T353 
 017 
 
 MANUAL 
 
 OF 
 
 DRAWING. 
 
 COOLIDGE. 
 
T 353 C77"™""'"*era'»y Library 
 A [janual of drawing. 
 
 3 1924 004 586 305 
 
 CORNELL 
 
 UNIVERSITY 
 
 LIBRARY 
 
 Given to the 
 COLLEGE OF ENGINEERING 
 
 ty the 
 Dept. of Machine-Design. 
 
Assistant Professor of Mac. 
 
 FIRST EDITION. 
 
 FIRST THOUSAND. 
 
 NEW YORK: 
 
 JOHN WILEY & SONS. 
 
 London : CHAPMAN & I^ALL, Limited. 
 
 1902. 
 
Copyright, igoa, 
 
 BY 
 
 C. E. .COOLIDGE. 
 
 ROBERT DRUMMOND, PRINTER, NEW YORK. 
 
PREFACE. 
 
 The officers of instruction in the Department of Machine Design of Sibley 
 College, Cornell University, in addition to a great many other kindred things, 
 are charged with the responsibility of instructing the Sophomore, Junior, 
 and Senior Classes in the art of commercial mechanical drawing. 
 
 We recognize the fact that the student is often unnecessarily perplexed, 
 distressed, and even retarded in the advancement of his work because he 
 has no single, definite, or comprehensive system which he can follow in his 
 drawing. 
 
 Thus the object of this Manual is to put into permanent form a single 
 and standard drafting-room system which will tend to alleviate unnecessary 
 burdens thrust upon the student. 
 
 It is conceded beforehand that the student is not and should not be held 
 in the same status as a full-fledged and experienced commercial draftsman. 
 Therefore he should be informed of more than one route which will take 
 him to the same destination. 
 
 That information can be imparted by informal talks given in the class- 
 room or lecture-room. But a single and definite system could and should be 
 followed, to facilitate advancement in too short a course in drawing; to give 
 him, as far as possible, the atmosphere and sensation of the commercial 
 drafting-room; and, if nothing else, to teach him one good system well. 
 
 The system that has been evolved, and embodied in this book, is intended 
 to be the average of the Drafting-room Systems which are in use in the 
 United States at the present day, and is fully substantiated by the solicited 
 data and information that have been received from about one hundred and 
 thirty of the largest concerns in the United States in various lines of 
 manufacturing. 
 
 A cursory glance through the book will disclose blank pages alternating 
 
17 
 
 With the printed ones in the front part of the book and with the iUustrated 
 ones in the back part. 
 
 The drafting-room system as elaborated in this book is, by virtue of its 
 predesigned scope, by no means complete. 
 
 It thus devolves upon the instructor to give and the student to note on 
 the blank pages what is left out in the text. 
 
 It was the primary object of the writer to elaborate, as described above, 
 only on what is produced by means of drawing-instruments. He soon 
 reahzed, however, the fact that that is only the end of things, and the begin- 
 ning cannot be detached when it is probably the most important part of 
 the technic of mechanical drawing. Therefore the writer has discussed in 
 detail. the salient points in the selection, treatment, and adaptation of the 
 drawing instruments and materials that are used in a commercial drafting- 
 room. 
 
 The pressing need of this imperfect little book to assist in advancing 
 the interest of the student, was the sole incentive which caused the author 
 to write it. He will be repaid if its mission is partly fulfilled. 
 
 He is under obligation to Professor John H. Barr, the head of the Ma- 
 chine Design Department, for reading the manuscript and for rendering 
 substantial assistance which aided in the completion of the book. 
 
 He desires especially to thank Mr. Sanford A. Moss, who has collaborated 
 with him in advancing a set of standard drafting-room conventions for the 
 use of the Machine Design Department. 
 
 Thanks are also due to all others who have in any manner lent assistance 
 or given encouragement. 
 
 C. E. COOLIDGE. 
 Ithaca, N. Y., September, 1902. 
 
Manual of Drawing. 
 
 PROPERTY 
 
 DEPARTMENT 
 MA^fJJNF DESIGN 
 
 SIBLEY SCHOOL 
 CORNELL UNIVERSITY 
 
 ...J 
 
PART I. 
 MATERIALS AND INSTRUMENTS. 
 
 The materials used in drawing may be di- 
 vided into two distinct parts. One part would 
 represent the materials on which drawings are 
 made and reproduced before any substances are 
 applied to make that contrast which pronounces 
 it a drawing for the manufacturer or builder 
 in commercial mechanical lines, to produce, by 
 means of it, that which has utility and a com- 
 mercial value. The other part would repre- 
 sent such substances as are necessary to apply 
 to the drawing materials, for the purpose just 
 described. 
 
 The materials on which drawings are made 
 and reproduced would include drawing-paper, 
 bond-paper, tracing-paper and -cloth, print- 
 paper, etc. 
 
 The substances applied for making drawings 
 would include lead, ink, chemicals for prints, 
 etc. 
 
 The instruments and other accessories which 
 
 3 
 
Cornell University 
 Library 
 
 The original of tiiis book is in 
 tine Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924004586305 
 
are used in applying the different substances 
 to the surfaces of drawing materials must be 
 selected for their adaptation to the execution 
 of a commercial mechanical drawing. 
 
 Commercial mechanical drawing-instruments 
 and other accessories would include the 
 drawing-board, T-square, compass, dividers, 
 etc. 
 
