ ~ ' 
 
 o — ^ 
 with double butt straps ; C = 65,000, when the longitudinal 
 
 „ , •■^j-i -.i ji ij/- £ Where t = thickness of plate in inches ; i" = surface sup- 
 seams are lap jointed, single riveted and beveled; C = 60,000, ^ , ^ ^ a ^ t, 
 
 when the longitudinal seams are lap jointed, single riveted, P°^'^'* ^^ °"^ ^'^^ '" =1"^^^ ^"*«= ^ = ^°'"'^'"= P'^'"'''^ '" 
 
 punched and not beveled. P°""^' P^' "^''^'^ '""=^; ^ = ^ '=°"^'^"* ('" ^^'^ ^^'^ '"S)- 
 
 T i 1 ij u J 1 J i ii 1^ ■ 1 ^u Substituting as follows in the above formula we have: 
 
 Ten percent should be added to the result given by the ^ 
 
 above formula, providing it does not exceed that found by the '-5 (l" X -3125 -|- l)" 
 
 , „ . , , ^43 pounds working pressure per 
 
 following formula; no 6 
 
 9,000 X thickness of plate in inches ^^^^^ i^^j^. ^^ p^^,^^^ p^^ ^^^^^^ ;_^^j^ j^ ^^^^^ ^^^ ^.^^^^^^ 
 
 Outside diameter of flue in inches. working pressure that could be carried on the old boiler after 
 
 As the furnace in the boiler for which we are giving an it was repaired, unless additional stays were placed in the 
 
 estimate is only single riveted, and not beveled, the constant steam space. 
 
MISCELLANEOUS CALCULATIONS 
 
 275 
 
 Solving for 5, the area to be supported by one stay at 125 
 
 125 (16 X -3125 + 1)- 
 
 pounds working pressure, we find 5" = 
 
 125 + D 
 
 + 6 = 42 square inches. The diameter of the stay rod may be 
 
 found from the following formula : 
 
 Let d = least diameter of stay in inches ; ; = area supported 
 by one stay in square inches; P ^ working pressure in pounds 
 per square inch ; K = constant ; / ^= safe stress allowed on 
 one stay in pounds per square inch. 
 
 Value of A' = .0168 .0160 .0146 .0140 .0135 .0130 .0126 
 / = 4,500 5,000 5,500 6,000 7,000 7,500 8.000 
 
 Wrought iron stays, made from solid bars, which have not 
 been worked in the fire, are allowed a stress of 7,000 pounds. 
 
 Therefore, from the preceding table, K = .0135. The 
 formula is rf = 7v X V~P X A. Solving, d = .0135 X 
 V 125 X 42 = .978 inch. 
 
 Therefore, the least diameter of the stay, or the diameter 
 at the bottom thread, must be as great as .978 inch. A i]i- 
 
 the total number of holes to be punched in the shell plate is 
 274. The punch would average about five holes per minute, 
 so that the plate could be slung and punched in one hour. 
 Cost, one puncher one hour at 17 cents ; two helpers, one hour 
 each at 15 cents; total, 47 cents. Shearing the inside of the 
 lap joint, turning over the plate, beveling three edges in the 
 bevel shears, turning over the plate again, thinning out two 
 inside corners of the plate at the fire, and then rolling up 
 the plate would take one boiler maker an hour and a half at 
 24 cents per hour ; two helpers one hour and a half each at 
 15 cents; total cost, 81 cents. 
 
 In the furnace plate there are 140 holes to be punched, which 
 would take one puncher one-half hour, two helpers one-half 
 hour each, making a total cost of 23H cents. Beveling the 
 two ends, thinning out two corners of the plate at the fire 
 and rolling up would take one boiler maker one hour ; two 
 helpers one hour each ; making the total cost 54 cents. 
 
 The plates for the heads are each 47 inches in diameter. 
 Therefore they can be flanged in one heat. The inner tube 
 
 SMALL SINGLE-FUSNACE SCOTCH BOILER. 
 
 inch screw stay, seven threads to the inch, is 1.067 inches in 
 diameter at the bottom of the thread. It would be necessary 
 to use five of these with double nuts and washers, the wash- 
 ers to be at least three times the diameter of the stay and 
 two-thirds the thickness of the plate. Stay bars, i}4 inches 
 diameter, 36^^ feet long at 4 pounds per running foot, would 
 weigh 146 pounds. The balance of the total cost of the mate- 
 rial for the boiler is, therefore, as follows : 
 
 146 pounds of stay-bar iron at 2 cents a pound $2.98 
 
 10 pounds of nuts and washers at 2% cents per pound. . .25 
 
 126^ feet, 2jX-inch diameter, tubes at 15 cents per foot. 18.98 
 
 no pounds of rivets at 3H cents per pound 3.85 
 
 82 staybolts (70 pounds) at 2 cents per pound 1.40 
 
 3 handhole doors with covers 3.00 
 
 3 gaskets for handhole doors 30 
 
 2,354 pounds of plate at $2.10 per hundred pounds. ... 49.43 
 
 Total cost of material for new boiler $80.13 
 
 We will get an estimate of the cost of labor by taking up 
 each operation in turn and finding how many men will be 
 required to do each part of the work and how long it will 
 take them. 
 
 In the first place, laying out the boiler would take one layer- 
 out about ten hours, and at 25 cents an hour this would cost 
 $2.50. As there are seventy-two holes to be punched in each 
 end of the shell plate, and sixty-five for the longitudinal seam. 
 
 sheet and back of the firebox can also be flanged in one heat ; 
 all four plates being finished in three hours, including chang- 
 ing the dies, or formers. The men required would be one 
 boiler maker at 24 cents an hour; three helpers at 16 cents 
 an hour each. Therefore, the total cost for three hours' 
 work would be $2.16. The front end and tube sheet are then 
 marked for the furnace holes. Punching the furnace holes 
 would take one puncher half an hour, and two helpers half 
 an hour each ; making the total cost 23^ cents. The front 
 head and tube sheet then go back to the flanger, and the hole 
 is flanged in each plate in one heat ; the time for flanging out 
 furnace holes would be one boiler maker an hour and a half ; 
 three helpers an hour and a half each; total cost, $1.08. 
 
 Punching seventy-two holes around the flange of each head 
 and also the holes around the flange of the tube sheet and 
 back of firebox, as well as all staybolt holes for J'g-mch stay- 
 bolts and three small hand holes, will take one puncher an 
 hour and a half ; two helpers an hour and a half each ; total 
 cost, yoyi cents. Drilling forty-six pilot holes and cutting out 
 forty-six tube holes for 2j^-inch tubes will take one helper 
 eight hours, at 17 cents an hour; total cost, $1.36. Fitting the 
 tube sheet on the furnace and fitting out the firebox will take 
 one boiler maker twenty hours; two helpers sixteen hours 
 each ; making a total of $9.60. Reaming rivet holes will take 
 two helpers five hours at 15 cents an hour; total cost, $1,50. 
 
 Riveting in the front head and the lap joint of the shell on 
 
276 
 
 LAYIXG OL'T FOR BOILER .MAKERS 
 
 the bull niacliinc would taUe one hands man two and one-half 
 hours, at 20 cents an hour; one helper two and one-half hours, 
 at 16 cents per hour; and one boy two and one-half hours, at 
 10 cents an hour. Riveting the lap joint of the furnace around 
 the flange of the inner tube plate, one handy man an hour 
 and a half; one helper an hour and a half; one boy an hour 
 and a half. Riveting the sides and top of the firebox to the 
 tube sheets, and also riveting up the furnace mouth and back 
 end of the boiler after it is in place would take one handy 
 man two and one-half hours ; one helper two and one-half 
 hours; one boy two and one-half hours. The total cost, there- 
 fore, for hydraulic riveting would be $2.99. 
 
 Riveting the back of the firebox by hand ; two boiler makers 
 three hours each : one helper three hours ; one boy three 
 hours ; total cost, $2.22. Drawing the furnace into the boiler, 
 bolting up, etc., will take a boiler maker five hours and a 
 helper five hours ; total cost, $1.05. 
 
 The staybolt work includes tapping of staybolt holes, run- 
 ning in the staybolts, setting them and cutting them oflf, and 
 would require two helpers eight and one-half hours each, at 
 16 cents an hour : making a total cost of $2.92. Riveting up 
 the staybolts would take two boiler makers nine hours each, 
 and one helper nine hours ; total cost, $5.76. 
 
 Getting the new tubes from the store room and grinding of? 
 the sharp edge from one end of each tube would take a boy 
 about an hour and a half, costing 15 cents. Inserting and ex- 
 panding the tubes would take a boiler maker ten hours at 24 
 cents an hour, costing $2.40. Inserting five through stays in 
 the steam space would take a boiler maker four hours at 24 
 cents an hour, one helper two hours at 15 cents an hour; 
 making a total of $1,26. 
 
 The remaining work on the boiler includes calking, which 
 one boiler maker could do with an air hammer in ten hours, 
 at a cost of $2.40; testing the boiler with hydraulic pressure, 
 requiring two boiler makers seven hours each at 24 cents an 
 hour, at a total cost of $3.36; also in the staybolt work no 
 account was taken of the time necessary for heading and 
 threading the staybolts and stay bars. Heading the stay- 
 bolts in a bolt machine will take one handy man half an hour 
 at 22 cents per hour, at a total cost of 11 cents; and thread- 
 ing the staybolts and stay rods would take one handy man 
 two hours at 18 cents an hour, at a total cost of 36 cents. 
 
 Having determined the number of men required, the time 
 taken and the cost of each operation in building the boiler, we 
 can now- tabulate the total cost of labor as follows : 
 
 Laying out 
 
 Punching shell plate 
 
 Planing and rolling shell plate 
 
 Punching the furnace plate 
 
 Planing and rolling furnace plate 
 
 Flanging heads with the hydraulic press.... 
 
 Punching furnace holes 
 
 Flanging furnace holes 
 
 Punching rivet holes in flanges of heads.... 
 
 Drilling tube holes 
 
 Fitting up the firebox 
 
 Reaming rivet holes 
 
 Riveting, hvdraulic machine 
 
 $2.50 
 
 •47 
 
 .81 
 
 ■23H 
 
 •54 
 2.16 
 
 •23'/< 
 1.08 
 
 .70/. 
 1.36 
 9.60 
 I. SO 
 2.99 
 
 $24.i8'X 
 
 Urought forward $24.18^ 
 
 Riveting by hand 2.22 
 
 Fitting the furnace into the shell i 
 
 Tapping holes and fitting staybolts 2 
 
 Riveting staybolts 5 
 
 Grinding tube ends 
 
 Inserting and expanding tubes 
 
 Fitting up the through stays 
 
 Calking 
 
 Testing 
 
 Heading staybolts 
 
 Threading stavs 
 
 95 
 •..72 
 ■,■76 
 • 15 
 
 !.40 
 
 :.26 
 
 !.40 
 
 (■36 
 .11 
 .36 
 
 Total estimated cost of labor $46,875/2 
 
 Total for material 80.1s 
 
 Total for material and labor $127.01 
 
 One hundred and twenty-seven dollars and one cent repre- 
 sents merely the cost of material and labor in the boiler, and 
 makes no allowance for depreciation of machinery and other 
 fixed charges. In this case 30 percent of the cost of material 
 and labor will be taken as the amount of fixed charges. This 
 might vary in different shops, depending on the kind of 
 equipment which the shop has, the facilities for handling 
 material, etc. 
 
 Thirty percent of $127.01= $38.10; $127.01 + $38.10 = 
 $165.11, the cost of the boiler. To this must be added a cer- 
 tain percentage for profit to get the selling price to be quoted 
 to the purchaser. Allow'ing 10 percent for profit, the selling 
 price would be $181.62. Therefore, the price quoted for the 
 boiler, exclusive of mountings, such as valves, up-take, etc., 
 would probably be $185. 
 
 Estimating the Cost of a Return Tube Boiler. 
 
 There are no hard and fast rules that can be laid down for 
 figuring out the cost of a boiler. The price of labor will vary 
 considerably in diiiferent manufacturing plants. Then, on ac- 
 count of freight rates, etc., one firm will be able to lay dow-n 
 the material much more cheaply than its competitor, who may 
 be situated at a greater distance from the source of supply. 
 Again, the facilities for handling the work in the shop are 
 hardly ever the same in any two plants, costing much in some 
 and little in others. The labor in one shop may be of better 
 quality than in others, and so on, all of which goes to show 
 that, as has been stated, no hard and fast rules can be laid 
 down in estimating the cost of a boiler before any work has 
 been done on it. 
 
 The object of this article, therefore, is to show how the 
 cost of a boiler is estimated in instances which have come 
 under the writer's observation, and perhaps it ma}' serve as a 
 guide to those whose duty it is to figure on similar boilers or 
 any other type of boiler, tank or stack. 
 
 It is obvious that at the outset one should know the dif- 
 ferent stages of manufacture, the men employed and the ap- 
 proximate time it takes to complete each stage. The following 
 table gives the various stages gone through ; the number of 
 men employed and the average wage of each one in the par- 
 ticular shop in which the boiler we are about to consider is 
 to be built : 
 
MISCELLAXEOUS CALCULATIONS 
 
 277 
 
 Stage 
 Laying out. . . 
 
 Shearing 
 Punching [ each . 
 Rolling 
 Planing 
 
 Wage 
 Men Employed Per Hour 
 
 . I layerout $0.40 
 
 I assistant 20 
 
 1 handy man 
 
 2 helpers .. . . 
 
 .iS 
 
 .10 each 
 
 Flanging 
 
 Cutting tube holes. 
 Riveting 
 
 ( bull machine) . 
 
 Riveting 
 
 (,air machine) . . 
 
 . I handy man uS 
 
 1 helper 16 
 
 . I Hanger 30 
 
 2 helpers 16 each 
 
 . I handy man 18 
 
 . I riveter 18 
 
 2 helpers 16 each 
 
 Making stays, crow- 
 feet, etc 
 
 I riveter . . 
 I holder-on 
 I rivet bov 
 
 .22 
 ■17 
 .10 
 
 Inserting stays.. 
 Inserting tubes. 
 
 Calking . 
 Painting 
 
 I blacksmith 30 
 
 I hammer man 18 
 
 I man 25 
 
 I helper 16 
 
 I man , 25 
 
 I helper 16 
 
 I man 20 
 
 I painter 22 
 
 In addition to the above must be added the cost of testing 
 and shipping the boiler. The total cost of this for any size 
 boiler can easil}- be covered by $10.00. 
 
 We will assume that we have had an inquiry from some 
 person who desires a quotation on one horizontal return tubu- 
 lar boiler /2 inches diameter and 18 feet long, containing 
 seventy-four 4-inch tubes, to be built for a working pressure 
 of 125 pounds per square inch, and to be built "open for in- 
 spection'' under the rules for the Inspection of Steam Boilers 
 for British Columbia. The above rules have been chosen, 
 as they are the stiffest and best defined of the Canadian rules 
 for land or stationary boilers. 
 
 The cost of a boiler will invariably depend upon the working 
 pressure, because it is this pressure which will (under all 
 inspection rules) determine the thickness of plate, the style of 
 joint, etc. Therefore, first determine the thickness of plate 
 and style of joint necessary for the boiler when the holes have 
 all been punched full size before bending, which is, of course, 
 the cheapest method. Now, the least expensive joint is an 
 ordinary lap joint, so we will see what the least thickness of 
 plate is which we may use with this joint, making it treble 
 riveted. 
 
 According to the British Columbia laws: 
 "When cylindrical shells of boilers are made of the best 
 material (either iron or steel) with all holes drilled in place, 
 the plates afterwards taken apart and the burrs removed, and 
 all longitudinal seams fitted with double-butt straps, each at 
 ' least five-eighths the thickness of the plates they cover, the 
 seams being double riveted with rivets having an allowance 
 of not more than 75 percent over single shear, and having the 
 circumferential seams constructed so that the percentage is at 
 least one-half of that of the longitudinal seams and provided 
 that the boiler has been open for inspection during the whole 
 period of construction, then 4 may be used as a factor of 
 safety. 
 
 "But when the above conditions have not been complied with 
 the additions in the following scale must be added to the 
 factor of safety according to the circumstances of each case : 
 
 ".15— To be added if all holes arc fair and good in tlie cir- 
 cumferential seams but punched before bending. 
 
 ".3— To be added if all holes are fair and good in the longi- 
 tudinal seams but punched before bending. 
 
 ".07— To be added if double-butt straps are not added to the 
 longitudinal seams and the said seams are lap and treble 
 riveted." 
 
 According to our assumption then and the above rules, our 
 factor of safety will be 4.52. 
 
 The next point we must consider is the pitch of the rivets, 
 in order that we may figure the percentage strength of the 
 joint. The British Columbia rule governing the pitch is 
 exactly the same as that of the British Board of Trade. It 
 depends upon the thickness of the plate as well as the style 
 of joint. Thus we have one more assumption to make, viz.: 
 the thickness of plate we should use with our boiler having a 
 treble riveted lap joint. 
 
 Let us assume 7/16 inch to be the thickness of plate, and 
 figure through to see if we will be allowed 125 pounds per 
 square inch working pressure on the boiler. For the pitch we 
 have CXT + iys = P where 
 C =^ Constant = 3.47. 
 r= Thickness of plate. 
 P = Maximum pitch. 
 Substituting values we have 
 
 3-47 X. 4375 + 1?^ = 3- 143, or S'A inches. 
 Using M-inch rivets in 13/16 holes, this value of P gives us 
 in the formula for percentage strength of plate. 
 
 (3.12s — .8125) X 100 
 = 74 percent. 
 
 3-125 
 If this percentage is less than that of the rivet section it will 
 be the one used in figuring the working pressure. To consider 
 the rivet section, the British Columbia laws give us the follow- 
 ing formula for finding the percentage strength : 
 
 looX A X N X y X C X F 
 = percent, 
 
 4X r xP XT 
 
 where A = area. of rivet when driven (in square inches). 
 Af^ number of rivets in one pitch. 
 F = 23 for steel plates and steel rivets. 
 C=i for lap joints and i.yS for double-butt strap 
 
 joints. 
 F= factor of safety. 
 I" — 28 for steel plates and steel rivets. 
 P = pitch. 
 
 T^thickness of plates (in inches). 
 Substituting we have 
 
 100 X .5184 X 3 X 23 X 4.52 
 
 4 X 28 X 3-125 X .4375 
 The British Columbia formula for findi 
 sure is 
 
 Ts X r X 2r 
 
 = 105 percent, 
 ig the working pres- 
 
 = B, 
 
 where 
 
 D X F 
 
 Ts = tensile strength of plate. 
 ;-= smallest percentages divided by 100. 
 T — thickness of plate in inches. 
 D — inside diameter of largest course in inches. 
 
278 
 
 F=: factor of safety. 
 5 = working pressure. 
 Substituting we have 
 eo,ooo X -74 X -875 
 
 LAYING OUT FOR 
 
 119 pounds per square inch. 
 
 72 X 452 
 Therefore, 7/16-inch plate is too thin. 
 
 Trying ^-inch plate and following through as above we get 
 the maximum pitch to be zVi inches, percentage of plate 76, 
 percentage of rivet section 85.6, and working pressure 140 
 pounds per square inch. Therefore, if we desire, we may use 
 ^-inch plate and ^-inch rivets with treble riveted lap joints. 
 
 Now, let us see what thickness of plate we could use with a 
 double-butt strap treble riveted joint, in which case we would 
 have two inside rows of rivets through both straps and plate, 
 and the outside row through one strap (the inside one) and 
 plate. Our factor of safety in this case would be 4 plus the 
 following : 
 
 .3 to be added if holes are fair and good in the longitudinal 
 seams but punched before bending. 
 
 .15 to be added if all holes are fair and good in the circum- 
 ferential seams but punched before bending, making a total 
 of 445- 
 
 In figuring the pitch for this style of joint the same formula 
 is used as before, but the constant changes. This constant is 
 3.5, and not 4.63, as one might be led into thinking, by the fact 
 that the joint is called "treble" riveted. The reason the con- 
 stant is 3.5 and not 4.63 is because there are only two rows 
 of rivets in double shear, hence to find the maximum pitch 
 we treat the joint as though it were a double-riveted, double- 
 butt strap joint, and omit every other rivet in the outer row 
 to make the percentage strength of the plate higher. If we 
 extend the outer strap to take in these rows of rivets the large 
 pitch would raise difficulties in calking the boiler, although 
 the joint would be stronger through the rivet section. 
 
 Our pitch, therefore, becomes for the inner rows using 
 7/16-inch plate, 
 
 (3-5 X -4375) + 1-625 — 3-156, or 3^ inches, 
 making the pitch of the outer rows 6J4 inches. 
 
 Now, we have three percentages to find, viz. : 
 
 (i) The percentage strength of the plate, which will be that 
 at the outer row of rivets. 
 
 (2) The percentage strength of the rivet section, which will 
 \)<t that of the two inner rows added to that of the outer row. 
 
 (3) The combined percentage strength of plate and rivet 
 section, which will be the percentage strength of plate at the 
 inner rows added to that of the rivets of the outer row. 
 
 For (i), with 54-inch rivets and 13/16-inch holes, we have 
 
 (6.25 — .8125) X 100 
 
 ^ 87 percent. 
 
 6.2s 
 For (2) 
 
 100 X .5184 X 2 X 23 X I-7S X 4-45 
 
 + 
 
 4 X 28 X 3-125 X .4375 
 
 100 X .5184 X I X 23 X I X 4-45 _ 
 
 4 X 28 X 6.25 X -4375 
 
 121 -j- 17 =: 138 percent. 
 For (3) 
 (3-125 — .8125) X 100 100 X -5184 X I X 23 X I X 4-45 
 
 4 X 28 X 6.25 X .4375 
 
 74 -f- 17 ^ 91 percent. 
 
 3-I2S 
 
 BOILER AIAKERS 
 
 So by using the smallest of these percentages, 87, our allow- 
 able working pressure is 
 
 60,000 X -87 X -875 
 
 ^ 142-5 pounds per square inch. 
 
 72 X 4-45 
 This is in excess of what we want, but if we use ^-inch plate 
 we could get only 120 pounds, so we will use 7/16-inch plate 
 if we decide on this style of joint. 
 
 We have, therefore, the option of using ^-inch plate and 
 treble-riveted lap joints, or 7/16-inch plate with treble-riveted 
 double-butt strap joints; so, to decide, we will figure out the 
 cost of a shell made each waj'. Just here might be noted the 
 cost prices, laid down at the factory, of the materials used in 
 this boiler. They are 
 
 Flange steel, per 100 pounds $2.10 
 
 Shell steel, per 100 pounds 2.00 
 
 Tubes (4 inches diameter), per foot 0.18 
 
 Stay iron, per 100 pounds 2.00 
 
 Cast iron, per 100 pounds 2.50 
 
 Rivets, per pound 03 
 
 Angle iron, per pound 0225 
 
 COST OF LAP JOINTED SHELL. 
 
 First we will consider the lap jointed boiler, and start by 
 .finding the weight of plate to be used. For this style of joint 
 the plates will be (allowing the finishing) large course, 1075^ 
 inches by 234J4 inches by V2 inch, and the small course 107^ 
 inches by 231 inches by Yz inch. The weight of these will be: 
 
 107.S X 234.25 X 44* X I 
 
 Large course = 3,850 
 
 144 X 2 
 107-5 X 231 X 44 X I 
 
 Small course ^ 3.794 
 
 144 X 2 
 
 Total 7,644 lbs. 
 
 The cost price of this at 2 cents per pound equals $152.88. 
 The first work done on the plates is, of course, laying them 
 out. This, including the handling, ought to be done in six 
 hours. Cost : layer-out at 40 cents equals $2.40 and assistant at 
 20 cents equals $1.20, total $3.60. Next in order comes the 
 shearing of the plates. Including the handling this will take 
 about three hours. Cost : one handy man at 18 cents equals 
 $0.54, two helpers at 16 cents each equal $0.96, total $1.50. 
 Then comes the punching. The number of holes to be punched 
 will be: 
 
 114 in each girth seam, or in 4 seams 456 
 
 190 in each longitudinal, or in 2 seams 380 
 
 Holes for stays, nozzles, brackets, etc., about 150 
 
 Total holes to be punched 986 
 
 The gang on this job should average 125 holes an hour, in- 
 cluding handling. This will make the time for punching about, 
 eight hours. Cost : one handy man at 18 cents equals $1.44, 
 two helpers at 16 cents each equal $2.56, total $4.00. Planing 
 the plates will take about six hours. Cost : one handy man at 
 18 cents equals $1.08, one helper at 16 cents equals $0.96, total 
 $2.04. Next, the rolling will consume about four or five hours. 
 Cost: one handy man five hours at 18 cents equals $o.go, two 
 helpers at 16 cents each equals $1.60, total $2.50. 
 
 In riveting up we will use the bull machine for the center 
 girth seam and the longitudinal seams. Taking 114 rivets in 
 the girth seam and 190 in the longitudinal seams we will have 
 
 * Forty-four pounds being taken as the weight of 1 square foot of 
 steel 1 inch thick. 
 
MISCELLANEOUS CALCULATIONS 
 
 279 
 
 304 rivets to drive. Having the plates properly fitted, the 
 riveting gang should average a rivet a minute, taking five 
 hours. Usually, though, the plates have to be "squeezed" and 
 fitted into place, holding bolts removed, etc., so it would be 
 safe to add about four hours to cover this, making a total of 
 nine hours. Cost: one riveter at 18 cents equals $1.62, two 
 helpers at 16 cents each equals $2.88, total $4.50. Calking 
 seams, five hours at 20 cents equals $1.00. 
 
 Summing up we have a total cost for the naked 3^-inch 
 shell, with treble-riveted lap joints, of $172.02. 
 
 COST OF BUTT JOINTED SHELL. 
 
 Considering the naked shell with the butt strap joint and 
 7/16-inch plate we have the large course, 107.5 inches by 228 
 inches by 7/16 inch, and the small course, 107.5 inches by 226 
 inches by 7/16 inch. The weight of these plates will be : 
 
 107.5 X 228 X 44 X 7 
 
 Large course = 3,278 
 
 144 X 16 
 
 107.5 X 226 X 44 X 7 
 
 Small course := 3,214 
 
 144 X 16 
 
 Total 6,492 lbs. 
 
 Cost price of this at 2 cents per pound equals $129.84. In this 
 shell there are the butt straps to be considered. The outer 
 ones will be 8^4 inches by 107 inches by 3^ inch, and the 
 inside ones 14 inches by 107 inches by ^ inch, and the total 
 weight 552 pounds. Cost price at 2 cents equals $11.04, making 
 a total for the plate of $140.88. 
 
 The laying out of these plates would take longer than in the 
 first case, on account of the extra rows of rivets and the butt 
 straps. It should take about seven hours ; cost, $4.20. The 
 shearing and planing would cost about 15 p'ercent more than 
 with the lap joint, which would amount to: shearing $1.73, 
 planing $2.35. Punching — we have the same number of holes 
 in the girth seams but less in the longitudinal seams, and also 
 the holes in the butt straps. 
 
 Holes in girth seams 456 
 
 Holes in longitudinal seams, 158 in each seam. . . . 316 
 Holes for stays, nozzles, brackets, etc 150 
 
 Total in shell 922 
 
 Holes in butt straps ~ 316 
 
 Taking the rate for the holes in the shell the same as before, 
 viz. : 125 per hour, the time consumed for the plates would be 
 about 7}i hours ; cost $3.75. As the butt straps are small and 
 more easily handled the holes in them would be punched at 
 the rate of about 200 per hour. Time for 316 holes being 1.58 
 hours; say ij/^ ; cost $0.75. The total cost for punching, there- 
 fore, equals $4.50. Rolling the plates would be the same as 
 with the lap joint, viz., $2.50. Rolling or bending butt straps 
 would take three hours ; cost $1.50. Riveting the shell on the 
 bull machine will cost about 20 percent more than the lap 
 joint, on account of the extra fitting necessitated by the butt 
 straps, making the cost of riveting $5.40. Calking would also 
 take longer, say six hours ; cost $1.20. 
 
 Summing up the total cost for the naked shell with butt 
 straps it is found to amount to $164.26. Thus we see that the 
 smaller first cost of the thinner plate used with a butt strap 
 joint is more than enough to offset the more expensive style of 
 
 jdint, showing us that it will be cheaper to use the thin plate 
 and expensive joint than to use the cheaper joint and thicker 
 plate. Also, we get a much lower factor of safety with the butt 
 straps, and a saving in weight of about 600 pounds with a 
 consequent saving in freight rates on the plate coming in and 
 the boiler going out, which will amount to quite an item if the 
 distances are at all great. 
 
 To the casual observer, all the detailed figuring, as above, 
 would appear superfluous and apart from the main subject of 
 this article. The reason it has been set down in full here is to 
 give the layman an idea of the differences in the two modes of 
 manufacture. Usually all this figuring of the weight of the 
 shell of boilers, according to the pressure, need be carried 
 through only once for each size of boiler and for two or three 
 pressures. These results should be tabulated and kept on 
 record for future rapid reference. 
 
 COST OF COMPLETED BOILER. 
 
 Having decided on the butt joint and 7/16-inch plate, we will 
 now carry through the complete estimate for our boiler. The 
 diameter of the larger head being 7854 inches, the weight is 
 (using ^-inch plate) 745 pounds, and the small head being 
 77}i inches diameter, weighs 726 pounds, total weight of heads 
 1,471 pounds; cost of material at 2.1 cents per pound equals 
 $30.89. Laying out the heads would take about four hours, 
 and from our wage table cost $2.40. The flanging of the heads 
 is usually done before the head is laid out for the tubes, and 
 in this instance was done by hand. This would take, for both 
 heads, all of fifteen hours, costing: one flanger at 30 cents, 
 $4.50 ; two helpers at 16 cents each, $4.80, or a total of $9.30. 
 Punching the holes, of which there are 316 in the two heads, 
 made up as follows: 114 holes in each circumference and 44 
 holes for stays, would take about three hours, and cost : one 
 handy man, $0.54; two helpers, $0.96; total, $1.50. 
 
 Next, the heads go to the drill to have the tube holes cut. 
 The centers are first drilled out, taking about four minutes per 
 hole; and as there are 148 holes, this would consume about ten 
 hours ; cost, one handy man at 18 cents, $1.80. Cutting the 
 full size hole would take ten minutes per hole, or 24^ hours, 
 and cost $4.41. As there is a manhole in one end, this must be 
 reinforced with a wrought iron ring shrunk on and then planed 
 square. Making the ring and shrinking it on will take a black- 
 smith and a hammer man all of five hours and cost $2.40. 
 Planing will take about three hours, and adding one hour for 
 handling, make four hours ; cost for one machinist at 25 cents 
 per hour equals $1.00. 
 
 In riveting the heads to the shell, the bull machine is used 
 for one head, and will take, with fitting, etc., two hours, cost- 
 ing $0.68. The other head must be riveted up by air hammers. 
 There are 114 rivets to drive, and the air gang should drive 
 one every three minutes ; total, 5.7 hours, or six to cover 
 time taken in fitting, etc.; cost: one riveter, $1.32; one holder- 
 on, $1.02; one rivet boy, 60 cents; total, $2.94. 
 
 The shell being completed and the heads in place we now 
 come to the stays. There are forty-four of these, and they are 
 made by the blacksmith. First of all he makes the crowfeet, 
 and figuring that he, will do one in four heats, or about fifty 
 minutes, the total time will be about thirty-seven hours ; cost : 
 one smith at 30 cents equals $11.10, one hammer man at 18 
 
28o 
 
 LAYING OL'T FOR BOILER AIAKERS 
 
 cents equals $6.66; total, $17.76. Forging the palms of the 
 stays and welding the crowfeet to them will take about an hour 
 each, totaling forty-four hours and costing $21.12. In riveting 
 these stays there will be eighty-eight rivets to drive at about 
 four minutes each, taking about six hours ; cost, $2.94. Cutting 
 the threads on the two lower through stays, one hour at 18 
 cents, equals $0.18. Making the eyes in the other end of these 
 stays will take about two hours, and welding them to the stays 
 will take two hours ; total, four hours ; cost, $1.92. 
 
 The tubes must now be inserted. It will take all of twenty 
 minutes per tube to insert, expand and bead them, or twenty- 
 four and one-half hours; cost, one handy man at 18 cents 
 equals $4.41. Placing the brackets and nozzles gives about 
 seventy rivets to be driven with the air hammer. At four 
 minutes per rivet this takes about four and one-half hours, and 
 costs $2.20. 
 
 The boiler is now finished with the exception of calking 
 the heads and the plate under the nozzles, testing, painting and 
 loading. Calking the heads, etc.. would take about three 
 hours ; cost at 20 cents equals $0.60. Painting will take two 
 hours at 22 cents, equals $0.44, and 5 pounds of paint at 25 
 cents equals $1.25 ; total, $1.69. Testing and loading can safely 
 be estimated at $10.00. Summing up our total cost we have : 
 
 Laying out shell plates and butt straps $4.20 
 
 Shearing plates and butt straps 
 
 Planing plates and butt straps 
 
 Punching plates and butt straps 
 
 Rolling plates and butt straps 
 
 Riveting shell (bull machine) 
 
 Calking shell 
 
 Laying out heads 
 
 Flanging heads 
 
 Punching heads 
 
 Drilling centers, tube holes, $1.80 \ 
 
 Cutting tube holes, $4.41 ' ' " 
 
 Making, shrinking and finishing manhole ring 
 Riveting heads to shell bull machine, $0.68 \ 
 Riveting heads to shell air hammer, $2.94 J 
 Making crowfeet, $17.76 \ 
 
 Forging and welding stays, $21.12 ' 
 
 Riveting stays 
 
 Through stays 
 
 Inserting tubes 
 
 Riveting brackets and nozzles 
 
 Calking heads and nozzles 
 
 Painting 
 
 1.73 
 2.3s 
 4.50 
 4.00 
 5-40 
 1.20 
 2.40 
 9-30 
 1.50 
 
 6.21 
 
 340 
 . . . 3.62 
 
 . . . 38.88 
 
 2.94 
 2.10 
 4.41 
 2.20 
 0.60 
 1.69 
 Testing and loading 10.00 
 
 Total labor $112.63 
 
 For our material we have : 
 
 Shell plates, 6,492 .pounds, at 2 cents $129.84 
 
 Butt straps, 552 pounds, at 2 cents 11.04 
 
 Heads, 1,471 pounds, at 2.1 cents 30.89 
 
 172 feet, ij^-inch stay iron = 585 pounds, at 2 cents. . 11.70 
 
 20 feet, iJ/2-inch stay iron = 120 pounds, at 2 cents. . . . 2.40 
 37 feet, 2j^-inch by j4-inch iron (crowfeet) = 231 
 
 pounds, at 2 cents 4.62 
 
 5 feet, 4-inch by 4-inch by J^-inch angles = 64 pounds, 
 
 at 2J4 cents 1.44 
 
 1,332 feet, 4-inch tubes, at 18 cents per foot 239.76 
 
 Rivets (4 percent plate) = 340 pounds, at 3 cents per 
 
 pound 10.20 
 
 Cast iron, 250 pounds, at 2jX cents 6.25 
 
 Total cost material $448.14 
 
 Total cost of boiler $560.77 
 
 THE SELLING TRICE. 
 
 To get the ultimate selling price to give to the inquirer we 
 have two more additions to make to the cost price. One is 
 what is called "fixed charges," and is added to cover the non- 
 productive expenses, such as foreman's salary, depreciation of 
 plant, interest on investment, taxes, office expenses, etc. This 
 will vary in almost every plant, and in this case is figured as 
 30 percent of the cost of manufacturing. Then 30 percent of 
 $560.77 equals $168.23, making the total when added $729.00. 
 The other addition is the profit, and in this case it is taken as 
 10 percent of the total cost of the boiler, or 10 percent of 
 $729.00, which equals $72.90. Adding this we get $801. go as 
 the price sent to inquirer. Now, as round figures are generally 
 used the price sent would probably be $805.00. 
 
 Anyone who intends to do estimating along these lines 
 should keep tab on the different jobs as they go through the 
 shop, putting down in a notebook, in tabulated form, the time 
 taken for each part of the work and the cost of same as shown 
 by the factory cost cards (if such are kept). On comparing 
 these with his first approximation he will be able to see just 
 where he has over or under estimated, as the case may be, and 
 will be able to average very closely the right charge or cost 
 for future reference. 
 
 The preceding method of estimating the cost of boiler work 
 is very similar to that used on all descriptions of tank work, 
 and the estimator would find it very convenient to have tank, 
 boiler, stack and similar work divided into ditiferent classes 
 under such heads as the following: 
 
 Heavy straightforward work (return tube boilers, etc.). 
 
 Heavy difficult work (marine boilers, flumes, kettles, etc.). 
 
 Light work (tanks, 3/16-inch plate and under, etc.). 
 
 Stack work, etc. 
 
 Having tables of work like this ready at hand, with the 
 cost computed at so much per pound of material (averages 
 being struck from various jobs), the estimator will be able to 
 quote prices very closely by just figuring the weight of the 
 proposed work. It is interesting to note how comparatively 
 small is the variation of the ratios of cost of labor to cost of 
 material under the different headings as just outlined. 
 
TOOLS FOR BOILER MAKERS AND THEIR USES 
 
 Boiler makers' tools may be divided into two groups — those All this must malce for quality and far less cost, and it is our 
 
 which are made of one piece, as, for instance, the chisel, and counsel to boiler makers to buy and not make their small 
 
 those which arc made up of moving parts, such as the power tools. 
 
 punch or press. Both uf these classes of tools require thought A staybolt tap should not be too hard, for it will break, nor 
 
 for their use to the best advantage, or to any advantage at all. too soft, for it will not cut. A tap too hard can with care 
 
 Taking up the single piece tool, attention is directed first be used without breaking, but it must not be "yanked" around 
 
 to its main requirement, which is quality. Quality depends with a single-handled wrench when it is possible to use a 
 
 first upon proper material and second upon workmanship double-handled one, and even then the lurning must be dfjne 
 
 coupled with proper shape. e\enly. 
 
 Thread 
 Taper j Straight 
 
 — JV.^.AM..A/AArtA«AV...VVW/W/^WVAWV^VVW.V.'.^WVM'tf/' 
 
 FIG. I. — STAYBOLT TAP. 
 
 St.wbolt Taps. 
 
 The staybolt tap, shown in Fig. I, at times gives the user 
 trouble. Such a tap is difficult to make, and when hardened it 
 is almost sure to warp and get out of line. This defect is 
 easy to see, consequently there is no excuse for a man to use 
 a tap which has this defect, but a more difficult defect to detect 
 is a twist in the tap which prevents the threads from "track- 
 ing." This defect is better explained, perhaps, by saying 
 that in the process of hardening and drawing the body makes 
 a partial turn in some part of its length, with the result that 
 when used the holes tapped do not allow the staybolt to enter 
 properly or make a snug job. 
 