 MATERIALS ON WHICH COMMERCIAL ME- 
 CHANICAL DRAWINGS ARE MADE AND 
 REPRODUCED. 
 
 Commercial mechanical drawings are, at the 
 present time, usually made first in pencil on 
 inexpensive drawing-paper and then traced 
 with ink on tracing-paper or -cloth; and, finally, 
 printed on chemically prepared paper. 
 
 Occasionally drawings are penciled and 
 inked on a good quality of white or brown 
 paper, or bond-paper and prints are taken from 
 the inked bond-paper drawing. 
 
 Drawing Paper. 
 
 The ideal drawing-paper should be of tough 
 fiber, imiform thickness and surface, neither 
 repel nor absorb ink before or after it is rubbed 
 with an ink-eraser, and take the ink without 
 wrinkling the surface. 
 
Whatman's Hand- 
 made Paper. 
 
 Manilla Paper. 
 
 Duplex Paper. 
 
 Egg Shell Paper. 
 
 Bond Paper. 
 
 Whatman's hand-made paper approaches 
 most nearly the ideal drawing-paper. It is 
 about the most expensive drawing-paper made, 
 and for that reason it has a very limited use 
 in commercial establishments. 
 
 Manilla wrapping-paper is a brown paper 
 and one of the cheapest brands of paper made. 
 It should never be used for finished inked draw- 
 ings. 
 
 Keuffel & Esser's Duplex (or equivalent) 
 drawing-paper is a brown- or cream-colored 
 drawing-paper and is a little better quality 
 than the average commercial grade. It will 
 bear a fair amount of careful rubbing and ink- 
 ing. 
 
 Egg-shell paper, with a linen back and rough 
 surface, is occasionally used for a drawing made 
 to stand out in bold relief for pictorial effect. 
 It is a very durable paper and wiU bear very 
 rough handling. 
 
 Bond-paper is a thin and comparatively 
 translucent white paper which has the dis- 
 tinctive advantage that the original drawing 
 can be directly printed from on print-paper or 
 cloth, and thus avoid mistakes of omission 
 and commission made in tracing from a 
 drawing. 
 
 Bond-paper is very easily wrinkled and can 
 be rubbed through very quickly. Therefore 
 
it requires most careful handling; and an inked 
 drawing on bond-paper should not, as a rule, 
 be rubbed with anything except a fine iak- 
 eraser. The extended commercial use of bond- 
 paper is increasing. 
 Cross Section Cross-sectiou paper, whose checks are con- 
 
 Paper. . f f ' j. j • 
 
 veniently spaced, has the advantages found m 
 bond-paper, and the added advantage of 
 drawing on it without the assistance of a 
 scale. 
 Laying Paper on Drawing-paper, when it comes in rolls, should 
 
 Board. 
 
 usually be laid with the convex side next the 
 drawing-board, and the water-mark should 
 always be on top. 
 stretching Draw- Drawing-paper is occasionally stretched on 
 
 ing Paper. 
 
 the board when it is not to be taken off for 
 some days; but after it is taken off the paper 
 usually contracts and the scaling is affected. 
 
 The paper is stretched on the board in the 
 following manner: first, clip off the corners so 
 that the four edges can be folded over for three 
 fourths of an inch; second, wet all the surface 
 except the turned edges, with a sponge; third, 
 lay the wetted surface next to the drawing- 
 board; fourth, smooth the paper by rubbing 
 from the center out to the edges; fifth, glue 
 down the edges with very strong gum arable 
 or like material. 
 Mounting Drawings. A paper drawing may be longer preserved 
 
10 
 
 by mounting on straw-board and varnishing 
 its surface with white shellac 
 
 Tracing Paper. 
 
 Tracing-paper is a firm and transparent 
 paper having a smooth and glossy or oily sur- 
 face, and can be easily printed from on print- 
 paper. It should be of tough fiber, uniform 
 thickness and surface, neither repel nor absorb 
 ink before or after it is rubbed with an ink- 
 eraser, and take ink without wrinkling the sur- 
 face. 
 
 Tracing-paper should not generally be used 
 when permanency of a drawing is the chief 
 object. 
 Tracing Alternate Tracuig-paper is used somewhat for tracing 
 alternate positions of a piece of mechanism, in 
 order to facilitate a design, when the relation 
 of the piece of mechanism to the other parts 
 of the machine is known. 
 
 Tracing Cloth. 
 
 Tracing-cloth or -linen should have one of its 
 surfaces well glazed and no open pores. It 
 possesses the same properties and uses as trac- 
 ing-paper, besides being more permanent. It 
 has a more extensive use commercially. 
 Tear off Edge. Before tracing-cloth is laid on the board the 
 
12 
 
 wrinkled portion along the .edges should be 
 torn off and its surface should be stretched 
 smooth. (Tracing-cloth will tear straight par- 
 allel, to its edges only.) 
 