 In the staybolt taps made by professional manufacturers 
 neither of these troubles is apt to be found, but all taps, 
 wherever made, should be inspected with great care when 
 received, so that when they are required for use no delay 
 will occur nor any bad work result by their use. Home-made 
 
 It is safe to say that in handling all taps in boiler work 
 they are not turned at a proper speed. Of course it is not 
 possible in many cases to get at a tap so that it can be handled 
 to advantage, as in most places where a hole is tapped by hand 
 the operator is cramped for room, but, nevertheless, "sawing 
 a tap back and forth," as is often done, is bad practice and 
 generally shows that the drilled hole is too small for the size 
 of tap used or its user was not up in his trade. 
 
 riG. 3. — set of st.'\nd.\rd taps. 
 
 FIG 2. — special staybolt TAP. 
 
 taps are pretty sure to be not only warped and twisted, but 
 also out of size — a fault which is almost unknown in profes- 
 sionally made taps. 
 
 We wish to say a word right here about the making of 
 boiler makers' tools instead of buying them from those who 
 by long experience are in a position to produce them far more 
 accurately, cheaply and quickly than the home-made article 
 can be made. A concern which gives constant attention all 
 the time to the selection of a material which experience guides 
 them in buying, is sure to get just the quality suited for the 
 work, and workmen who are doing every day the various 
 operations necessary to produce the article become far more 
 skilled than a man who only occasionally does such work, and, 
 besides this, a manufacturer has at hand erery appliance with 
 which to test the finished article before it leaves the shop. 
 
 In using a staybolt tap, there is less chance of tapping a 
 hole crooked, as the support of the tap is double — that is, the 
 tap is entered through one plate into a second plate. This, of 
 course, steadies the tap and guides it. In all tapping oil 
 should be used freely: lard oil is the best for this purpose. 
 
 A special staybolt tap is shown in Fig. 2. The unthreaded 
 part acts as a guide to keep the tap straight where the usual 
 long taper tap cannot be used. Fig. 3 shows a set of standard 
 taps. 
 
 The taper tap is used to start the thread and even to com- 
 plete it, where the hole is so placed the tap can pass through 
 the plate. It is often followed by either the plug or bottoming 
 tap. The plug tap is used to start the thread in a hole, which 
 is not drilled through the sheet. The bottoming tap threads 
 the hole to its full depth. It will be noticed that in using 
 a taper tap more efTort is required to work it than the bot- 
 toming tap. This is generally attributed to the fact that the 
 
282 
 
 LAYING OUT FOR BOILER MAKERS 
 
 taper tap has cut most of the metal away, thus leaving less 
 metal to be removed. While this is true to a certain extent, 
 it must be remembered that in the taper type the teeth, as they 
 are called, are all doing more or less cutting, thus they have 
 a very considerable grip; while in a plug, and especially in a 
 bottoming tap, only the leading threads are doing any work, 
 therefore less effort is required to drive them. 
 
 Considerable skill is required to tap a blind hole — that is, 
 one which does not go through the plate, and the plug tap 
 should be used first if possible in order to catch the thread. 
 Care should be taken to prevent the tap from starting crooked, 
 whichever tap is used. Taps can be ground on the face of 
 the flute if a proper emery wheel is at hand, and before trying 
 to tap a blind hole the taps should be ground, as then the 
 thread catches more easily. 
 
 ■ Pipe Taps. 
 
 What are known as pipe taps (Fig. 4) give the apprentice 
 - a good deal of trouble at first, as there is no place on these 
 taps where the measurement of the normal size of the tap can 
 be found, so an apprentice who goes after a one-inch pipe 
 tap (if the size stamped on the shank is obliterated) is at a 
 loss as to how to pick it out. After a time the eye becomes 
 so accustomed to sizes that this trouble is not experienced. 
 
 Table i gives some information which is very useful, as it 
 gives the various sizes of drills to be used when a given size 
 of pipe tap is to be used. Table 2 is a table of drill sizes 
 which is recommended for holes in boiler plates. It will be 
 noticed by some that these sizes are not always those gen- 
 
 its radius. Table 3 gives the diameters and pitches of these 
 standard threads. 
 
 The form of a Briggs standard pipe tap (Fig. 8) is slightly 
 rounded at the top and bottom and the angle is 60 degrees. 
 The taper of the tap is }i inch to the foot, or, to make it 
 
 
 
 
 
 
 T.^BLE 1. 
 
 
 Size of 
 
 
 
 
 Size 
 
 of 
 
 
 Size of 
 
 Size of 
 
 Pipe. 
 
 
 
 
 Tappi 
 
 ng. 
 
 
 Pipe. 
 
 Tapping. 
 
 ^ 
 
 
 
 
 ■-■Vr,4 
 
 
 
 1 
 
 IV i« 
 
 M 
 
 
 
 
 ■^Im 
 
 
 
 IJi 
 
 Ii'/Ji 
 
 }| 
 
 
 
 
 
 
 
 ■ f" 
 
 2V1. 
 
 H 
 
 
 
 
 »/l« 
 
 
 
 
 
 
 
 
 
 
 TABLE 2. 
 
 
 y» H 
 
 % 
 
 H 
 
 Va. 
 
 1 
 
 IK 
 
 IH 2 2H 3 
 
 31^ 4 
 
 % 'V!2 
 
 % 
 
 % 
 
 1 
 
 IM 
 
 IV16 
 
 1= 
 
 hi 2Vi« 211/16 3V 
 
 18 31V1. 4Vi. 
 
 TABLE 3.— TABLE OF DIAMETERS WITH CORRESPONDING 
 PITCHES. 
 
 
 No. of Threads per Inch. 
 
 Diam. 
 
 No. of Threads per Inch. 
 
 Diam. 
 
 
 
 
 
 
 
 
 
 U.S. A 
 
 L. 
 
 •■V." 
 
 Whit- 
 
 
 U.S. 
 
 "V." 
 
 Whit- 
 
 
 Standard A. 
 
 M. 
 
 
 worth 
 
 
 Standard 
 
 
 worth 
 
 Inch. 
 
 
 
 
 
 Inch. 
 
 
 
 
 Va. 
 
 20 ; 
 
 !8 
 
 20 
 
 20 
 
 IK 
 
 5 
 
 i}4 
 
 4H 
 
 Vii 
 
 18 i 
 
 i4 
 
 IS 
 
 18 
 
 2 
 
 4M 
 
 4M 
 
 4K 
 
 '<K. 
 
 16 i 
 
 i4 
 
 16 
 
 16 
 
 2H 
 
 4H 
 
 4H 
 
 4H 
 
 14 S 
 
 !0 
 
 14 
 
 14 
 
 214 
 
 4M 
 
 4H 
 
 4 
 
 Yf 
 
 13 ; 
 
 iO 
 
 12 
 
 12 
 
 2M 
 
 4 
 
 4K 
 
 4 
 
 Vn 
 
 12 
 
 8 
 
 12 
 
 12 
 
 2}| 
 
 4 
 
 4 
 
 4 
 
 ,^ 
 
 11 
 
 8 
 
 11 
 
 11 
 
 2J^ 
 
 4 
 
 4 
 
 4 
 
 s/" 
 
 
 6 
 
 11 
 
 11 
 
 2% 
 
 4 
 
 4 
 
 3M 
 
 Y^i 
 
 10 
 
 b 
 
 10 
 
 10 
 
 2% 
 
 31^ 
 
 4 
 
 3H 
 
 'Vi= 
 
 
 
 10 
 
 10 
 
 3 
 
 31^ 
 
 SH 
 
 3J4 
 
 y% 
 
 9 
 
 14 
 
 9 
 
 9 
 
 3J^ 
 
 3K 
 
 3M 
 
 3M 
 
 I'/lE 
 
 
 
 9 
 
 9 
 
 3M 
 
 314 
 
 3'A 
 
 3H 
 
 
 S 
 
 4 
 
 8 
 
 8 
 
 3H 
 
 3H 
 
 3M 
 
 3M 
 
 7 
 
 
 7 
 
 7 
 
 ■iVi 
 
 3H 
 
 34< 
 
 3Ji 
 
 7 
 
 
 7 
 
 7 
 
 iVs 
 
 3'A 
 
 3M 
 
 3M 
 
 6 
 
 
 6 
 
 6 
 
 3% 
 
 3 
 
 3 
 
 3 
 
 IK 
 
 6 
 
 
 6 
 
 6 
 
 3H 
 
 3 
 
 3 
 
 3 
 
 1^ 
 
 5M 
 
 
 5 
 
 5 
 
 4 
 
 3 
 
 3 
 
 3 
 
 iJi 
 
 6 
 
 
 5 
 
 6 
 
 
 
 
 
 e 
 
 ^^WV^•.^'rW.AA^/. 
 
 FIG. 4. — PIPE TAP. 
 
 erally recommended, but it is believed that it is better to get 
 a hole tapped with a thread which is not "chewed up," even 
 if it is not a full thread, than to have the metal torn away 
 at the mouth of the hole. 
 
 In the United States taps are made to standards. Two 
 forms are used. First, the sharp V thread (Fig. 5), and 
 second the U. S. thread (Fig. 6), which has a flat top and 
 bottom. In both of these types the angle is 60 degrees. In 
 England the form of the thread is as shown in Fig. 7. Here 
 the angle is 55 degrees, and the top and bottom of the thread 
 are rounded. This English form is usually known as the 
 Whitworth thread, as it was developed by Sir Joseph Whit- 
 worth. It must be noticed that the rounded top and bottom of 
 the Whitworth thread are difficult to produce, as the amount 
 of round is very small. The idea of the round is that the top 
 of the tap's tooth very soon becomes rounded or blunted in 
 use, and it is therefore better to start with it so. The angle 
 of 55 degrees is supposed to be an advantage in not throwing 
 so great a strain on the metal, since it approaches more nearly 
 the effect of a right angle surface to the line of effort. The 
 angle of 55 degrees, however, is difficult to lay out, while 60 
 degrees is very easy to lay out, being one-sixth of a circle or 
 
 
 TABLE 4. 
 
 — BRIGG STANDARD PIPE THREADS. 
 
 
 Diam. 
 
 ofTubeinlns. 
 
 J 
 
 
 
 
 
 
 
 
 
 
 
 J(2 
 
 II 
 
 2S 
 
 Pipe Thread Dimensions. 
 
 
 
 3-S 
 
 II 
 
 °s 
 
 •Sir 
 
 
 
 
 
 
 ■^S- 
 
 il"^ 
 
 B. 
 
 A. 
 
 P 
 
 
 C. 
 
 D. 
 
 E. 
 
 F, 
 
 N, 
 
 H 
 
 V, 
 
 0.270 
 
 0.405 
 
 .24 
 
 .057 
 
 .334 
 
 .393 
 
 .19 
 
 ,41 
 
 27 
 
 11/11 
 
 J4 
 
 0.364 
 
 0.540 
 
 .42 
 
 .104 
 
 .433 
 
 .622 
 
 .29 
 
 ,62 
 
 18 
 
 =•/.. 
 
 
 0.494 
 
 0.675 
 
 .65 
 
 .192 
 
 .567 
 
 .656 
 
 .30 
 
 ,63 
 
 IS 
 
 »/«i 
 
 1^ 
 
 0.623 
 
 0.840 
 
 .83 
 
 .305 
 
 .702 
 
 .816 
 
 .39 
 
 ,82 
 
 14 
 
 "/•I 
 
 
 0.824 
 
 1.050 
 
 1.11 
 
 .533 
 
 .911 
 
 1.025 
 
 .40 
 
 ,83 
 
 14 
 
 I'/i. 
 
 1 
 
 1.048 
 
 1.315 
 
 1.66 
 
 .863 
 
 1.144 
 
 1.283 
 
 ,51 
 
 1,03 
 
 UH 
 
 l'/i« 
 
 l^i 
 
 1,380 
 
 1.660 
 
 2.24 
 
 1.496 
 
 1.488 
 
 1.627 
 
 ,54 
 
 1,06 
 
 11}^ 
 
 li'/j. 
 
 Wi 
 
 1.610 
 
 1.900 
 
 2.67 
 
 2.038 
 
 1.727 
 
 1.866 
 
 ,55 
 
 1,07 
 
 IIH 
 
 l"/s< 
 
 2 
 
 2.067 
 
 2.375 
 
 3.60 
 
 3.355 
 
 2.200 
 
 2.339 
 
 ,58 
 
 1,10 
 
 IIH 
 
 2V, 
 
 21^ 
 
 2.468 
 
 2.875 
 
 5.73 
 
 4.783 
 
 2.618 
 
 2.818 
 
 ,89 
 
 1,64 
 
 8 
 
 2!i/ji 
 
 3 
 
 3.067 
 
 3.500 
 
 7.53 
 
 7.388 
 
 3.243 
 
 3.443 
 
 ,95 
 
 1,70 
 
 8 
 
 31V" 
 
 31^ 
 
 3.548 
 
 4.000 
 
 9.00 
 
 9.887 
 
 3.738 
 
 3.938 
 
 1,00 
 
 1,76 
 
 8 
 
 3M/.I 
 
 4 
 
 4.026 
 
 4.500 
 
 10.66 
 
 12.73 
 
 4.233 
 
 4,443 
 
 1,05 
 
 1,80 
 
 8 
 
 4'/m 
 
 4.V. 
 
 4.508 
 
 5.000 
 
 12.34 
 
 15.93 
 
 4.733 
 
 4.933 
 
 1,10 
 
 1,85 
 
 8 
 
 4»/ll 
 
 5 
 
 5.045 
 
 6.563 
 
 14.50 
 
 19.99 
 
 5.289 
 
 6.489 
 
 1,16 
 
 1,91 
 
 8 
 
 511/11 
 
 6 
 
 6.065 
 
 6.625 
 
 18.76 
 
 28.88 
 
 6.347 
 
 6.547 
 
 1,26 
 
 2,01 
 
 8 
 
 6»/,. 
 
 7 
 
 7.023 
 
 7.625 
 
 23.27 
 
 38.73 
 
 7.340 
 
 7.640 
 
 1,36 
 
 2,11 
 
 8 
 
 
 8 
 
 7.982 
 
 8.625 
 
 28.17 
 
 50.03 
 
 8.332 
 
 8.532 
 
 1.46 
 
 2.21 
 
 8 
 
 
 9 
 
 9.00 
 
 9.625 
 
 33.70 
 
 63.63 
 
 9.324 
 
 9.624 
 
 1,66 
 
 2,31 
 
 8 
 
 
 10 
 
 10.019 
 
 10.750 
 
 40.06 
 
 78.83 
 
 10.44 
 
 10,64 
 
 1,67 
 
 2,42 
 
 8 
 
 
 clearer, the taper is ^ inch to the foot on each side of a line 
 drawn through the center of the tap. It is found in practice 
 that the pipe tap threads are not made to the standard form, 
 but are V-shaped. The standard pipe sizes were originated, 
 or at least were established, into exact form by a Mr. Briggs, 
 and his name is used very properly in connection with the 
 table of pipe tap dimensions. Table 4 gives his formula as to 
 form and sizes. 
 While to-day studs and bolts are usually handed to a boiler 
 
TOOLS FOR BOILER MAKERS AND THEIR USES 
 
 28.1 
 
 maker ready for use, it is often the case that he has to cut 
 the threads with a die. With the exception of pipe dies of the 
 cheaper variety all screw cutting dies are adjustable, and to 
 use them attention is called to the following. First, brush 
 the scale off the rod or forged bolt with a file, as the scale 
 is hard on the dies. Open out the die and slip it over the 
 
 
 60°, 
 
 P = Pitch = 
 
 No. of threads per inch 
 D = Depth = P X .8660 
 
 FIG. S. — V THREAD. 
 
 ^ — p — -^ 
 
 
 P = Pitch = 
 
 No. of threads per inch 
 
 D = Depth = P X .6495 
 P 
 
 F = Flat = — 
 8 
 
 FIG. 6. — THE 
 
 U. 
 
 S. STANDARD THREAD. 
 
 u — p-*l 
 
 P = Pitch = 
 
 No. of threads per inch 
 D = Depth = P X .64033 
 R = Radius = P = . 1373 
 
 FIG. 7. — WHIIWORTH THREAD. 
 
 screw. Set up the die until it gets a fair grip on the screw, 
 the end of the bolt being flush with the face of the die. Be 
 sure to oil the die well and then turn it about two turns. Run 
 the die back and set up on it a little, then run it right down 
 to the length of thread required, after which run the die back 
 
 its use. This is equally true of a cold chisel, as it is usually 
 called. To chip a scam true and to do the work quickly is 
 an art, and only practice will enable a man to become ac- 
 complished in it. Therefore, we will not go into the subject 
 of these two hand tools further, but simply advise the appren- 
 tice to try and handle a hammer in either hand, as at times 
 it is most convenient to be able to chip left-handed. As a 
 matter of fact, there are very few who can do it, although it 
 is a faker's usual boast that he can chip equally well with 
 either hand. 
 
 Calking Tools. 
 
 We will, however, direct attention to the use of a hammer 
 and calking tool. The latter is nothing more or less than a 
 blunt chisel. If a round-nosed tool, as is shown in Fig. 9, 
 is used, the result will be that shown in Fig. 10. Here it will 
 be noticed the top plate is forced away from the bottom 
 plate and a thin edge is forced down tight to the bottom plate. 
 Such work is not as satisfactory as the method shown in Fig. 
 
 FIG. 9. 
 
 -p 
 
 1— 
 
 ' ""•"•^-^^-^ijvwww :":-! 
 
 A — Outside diameter of perfect 
 thread or actual outside diameter of 
 pipe. 
 
 B — Inside diameter of pipe. 
 
 C — Root diameter of thread at end. 
 
 D — Outside diameter of thread at 
 end. 
 
 E — Length of perfect thread = 
 P(4.8-l- 0.8A). 
 
 F — Total length of thread or length 
 of taper at top. 
 
 N — Number of threads per inch. 
 1 
 
 P — Pitch of thread = — 
 N 
 
 Taper of thread. V<" per foot or 1 
 in 32 to axis of pipe. 
 
 FIG. 8. — BRIGGS STANDARD PIPE THREAD. 
 
 and set up again. It should not take more than three cuts 
 to produce a good thread with a good die. Never "seesaw" 
 the die back and forth or try to produce a full thread at one 
 cut, as the result will be a torn and very likely badly distorted 
 thread which will not fit the tapped hole, or make a tight 
 joint or give proper holding power. 
 
 The Hammer 
 
 No single tool in any trade is as useful as the hammer, yet 
 it is absolutely impossible to give any practical directions for 
 
 II. Here the form of the tool is square, and it is used so as 
 to set the upper plate down tight to the lower. This should 
 not be done with too heavy a blow, otherwise the top plate 
 will be lifted away from the lower plate, as in the case of 
 the round tool. It must be remembered that a blow stretches 
 the metal which is struck, and great care should be observed 
 not to hammer a plate until it buckles, as besides becoming 
 distorted it also becomes brittle. 
 
 Beading Tubes. 
 