 Advantages and There is Considerable discussion and con- 
 
 Disadvantages of . . , 
 
 Glazed and Un- teutiou as to whether the glazed or unglazed 
 glazed Sides. gide of traciug-cloth should be used. There 
 are advantages and disadvantages in using 
 either. It must be admitted that the glazed 
 side was primarily intended for use; that draw- 
 ing-ink, especially red ink, when used, will eat 
 deeper into the unglazed surface with conse- 
 quent difficulty in rubbing; that it is usually 
 rolled with the glazed side in, which would nat- 
 urally bring the glazed side on top, as the convex 
 surface is placed next the board; that the trac- 
 ing does not curl so much when inked on the 
 unglazed side as on the glazed side; and also 
 that the tracing will eventually smooth itself 
 out when inked on the glazed side if placed in 
 the drawer with the glazed side down. There- 
 fore the writer must insist that, from his present 
 knowledge and past experience, no change from 
 ancient customs should be made unless a draw- 
 ing is penciled on the cloth, when it is abso- 
 lutely necessary that the unglazed side should 
 be used in order to see the pencil-lines clearly. 
 Pr ration f Sur- Before usiug tracing-cloth, and especially if 
 Qoth." "^"""^ its surface has been exposed to the air, it should 
 
14 
 
 be rubbed with a fine powder or blotter and 
 then brushed off thoroughly. 
 Effect of Moisture Tracinff-cloth is very susceptible to moisture 
 
 on Tracing Cloth. ° . . 
 
 in the atmosphere, and it will become taut or 
 loose with a change of weather. 
 
 Water will ruin tracing-cloth, and care should 
 be taken that perspiration from the hands is 
 prevented from coming in contact with its 
 surface. 
 
 The sizing can be dissolved or soaked off, 
 and the linen left makes a very desirable pen- 
 wiper. 
 Cleaning Tracings. Tracings can be cleaned with gasolene, ether, 
 benzine, or any highly volatile substance. 
 
 Sheet Celluloid. 
 
 Sheet celluloid is used in the same manner 
 as tracing-paper for tracing alternate positions 
 of a piece of mechanism. It is more durable 
 than either tracing-paper or -cloth, and is han- 
 dled more easily. 
 
 Print Paper. 
 
 Print-paper should be of tough fiber to admit 
 of considerable handling, and should print 
 quickly with clean-cut lines in ordinary sun- 
 light, 
 to Print from a To print from a drawing proceed as follows: 
 rawing. ^^^ ^^^ drawing in the printing-frame with the 
 
mg. 
 
 16 
 
 ink-lines next the glass; then lay the sensitized 
 surface of the print-paper next the drawing; 
 expose for a suitable time to the sunlight 
 and then remove the print and place in a fixing 
 solution for a suitable time, which will vary 
 with the kind of print-paper used. 
 
 Blocking Out. If there are certain lines, figures, etc., on the 
 
 tracing that are not desired on the blue-print, 
 they can be retained on the tracing and left 
 off of the blue-print by placing a piece of opaque 
 paper over them when' printing. 
 
 Principle of Print- The principle involved in printing lies in the 
 chemical change after the sensitized surface of 
 the print-paper has been exposed to the light 
 and passed through a fixing solution. That 
 part of the surface of the print-paper under the 
 inked lines, figures, etc., on the drawing is 
 shielded more or less (depending on the color 
 of ink used) from the light; therefore after the 
 fixing solution is used, the necessary contrast 
 which is desirable on the print obtains. It is 
 thus evident, from the known relation of color 
 to light, that, when the most distinct lines 
 are required on the print, the blackest and 
 most opaque ink must be used to entirely 
 exclude light from the surface of the print- 
 paper. 
 
 Use of Colored Colored inks, which are of course not so im- 
 
 pervious to the light as black ink, are occa- 
 
 Inks. 
 
18 
 
 sionally designedly used on drawings to give a 
 less distinct line on the priat; but, for commer- 
 cial use, thin black lines of different character 
 from the lines of projection on the drawing are 
 far more desirable, for many reasons which are 
 noted through the text, and serve the same 
 purposes that colored lines usually do in com- 
 mercial mechanical drawings. 
 
 In a resume of the foregoing it is evident that 
 the time of exposure of the print-paper to sun- 
 light varies according to the sensitiveness of 
 the chemicals used; with the materials upon 
 which the drawing is made; with the substance 
 applied in making the lines, figures, etc., on the 
 drawing; and the intensity of sunlight — ^which 
 is usually more effective in winter than in sum- 
 mer — or artificial light. 
 Printing by Eiec- Apparati of Several designs have been de- 
 
 ■ trie Light. .... i • i i , . ,. , 
 
 Vised m which the electric light is used for 
 printing, and they are especially convenient in 
 cloudy or stormy weather. 
 
 Care of Print All print-paper should evidently be -as fresh 
 
 ^^^^^' as possible; and, when not in the printing- 
 
 frame, it should be kept from the light in a 
 covered can or case placed in a dark room. 
 
 Shrinkage of Print It must be borne in niind that print-paper 
 usually un-uniformly shrinks, and therefore it 
 must never be scaled for actual dimensions. 
 
 Blue Print Paper. Blue-print paper is decidedly the most used 
 
20 
 
 Over Exposure. 
 
 Fixing. 
 
 commercially. It produces a white line on a 
 blue field. 
 
 The field of a blue-print darkens according 
 to the amoimt of exposure; and, as none of the 
 black drawing-inks are absolutely opaque, the 
 value of a print can be annulled by over-ex- 
 posure. 
 
 After exposure to sunlight, blue-print paper 
 is immediately immersed in water (which is the 
 fixing solution), and then all loose substances 
 on the printed surface should be washed off 
 with a hose filled with water under pressure. 
 The print should remain in the water for at 
 least ten minutes. 
 Time of Exposure. The Ordinary blue-priut paper requires about 
 four or five minutes' exposure to bright sim- 
 light. 
 
 There is a quick blue-print paper which re- 
 quires about two minutes' exposure in bright 
 sunlight when printing from a drawing made 
 on tracing paper or cloth or their equivalent. 
 
 In printing from bond paper and cross-sec- 
 tion paper, a longer exposure to the light is re- 
 quired than for printing from tracing-paper 
 or tracing-cloth. 
 
 Blue-print cloth is printed in the same man- 
 ner as blue-print paper. It is much more per- 
 manent than blue-print paper, as it will bear 
 rougher usage. 
 
 Quick Blue Print 
 Paper. 
 
 Printing from 
 Bond and Cross 
 Section Paper: 
 
 Blue Print Cloth. 
 
22 
 
 White Print Paper. White-print paper produces a blue line on a 
 white field, and is treated similarly to blue-print 
 paper. 
 
 Black Print Paper. Black-print paper produces a black line on a 
 white field and is immersed in a chemical bath 
 first, if there is no chemical developer in the 
 coating of the paper. It is afterward carefully 
 washed in water in the same manner as blue- 
 print paper. 
 
 Brown Print Paper. Brown-print paper produces a white line on 
 a brown field. It should be immersed in a fix- 
 ing solution and then washed in water in the 
 same manner as the other print-papers. 
 
 Mounting Prints. A print may be longer preserved by mount- 
 ing on straw-board and varnishing its surface 
 with white shellac. 
 
 SUBSTANCES APPLIED FOR PRODUCING LINES, 
 FIGURES, ETC., ON COMMERCIAL MECHANI- 
 CAL DRAWINGS. 
 
 AH substances which are used on the surfaces 
 of drawings should be selected for their adap- 
 tation to the purpose. No inferior grades 
 should be used. 
 
 Pencils. 
 
 A good drawing pencil or "lead" (misno- 
 mer and conventional) is essential for produc- 
 ing plain, clean-cut, and uniform lines. 
 
24 
 
 Soft Pencil. 
 
 Grade of PenciL 
 
 The pencil should be made of a uniform grade 
 of material throughout; and a suitable grade 
 of hardness should be selected for the type of 
 drawing which is to be made. 
 ' A soft pencil draws smoother, easier, and 
 faster than a hard pencil. 
 
 A drawing which is to be either inked or 
 traced over, should be made with a soft pencil 
 of HHH or HHHH grade. A drawing made for 
 permanent use and not to be inked or traced, 
 should be made with a hhhhhh to hhhhhhhh 
 grade pencil. 
 
 Hever Thin Draw- 
 ing Ink. 
 
 Red Ink. 
 
 Inks. 
 
 Black drawing-ink should be opaque, water- 
 proof, and non-decomposable; and should flow 
 freely, dry quickly, and not eat into the surface 
 of the drawing material. 
 
 Black drawing-ink can be prepared from 
 stick India ink; but it is more convenient when 
 purchased in the bottles of the prepared com- 
 mercial water-proof drawing-ink. 
 
 The commercial prepared water-proof draw- 
 ing-ink must never be thinned. If the ink 
 does not flow satisfactorily, examine the pen 
 for the source of the trouble, or, if the ink has 
 actually changed (which is almost invariably 
 not the case), procure another bottle. 
 
 Red or carmine drawing-ink — ^used only when 
 
26 
 
 absolutely necessary — should be water-proof 
 and non-decomposable. It should flow freely, 
 dry quickly, and not eat into the surface of the 
 drawing material. 
 Care of Ink. All ink, when in use, should be kept in an 
 
 open drawer, within convenient reach, or at a 
 sufficient distance away from the drawing to 
 prevent it from being upset on the drawing. 
 
 Substances for Preparing a Surface to be Inked after it 
 is Roughened. 
 
 When the fibers of a surface have been torn 
 up by careless rubbing, the prepared varnishes 
 painted on it, or the rubbing of the affected 
 surface with soapstone, hard beeswax, bone, 
 or the end of the finger-nail, will effectually 
 prepare it for inking. 
 
 Substances used in Preparing and Altering Blue Prints 
 
 The sensitizing chemicals for blue-prints are 
 prepared from several formulae in varied pro- 
 portions. 
 Sensitizing Solution A good sensitized surface is prepared as fol- 
 
 for Blue Print ,-,11 i 1 • 
 
 Paper. lows: In a dark room, make a solution of 
 
 Citrate of iron and ammonia ... 1 part. 
 
 Water 5 parts. 
 
 Then make a solution of 
 
 Red prussiate of potash 1 part. 
 
 Water 7 parts. 
 
28 
 
 Mix equal parts of the two solutions and ap- 
 ply with a sponge, for about two minutes, to a 
 paper having a hard and smooth surface; then 
 drain off the superfluous liquid and hang up to 
 dry. The paper thus prepared will have a 
 bright yellow hue. 
 
 The sensitizing solutions can be kept sepa- 
 rately for a long time, but when mixed must 
 . be kept from the light. 
 Altering Blue Soda, potash, quicklime, or any alkali in so- 
 
 lution with water and a little gum arabic added 
 to keep the liquid from spreading on the paper 
 will produce a white mark on the surface of a 
 blue-print. Such solutions are used for mak- 
 ing alterations in the print. 
 