 In well-equipped boiler shops compressed air is generally 
 used in beading boiler tubes. Fig. 12 shows a detailed drawing 
 of a beading tool which is designed for use with an air ham- 
 mer, .while Fig. 13 shows the application of beading tools and 
 the method of using the ball end of a hammer to start beading. 
 In this operation it should be remembered that heavy blows 
 
284 
 
 LAYIXG OUT FOR BOILER AlAKERS 
 
 must be avoided, and care should be taken not to strike the resuhing in dilificult and unsatisfactory work. On the other 
 
 tube too often in the same spot, as it will make the end of hand, if the angle is too slight the feeding action will be un- 
 
 the tube hard and brittle. The peening eflfect of the ball face certain. 
 
 of the hammer stretches the metal in the tube and lays it over It is far from wise for a shop to try to make its own ex- 
 
 so that the use of the beading tools, P, N and IV, Fig. 13, can panders, as the quality of the steel as well as the design has 
 
 be used to fold over the tube, as shown at G. which represents much to do with the satisfactory working of the expander, 
 
 FIG. 12. — DET.MLS OF A ST.\NDAKD lli:.\DING TOOL. 
 
 the finished beading. The manner in which the tube was first and. of course, with its lasting qualities. One thing must be 
 laid over by blows with the hammer is shown at -Y. Skill is remembered in the use of a tube expander, and that is that the 
 required to bead a tube well, and it must be borne in mind metal must be allowed sullficient time to flow in front of the 
 
 roller. It is evident that as the small rollers are forced out 
 they imbed themselves to a certain extent in the metal of the 
 tube, and as the rotary action takes place a wall or wave of 
 metal rises in front of the rollers. If the rotary action is too 
 quick this wall will be mounted by the rollers and the metal 
 will not be spread as it should be in order to make a tight 
 ioint. Too much rolling is as bad as not enough: in fact, it is 
 
 FIG. 13. — BE.NDING BOILER TOOLS. 
 
 that the heading is done only after the expanding of the tube 
 is completed. 
 
 Tube Expanders. 
 
 A tube expander is a tool which is designed to expand the 
 walls of a tube by means of a rolling action coupled with a 
 direct rotary pressure, or, in other words, small rollers are 
 forced against the tube by means of a tapered pin, and then the 
 entire expander is revolved and the action of the small rollers, 
 coupled with the pressure of the tapered mandrel, spreads the 
 metal against the tube sheet, thereby making a tight joint. 
 
 Expanders are divided into two classes — self-feeding and 
 those which have to be fed by light blows with a hammer. 
 The self-feeding expander is most frequently used on tubes 
 of small diameter. Fig. 14 shows an expander of the self- 
 feeding type. Here it will be noticed the rollers are set at an 
 angle. This results in obtaining a screw-like motion whicn 
 feeds the rollers automaticallj'. The angle is important in this 
 class of tools, since if it is too great the feed will be too quick. 
 
 FIG 14. — ROLLER EXPANDER. 
 
 better to do too little, as it is possible to re-roll a tube if the 
 tube has not been thinned out by excessive rolling. If the life 
 has been squeezed out of the tube by too much rolling a good 
 iob cannot be made of it, and, besides this, the tube sheet by 
 injudicious rolling may be badly injured and a new tube sheet 
 will be required, which, at best, is an expensive thing. In 
 using an expander a good supply of oil is necessary, and in 
 small tulies the author reconunends that the expander be 
 dipped in oil as a convenient method of lubricating it thor- 
 oughl}'. A most important point to be borne in mind is that 
 the thinner the tube the more care must be taken with rolling. 
 Those who are just learning to use expanders should be cau- 
 tioned that if the taper pin is driven in too hard it is liable 
 to fly out and seriously hurt the operator. The tirst few lilows 
 nn the pin should be gentle. 
 
 There are tube expanders on the market called sectional 
 expanders which are made with flats on the taper pin and, of 
 
TOOLS i'"oK i;oil1':k afakkks and their usrs 
 
 course, with corrcspunding' Huts on the segmfiils. This slyle 
 of expander is not given a rotary motion, but the expanding is 
 done by the pressure obtained by driving the pin into the seg- 
 ments. After a few blows with the hammer the pin is then 
 withdrawn and the expander is turned a Httle. 
 
 It is claimed that these Hat surfaces give a much larger 
 bearing surface than when a round pin is used, and that they 
 consequently present a greater wearing surface, which results 
 in a longer life for the tool. This type of tool is used where 
 the tube is double beaded, as shown in Fig. 17. In this case 
 a ferrule is used. Fig. 16 shows the general construction of a 
 sectional expander. 
 
 Before going further with the description of boiler makers' 
 hand tools it will be well to get a clear idea of the material 
 used in making them. It would not be possible to go fully 
 
 FIG. 15. — SECTI0N.\L EXPANDER. 
 
 into the very interesting subject of steels, as that of itself is 
 a most complex stud)', yet we can explain certain of its fea- 
 tures to advantage briefly. 
 
 Tool Steel. 
 
 Cast steel, or, as it is often called, "tool steel," is made in 
 many grades, some being admirably adapted for tools where a 
 keen cutting edge is required, but where in its use there is no 
 shock, as, for instance, in a razor blade. For such purposes 
 keenness is demanded, but no blow-resisting qualities are re- 
 quired. On the other hand, in a chisel there must be blow- 
 resisting qualities and a lasting edge. In the razor the steel 
 is in a state of brittleness, but in the chisel there is toughness. 
 The same grade ofi steel can be used in both articles and meet 
 the requirements, but as a rule two grades are selected for the 
 two tools, although the treatment must differ. 
 
 Broadly, the treatment is this : The steel is forged to the 
 required shape, care being taken not to overheat it while 
 working. After forging it is brought to a good, read heat ; 
 that is, a heat which in a moderate light shows red. At this 
 heat the tool is plunged into water and cooled down so no 
 color shows. With a piece of emery cloth tacked on a piece 
 of wood, say a piece of lath, the cutting edge is rubbed bright. 
 It is then held over the fire and reheated slowly. The bright 
 part will then begin to show what is called "color." At first a 
 very faint yellow will appear. This soon deepens into a darker 
 yellow, or straw color, and then a faint tinge of blue appears 
 and darkens to a very deep blue, until finally this color disap- 
 pears and the steel assumes the color of the bar before it was 
 forged. 
 
 When the steel is plunged into water its condition at first 
 is very hard and very brittle. In this state we say the steel, 
 or tool, is "hardened." The operation of reheating, polishing 
 and allowing the colors to run is called "drawing." In its 
 
 hardened state the steel is not suited for ordinary tools on 
 account of its extreme brittleness, but when the faint yellow- 
 starts this condition begins to change to greater toughness and 
 less hardness. It also becomes f.pringy. .\s the color deepens 
 this condition goes on, and as the blue licgins to show the 
 springiness is increased. But this also soon stops, and the 
 steel, when it again assumes its original color, is in the same 
 state as before it was forged. It could be said that this re- 
 
 FIG. 16. — CENER.VL CONSTRUCTION OF SECTIONAL EXPANDER. 
 
 heating completes a cycle from the original state through all 
 the degrees of hardness and elasticity back to what it was be- 
 fore being forged and treated. Generally it may be said that 
 light straw colors are proper for such tools as are used by 
 machinists in lathes, planers, etc., while yellows are suitable 
 for boiler makers' hand tools. 
 In order to fix the color wanted, when it appears the tool 
 
 is instantly plunged into water. This arrests the action of 
 the heat and the tool is ready for grinding. It is advantageous 
 to mix some cominon salt with the water, and the water 
 should not be too cold. A temperature of about 60 degrees is 
 good. 
 
 In order to harden and draw tools properly considerable 
 skill is required, and, of course, this comes only with practice, 
 fhe various grades and qualities need quite different treat- 
 ments. Some are what is called "tender" ; that is, they require 
 to be heated just so and brought to just such a heat or they 
 are ruined. Such steels are, however, very serviceable, while 
 on the other hand there are steels which need much less care 
 in working and from which verv good results can be obtained. 
 
286 
 
 LAYING OUT FOR BOILER T^IAKERS 
 
 High-Speed Steel. 
 
 Again, there are steels of special grades known to-day as 
 "high-speed" steels, or self-hardening, although this latter 
 name is misleading at times. This grade of steel requires no 
 drawing, but some require a special cooling process by means 
 of an air blast. These high-speed steels must usually be 
 forged at a very low heat and with great care, yet there are 
 steels of tliis grade which we are told to work at high heats. 
 When no air blast is to be used the tools are left to cool in' 
 any dry place, but they muust never be thrown on the floor 
 where there is any dampness, since if cooled suddenly they 
 crack. In the old times the machinists and boiler makers were 
 able to forge most of their hand tools. This was not as true 
 of the boiler makers' trade as in the machinists' trade, but 
 to-day it is rather uncommon to find men in either trade that 
 can do such work — more's the pity. 
 
 The steel which boiler makers now use as the material for 
 boilers is not at all like the steels just described, as what is 
 wanted in boiler steel are purity and toughness. This grade of 
 steel is what is known as "low-carbon" steel. It is very ductile 
 or pliable ; that is, it can be worked into various forms without 
 cracking. 
 
 From this very short description it can be well understood 
 that much depends on the quality of the tool steel used in hand 
 tools. If a good selection of material is not made good results 
 cannot be expected. It is impossible to tell just what a steel 
 is by looking at it. Many men will look at a broken piece of 
 steel and say "it shows a good fracture," and look very wise; 
 but the only way to know, how good a steel is for your work is 
 to try it. In fact, the name of the steel maker is about the 
 best guide as to its quality. There are many reputable makers 
 who have made steels for years, and what such makers state 
 can be relied upon, Their experience is freely given to those 
 who want steel for any purpose, but they must be told just 
 what the work to be done is, and the material must be handled 
 as they advise. 
 
 Anne.aling Steel. 
 
 We have remarked that hammering steel makes it brittle, so 
 in turning flanges and in many kinds of boiler work wooden 
 "malls" are used in place of sledges, but where hammering has 
 to be done brittleness can be overcome by what is called 
 "annealing." This is nothing more or less than heating the 
 piece to a good, red heat, then letting it cool slowly. This can 
 be done by covering the piece well with ashes, and if special 
 softness is wanted by packing in charcoal, and then covering 
 the charcoal with ashes. Several hours must be given the 
 steel to anneal, and the slower it is done the better. The an- 
 nealing restores the strength of the metal by relieving the 
 strains set up by hammering, and turns the crystalizing par- 
 ticles back into fibrous conditions, or. as one might say, it 
 turns the crystallized lump sugar into stringy molasses candy. 
 
 Chisels. 
 
 Fig. i8 shows a cold chisel. Here it will be noticed the edge 
 is hardened while the end is left soft, or just as it comes from 
 the bar. If the end or head were hard the blows of the ham- 
 mer would soon crack it to pieces, while if the cutting edge 
 
 were not hardened and drawn, it would very soon be blunted 
 and of no use. In dressing a cold chisel the head is worked 
 down into a cone shape, as this form prevents a heavy burr 
 being formed by tlie blows, yet this burring will take place 
 even when the end is coned, and it should be ground off from 
 time to time. 
 
 Chitping. 
 
 To chip well is an art, which is not possessed to the extent 
 it once was, as to-day there is less of this work done than, 
 say, twenty-five years ago. The introduction of air-actuated 
 tools has changed the chipping work, and later on we will 
 
 D 
 
 FIG. l8. — COLD CHISEL. 
 
 describe the air tools and their uses which have made such a 
 great change in boiler shops. It is only by practice that a man 
 can learn to chip ; a book full of explanations would not prc- 
 \ent him from knocking the skin ofif his knuckles and the chisel 
 out of his hands. The eye and muscles require training, and 
 mental thouglit will not by itself give manual skill. This is a 
 fact that all who wish to become skilled boiler makers will 
 do well to remember. The best advice is to say, "Keep at it 
 and use your brains as well as your hands, and you will at last 
 accomplish the end." The swing of a hammer in the hands 
 (jf a first-class chipper is a delight to watch, and when this. 
 
 33 
 
 FIG. 19. — C.\PE CHISEL. 
 
 swinj.js oni;e learned it is Snever forgotten. A man may and 
 will becoilfj fusty in the use of a hammer, but it takes but a 
 short tim? &r him to strike his "stride" again. 
 
 In chipping, the chisel shown in Fig. 19 is advantageously 
 used. This form is known as a "cape" chisel, and when there 
 is considerable metal to be removed furrows are chipped out, 
 leaving, say, ',4 inch between them. This metal is then cut ofif 
 with the chisel shown in Fig. 18. It can easily be seen that 
 this method has its advantages, as the smaller surface of the 
 cape chisel is more easily driven through the metal, and the 
 metal left between the furrows is likewise cut oft' with less 
 effort. It must be understood that to make a nice, smooth job 
 the cape chisel must leave enough metal to allow a dressing cut 
 to be taken with the flat chisel. Sometimes, when space will 
 permit, a second row of furrows is chipped at right angles to 
 the first. This leaves a lot of squares w-hich can be cut off 
 with ease, and when the metal is cast iron much time is saved, 
 as the squares break off with little effort, a smoothing chip 
 lieing taken, of course, to make a good finish. 
 
 On the edge of a steel plate this system cannot be used. In 
 very heavy chipping another form of chisel is used which 
 
TOOLS FOR BOILER ALVKERS AND THEIR USES 
 
 287 
 
 differs from that described. Fig. 21 shows such a tool. This 
 is often called a "rivet buster." It is a chisel so made as to 
 receive a handle. This handle is very often made from tlic 
 s^oke of an old or broken wagon, and for this purpose dis- 
 carded spokes are excellent, as they are cheap, strong and 
 
 FIG. 20. — DI.\M0ND POINT CHISEL. 
 
 easily fitted to the eye of the chisel. They can be used to 
 advantage in a number of tools about a boiler shop. 
 
 Instead of the ordinary hand hammer a sledge is used with 
 the "buster," and sledges are to be had in a number of wei.§hts, 
 the class of work determining which to use. Of course, the 
 heavier the work is the heavier must be the sledge. One man 
 
 foot of a pair of dividers can be placed in the punch mark for 
 this work. 
 
 .\ light hammer is used with the center ])unch, and while the 
 illustration shown is the usual style used a round piece of 
 steel is often used, and when a boiler maker wants to be very 
 much up-to-date he buys a prick-punch like the one shown in 
 Fig. 26, This is the same old center punch, but it looks as if 
 it had been to college. While on the subject of college-looking 
 tools we wish to say that while the boiler makers' trade is a 
 rough one there is no reason why nicely finished hand tools 
 should not be used by a boiler maker. In fact, by being will- 
 ing to use any old too! the boiler maker makes his trade 
 rougher than it need be, and we hope when any young boiler 
 
 FIG. 25. — USUAL TYPE OF CENTER PUNCH. 
 
 FIG. 2T. — CENTER CUT CHISEL OR RIVET BUSTER. 
 
 FIG. 26. — SPECIAL CENTER PUNCH. 
 
 FIG. 22. — BACKING OUT PUNCH. 
 
 FIG. 23. — SIDE CUT CHISEL. 
 
 o 
 
 (I 
 
 FIG. 24. — HANDLE RIVET SET. -fg 
 
 holds the buster and a second man swings the sledge. Fig. 23 
 represents what is called a "side-cut" chisel, which is of use in 
 many cases where the one shown in Fig. 21 could not be used 
 to advantage. 
 
 Center Punch. 
 
 ■A hand tool which is of very great value to the boiler 
 maker is the center punch. This is sometimes called a "prick- 
 punch," and it may be said that it is the "lighthouse" of the 
 boiler maker ; that is, it marks the path or shows where to go. 
 A very usual form is shown in Fig. 25. In laying out work it 
 is used to prick-punch the lines which have been drawn on 
 the boiler plate in chalk, so that in handling them the marks 
 if rubber out can be remade with ease. Again, the center 
 punch can be used to prick-punch a point in laying out any 
 work which requires a circle to be drawn or struck, as one 
 
 maker wants a hammer or a prick-punch he will get a nice- 
 looking one. 
 
 In using the prick-punch the novice will find trouble in hold- 
 ing it, as it has a way of flying out of his fingers when struck 
 with a hammer, so the octagonal steel or the knurled body has 
 an advantage over just a round piece of steel. A prick-punch 
 must be kept in good shape ; that is, the point must be sharp. 
 To grind it on an emery wheel or grindstone is cjuite a trick. 
 The angle is about 45 degrees, and as it is pressed against the 
 stone a rotary motion must be given to it so as to produce a 
 true cone. Some practice is necessary to do this, especially it 
 the emery wheel or grindstone is in the condition usually found 
 in boiler shops. Some very bad accidents have been known 
 to occur from the disgraceful condition of these two shop 
 tools. Care should be taken by those who try grinding any 
 tool for the first time, as the pressure of the tool against the 
 wheel tends to drag it down, and the hand can easily be 
 drawn against the stone with the possibility of a very painful 
 wound. 
 
 When grinding any tool water should be used, as otherwise 
 the heat which results from the pressing of the tool against 
 the emery wheel will draw the temper. Neglecting to have 
 water at hand has resulted in a very great loss to shop own- 
 ers. It is very hard to get them to believe this; but when they 
 remember that any lo-cent store will sell them a tin pail which 
 does not leak, and that the old rusted-nut tomato can now 
 in use requires a trip to the sink every tim.e a 40-cent man 
 wants to grind a tool, the value of the investment will be clear 
 to them. 
 
 R.atchets. 
 
 In many cases holes have to be drilled in boiler and tank 
 work by hand, and what is known as a ratchet is used for 
 this work in connection with a drill. Fig. 27 shows one of 
 the many forms of this very useful tool. The particular type 
 
LAYING OUT FOR BOILER MAKERS 
 
 illustrated is called a differential ratchet, and was the inven- 
 tion of' Mr. T. A. Weston, who also invented the differential 
 pulley block, a device which is used so extensively in lifting 
 work about boiler shops. 
 
 The main trouble in making a good substantial ratchet lies 
 in the necessity for strong teeth, and yet they must be made so 
 that the swing of the handle will not be too great for confined 
 spaces, otherwise a tooth would not be caught by the pawl. If 
 made small they are apt to break or soon wear out. Mr. 
 Weston overcame this difficulty by using two ratchets and two 
 pawls, one set above the other, with the teeth set "staggering"; 
 that is, so that the teeth of the upper ratchet were between the 
 teeth of the lower ratchet. This gave great strength and yet 
 allowed a short swing of the handle. In England the makers 
 of this ratchet used to advertise that no burglar's kit of tools 
 
 can be fitted with a taper or square shank, and. of course, the 
 ratchet socket must be made to suit. The tiat drill has held 
 its place for years and in confined spaces it is easier to handle. 
 Very short drills are made, and special short ratchets are on 
 the market to be used where the limits of space demand it. 
 Fig. 31 shows one of the special short ratchets. 
 
 The "Old M.\x." 
 When using a ratchet some kind of backing has to be pro- 
 vided in order to steady the drill and allow it to be fed into 
 the material. Usually what is called an "old man" is used, 
 as this is easily made and attached. The material is iron or 
 steel, and for everyday work is about 3-,s inch thick and 2 
 inches wide. The reach can be made any length desirable, 
 but a length of about 8 inches is handv. The height under the 
 
 FIG. 27. — R.\TCHET FOR GENERAL PURPOSES. 
 
 FIG. 28. — REVERSIBLE RATCHET. 
 
 FIG. 29. — TAPER, SQUARE SHANK, RATCHET TWIST DRILL. 
 
 was ever captured that did not have one of the Weston dif- 
 ferential ratchets in it 
 
 There are a great many good ratchets in the market, a 
 representative type of which is illustrated in Fig. 28. The 
 higher grade of material now obtained allows the use of finer 
 teeth without the danger of their breaking. Some ratchets are 
 made to work by a friction device, and in this case no teeth 
 are required. 
 