 Chinese white and other commercial pastes 
 are also used for making alterations; but the 
 writer beUeves that there is nothing more sat- 
 isfactory for the purpose of making corrections 
 or additions on a print than to use black ink 
 on a light print and red ink on a dark print. 
 
 INSTRUMENTS AND OTHER ACCESSORIES 
 USED IN THE EXECUTION OF MECHANI- 
 CAL DRAWINGS. 
 
 The proper selection of instruments is of 
 prime importance. It is universally conceded 
 by first-class draftsmen that good instruments 
 are absolutely essential for the best execution 
 of drawings in the shortest time. 
 
30 
 
 The term "good instruments" does not neces- 
 sarily imply that a draftsman should have all 
 the new-fangled specifics that are afloat on the 
 market ; as, section-liners, dotters, etc. A 
 good instrument, legitimately interpreted, is 
 one which is indispensable and of the best grade. 
 
 Drawing Board. 
 
 The drawing-board should be made of soft 
 and well-seasoned wood of uniform grain; should 
 have two adjacent edges straight and at right 
 angles to each other; should have its working 
 surface very slightly crowning in the center; 
 and should be designed to allow for the changes 
 due to atmospheric conditions. 
 Working Straight If a permanent working straight-edge on the 
 ^^^' board is desired, a heavy cast-iron or steel strip 
 
 may be securely fastened to it. 
 Testing the Work- The truth of the straightness of the working 
 mgEdge. edge of the board can be tested by applying 
 
 a standard straight-edge. 
 
 T Square. 
 
 A T square of the best grade and design 
 should have a fixed head and blade, with ebony- 
 lined edges. 
 
 The blade should be dovetailed or let into 
 the head, but the upper surface of the head 
 should always be flush with the working siu-- 
 face of the drawing-board. 
 
32 
 
 Double Head. 
 
 Beveled Blade. 
 
 Celluloid Lining. 
 
 Testing the Edge of 
 Blade. 
 
 Testing Head. 
 
 Pear Wood 
 T Square. 
 
 If the blade is fixed to the head with screws, 
 not less than five screws should be used. 
 
 As a rule, adjustable heads are undesirable; 
 but a design having a double head is practicable, 
 and is reconunended when one head is perma- 
 nently fixed, as specified above, and the other 
 detachable, adjustable, and fastened with two 
 binders. 
 
 The blade should have its working edge bev- 
 eled to not over one sixteenth of an inch thick, 
 and the ebony fining well secured. 
 
 Experience has proved that the celluloid 
 lining, while possessing some slight advantages, 
 warps and loosens, which fact makes it un- 
 satisfactory. 
 
 To prove the straightness of the edge of the 
 T-square blade, proceed as follows: first, draw 
 with it a line; second, turn it end for end and 
 place the edge of the blade to exactly coincide 
 with each end of the line which was drawn; 
 third, draw another line; fourth, observe the 
 coincidence of the lines which were drawn, to 
 prove the truth of the straightness of the edge. 
 
 The truth of the straightness of the head 
 can be tested by applying a standard straight- 
 edge. 
 
 A good pear-wood T square, designed as 
 above, makes a cheap and altogether decent 
 instrument. 
 
34 
 
 Mckel Plated 
 T Square. 
 
 Transparent Tri- 
 angle. 
 
 Hard Rubber Tri- 
 angle. 
 
 Pear Wood Tri- 
 angle. 
 
 A nickel-plated steel T-square has the decided 
 advantage of maintaining its truth; but its 
 surface gathers dirt and smuts the drawing, 
 which fact makes it less desirable than the 
 other types. 
 
 Parallel Straight Edge. 
 
 A parallel straight-edge, which is fastened to 
 a cord or wire running in grooved rolls which 
 are secured to the comers of a drawiag-board, 
 replaces the T-square, and, consequently, the 
 the working edge on the drawing-board. 
 
 There are other arrangements of the parallel 
 
 straight-edge, and nearly all of them are most 
 
 desirable. 
 
 Triangles. 
 
 The transparent triangle appears to be the 
 most popular triangle used at present. It is 
 subject to change in planeness and accuracy, 
 and the very best material used in its manu- 
 facture is none too good. It possesses the ad- 
 vantages of not obstructing the view of any- 
 thing on the drawing when in use, and of 
 keeping a drawing cleaner than other triangles. 
 
 The hard-rubber triangle warps somewhat, 
 but usually keeps its planeness longer than the 
 transparent one, and smuts the drawing more. 
 , The pear-wood triangle is cheaper, but sub- 
 ject to change due to atmospheric conditions. 
 It does not smut the drawing like rubber. 
 
36 
 
 Hickel Plated Steel 
 Triangle. 
 
 30° X 60° and 45° 
 Triangles. 
 
 Inside Edge Cut 
 Out and Beveled. 
 
 Inserted Knob. 
 
 Combination Tri- 
 angle. 
 
 To Draw 30°, 60°, 
 and 90° Lines. 
 
 To Draw 45° and 
 90° Lines. 
 
 The nickel-plated steel triangle maintains its 
 planeness and truth, but, like other steel in- 
 struments, it gathers dirt and smuts the drawing. 
 
 The 30° X 60° and 45° triangles are most com- 
 monly used; but there are a large variety whose 
 sides make other angles with each other. 
 
 If the central portion of a triangle is cut out, 
 the inside edge may be beveled on one side to 
 facilitate handling when it is transferred from 
 one part of the drawing to another. 
 
 An inserted knob is also used, and perhaps 
 is more convenient than the beveled edge for 
 picking up the triangle. 
 
 The combination triangle designed by D. J. 
 Kelsey, New Haven, Conn., combines all the 
 functions of the common 30°X60° and 45° tri- 
 angles, except the drawing of parallel lines, 
 lines perpendicular to each other, and a line 
 making 75° with the horizontal. It has the 
 inserted knob and generally takes the place of 
 30°X60° and 45° triangles, when used in com- 
 bination with the T square. 
 
 By properly combining the T square and the 
 30°X60° triangles, lines can be drawn making 
 30°, 60°, and 90° with the horizontal and verti- 
 cal. 
 
 By properly combming the T square and 45° 
 triangle, lines can be drawn making 45° and 
 90° with the horizontal and vertical. 
 
38 
 
 To Draw 15° and By properly combining the T square, 30° X 
 75 ines. g^o triangle, and 45° triangle, lines can be drawn 
 
 making 15° and 75° with the horizontal and 
 vertical. 
 
 To Draw ParaUei By properly combining a triangle and T 
 i^^tals!'*"^''' square or the 30° X 60° and 45° triangles, paral- 
 lel and perpendicular lines can be drawn. 
 
 To Prove 90° Both triangles are proved for the truth of 
 
 their 90° angles as follows : first, place the short 
 side of the triangle against a straight-edge; 
 second, draw a line; third, reverse the triangle 
 and draw another line directly over the first; 
 fourth, observe the coincidence of the lines, 
 which wiU prove that the angles are correct. 
 
 To Prove 30° and The 30° and 60° angles can be proved for 
 ^^^' their truth as follows: first, place the short 
 
 side of the triangle against the edge of the T- 
 square blade; second, draw through a point, 
 with the 60° side of the triangle, the two lines 
 made with the triangle after it is turned first 
 on one side and then on the other; third, draw 
 a horizontal line across the extremities of the 
 lines just made; fourth, measure the triangle, 
 formed by the lines drawn, to prove the equi- 
 lateral triangle which obtains for a true 60° 
 angle. 
 
 To Prove 45° The 45° angle can be proved for its truth as 
 
 Angles. follows: fiirst, place one of the short sides of 
 
 the triangle against the edge of the T-square 
 
40 
 
 blade; second, draw through a point, with the 
 45° side of the triangle, the two lines made 
 with the triangle after it is turned first on one 
 side and then on the other; third, draw a 
 horizontal line across the extremities of the 
 line just made; fourth, measure the triangle, 
 formed by the lines drawn, to prove the isos- 
 celes triangle which obtains for a true 45° angle. 
 The triangle sTiould always be used with its 
 working edge next to the light to avoid shad- 
 ows. 
 
 Working Edge to The Working edge for a right-hand person 
 
 ^ is naturally on the left; and the drawing-table 
 
 should be arranged accordingly, in order to 
 
 have the light on the proper side of the triangle. 
 
 Light for Drafting Northern exposure and diffused light through 
 '"""■ skylight windows is undoubtedly the ideal 
 
 light for a drafting-room. 
 
 Scale. 
 
 Triangular Box- The scale is made in many forms, but prob- 
 
 woo cae. ^-^^^ ^^^ triangular boxwood scale is the most 
 popular. It is easily read and manipulated, 
 and will admit of combining, in one scale, all 
 the graduations which are usually used in 
 making any particular type of commercial 
 mechanical drawing. 
 
 Scale Guard. A scale-guard should be used with the trian- 
 
 gular boxwood scale to obviate the usual expe- 
 
42 
 
 Nickel Plated 
 Sheet Steel Scale, 
 
 Marking off Dis- 
 tances. 
 
 Turning Scale. 
 
 Reflecting Light. 
 
 flat Boxwood 
 Scale. 
 
 Scales in Sets. 
 
 rience of inconvenience from placing the scale 
 on the wrong side when it is in use. 
 
 Undoubtedly the nickel-plated sheet-metal 
 steel scale conduces to most accurate work, 
 which is vitally essential in well-made drawings. 
 
 The marking off of distances is greatly facili- 
 tated by running the pricker-point or pencil- 
 point down the indents on the steel scale which 
 indicate the graduations. 
 
 As there are but two graduated edges on the 
 steel scale, the annoyance experienced of fre- 
 quently turning the scale, is eliminated. 
 
 The ancient cry that the eyes are injured by 
 the reflection of light from the nickel-plated 
 steel scale, has been unsubstantiated. The 
 writer sees no reason why a steel scale should 
 injure the eyes more than a white enameled 
 one. 
 
 A fiat boxwood scale with beveled edges has 
 less pitch on its sides, and, for that reason, is 
 considered by some to be more quickly and 
 easily, read than any other form. It is not, 
 however, as readily manipulated as any of the 
 others. 
 
 Both sheet-steel and boxwood scales can be 
 obtained in sets to suit the requirements, but 
 the former scale is recommended as superior 
 to all others. 
 
 The ordinary scale was never designed for a 
 
44 
 
 straight-edge or ruler, or for any other purpose . 
 than to take distances from. 
 