 There are several tools of the ratchet type where the drill 
 is given an almost continuous turning movement by having 
 the ratchet pawl reverse and act through a second ratchet and 
 pawl, but it has not become very popular with those who have 
 to swing the handle, since to push against the cut of the drill 
 and also pull against it becomes very tiresome in heavy work. 
 
 Ratchet Drills. 
 
 Two styles of drills are used in ratchets — the twist drill 
 (Fig. 29) and the flat drill (Fig. 30). Either of these drills 
 
 FIG. 30. — FLAT drill. 
 
 FIG. 31. — RATCHET FOR CONFINED SPACES. 
 
 arm should be 12 inches. The foot is usually a little longer 
 than the arm, say 3 inches more, and a series of holes fj inch 
 diameter is drilled in it. On the under side of the arm is 
 provided a series of heavy prick-punch marks, and into one 
 of these the head of the feed screw of the ratchet is placed 
 after the "old man" is bolted to the plate. 
 
 Referring to Fig. 32, a very handy style of "old man" can 
 be seen which can be bought at any supply house. Its value 
 lies in the fact that the arm is adjustable in height and it can 
 also be swung around the vertical bar into any desired posi- 
 tion. This in itself is a great advantage, as at times the 
 positions of the holes in the boiler or plate to which the foot 
 must be bolted cannot be reached with the ordinary style of 
 "old man," but, in spite of this fact, it is strange that very few 
 boiler shops are properly pro\ided with this valuable tool. 
 
 Operation of a Ratchet Drill. 
 
 The feed screw of the ratchet has a cone-shaped head, as can 
 be seen in Fig. 31. In this head are drilled holes into which a 
 pin is inserted in order to turn the feed screw. The cone- 
 shaped point very soon wears down, or becomes cut. due to the 
 fact that oil cannot be fed to the cone, a.^, when in operation, 
 it is under the arm. It is quite a simple manner, however, to 
 provide means for oiling the screw head by drilling small 
 holes, say, with a No. 40 drill, through the arm into the 
 prick-punch marks. Through these small holes oil can be 
 easily fed to the cone head. 
 
 It is wise to countersink the prick-punch hole enough to give 
 
TOOLS FOR BOILER MAKERS AND THEIR USES 
 
 289 
 
 the screw head a larger bearing surface than is provided by the 
 prick-punch marks. 
 
 When the head is turned by means of the pin it forces the 
 drill into the plate, and by oscillating the handle of the ratchet 
 the drill is revolved and a chip taken. There is a certain 
 amount of spring in the "old man," no matter what style is 
 used, which acts while drilling, making the feed fairly constant 
 
 The Sledge. 
 The sledge, which has already been referred to, is only an 
 overgrown hammer, but it is a very handy tool in a boiler 
 shop. At first sight it looks like quite an easy task to swing a 
 sledge, yet it requires practice and skill to use it to advantage 
 without hurting your fellow workmen or yourself. In fact, 
 some very serious accidents have resuhed from a glancing 
 
 for a few turns; but it must be remembered that, as the drill hinw fmm , ci»rio-e tu^ „■.<.,, (^, tu i a 
 
 ' Diow irom a sledge. Ine uses tor the sledge are too numerous 
 
 is about to break through the metal, the feed must be made 
 very light, or the drill will catch and it will have to be taken 
 
 out and the last part of the hole chipped out, which does not 
 
 FIG. 32. — DRTLL POST OK OLD MAN. 
 
 make a nice job. For this work, therefore, the driller should 
 remember "feed slow when the point of the drill comes 
 through the plate." 
 
 When drilling, oil should be used freely on all material ex- 
 cept cast iron or brass. On these two materials oil is of no 
 value. 
 
 In getting a hold for the "old man" considerable skill is re- 
 quired, and much ingenuity is shown in such work. A chain 
 passed entirely around the boiler is a handy way to get an 
 anchorage. Sometimes a piece of rope and a board can be 
 used when no other way can be found to back up the drill. 
 
 In feeding the drill to the work, as already noted, a pin is 
 •used to turn the feed screw. Some ratchets, however, are not 
 made with a screw, as described in the preceding paragraph. 
 Fig. 27 shows a ratchet where the feed screw is provided with 
 a threaded sleeve which fits the thread of the feed screw. It 
 is provided with squares on which a wrench can be used to 
 ■get the feed. 
 
 Other Ratchet Tools. 
 
 The ratchet idea is used in many ways in machine work, one 
 use of the idea being to set up nuts. Fig. 33 shows a wrench 
 for such work, in which, of course, the hole in the ratchet can 
 "be either a square or a hexagon and of any required size. 
 This tool is a money-saver, but it is not found as often as it 
 should be in boiler shops. In fact, it is very seldom seen 
 there. 
 
 In a very confined space it is convenient to have a ratchet 
 with a handle which swivels, as it allows a man to work the 
 handle at different angles. A ratchet of this class is shown 
 in Fig. 34. 
 
 to mention. In backing out rivets, driving drift pins and 
 driving rivet sets the sledge is, of course, indispensable. 
 
 A rivet set is a piece of tool steel turned up on the shank 
 when used in what is called an "air gun," or forged, as shown 
 in Fig. 24, and cupped out so as to form either a round or cone- 
 shap'ed rivet head. When the rivet is driven the workman 
 
 FIG. 33. — REVERSIBLE R.\TCHET WRENCH. 
 
 FIG. 34. — SWIVEL H.ANDLE RATCHET. 
 
 holds the set over the roughly- formed rivet head, and the 
 helper swings the sledge, with the result that the rough rivet 
 head is worked into a smooth form, making the work look 
 shipshape. 
 
 Use of the Drift Pin. 
 The drift pin is called in some parts of the world "the boiler 
 maker's best friend," but it is the enemy of good work. It has 
 its legitimate use in assembling boiler work, but it is used far 
 too often to correct poor punching, with the result that sheets 
 are strained and trouble results. Not infrequently deaths have 
 been attributed directly to the use of the drift. The drift in 
 itself is a piece of tool steel drawn to a taper and hardened. 
 The small end may be about H inch diameter and the taper 
 6 inches or 8 inches long. When two rivet holes do not match 
 up the drift is driven into the opening and the sledge swung 
 onto it. Thus the two holes are made to line up after a fash- 
 ion, but a botch job is made. Most boiler shop proprietors 
 have the idea that in their works the drift is not used, but that 
 in all other boiler shops it is used to a very great extent. It is 
 true that since the electric and air drills have come into use 
 the drift is not employed as much as it was some years ago, 
 but its use has not been discarded as it should be. The heavy 
 plates now used make the drift a danger even in the hands of 
 a skilled man. Cases have been known where the drift when 
 driven flies out with a force great enough to break a man's 
 arm. 
 
2C)0 
 
 LAYlXc; OUT FOR BOILER MAKERS 
 
 In iiackinj mit rivets tor rc])air wurk. or in backing out a 
 faulty rivet, the rivet's head is lirst cut off with a rivet buster. 
 as was described earlier in this article. Ihen the backing-out 
 punch, Fig. 22, is held against the rivet and a few sharp blows 
 knock the rivet out. We say "sharp blows." because if light 
 tapping blows are given the rivet will be upset on its end and 
 it will become so firmly set that it will have to be drilled out, 
 which is a long process compared with backing it out. There 
 
 lield in place by means of cap screws, a countersink of proper 
 size for the bolt used is employed, but it should not be the 
 ordinary type of countersink, but one which is provided with 
 a "pilot" ; that is, a teat on the small end which fits the tapped 
 hole. This teat acts as a guide for the countersink and reams 
 out a cone-shaped bole which is concentric with the tapped 
 hole, so when the patch bolt is screwed home the bevel on the 
 liolt will tit nice and snug and make a good, tight joint. 
 
 F!C- 35- — STEEL BOII.EH BOI-T. 
 
 [mmm 
 
 '•^W^A/n/ A/vA^^ 
 
 FIG. 36. — I^VTCH BOLT TAP 
 
 FIG. 37. — BOILER PjVTCH BOLT. 
 
 are times, however, when the very heavy blows should not be 
 used, as in Hange turning, where a number of light blows 
 delivered along the edge of the plate being flanged do not 
 strain the iron or stretch it too much. In such work a wooden 
 maul is very often used, as it does not dent the metal liut still 
 forms up the material. 
 
 P.VTCii Bolts .vnd P.\tch Bolt T.vps. 
 
 Taps of various kinds have been mentioned before. There 
 is, however, another very useful kind of tap known as a patch 
 bolt tap, Fig. 36, which has not been mentioned. This tap 
 differs from the standard taps by having a slight taper. This 
 results, of course, in producing a taper-tapped hole so that in 
 screwing a bolt into it a tight joint is made. For use in con- 
 nection with this tap there is a special patch bolt, as shown in 
 Fig. 37- 
 
 In using the patch bolts the patcli is fitted to the shell of the 
 boiler or wherever it may be required. It is then taken to the 
 drill press, and the holes are drilled as seems best suited to 
 make the patch hold. It is again laid on the sheet and the 
 links marked from it. These holes are then drilled after the 
 patch is taken ofl again, but it must be remembered that these 
 holes in the sheet have to be of tapping size, and not as large 
 as those in the patch. These holes are then tapped with the 
 patch bolt tap and the patch is placed in position. .After suit- 
 able packing has been properly applied, and the patch firmly 
 
 Erectixg Bolts. 
 
 In assembling lioiler and pLite work it is. of course, advan- 
 tageous to get the sections together as quickly as possible. 
 The regular bolts to be found in the inarket have standard 
 threads, as explained before. In boiler work it is rare to 
 find bolts of less than 54 inch diameter or larger than I'A 
 inches diameter. Fig. 35 shows a bolt on which a coarse 
 thread is used: that is, there are fewer threads to the inch 
 than is usual, which makes it possible to run the nuts on them 
 much quicker, but it must be remembered that these quick- 
 thread bolts do not hold well nor can the nut be set up snug 
 or solid, but since the nuts are made loose the\- can be put on 
 with the thumb and finger and the plates- brought together 
 rapidly. The following table gives diameters and lengths of 
 these quick-thread iiolts. all of which can be secured in the 
 open market : 
 
 Di.vMETERS .\xi) Lengths of Erecting Bolts 
 
 Diameter in 
 
 Length in 
 
 Diameter in 
 
 Length in 
 
 Inches 
 
 Inches 
 
 Inches 
 
 Inches 
 
 'A. 
 
 T-'A 
 
 ■H 
 
 2 
 
 'A 
 
 m 
 
 V4 
 
 2/2 
 
 Vs 
 
 i;/2 
 
 Va 
 
 3 
 
 H 
 
 2 
 
 n 
 
 2 
 
 n 
 
 2V2 
 
 n 
 
 2/2 
 
 54 
 
 vA 
 
 H 
 
 3 
 
 Drills can be bought which combine both a drill and a coun- 
 tersink and which are very useful for fitting patch bolts. 
 They are very handy tools and make a good job of the drill- 
 ing and countersinking at one operation, requiring less skill 
 for their use than two separate tools. When a job of patch- 
 ing has to be done far from the shop and where no air or 
 other drive is available the countersinking can be done very 
 well by the use of a specially designed tool where the threaded 
 stem is screw'ed into the tapped hole and the bevel mill, as it 
 may l)e called, is turned on the unthreaded portion of the 
 stem and so arranged that at the same time a feed for the mill 
 can be given. It will pay our readers to remember this tool. 
 
 In all the tools used to cut metal, e.xcept cast iron, oil 
 should be used freely, and it -is our recommendation that with 
 cast iron both reamer and tap should be used. Many dispute 
 the use of oil when using a reamer, but few dispute its use 
 when tapping, yet we know oil saves a reamer from undue 
 wear. -A sharp cutting elge is always advantageous, and 
 boiler makers do not remember this fact as they should. A 
 light touch of a tap along its flutes, and a little stoning of the 
 edges of the bevel mill above described, make a vast change 
 in the amount of work done and a better job. We wish to 
 say that it is a very short-sighted idea to try to use any hand 
 tool which is not in good condition, and about the first thing 
 
TOOLS FOR ]'.oilp:r ^[akers and their uses 
 
 291 
 
 a boiler maker should do after he gets his kit of tools ready and replaced li\- those who have iiotliiiig to do while ihe 
 for an outside job is to look over every tool closely and be boiler is being repaired, and such work wmII be less expensive 
 
 sure that every tool is sharp and otherwise in such condition 
 as will not require returning to the shop to put it in working 
 order. The profit on many a job has been lost by neglecting 
 these precautions. 
 
 No boiler maker will disagree with us when we say that to 
 estimate repairs on a boiler takes the greatest care and e.xpe- 
 rience, and even then there is always something that may come 
 
 if done with care, and when a boiler maker is sent to a mill 
 to patch a boiler he will care little whether the (jwner has a 
 big bill to pay for covering or not : his work is to make the 
 repairs and get l.iack to the shop. 
 
 People are apt to get an idea that repairs should lie done 
 at about so much. Just why they get these ideas would lie 
 hard to say, but about every liill nf repairs is disjiuted. It 
 
 FIG. 38. — .VIOTOR-DRIVEN /J-JNCH THK0.\T HILLES & JONES PUNCHING MACHINE. 
 
 up to upset the calculations. Most repairs are required in 
 parts of the boiler which are difficult to get at and to reach 
 the place where repairs are required is often as much work 
 as are the repairs themselves. Brick work has to be taken 
 down, coverings and pipings got out of the way, and what 
 is often forgotten is that all this work has to be replaced. 
 Again, water has to be drawn off, fires dumped and time must 
 be taken to let the boiler cool. The boiler must be refilled 
 and a pressure put on it. Now all this takes a lot of time, 
 and time that has to be paid for. Owners are very often at 
 fault and object to a bill when it has been made larger than 
 was e.xpected by their not having the boiler ready for the 
 boiler maker to begin work on. No one can expect a man 
 to go into a hot boiler, nor can he be expected to do a proper 
 amount of work if he is burning his knees or elbows, or 
 obliged to breathe air highly heated. The men in charge of 
 a boiler are able to take off handhole plates, and wash out a 
 boiler and have it ready so that some comfort can be had by 
 the workmen who have to enter it. Coverin'? can be removed 
 
 seems a very simple job to put in three rivets, and the three 
 rivets are all they think about, but the work required to reach 
 the defective part is usually more than is expected, as in most 
 cases the work which can be seen is far from what will be 
 found must be done, and if less work is required the con- 
 dition is that an unfair amount of profit is made. If more, 
 the owner gets something for nothing and in neither case is 
 there equity. 
 
 The question of repairs cannot be considered as presenting 
 an uninteresting part of boiler work, and we think the very 
 greatest skill is often shown by boiler makers in doing such 
 work, and a nice job of this kind is nice to be proud of, yet 
 w'ould it not be wise to undertake all repairs at dav' rates? 
 If a boiler maker is not trusted by a firm, no business should 
 be done with him. If he is, why not show the trust by letting 
 him do the repairs at so much an hour? A better job will 
 result and all concerned will have given or received what is 
 justly due. 
 
 Boiler makers' shop tools must necessarily be ponderous, as 
 
-2y2 
 
 LAYING OUT FOR BOILER MAKERS 
 
 the work done by them demands great strength in design and 
 great power in the drive. There are two distinct types of 
 these tools — one where rotary motion is used, the other where 
 
 0| 
 
 
 i 
 
 
 E 
 
 
 © 
 
 1 
 
 
 
 c 
 
 
 ^ 
 
 FIG. 39. 
 
 power in the drive. A good wide belt is required, but if it is 
 run too slow a broad belt may not mean a strong drive. It 
 may be said that all well-known manufacturers of boiler 
 makers' tools now have machines which long experience has 
 made almost perfect, but still there is room for improvement 
 in many ways. 
 
 The principal tools required in a boiler shop are as follows: 
 The punch, shears and rolls. All of these tools should be sup- 
 plied with means for handling the material brought to them, 
 and far too often this is neglected. Without proper cranes 
 and hoists work is made to cost far more than it should, and 
 lack of handling appliances is often the cause for failure to 
 make a satisfactory profit, or any at all. 
 
 A very good example of a well-designed punching machine 
 is shown in Fig. 38. Here it is seen how massive such tools 
 must be, but in the tool illustrated the solidity is a little 
 unusual, as the opening in the frame is 72 inches deep. This 
 opening is called the "throat," or more often the "reach," 
 and it means when you say 72-inch "reach" that a hole can 
 be punched 72 inches from the edge of a plate. Most of the 
 
 FIG. 40. — HEAVY, BELT-DRIVEN CLEVELAND PUNCH. 
 
 a liquid or air is employed. The rotary type can be driven by 
 Tielts or by being direct connected to a steam engine or motor. 
 In some localities water power is alsgi used to drive belted 
 tools. One of the first things to be considered, therefore, in 
 selecting an equipment for a boiler shop is the design of the 
 tools, and particularly the strength of the tool. It can be well 
 understood that a good design can be offset by having too 
 little metal in the machine; and, again, there may be ample 
 metal but it may not be put in the right place. A heavy tool 
 may not be a strong one. 
 After strength in a machine itself, we must look to the 
 
 holes punched in boiler plates are punched but a few inches 
 from the edge of the material, but often hand and manholes 
 have to be worked out in the middle of a sheet and the long 
 reach as shown becomes of value. 
 
 The drive of the tool shown is by means of an electric 
 motor. On the shaft of the motor is a pinion which is com- 
 paratively small in diameter and runs at a high speed. This 
 pinion meshes into a larger gear, and just to the right of this 
 gear a handle will be noticed. This handle moves a clutch, 
 which when thrown out disconnects the large gear from its 
 shaft, whereupon the gear continues to run, but the shaft 
 
TOOLS FOR BOILER MAKERS AND THEIR USES 
 
 29J 
 
 stands still. This clutch therefore controls the starting and 
 stopping of the train of gears which actuate the machine. 
 The clutch shaft extends to the left and is carried in a bear- 
 ing. Just next the clutch gear, and still further to the left, 
 a second bearing will be noticed. To the right of this bearing 
 a pinion will be seen meshing into the teeth of the large spur 
 gear, and to the extreme left, on the clutch shaft, a heavy 
 flywheel is keyed, the value of which will be explained later. 
 The shaft on which the large spur gear is mounted extends 
 from a bearing on the support, which can be seen through the 
 arms of the spur gear, and it extends to the right, through 
 the frame to its very front, but the large spur gear is not 
 keyed to the shaft. To the right of the hub of this gear will 
 be noticed a system of levers, one being horizontal, and to the 
 end of which is attached a spring which in turn is made fast 
 to a lug cast on the frame. In a vertical position is a lever 
 attached to what is called a "bell crank," and on the opposite 
 side of the punch, running along the floor, is a rod which is 
 
 FIG. 41. — HYDRAULIC PLATE SHEAR. 
 
 connected to the bell crank lever. This lever extends to the 
 end of the punch. These levers are connected to a clutch 
 which is keyed on the long shaft which carries the large spur 
 gear. Now, if a man puts his foot on the end of the long 
 lever, on the other side of the punch, by pressing down, the 
 clutch, which is keyed on the shaft in such a way as to slide 
 on it yet revolving with it, will engage the clutch and the 
 large spur gear, and as the shaft and clutch are revolving 
 together the large spur gear will be made to revolve also 
 and the sliding head of the punch will be actuated through the 
 long shaft. 
 
 The operation of the machine is as follows : The motor is 
 started, the first clutch thrown in, which, of course, drives the 
 pinion engaging with the hub of the large spur gear; when 
 the sheet is in position the operator presses the lever on the 
 floor, and in so doing throws in the clutch on the long shaft 
 which sets in motion the shaft and the punch is forced down 
 through the plate. How is the rotary motion of the shaft 
 turned into a reciprocating motion, which is necessary in order 
 that the punch will act ? The revolving shaft has a pin turned 
 on it eccentrically — that is, the center of the pin is not in the 
 center of the revolving shaft, but offset from it. Fig. 39 will 
 make this clearer. Here B is the center of the revolving shaft, 
 A is the center of the pin and the distance D is the offset, and 
 
 this distance multiplied by two will give the length of the 
 stroke of the punch carrying reciprocating head. This pin 
 moves in a slot in a plunger C, which in turn carries the 
 punch. Guides are provided at E and E. This is the general 
 idea of the construction, and of course means have to be pro- 
 vided for the wear which will take place in any machine. An 
 eccentric is sometimes used instead of an eccentric pin. In 
 so large a punch as the one illustrated the punch carrying 
 head is very heavy, and in order to make some compensation 
 for the weight a spring is used, which relieves the machine. 
 
 In the throat of the machine will be seen a lever which is 
 forked, and the punch is between the forks. This lever can 
 be raised or lowered by turning the little adjusting wheel 
 shown at the extreme left of the lever. The use of this fork 
 is to prevent the plate after being punched from being lifted 
 up with the punch, and the forked piece is called a "stripper." 
 It might be supposed that this stripper was not necessary, as 
 if a punch has punched a hole the punch should be drawn out 
 of it without any friction, but this is not the case. The fact 
 is that the punched hole is only the size of the punch, and if 
 the plate is canted the least little bit the punch cramps and 
 sticks in the hole. The stripper therefore obviates any trouble 
 from cramping. 
 
 Now why so many gears? Why not connect direct with the 
 long shaft? The reason is this, there would be no trouble 
 in doing this if room and money were available, but to get the 
 power required by direct drive would demand a motor of 
 very great size, turning at a very slow rate, and such a motor 
 could hardly be built. It must be remembered that the punch 
 does not move fast, but requires great power, while the motor 
 shown in the illustration runs at a high rate of speed.. Now 
 all these gears are nothing more or less than levers ; the long 
 end is the circumference of the gear wheels and the short 
 ends are the shafts. It comes down to power and distance. 
 The motor makes, we will say, 3,000 revolutions, while the 
 long shaft turns but ten turns a minute, each stroke of the 
 punch is 300 times as powerful as one revolution of the motor, 
 but it must be borne in mind that the distance traveled by 
 the punch is 300 times less than that traveled by the motor. 
 There is no power gained, but there is great convenience 
 obtained. No friction has been considered in these statements. 
 
 It is, of course, evident that instead of an electric drive 
 a belt drive could be employed as shown in Fig. 40. Here tne 
 clutch and foot rod are clearly shown and a flywheel is again 
 provided. We referred to a flywheel a little earlier and said 
 we would remark on it later, and we now say that the value 
 of a flywheel lies in the fact that it is a storage of power, or 
 energy. It will be clear on a moment's thought that were no 
 stored energy available, very much more applied power would 
 be required, but with the flywheel as the punch comes in con- 
 tact with the sheet and begins to do its work, the stored 
 energy is given out and the punching is accomplished with 
 ease. 
 
 In Fig. 40 the belt is run on a "tight and loose" pulley and 
 the operator shifts the belt from the loose pulley to the tight 
 one when he starts the machine, and applies the clutch when 
 he has the plate in position. When a plate is to be sheared 
 the same system is used, only the punch is replaced by shears. 
 
294 
 
 L.WIXC, OL'T FOR BOILER MAKERS 
 
 In Fig. 41 is shown a special type of shears. It is special 
 only, however, because the shear blades allow a very much 
 longer cut to be made than is possible with a standard tool. 
 Of course any length of cut can be made by shifting the plate 
 at each stroke with any shears, but the tool shown allows 
 a longer single cut to be made in a way which at times is most 
 advantageous. 
 
 The frame of tliesc shears, instead of being single or throated, 
 is double, strongly braced by a connecting girder, a lower 
 girder acting as a table on which the sheet rests. This lower 
 girder is fi-xed. but the upper one is made to move up and 
 
 rods being made fast to a stationary girder. These rods are 
 called "gag holddowns." and they act as do the strippers on 
 a punch and prevent the plate from rising after the cut is 
 taken. These gags swing towards the front of the tool when 
 the plate is withdrawn, thereby preventing any binding. Gags 
 of this type are patented, we understand. 
 
 Now this wide-bladed tool is not made to work by an elec- 
 tric drive or steam power, but by h\draulic pressure. A cylin- 
 der is used and one can be seen at the right-hand end of the 
 illustration. In this and the other cylinders on the other end 
 not shown, water or some other liquid is used ; quite often 
 .glycerine is emploj'ed, as it does not freeze. In these cylin- 
 ders are pistons on which the liquid under pressure acts, and 
 they are forced forward when required. 
 
 Fig. 42 shows a vertical hydraulic flanging press in which 
 this very satisfactory system is used. In many cases having the 
 work stand vertical is an advantage. The shell of a boiler 
 can be punched at one handling in such a tool, as the shell is 
 
 [<—l%, H 
 
 Ftn. 42. — HYDR.VULIC FLANGI>fC PRESS. 
 
 
 -Ah 
 
 1 
 
 
 *'%'^ 
 
 =^ 
 
 
 
 
 
 ■■\y 
 
 _^i 
 
 
 FIG. 
 
 43. 
 
 IT 
 
 
 FIG. 44. 
 
 "X7 
 FIG. 45 
 
 down and carries with it one of the shear blades. The other 
 blade is fixed to the lower stationary table. 
 
 The motion of the upper girder is obtained as in the punch, 
 only instead of a single pin two connecting levers are used to 
 apply the power at each end. 
 
 In Fig. 40 is shown clearly a feature not before referred 
 to, that is, a counterweight on the ram. The reason for using 
 this counterweight is to take the weight off the eccentric or 
 driving pin. In this design it will be noticed that the flywheel 
 is not large in diameter, but it is very thick across its face or 
 rim. This would indicate that the shaft which carries the fly- 
 wheel is run at a high speed, but the storage of energy would 
 be just as effective. 
 
 Referring again to Fig. 41 it will be noticed that the shear 
 blade on the moving girder is not set parallel to the table, 
 and this is most always done except in very small shears for 
 light metal. The reason for setting the blade at an angle is 
 this: It is evident that if the shear blades were parallel the 
 entire length of the blades would come together at the same 
 time and a very great force would be required in order to 
 make the cut, while with the blade set at an angle only one 
 point is cut at a time ; thus the power required is very much 
 reduced. This may be made clearer by calling attention to 
 an ordinary pair of hand shears. When used to cut a piece 
 of paper the two edges of the blades cut the paper only at 
 one point. 
 
 In Fig. 41, just in front of the moving blade, can be seen 
 rods on the lower ends of which are round bases or feet, the 
 
 raised by means of an overhead crane or hoist and it can be 
 turned for the pitch of the rivet at its ends and raised for the 
 vertical seam. 
 
 It was not mentioned in describing deep-throated punches 
 that to make the tool stiffer when only edge work is being 
 done tie bolts are used. 
 
 They can be put in place or taken out in a few moments, 
 and of course add to the stiffness of the punch if heavy work 
 lias to be done. 
 
 In the punches and shears, and in fact in all the tools on 
 the market, there are many very clever devices, such as 
 clutches, die blocks, etc., which are mostly patented, and 
 which it would be impossible to describe even if only the lead- 
 ing ones of each class were chosen. Some parts of the 
 punches are made to standard, and the punches and dies are 
 so made. Figs. 43, 44 and 43 show a few examples of punches 
 and a die. The punch is held in the machine as follows: In 
 the sliding head or ram a hole is drilled into which fits a piece 
 of steel held in place by a set screw. On the end of this piece 
 of steel or holder is cut a thread on which fits a nut. This 
 nut is so made as to allow the punch to pass entirely through 
 except the head. By screwing up the nut on the holder after 
 the punch is passed through it, the punch is firmly held in 
 place. The threads are made to standard sizes, which is a 
 great convenience to the users of punches. 
 
 Each manufacturer of boiler-making tools has his own de- 
 signs, and he is very glad to send to those interested a full 
 description of any part, or the entire machine if asked, and 
 
TOOLS I'OR liOILKR .\[AKI':RS AXI) Tlll-.IR USRS 
 
 29s 
 
 no man should run a tool any length of time without under- 
 standing all its working parts. The men who try to know 
 more than just pull a lever or shift a belt are the ones who 
 advance in their trade. 
 
 The action of punching a hole tears the metal around it t" 
 some extent, and it is usual to ream punched holes, especially 
 if the plate is heavy, for on thin material this tearing effect 
 is of little moment. To overcome this difficulty drilling is at 
 times resorted to. In fact, on plates in boilers for high pres- 
 sures drilled holes are demanded, and after the holes are 
 drilled in a flat plate and the plate is rolled up the holes in 
 the second plate have to be drilled from the holes in the 
 first. It is usual to hear that drilling is a very much more 
 expensive process, but when it is remembered that reaming 
 has to be resorted to after punching this idea will be found 
 not to be true. With a multiple drill press or a machine 
 
 A i 
 
 ^ 
 
 KIG. 46. 
 
 where a gang of drills is used the cost of drilling is perhaps 
 less than punching" and reaming. It will be seen that it 
 would not be possible to get the heads of the drills close 
 enough together to drill the holes in the plate close enough 
 for ordinary boiler work, so every third or fourth hole is 
 drilled and the sheet is then shifted and another lot of holes 
 are drilled, which finally results in the holes being properly 
 pitched. 
 
 When holes are drilled their diameters need not be con- 
 sidered, as is the case in punching. It is usually thought 
 that a hole cannot be punched smaller than the thickness of 
 the plate; but this is not strictly true, as now the better quality 
 of steels allows punching to be done that disproves this 
 idea. As far back as 1876, in Philadelphia, nuts 2 inches thick 
 were punched with a quarter-inch punch, but this was only 
 as an exhibition and not an every-day possibility. 
 
 Attention was directed to the shearing effect when the 
 blades were set at an angle. Some punches are made on the 
 same idea — that is, the face of the punch is not left square, 
 but two spirals are filed, each starting from the face on oppo- 
 site sides and running back half around the punch very much 
 as if a partial thread was cut. This, therefore, shears two 
 points of the plate at a time, and therefore makes the punch 
 drive with greater ease and gives a cleaner hole. 
 
 There are, of course, many modifications of punches and 
 many tools for boiler makers which may be called special foi 
 the class of work which the shop has taken up. We have 
 given some illustrations of such tools, and when well pro- 
 vided with work thej^ are great money savers. 
 
 The idea of the hydraulic press may be illustrated by means 
 of Fig. 46, which shows a cylinder, A. and a piston, B. 
 Through a pipe, C, the li(|uid is forced by means of a small 
 pump, D. and as water or other fluids are non-compressible, 
 whatever pressure is received from the small pump is exerted 
 on tlie surface of the piston li. If. now, the area of the 
 piston B is 100 square inches and the pipe C leading to the cyl- 
 inder has I pound pressure in it obtained from the small pump 
 D, the total pressure on the surface of the piston B will be 
 100 pounds, as the l-pound pressure will be exerted on each 
 square inch. This would not be so if the fluid were com- 
 pressible. 
 
 The bending rolls shown in Fig. 47 are, next to the punch 
 and shears, the most used tool of a boiler shop, excepting tlic 
 riveter. The flat plate, if passed through the rolls, is formed 
 into a curved surface and a complete circle can be produced 
 if desired. If the illustration is examined closely it will be 
 noticed that the two lower rolls are geared so as to revolve, 
 but the top roll has no drive and revolves only by friction when 
 a plate is passed between the rolls. This top roll has a long 
 extension, which shows at the left of the illustration, and at 
 its end is a pair of rods made fast to the bed of the machine, 
 and across the top of this frame is a cross bar through which 
 passes a screw, which when turned will press against the long 
 extension. At the extreme right-hand end of the top roll 
 can be seen a loop, or perhaps it will be clearer to call this 
 a U, in which the right-hand end of the top roll lies. Across 
 the opening of the U is seen a bolt passing through the two 
 lugs which form the sides of the U. This bolt can be pulled 
 out, leaving a free opening above the end of the roll. If, now, 
 the screw at the left of the long extension is screwed down, 
 the right-hand end of the roll will be lifted out of its bearings, 
 and if a sheet has been rolled up into a complete circle it can 
 be drawn off the machine. The bearing to the left of the top 
 roll swings on a pin, as shown. 
 
 When the rolls are very long, bearings are placed at the 
 center in order to prevent their springing. Means are pro- 
 vided so the rolls can be adjusted — that is, made to come 
 more or less close — as on their position depends the amount 
 of curve which is given to the plate. 
 
 To-day, with the very thick plates used, the edges have to 
 be planed to a bevel, and this is done in a machine especially 
 designed for the purpose. It is a long bed on which the plate 
 is clamped, and a tool carrying sliding head is provided which 
 can be adjusted in the same manner as the tool post of a 
 regular planer. The sliding head is fed along a rail, like the 
 cross rail of a planer, by means of a quick pitched screw, the 
 motion of the screw being reversed at the end of the stroke. 
 This tool is not often found in any but the larger shops. 
 
 There are many special machines which can be used in a 
 boiler shop, such as the rotary bevel shear shown in Fig. 48. 
 Of course tools of this class are expensive and must have 
 sufticient work to make them pay. 
 
 Proper overhead cranes or hoists are necessary with most 
 of the machine tools. Fig. 49 illustrates a simple, inexpensive 
 and serviceable crane and a very convenient chain hoist. In 
 order to hoist a plate it must be gripped in some way, and 
 Fig. so shows a clamp which is most convenient for lifting 
 
296 
 
 LAYING OUT FOR BOILER MAKERS 
 
 plates. A device of this kind saves a world of time over wrap- 
 ping a chain around the plate. We strongly urge those who 
 have practical boiler shop work to do to look into the many 
 time-saving appliances which are now on the market, as we 
 are sure that if used more profits can be made and jobs which 
 show no profit can be made to pay. 
 
 and it is necessary to compress to a higher degree in the 
 cylinder in order to fill a receptacle to a desired pressure. 
 
 It is somewhat perplexing to accept the assertion that all 
 work of compressing air is turned into heat, as we are con- 
 stantly trying to provide means of extracting the heat pro- 
 duced by compression. Were we able to do so it would seem 
 
 FIG. 47. — BENDING KOLLS. 
 
 Compressed Air ."vnd Its Uses. 
 
 The atmospheric air is a mechanical mixture and not a 
 chemical combination — that is, it is made up of 21 parts of 
 oxygen gas and 78 parts of nitrogen gas, when we consider its 
 volume. By weight air has 23 parts of oxygen and "jy parts of 
 nitrogen. Air also contains a small amount of carbonic acid 
 gas and some water vapor. 
 
 We have to take a given temperature when we speak about 
 the volume of air, and 32 degrees is used as a basis, at which 
 temperature i pound of air equals 12.382 cubic feet. 
 
 The weight of air at 32 degrees is .080728 pound at a pres- 
 sure (barometric) of 29.92 inches of mercury, equal to 14.6963 
 pounds per square inch, or 2116.3 pounds per square foot. It 
 is usual to call the weight of air on a square inch area as 14.7 
 pounds. 
 
 Air expands by heat ■ 
 
 of its volume for each degree, or 
 
 49.2 
 
 about one-fiftieth of its volume, and its volume increases in- 
 versely as the pressure. 
 
 When air is compressed its temperature is raised, and this is 
 unavoidable ; but it must be remembered that this development 
 of heat is a loss of work. If a volume of air is compressed 
 at 30 degrees to one-quarter of its original volume its tem- 
 perature rises 376 degrees, if no heat of compression is radi- 
 ated or lost. As the heat of compression increases small 
 clearances become necessary in a well-designed compressor, 
 
 that we are simply wasting power to compress the air if we 
 at the same time dissipate all the heat, as without the heat 
 we would have no energy, or only that of the air before com- 
 pression. If the temperature of the air after compression is no 
 higher than before compression this would be true, but by 
 compression the air's energy is made more available in its 
 
 FIG. 48. — ROT.'^RY BEVEL SHE.\R. 
 
 form. When air is compressed its intrinsic energy is obtained 
 through its expansion after it has reached its thermal equilib- 
 rium with the atmosphere. The total energy of uncompressed 
 and compressed air is the same if the temperatures are the 
 same, but it must be remembered that the available energy is 
 much greater in compressed air. 
 
 The higher air is compressed the more it heats, and with 
 this rise in temperature the more necessarj' it becomes to have 
 
TOOLS FOR BOILER MAKERS AND THEIR USES 
 
 297 
 
 quick-closing valves and small clearances. It must be remem- 
 bered that air is a very elastic fluid; it is just the opposite to 
 water, and the two cannot be handled in the same way. A 
 water pump can be made without regard to clearances, as. 
 
 FIG. 49. — CR.^NE AND HOIST FOR H.'^NDLING PLATES. 
 
 since water is almost non-compressible, it at once fills all 
 clearances with a substance (itself) which, of course, results 
 in there being no clearance. Air can be compressed until it 
 liquefies, but in liquefying it the temperature must be lowered 
 to 317 degrees below zero. 
 
 We have said that air must be compressed beyond the 
 
 FIG. 50. — "never slip" safety clamp for holding plate. 
 
 pressure wanted, in order to be able to deliver a given amount 
 at a given pressure : we will give a table, which ^Ir. F. Rich- 
 ards worked out some years ago, shovv'ing how much horse- 
 power it takes to compress a cubic foot of air to a given pres- 
 sure and how much horsepower it takes to deliver the same 
 pressure ; a 10 percent allowance was made for the friction in 
 the compressor. 
 
 Power Required for Compressing .\ii(. 
 Horsepower required to compress i cubic foot of free air 
 per minute to a given pressure with no cooling of the air dur- 
 ing the compression; also the horsepower required, supposing 
 the air to be maintained at constant temperature during the 
 compression : 
 
 Gage 
 
 Air Not 
 
 Air Constant 
 
 ressure 
 
 Cooled 
 
 Temperature 
 
 100 
 
 .22183 
 
 •14578 
 
 90 
 
 .20896 
 
 •I39S4 
 
 80 
 
 .19521 
 
 ■I3251 
 
 70 
 
 .179S9 
 
 .12606 
 
 60 
 
 .164 
 
 • iiSSS 
 
 50 
 
 .14607 
 
 .10565 
 
 40 
 
 •12433 
 
 .093667 
 
 30 
 
 .10346 
 
 .079219 
 
 20 
 
 .076S0S 
 
 .061188 
 
 10 
 
 .044108 
 
 .036944 
 
 S 
 
 .024007 
 
 .020848 
 
 Horsepower required to deliver I cubic foot of air per 
 minute at a given pressure with no cooling of the air during 
 the compression ; also the horsepower required, supposing the 
 air to be maintained at constant temperature during the com- 
 pression : 
 
 Gage 
 
 Air Not Air 
 
 "onstant 
 
 Pressure 
 
 Cooled Tern 
 
 perature 
 
 100 
 
 I^73i7 I 
 
 1 380 1 
 
 90 
 
 1.4883 
 
 99387 
 
 80 
 
 1.25779 
 
 8538 
 
 70 
 
 1.03683 
 
 72651 
 
 60 
 
 •S3344 
 
 58729 
 
 50 
 
 64291 
 
 465 
 
 40 
 
 .46271 
 
 34859 
 
 30 
 
 ■31456 
 
 24086 
 
 20 
 
 .181279 
 
 14441 • 
 
 10 
 
 .074106 
 
 06069 
 
 S 
 
 .032172 
 
 027938 
 
 In computing the above tabies an allowance of 10 percent 
 has been made for friction of the compressor. 
 