 Scale to be Used. When a drawing is made on reduced scale, 
 the full size scale should not be used; but the 
 particular scale which is arranged and adapted 
 for the purpose. For example: a drawing may- 
 be made one fourth size in English measure, 
 or its equivalent, three inches to the foot, which 
 indicates that a graduation is to be found where 
 every three inches in length is marked in feet; 
 and also, one three-inch length is subdivided 
 into twelve equal parts which are marked 
 inches. 
 
 Scale Terms, Such terms as i scale or size and ^ inch to 
 
 to the foot must not be confounded when the 
 proper graduations are being sought on the 
 scale. A moment's reflection will make it clear 
 that the former stands for three inches to the 
 foot, and the latter for one fourth of an inch to 
 the foot; and their respective scales AviU be 
 graduated as indicated above. 
 
 To Prove a Stale. A scale can be proved for accuracy as follows : 
 Mark its equal subdivisions off on a straight 
 line and then reverse the scale and note if the 
 equal subdivisions coincide. 
 Limit of Accuracy The limit f or accuracy in scaling should be, 
 in commercial mechanical drawing, not more 
 than one hundredth of an inch. 
 
 of a Scale. 
 
46 
 
 Distances from the 
 Scale. 
 
 Straight Edge with 
 Scale. 
 
 One Setting. 
 
 If any number of equal or unequal distances 
 are to be divided off on a right line, they should 
 always be marked off directly from the scale. 
 
 When several distances within the limit of 
 the scale are laid off where there is no line on 
 which to lay the scale, a straight-edge should 
 be placed against the scale. 
 
 Consecutive distances within the limits of the 
 scale should be laid off at one setting. 
 
 steel Protractor. 
 
 Other Protractors. 
 
 Protractor. 
 
 The protractor is legitimately used for laying 
 off angles which cannot be gotten from the tri- 
 angles. 
 
 A steel protractor should be of first-class de- 
 sign and should have as little surface as possible 
 to come in contact with the paper. 
 
 Cheap German-silver and celluloid protrac- 
 tors are not recommended. 
 
 Universal Drafting Machine. 
 
 The Universal Drafting-machine is a recent 
 device which is advertised to combine all the 
 functions of the T square, triangles, protractor, 
 and scales. There is a great deal claimed for it 
 and it is well recommended by practical men. 
 It is perhaps too early yet to make favorable 
 or adverse criticism of it, but after a time its 
 true worth will be tested and rated. 
 
48 
 
 material. 
 
 Curved Ruler. 
 
 The curved ruler is often needed for deline- 
 ating certain irregular lines, but it should not 
 be used if circular arcs can be practically sub- 
 stituted. 
 Selection of Curve. A Set of curves is of ten Selected for a certain 
 class of work; but one universal curved ruler 
 will often meet most of the requirements. An 
 average logarithmic spiral curve is recom- 
 mended for general use. 
 
 Curved rulers, are usually made of such mate- 
 rials, with the exception of steel, as are found 
 in triangles, and consequently they have the 
 same advantages and disadvantages as regards 
 convenience, etc.; hence, vmquestionably, a 
 transparent curved ruler is ultra-superior to 
 any other. 
 
 Drawing Pencil. 
 
 The drawing-pencil has already been dis- 
 cussed with reference to the lead contained in 
 it. 
 
 The form of the wood which encases the lead 
 should not be circular in section. 
 
 It is a good plan to sharpen both ends to 
 points not less than three eighths of an inch 
 and not over one half of an inch long; one with 
 a conical point and the other with a flat chisel 
 point. 
 
 Form of Pencil. 
 
 Sharpen Points. 
 
50 
 
 Use of Points. 
 
 Flat Point. 
 
 To Use Pencil. 
 
 Artist's Pencil. 
 
 The flat point should be used for drawing 
 Unes, and the conical point for free-hand work. 
 
 When lines are drawn with the flat point of 
 the pencil, it should be used for marking dis- 
 tances from the scale. 
 
 The pencil, when in use, should have all of 
 the available surface of the lead in contact with 
 the straight-edge which guides it; and it should 
 be held slightly inclined in the direction to 
 which it is being drawn. 
 
 The pencil should be pressed lightly down 
 and drawn from left to right and away from the 
 manipulator. 
 
 The Artist's pencil with movable lead is a 
 very desirable substitute for the ordinary 
 drawing-pencil. Two of them should be pro- 
 cured for convenience, one with a conical- 
 pointed and the other with a chisel-pointed lead 
 in it. 
 
 Ruling Pen. 
 
 The ruling pen is about the most important 
 instrument found among what are known as 
 the case instruments. 
 
 The unskilled draftsman has been very often 
 provoked into uttering undesirable epithets on 
 account of poor execution; due, almost entirely, 
 to poor material in the ruling-pen or to negli- 
 gence in repairing it. 
 
52 
 
 Selection and Care. It is of prime importance that the greatest 
 care should be exercised in the selection of the 
 pen; and it is of more importance to keep the 
 pen in first-class working condition. 
 
 Test of Ruling Pen. The ruling-pen should have its blades made of 
 the best tempered steel. It can be tested for 
 the softness or hardness of the material by- 
 drawing a Swiss file lightly across its nibs. 
 
 Blade. The iusidc of the blades of the ruling-pen 
 
 should be as little concave as possible. 
 
 Opening Device. One blade should be arranged with a properly 
 
 designed hinge, or a device for opening the blade 
 quickly and widely. 
 