 From this table it will be" seen that it takes 7.8 times 
 the power to deliver i cubic foot of air at 100 pounds 
 than it does to compress i cubic foot to 100 pounds, but this 
 proportion does not hold throughout the table, as at 5 pounds 
 pressure it only requires about 1.34 times the power to deliver 
 the I foot of air. 
 
 In compressing and delivering air there is always a very 
 large loss for the following reasons : 
 
 First, the loss of friction in the compressor, which is ordi- 
 narily 15 to 20 percent, and it cannot be made less than 10 
 percent. 
 
 Second, the losses caused by insufficient air supply ; that is, 
 not free enough air in-takes in valves, or large enough dis- 
 charge valves, poor water jacketing, lack of proper lubrication, 
 coupled with a poor selection of oil used. 
 
298 
 
 LAYING OUT FOR BOILER MAKERS 
 
 Third, losses in piping, leaks and piping of insufficient size. 
 The first cause of loss cannot be greatly reduced: and. as we 
 have said, there must be a compression loss of at least lo 
 percent. All the causes of loss mentioned in the second head- 
 ing can Ik- brought to a minimum, and should be. The third 
 named causes of loss are inexcusable ; neglect will allow a 
 leak to continue, and false economy will put in too small 
 piping; but whether or not the piping is too small, a continued 
 leak .should mean the discharge of the man in charge. 
 
 Another cause of loss is that the in-take of air is not out in 
 the open, but is taken from the boiler or engine room. It is 
 clear that cool air is of value, as it helps to cool the cylinder 
 and is more easily compressed. It is likely, also, to be freer 
 from dirt. The losses from this cause are from 8 to 10 percent. 
 As there is a gain of about i percent for every 5 degrees that 
 the temperature of the air is lowered below that of the com- 
 pressor room, it can be seen that a few dollars spent in leading 
 the in-take pipe to where cool air can be had is a wise e.x- 
 penditnre. 
 
 Wood or brick air inlet ducts are economical, these materials 
 being non-conductors. It should be remembered that in 
 piping air no very large sizes are used. To put in 3-inch pipe 
 costs little, if any, more than to put up 2-inch pipe, so all that 
 is saved by the use of small pipe is the difference in the first 
 cost of the pipe, and the advantage of the larger size of pipe 
 will very soon pay this difference. 
 
 It is asserted by manufacturers of air compressors that as 
 the friction increases in piping, valves and engine, the pressure 
 must increase to obtain economy, and that the pressure must 
 not be allowed to drop below a certain amount. The follow- 
 ing table gives the lowest pressures that can be used advan- 
 tageously, or rather shows the advantage of higher pressures 
 to overcome the effect of friction in piping : 
 
 J-Viction. pounds — 
 
 2.g 5.8 8.8 11.7 14.7 17.6 20.5 23.5 26.4 2g.4 
 
 Pounds at compressor — 
 
 20.5 29.4 .s8.2 47.0 52.8 61.7 70.5 76.4 82.3 88.2 
 
 Efficiency — 
 
 70.9 64.3 60.6 57.9 55.7 54.0 52.5 51.3 50.2 49.2 
 
 Tlie usal pressure at which air compressors are run is 100 
 pounds, but 80 pounds is sometimes used, and as high as 120 
 pounds is quite common. This gives a temperature of from 
 330 to 600 degrees. 
 
 Considerable trouble is encountered in air plants arising 
 from the condensation of water in the pipe lines. To eliminate 
 it the air should be cooled, but how best to do this depends 
 on the conditions, or more properly the available cooling water. 
 We know of one plant where the cooling coils were placed in 
 the water of a river which runs past the shop. Another case 
 was where the water was expensive, being taken from the 
 city water supplj-, a water tower was erected, and the water 
 after it had cooled the hot air ran to a reservoir, much like a 
 hot well in a ship. The hot water was then fed to the boiler. 
 This, of course, was economical. In another case the pipe line 
 
 was fitted with several air tanks, and the air cooling in them 
 precipitated the water, which was led to the boiler, proper 
 means being provided to handle it. Bagging placed in the in- 
 take pipes prevents grit working into the compressor, which 
 prolongs its life. 
 
 To recapitulate : Give ample room for the incoming air, as 
 well as ample room for the outgoing or compressed air. Have 
 the in-take so placed as to get its air from as cool a place as 
 possible, also as free from dust as is possible. Cool the air to 
 extract the moisture and keep the piping tight. 
 
 The question as to how fast air can be compressed is open 
 to discussion. It is believed, however, that 300 feet a minute 
 is about the maximum advisable for continual work, yet this 
 speed is considerably exceeded in some types of compressors. 
 The speed is largely controlled by the area of the valves, but 
 with the ordinary valve we cannct go beyond a certain point. 
 The present style of valve is by no means perfect, and it is 
 quite possible to design a valve for air compressors which will 
 do far better than wdiat we now have. 
 
 In the market to-day there are two styles of valves used in 
 compressors, one called the automatic and the other the 
 mechanically moved valve: the automatic valve is moved by 
 the var\ing pressures on the top and bottom of the valve, 
 while the mechanically moved valve is actuated by a positive 
 movement, such as an eccentric. There are advocates of each 
 style of valve, but, all things considered, the automatic valve is 
 the most satisfactory. By its use there is very little friction. 
 Such valves act just when they should, require no setting and 
 there is nothing to oil. The fact that the automatic valve can- 
 not be tampered with is a great advantage. They, of course, 
 have to be ground and their stems do break, and when this 
 takes place the inlet valves can cause considerable damage by 
 falling into the cylinder. 
 
 On the other hand, the mechanically moved valve cannot do 
 damage should it break. It has to be oiled, and if not properly 
 set very severe strains will be thrown on the compressor. 
 Their first cost is greater and their upkeep is greater, yet its 
 advocates claim greater economy for it. The automatic valve 
 is often placed in the cylinder head, and in so doing the least 
 possible clearance is obtained. The disadvantage of this loca- 
 tion is that if the valve stem breaks the head falls into the 
 cylinder, and is trapped between the piston and the cylinder 
 head, and is apt to break the latter. Also, the discharge pipe 
 has to be made up in the head, and this joint has to be broken 
 whenever the cylinder has to be inspected. When the valve 
 is placed in the cylinder walls the clearance is greater, but it 
 is more easily got at and it cannot fall into the cylinder. 
 
 Before describing the details of the commercial air compres- 
 sors, we want to say a word "about reheating compressed air. 
 It has been found that a very great advantage is obtained if 
 compressed air is heated just as it is to be used. It would not 
 be practical to have a heater next to an air hand drill, but if 
 air is used to run a motor reheating is possible. In an ordinary 
 compressor the loss is about 70 percent, and with a very good 
 compressor this loss may be but 60 percent: that is. without 
 reheating. If now the air is raised, say, from 80 degrees to 300 
 degrees, the volume would be increased about 40 percent, and 
 very little heat is required to effect this gain. It is, therefore, 
 
TOOLS FOR BOILER i\L\KLRS AND TIILIR USES 
 
 299 
 
 well to reheat the compressed air wherever possible. It is feature is that the air inlet to the valves is through a tube 
 asserted that the gain by reheating can be as much as 20 made fast to the piston, and the inlet valves are rings lilted 
 
 FIG. SI. — LONGITUDINAL SECTION OF STANDAI«D CLASS NE-l" INGERSOLL-RAND COMPRESSOR WITH "hURRICANE-INLEt" 
 
 AND "direct Lin" DISC1I.\KGE VALVES. 
 
 4600 A 
 
 FIG. 52. — LONGITUDINAL SECTION OF STANDARD CLASS "nE-i" INGERSOLL-RAND COMPRESSOR, WITH "DIRECT LIFT" INLET AND 
 DISCHARGE VALVES STANDARD CONSTRUCTION ON ALL SIZES UP TO AND INCLUDING THOSE OF I2-INCIT 
 
 CYLINDER DIAMETER. 
 
 percent above the power obtained by the compressor, and this in the head of the piston itself. This design must give very 
 
 with a fuel outlay so small as to be hardly noticeable. large inlet areas, and the inlet valves can have a very small 
 
 Fig. 51 shows a new design of air compressor. The new lift. The discharge valves are placed close to the cylinder 
 
300 
 
 LAYING OUT FOR BOILER MAKERS 
 
 bore and the cylinder is water jacketed, as are the heads. The 
 compressor is belt driven. 
 
 The only advantage which this design seems to possess is 
 that the inlet valves are very large, and this might be offset 
 by the stuffing-box, which the inlet tube requires, and a certain 
 loss of area on one side of the piston by the inlet tube. 
 
 Fig. 52 shows a compressor where the inlet and discharge 
 valves are fitted to the walls of the cylinder. The inlet valves 
 are on the lower side of the cylinder and the discharge valves 
 on the upper. This is the usual design found in the boiler 
 shops throughout the country. 
 
 valve and the other to depress it; but while the live air is en- 
 tering through the port M, some of the live air from the pas- 
 sage V is finding its way down a slotted passage (not lettered) 
 and through the small lassage M' into a circular space below 
 the valve. From this space the air finds its way through the 
 small hole N and through the somewhat larger hole 5, Fig. 53, 
 into the atmosphere. 
 
 It must be remembered that the valve is enclosed in a cage, 
 and that the incoming air, finding its way as described, cannot 
 pass around the valve cage, as the small vertical, unlettered 
 passage shown to the left of the valve cage. Fig. S3, is quite 
 
 m^ 
 
 ; T S ^ 
 
 FIG. S3. 
 
 __.,--l B f CD 
 
 FIG. 54. 
 
 Air or Pneum.'itic Tools. 
 
 We have referred previously to tools which are actuated by 
 air. We will now give a general description of such tools as 
 are usually found in boiler works, or, perhaps we should say, 
 should be universally found in boiler shops, as without them no 
 boiler shop can hope to compete successfully against those who 
 are well supplied with this very satisfactory type of tool. 
 
 First, we will refer to riveters. These may be placed in two 
 classes, when we have to consider their actuating mechanism. 
 One we may call the "valve class," and the other the "valve- 
 less class." Each has its advocates, and it is fair to say there 
 seem to be no bad tools of either type in the market. There 
 are, of course, preferences, and conditions may at times largely 
 direct which type or class of tool should be used. 
 
 We show in Fig. 53 a sectional view of a valve class hammer 
 or riveter. Here the moving parts are ready for the forward 
 stroke, which, of course, is the one which does the work. 
 Fig. 54 shows the moving parts in their position after the blow 
 has been given and all is ready for the return movement of the 
 piston. Live air enters through the passage V, Fig. 54, and 
 through the smaller passage M, Fig. 53, to an annular space 
 cut in the valve. Fig. 55 shows the valve on a larger scale 
 than the sectional view. The valve is made of steel and hard- 
 ened, great care being used in its production. This annular 
 space presents two surfaces of equal area to the action of the 
 live air; therefore the valve must be in balance, as the two 
 pressures are just the same as are the areas, one to lift the 
 
 FIG. SS. 
 
 narrow ; and, further, it must also be remembered that the 
 A^alve cage is so made that the exhaust passes out from the 
 drilled holes, or passages L and D, Fig. 54, to the atmosphere. 
 
 Now, the leakage of the air through the passages A' and S 
 is faster than the entrance of the air through the small pas- 
 sage M' , therefore the valve is not in balance, but the under 
 side of the annular central portion of the valve is acted upon 
 with the pressure of the live air, as is the lower annular part 
 of the valve; but as the pressure under the lower end of the 
 valve is reduced by the leakage described, the valve must be 
 held up against the top of the valve cage, as is shown in Fig. 53. 
 
 The live air passes around the reduced portion of the valve 
 and through the passage K, Fig. 54, onto the head of the 
 plunger or piston, and, of course, drives it forward. When the 
 piston reaches the position shown in Fig. 54 the live air passes 
 around the groove W through the port P' and the passage P 
 to the top end of the valve, creating thereon a pressure which, 
 of course, forces it down into the position shown in Fig. 54, 
 as we have shown that the lower end of this valve is being 
 acted upon by a less pressure than the air on the top, owing 
 to the leakage which we have described. 
 
 It must be again noted that when the piston is in its for- 
 ward position, as shown in Fig. 54, the port .Y is covered by 
 the piston, as is also the port P" , shown in Fig. 53 ; therefore 
 no air can escape through this hole or into this passage. A 
 long drilled hole, shown in dotted lines in both figures, repre- 
 sents the exhaust air passage to the valve cage, and this pas- 
 Sage leads to the front end of the piston and enters the cylin- 
 der through the hole /, Fig. 33. Through this passage and 
 hole the exhaust air acts on the back end of the piston ; and 
 as there is no pressure on the forward end of the piston it is 
 returned to its original position, as shown in Fig. 53, for 
 another stroke. These strokes are very rapid, and, of course, 
 their power will largely depend upon the pressure and length 
 of stroke. 
 
 The Unb.\lanced .\re.-\ System. 
 When a valve is so made as to have different areas on 
 which the incoming or live air acts, the same result is ob- 
 tained as above described, only, of course, it will be seen that 
 
TOOLS FOR BOILER MAKERS AND THEIR USES 
 
 301 
 
 there is no leakage to make an unequal pressure; but this 
 unequal pressure is obtained by making one end of the valve 
 larger than the other. 
 
 The advocates of the straight valve, actuated by a reduced 
 pressure in the valve chamber, claim that the same is very 
 simple to manufacture and can be produced with great ac- 
 curacy at very low cost, while the unbalanced valve makers 
 point to the waste of air by the leakage system referred to. 
 
 The No-V-\lve System. 
 
 When there is no valve used the piston in its movements is 
 -made to cover and uncover ports, and we describe the same by 
 
 therefore at once admitted to the top of the piston through 
 the tapered hole in same, and the piston is driven again to 
 the right ; but it must be remembered that the pressure on the 
 under side of the piston on the annular space marked B is 
 constant, and the blow, therefore, has for its power the pres- 
 sure of the air on a large area of the piston, less the pressure 
 due to its efifect on the annular surface B. It can certainly 
 be justly claimed by those who employ this system that it is 
 extremely simple. 
 
 There are numerous modifications of both the types of the 
 riveters and the hammers which we have described. There 
 are long-stroke and short-stroke hammers in various modi- 
 
 FIG. 56. 
 
 referring to Fig. 56. The piston here shown has two diam- 
 eters. The cylinder, of course, is bored to correspond to these 
 ■diameters. When the piston is at the bottom or end of its 
 stroke, as shown, the air which has driven it forward is ex- 
 
 FIG. 57. 
 
 "hausted from the bore E through a tapered hole in the piston 
 and the passages C and D. Live air from the passage A acts 
 on the under side of the enlarged part of the piston at B, thus 
 forcing the piston to the left until the port C in the piston 
 registers with the air inlet on the passage A. The live air is 
 
 One-Half Stroke 
 
 fications which are of value in certain cases, and the manu- 
 facturers of these tools are very glad at all times to put them 
 in competition with each other, and it is really difificult in a 
 short test to get any real idea of the superior values of a tool 
 of this class. 
 
 It must be remembered that the up-keep of any tool is a 
 most important matter, and often tools of this class are re- 
 ported as unsatisfactory when the trouble lies with the men 
 who use them. Often they are left without being oiled, thrown 
 into the dirt, or thrown ofif stagings, and treated in a way 
 which really would seem to make it impossible that they could 
 continue to operate after a very short time ; but they do stand 
 an enormous amount of hard abuse, which can. however, be 
 stopped by the foreman. 
 
 Other Forms of Air Tools. 
 
 The use of compressed air is not limited to merely tools of 
 this percussion type, but there are a number of rotary acting 
 
302 
 
 LAYIXC UL'T FOR CUILER .MAKERS 
 
 tools for drilling and countersinking, and in many cases the 
 use of air instead of electricity is advantageous in boiler work. 
 This is especially so when the work is to be done in a place 
 that is confined and warm, as the exhaust air from the tool 
 cools the atmosphere and furnishes pure air for the workmen. 
 There are also riveters on the market which use air, steam or 
 water for their motive power. We may call them hydraulic 
 and fluid-driven. The liydraulic tool and the fluid-driven tool 
 use an enormous power in a single efifort to do the riveting, as 
 against a multiplicity of blows, as in the tools we have just 
 described. These latter may be said to be merely a reproduc- 
 tion of the effect of hand riveting, while the hydraulic or 
 single-effort tool is quite the opposite. 
 
 Fig. 57 shows a cross section of one of the tools wherein a 
 single effort is obtained for riveting by the use of either air 
 or steam. The pressure on the piston carries it forward and 
 the power is transmitted by a .system of levers and links. It is 
 generally conceded that in an ordinary hydraulic riveter much 
 more power is required to drive a rivet than in the pneumatic 
 system. To overcome this a compensating action has been 
 invented which is known as the "Hanna motion." 
 
 Referring to Fig. 58 it will be seen that in this system the 
 machine goes through its toggling action during approximately 
 the first 6 inches of the piston stroke, and carries the die 
 
 through practically 3Vj inches of its travel. .At this point the 
 machine has reached its rated pressure, and the toggling action 
 is then automatically changed to the lever action, which is 
 maintained for the balance of the piston stroke, and for par- 
 ticularly the last half of die travel, thereby maintaining the 
 rated tonnage throughout this distance. This comparatively 
 uniform travel of the die under the rated tonnage for the last 
 half of he piston stroke is sufficient, once the die screw is 
 adjusted to the work, to take care of the ordinary variations 
 encountered in the length of the rivet, thickness of the plate, 
 size of hole, etc., without the necessity of readjusting the die 
 screw. 
 
 In selecting tools it is wise to look into the market most 
 thoroughly before making a selection ; and above all, while 
 we all know that money is a matter of great importance, a tool 
 not just suited for your work which you buy because it is a 
 little cheaper, is always an annoyance and rarely a money 
 maker. Find out first in selecting tools what is best, and make 
 your purchase not only for the moment but with an eye to the 
 future. 
 
 In the purchase of second-hand tools there is at times an 
 advantage, but such tools should be closely inspected before 
 purchase ; and it is advantageous to arrange, if possible, for 
 a short trial with a tool to see that everything is all right. 
 
INDEX. 
 
 Air Compressors 
 
 Air Tools 
 
 Alarms, High and Low Water 
 
 Allowance Between Inside and Outside Cylindrical Rings 
 
 .Mlowance for Bending due to Thickness of Material 
 
 Angle Iron Rings 
 
 Annealing Steel 
 
 Arched Smokebox 
 
 Area of Circle 
 
 Area of Circular Segments ^ 
 
 Area of Segment 
 
 Area of Plunger of Feed Pump 
 
 Arrangement of Feed Pipe and Injector on Locomotive Boiler. 
 Ash Pan 
 
 Back Corner Patches 
 
 Back Heads of Combustion Chambers IIC, 
 
 Backing Out Punch 
 
 Base Plate for Stack 
 
 Beading Tools 
 
 Bell-Shaped Portion of Stack 
 
 Belpaire Fire-Eox 
 
 Belpaire Throat Sheet 
 
 Belt Drive 
 
 Bending Rolls 
 
 Bill of Material for Tubular Boiler ' 
 
 Blow-Off Cock 61, 
 
 Blow-OIT Valves '. 61. 130, 
 
 Boiler: 
 
 Breeching, Scotch 
 
 Flue and Return Tubular 
 
 Horizontal Return Tubular 
 
 Lobster Back 
 
 Locomotive 
 
 Locomotive Intersection Between Dome and Slope Sheet 
 
 Scotch 
 
 Tubular 
 
 Dog House 
 
 Boiler Heads '. 
 
 Boiler Mountings 57, 98, 129, 
 
 Boiler Repairs 
 
 Boiler Saddles 
 
 Boiler Uptake, Scotch 
 
 Bolts, Erecting 
 
 Bolts, Patch 
 
 Bottom Blow-Off Valve 
 
 Bottom Course of a Stack 
 
 Brace Pins 
 
 Bracing of Tubular Boiler 
 
 Braces: 
 
 Diagonal 
 
 , Rivets in 
 
 Factor of Safety of 
 
 Size of 
 
 Strength of Direct 45, 
 
 Strength of Indirect 
 
 Brackets 
 
 Breeching 28, 126, 
 
 Breeching for a Scotch Boiler 
 
 Bridges Between Flues 
 
 Broken Stay-Bolts *! 
 
 Bridge Wall 
 
 Bulged Fire-Box, Repairing 
 
 ]>utt Joint with Inside and Outside Straps 
 
 Butt Straps 39, 
 
 Butt Straps, Thickness of 
 
 PAGE. 
 
 298 
 300 
 
 16 
 286 
 251 
 
 11 
 
 62 
 102 
 126 
 
 146 
 
 124 
 
 287 
 
 160 
 
 283 
 
 163 
 
 79 
 
 SO 
 
 293 
 
 295 
 
 41 
 
 130 
 
 135 
 
 Calculations for Area of Circular Segments 
 
 Calculations for Cost of Return Tube Boiler 
 
 Calculations for Cost of Small Scotch Boiler 
 
 Calcuations for Size of Plates for Self-Supporting Steel Stack Ba 
 
 Calculations of Lap Joints 
 
 Calking Tools 
 
 197 
 188 
 65 
 248 
 105 
 
 122 
 134 
 139 
 116 
 254 
 290 
 290 
 61 
 173 
 
 55 
 165 
 256 
 
 37 
 
 113 
 
 39 
 
 270 
 
 6 
 
 273 
 
 PAGE. 
 
 Camber of a Taper Course 236 
 
 Camber of Tapered Sheet 20 
 
 Cape Chisel 280 
 
 Center Punch 287 
 
 Check Valve 62, 135 
 
 Chipping 280 
 
 Chisels 285 
 
 Cinder Basket 95 
 
 Cinder Pocket 89 
 
 Circle, .\rea of U 
 
 Circle, Circumference of 11 
 
 Circular Hood for Smoke Stack by Triangulation 27 
 
 Circular Segments, Area of 270 
 
 Circumference of a Circle 11 
 
 Circumferential Seam for Boiler Shells 35, 113 
 
 Clamp 295 
 
 Cleaning Plug 101 
 
 Coal Chute, Cylindrical 15 
 
 Cold Chisel 280 
 
 Collapsing Pressure of Flues 44 
 
 Collar for Smokestack 247 
 
 Collar for Stacks 27 
 
 Combustion Chambers 116 
 
 Compound Curve, Pipe 210 
 
 Compressed Air 296 
 
 Compressors, Air 298 
 
 Concrete Mixer, Hopper for 223 
 
 Cone, Frustum of 19 
 
 Cones Intersecting 220 
 
 Conical Body Intersected by a Spout 230 
 
 Conical Elbow 206 
 
 Conical Roof of Tank 265 
 
 Conical Surfaces 17 
 
 Conical Surfaces Where the Taper is Small 19 
 
 Connection, Irregular by Triangulation 237 
 
 Connection of Smoke-Box Sheet to Boiler Shell and Tube Sheet.... 88 
 
 Connection of Smoke-Box Sheet to Smoke-Box Front Ring 88 
 
 Construction of Large Water Tank 261 
 
 Copper Converter Hood with a Round Top and Irregular Base.... 179 
 
 Corner Plug 79 
 
 Cost of Return Tube Boiler 276 
 
 Cost of Small Scotch Boiler 273 
 
 Cowls, Ship Ventilating 174 
 
 Cranes 295 
 
 Crown Sheet - 75, 78 
 
 Cylinder Opening 86 
 
 Cylinders Intersecting at an Oblique Angle 15 
 
 Cylinders Intersecting at Right Angles 15 
 
 Cylindrical Coal Chute l-'i 
 
 Cylindrical Surfaces 10 
 
 Cylindrical Tank 85 Feet in Diameter by 35 Feet High 166 
 
 Damper Regulator 64 
 
 Deflecting Plates 93 
 
 Deflecting Plate Slide 94 
 
 Diagonal Braces 47 
 
 Diagonal Pitch of Rivets 35 
 
 Diagram for Finding Efficiency of Riveted Joints 267 
 
 Diameter, Mean or Neutral 11 
 
 Diamond Point Chisel 287 
 
 Dies 294 
 
 Dished Dome Heads 52, 53 
 
 Dividers 7 
 
 Dome 51. 65, 200 
 
 Dome and Slope Sheet for Locomotive Boiler 248 
 
 Dome Braces 52 
 
 Dome Liner 68 
 
 Dome Sheet '-1. 66 
 
 Double Angle Pipe 241 
 
 Double Riveted Butt Joint 37 
 
 Double Riveted Lap Joint 35 
 
 Drain Cock 131. 136 
 
 Drift Pin 289 
 
304 
 
 INDEX 
 
 PAGE. 
 
 Drills, Ratchet 288 
 
 Driving Machine Tools 292 
 
 Dry Pipe 00, 129, 134 
 
 Effect of Punching, Drilling and Reaming Rivet Holes 39 
 
 Efficiency of Riveted Joints 267 
 
 Elbow, Conical 206 
 
 Elbow Exhaust 190 
 
 Elbow, Irregular 204, 207 
 
 Elbow, 90-Degree 202, 212 
 
 Elbow, Tapering 22, 183 
 
 Electric Drive 293 
 
 Erecting Bolts 290 
 
 Estimating the Cost of Return Tube Boiler 276 
 
 Estimating Cost of Small Scotch Boiler 273 
 
 Exhaust Elbow 190 
 
 Expanders 284 
 
 Factor of Safety, British Board of Trade Rules 31 
 
 Factor of Safety for Braces 49 
 
 Feed Pipe 63 
 
 Feed Pipe in Locomotive Boiler 102 
 
 Feed Pump 62 
 
 Fire-Box Back Sheet 73 
 
 Fire-Box Sheet, Outside 79 
 
 Fire-Box Sheet, Belpaire 79 
 
 Fire-Box Side Sheet 76 
 
 Fire-Box Tube Sheets 74 
 
 Fire-Box Wrapper Sheet 245 
 
 Fire-Box Wrapper Sheet, Sloping 250 
 
 Fire Door Holes 79 
 
 Fire Doors 79 
 
 Fire Engine Boilers 148 
 
 Flanging Press 294 
 
 Flat Drill 288 
 
 Flue, Rectangular 10 
 
 Flue Renewals 145, 148 
 
 Flue Settmg 148 
 
 Forge Hood • 228 
 
 Forms of Diagonal Braces 49 
 
 Four-Piece, 90-Degree Elbow 172 
 
 Front End, Locomotive 86, 90 
 
 Front Tube Sheet 69 
 
 Frustum of Cone 19 
 
 Furnace Doors 125 
 
 Furnace Fittings 125 
 
 Furnace Lining 126 
 
 Furnaces 125 
 
 Gage Cocks 63 
 
 Gage Glass 63 
 
 Gaskets on Patches 146 
 
 Granet for Oval Smokestack 240 
 
 Grate Bars 125 
 
 Gusset Plates 205 
 
 Gusset Siieet 71 
 
 Guyed Stacks 159 
 
 Hammer 283 
 
 Hangers 55 
 
 Head for Tank, Hemispherical 255, 260 
 
 Heads 199 
 
 Heads, Size of 42, 122 
 
 Heating Surface 43, 57 
 
 Hemispherical Tank 255, 260, 263 
 
 High and Low Water Alarms 63 
 
 High Speed Steel 286 
 
 Hoists 295 
 
 Holding Qualities of Flues 43 
 
 Hood for Oval Smokestack 240 
 
 Hood for a Semi-Portable Forge 228 
 
 Hopper for a Coal Chute by Triangulation 181 
 
 Hopper for a Concrete Mixer 223 
 
 Horizontal Return Tubular Boiler 197 
 
 Horsepower of Stacks 157 
 
 Hydraulic Flanging Press 294 
 
 Hydraulic Shears 294 
 
 Injector 61 
 
 Injector Check 62 
 
 Injector on Locomotive Boiler "102 
 
 Intersecting Cones 220 
 
 Intersection between Dome and Slope Sheet for Locomotive Boiler. 248 
 
 Intersection of a Cone and Cylinder at an Angle of 60 Degrees.... 18 
 
 Intersection of Cylinder with an Elbow by Projection 176 
 
 PAGE. 
 
 Intersection of Cylindrical and Plane Surfaces 16 
 
 Irregular Connection by Triangulation 237 
 
 Irregular Elbow 204, 207 
 
 Irregular Offset Piece 234 
 
 Irregular Pipe Connection 218 
 
 Irregular Spiral Piece 243 
 
 Irregular "Y" Pipe Connections 194 
 
 Joints, Efficiency of Riveted 267 
 
 Joints, Lap 266 
 
 Lagging 96 
 
 Lagging Cover 97 
 
 Lap 35 
 
 Lap Joints 266 
 
 Laying Out Tools 7 
 
 Laying Up a Bulged Fire-Box 147 
 
 Lever Safety Valve 69 
 
 Lining for Stack 161 
 
 Location of Butt Straps 114 
 
 Location of Stay-Bolts 83 
 
 Locomotive Boiler 65 
 
 Locomotive Boiler Intersection Between Dome and Slope Sheet.... 248 
 
 Locomotive Fire-Box Wrapper Sheet 245 
 
 Locomotive Frames 100 
 
 Locomotive Front End 86,90 
 
 Locomotive, Stack 92 
 
 Longitudinal Seams for Boiler Shells 36, 56 
 
 Main Steam Outlet 57 
 
 Manhole Liner, Size of 54 
 
 Manholes 54, 113 
 
 Manholes, Size of « 54 
 
 Marking a Plate 10 
 
 Material for Scotch Boiler 117 
 
 Mean or Neutral Diameter 11 
 
 Miscellaneous Problems in Laying Out 165 
 
 Mud-Ring 78 
 
 Netting Door 94 
 
 Neutral Sheet Under Dome 62 
 
 90-Degree Elbow 202, 212 
 
 90-Degree Tapering Elbow by Projection 22 
 
 90-Degree Tapering Elbow by Triangulation 183 
 
 Off-Set from a Round to an Oblong Pipe by Triangulation 170 
 
 OfE-Set Piece, Irregular 234 
 
 "Old Man" 288 
 
 Open Tank 13 
 
 Operation of Machine Tools 293 
 
 Outside Fire-Box Sheets 79 
 
 Palm of Braces . 49 
 
 Patch Bolts 144, 290 
 
 Patching Locomotive Boiler 145 
 
 Patch Bolt Taps 290 
 
 Patterns for a Rectangular Flue 10 
 
 Pin, Drift 289 
 
 Pipe Connection 194, 214 
 
 Pipe Connection, Irregular 218 
 
 Pipe, Double Angle 241 
 
 Pipe Intersecting Large Cylinder at Right Angles 216 
 
 Pipe, Rectangular Intersecting a Cylinder Obliquely 221 
 
 Pipe, Spiral 244 
 
 Pipe Taps 282 
 
 Pipe with Compound Curve 210 
 
 Pipes 57. 101, 129 
 
 Piping and Fittings for a Tubular Boiler 67 
 
 Pitch of Rivet Lines i 35 
 
 Plane Surfaces 9 
 
 Plane and Cylindrical Surfaces Combined 13 
 
 Plugging Flues 146 
 
 Pneumatic Hammer 300 
 
 Pneumatic Riveter 300 
 
 Pneumatic Tools 300 
 
 Power Required for Compressing Air 297 
 
 Preliminary Layout of Scotch Boiler , 105 
 
 Pressed Steel Dome Rings 65 
 
 Pressure Tank 12 
 
 Punch 292 
 
 Punch, Backing Out 287 
 
 Punch, Center 287 
 
INDEX 
 
 305 
 
 PAGE. 
 
 Ratchet Drills 288 
 
 Ratchets 287 
 
 Rectangular Flue 10 
 
 Rectangular Pipe Intersecting a Cylinder Obliquely 221 
 
 Regular "V" Pipe Connections I94 
 
 Regulator 9 
 
 Regulator, Damper 64 
 
 Removing Fire-Box After Door Sheet 146 
 
 Removing Radial Stays 145 
 
 Renewing Tubes in Watertube Boilers 153 
 
 Return Tubular Boiler I97 
 
 Return Tube Boiler, Cost of 276 
 
 Rivet Buster 287 
 
 Rivet Holes, Spacing of 9 
 
 Rivet Set 287 
 
 Rivets m Braces 49 
 
 Riveted Joints: 
 
 Butt Joint with Inside and Outside Straps 37, 113 
 
 Diagonal Pitch 35 
 
 Double Riveted Butt 37 
 
 Double Riveted Lap . 33 
 
 Efficiency of 267 
 
 Lap 266 
 
 Pitch 35 
 
 Triple Riveted Butt 37 
 
 Triple Riveted Lap 32, 34 
 
 Roller Expander 284 
 
 Rolls, Bending 295 
 
 Roof of Tank, Conical 265 
 
 Saddles for Scotch Boiler 116 
 
 Safety Valve 58, 152 
 
 Salinometer Pots 136 
 
 Scarfing Shell Plates 12 
 
 Scotch Boiler 105 
 
 Scotch Boiler, Breeching 256 
 
 Scotch Boiler, Cost of 273 
 
 Scotch Boiler Uptake 254 
 
 Scum Blow-Off 61 
 
 Sectional Expander 284 
 
 Segment, Area of 47 
 
 Segment of Sphere, Template for 257 
 
 Segments, Area of Circular 270 
 
 Self-Supporting Stack 159 
 
 Self-Supporting Steel Stack Base 258 
 
 Shears 294 
 
 Sentinel Valves 136 
 
 Shell 199 
 
 Shell Plate, Scotch Boiler 121 
 
 Shell Plates, Size of '. . . 40 
 
 Shell Sheets of Tubular Boiler 56 
 
 Ship Ventilating Cowls , 174 
 
 Side Cut Chisel 287 
 
 Size of Plates for Self-Supporting Steel Stack Base 258 
 
 Sledge 289 
 
 Slope Sheet 71 
 
 Slope Sheet and Dome for Locomotive Boiler 248 
 
 Sloping Fire-Box Wrapper Sheet 250 
 
 Smoke-Box, Arched 251 
 
 Smoke-Box Door 89 
 
 Smoke-Box Extension 89 
 
 Smoke-Box Liner 87 
 
 Smoke-Box Sheet 86 
 
 Smokestack Collar 247 
 
 Smokestack Hood 240 
 
 Spacing Rivet Holes 9 
 
 Spacing of Tubes 42 
 
 Spark Arrester 93 
 
 Specifications 200 
 
 Specifications for a Three-Furnace Single-Ended Scotch Boiler.... 133 
 Specifications of the Association of American Steel Manufacturers 
 
 for Boiler Steel 41 
 
 Spherical Segment, Template for 257 
 
 Spiral Piece, Irregular 243 
 
 Spiral Pipe 244 
 
 Spout Intersecting a Conical Body 230 
 
 Spring Loaded Safety Valve 60 
 
 Squaring up a Plate 9 
 
 Stability of Stack 161 
 
 Stack Base 258 
 
 Stacks 157 
 
 Stacks, Locomotive 92 
 
 Standard Taps 282 
 
 Stationary Fire-Tube Boilers 150 
 
 Stationary Water-Tube Boilers 153 
 
 PACE. 
 
 Stay-Bolts 114 
 
 Stay-Bolts, Location of gS 
 
 Stay-Bolt Taps 281 
 
 Steam Domes 5] ^5 
 
 Steam Gage ' as, 136 
 
 Steam Pipe 57 
 
 Steam Stop Valve 129, 135 
 
 Steel, Annealing 280 
 
 Steel, High Speed 280 
 
 Steel, Specification for 41, 173 
 
 Steel, Tool 285 
 
 Steel Stacks 157 
 
 Strength of Scotch Boiler ^ 112 
 
 Strength of Stack ; ici 
 
 Surface Blow-Off Valve 61 
 
 Surfaces; 
 
 Combined Plane and Cylindrical 13 
 
 Conical 17 
 
 Cylindrical 10 
 
 Intersection of Plane and Cylindrical 15 
 
 Plane 9 
 
 Suspension of a Tubular Boiler 54 
 
 Tank Head, Hemispherical 255, 260 
 
 Tank, Large Water 261 
 
 Tank, Open 13 
 
 Tank, Pressure 12 
 
 Taper Course 231, 235 
 
 Taper Course with a Flat Side 239 
 
 Taps, Patch Bolt 290 
 
 Taps, Pipe 282 
 
 Taps, Stay-Bolt 281 
 
 Template for a Segment of Sphere 257 
 
 Thickness of Butt Strap 39 
 
 Throat Sheet 80 
 
 Tool Steel 285 
 
 Top or Cap for Stack 163 
 
 Top Throat Sheet 80 
 
 Transition Piece 225 
 
 Transition Piece by Triangulation 233 
 
 Transition Piece, Tapered 231 
 
 Transition Piece, Special 227 
 
 Triangulation 25 
 
 Triangulation Applied to Irregular Connection 237 
 
 Triangulation Applied to Layout of Transition Piece 233 
 
 Triple-Riveted Butt Joint 38 
 
 Triple-Riveted Lap Joints 32, 34 
 
 Truncated Oblique Cone by Triangulation 25 
 
 Tube Expander for Watertube Boilers 154 
 
 Tube Expanders 284 
 
 Tube Ferrules 101 
 
 Tube Setting 148 
 
 Tubes: 
 
 Collapsing Pressure of 44 
 
 Holding Qualities 43 
 
 Spacing 42 
 
 Tube Sheets 122 
 
 Tubular Boiler 31 
 
 Tubular Boiler, Cost of 276 
 
 Twist Drill 288 
 
 Uptake for Scotch Boiler 254 
 
 Uptakes 126 
 
 Use of Dividers 10 
 
 Use of Regulator 10 
 
 Versed Sine of an Angle 19 
 
 Water Gage and Test Cocks 63 
 
 Water Space Corners 78 
 
 Water Space Frames 78 
 
 Water Space Plug 79 
 
 Water Tank 261 
 
 Welded Joints 39 
 
 Whistle Valve 130 
 
 Working Pressure of a Tubular Boiler 34 
 
 Wrapper Plates of Combustion Chamber 116, 124 
 
 Wrapper Sheet for Locomotive Fire-Box 245 
 
 Wrapper Sheet Sloping Fire-Box 250 
 
 "Y" Breeching 165 
 
 *'Y" Connection by Triangulation 28 
 
 *'Y" Pipe Connections 194, 214 
 
 Zinc Baskets 136 
 


 
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