 Hinged Ruling Pen. Many draftsmen oppose the hinged ruling- 
 pen on the ground that the joint for the hinge 
 impairs a certain rigidity which is essential 
 when the pen is in use. It is undeniably true 
 that a blade is more rigid when not jointed; 
 but hinged ruling-pens have been designed, 
 and there are some few on the market, which 
 meet all the essential requirements of rigidity. 
 It is vitally necessary that the hihged ruling- 
 pen be designed with an effective device for 
 taking up the wear at the joint. 
 
 To Clean Pen. ^ V^^ "^^^t be kept thoroughly clean; and a 
 
 pen is not necessarily thoroughly cleaned by 
 drawing a rag through it when the nibs are 
 close together; but, if it is necessary, each nib 
 should be rubbed off and smoothly polished. 
 
64 
 
 Handle. 
 
 Care of Nibs. 
 
 Repair Nibs. 
 
 Hence the convenience gained from a com- 
 mon-sense wide-opening pen. 
 
 The handle should be made of a material that 
 is not easily broken. Bone or ivory handles 
 are undesirable because they are easily broken; 
 but an aluminum or ebony handle is very satis- 
 factory, particularly the former. 
 
 The ends of the nibs must be kept in prime 
 condition. Such a condition obtains when the 
 ends of the nibs are perfect arcs whose radii are 
 not over one thirty-second of an inch; are sharp 
 as a pocket pen-knife, and both touch the paper 
 when the pen is placed with its axis in a plane 
 perpendicular to the plane of the paper. 
 
 To repair the ends of the nibs, proceed in the 
 following order: first, clean the pen thoroughly; 
 second, draw the nibs together until no light is 
 seen between them; third, round off the ends 
 with an oilstone into the shape of a circular arc 
 with a small one thirty-second of an inch 
 radius; fourth, spread the blades a little, and, 
 with one blade held at an angle of about 30° and 
 in contact with the plane surface of an oilstone, 
 draw it forward and backward on the stone, 
 and at the same time oscillate it, to keep the 
 configuration on the back, until the edge is as 
 sharp as a pocket pen-knife; fifth, rub lightly 
 the inside surface of each nib with the plane sur- 
 face of the oilstone to remove any possible burr. 
 
56 
 
 To Set the Pen. 
 
 To FiU the Pen. 
 
 Refill the Pen. 
 
 To Draw a line. 
 
 Ink on Outside of 
 Pen. 
 
 Wipe Pen. 
 
 The pen shotild always be set the proper 
 width by the eye; which is done by holding it 
 to the Ught or over a piece of white paper. 
 
 The pen should ordinarily be filled not deeper 
 than three sixteenths of an inch, unless an extra- 
 wide line is to be drawn. 
 
 If the ink does not flow, do not ruin the pen 
 by jabbing it iato a piece of wood or paper, but 
 start the flow by drawing it across the little 
 finger or a wet sponge; then if the ink fails to 
 flow, wipe out and refill the pen. 
 
 When a line is being drawn the pen should 
 be held with its axis in a plane perpendicular to 
 the plane of the paper, slightly inclined in the 
 direction to which the pen is being drawn; and, 
 with slight pressure on the pen, drawn from 
 left to right and away from the person. 
 
 When a pen is in use, care should be taken 
 that no ink is on the outside of the nibs and 
 that the guiding straight-edge does not come 
 in contact with the inked line. Carelessness 
 and disregard of this advice will usually be 
 followed by ink flowing under the instrument, 
 and consequent provocation to the use of strong 
 language. 
 
 Since most drawing-inks dry quickly and cor- 
 rode steel, they must always be wiped thor- 
 oughly after use, even if it is only for a short 
 interruption. 
 
58 
 Care, Use, etc., of It behooves every draftsman to read that 
 
 Instruments, Al- f ^ i r rm aij.jp 
 
 teneder & Sons. P^rt of the Catalogue of Iheo. Alteneder & 
 Sons, Philadelphia, Pa., which gives an admir- 
 able discussion of the ruling-pen and other in- 
 struments. 
 
 Pen for Widths of j^ medium-size pen can be used to advan- 
 tage for lines of all widths; and the belief held 
 by many that a fine line and a coarse line are 
 necessarily drawn with a small and large pen 
 respectively is a fallacy. 
 
 Pen for Red Ink. If red ink must be used, a separate pen should 
 
 be reserved for it, since it is very corrosive. 
 
 Compass. 
 
 The best compass of to-day has its main legs, 
 lengthening-bar, needle-point leg, and pencil- 
 leg made of a fine, uniform grade of German 
 silver. They should be sufficiently rigid to 
 prevent any bending when ordinarily handled, 
 and not easily broken or cracked when acci- 
 dentally dropped. 
 Joints. All joints should have large, dustless, and 
 
 non-bruisable bearing surfaces ; and simple and 
 well-designed devices for taking up wear. 
 
 Means for. Holding The COmpaSS should have simple and effect- 
 Detachable Parts. 
 
 ive means for holding detachable parts. Un- 
 doubtedly the round shank and corresponding 
 split socket with its clamping-screw is the best 
 design obtainable for connecting and discon- 
 
60 
 
 Handle; 
 
 Flexible Joints. 
 
 Pen of Compass. 
 
 Pencil of Compass. 
 
 ITeedle Point. 
 
 Device for Holding 
 Needle Point 
 
 necting the detachable parts to the compass- 
 legs. 
 
 The cylindrical handle, on the yoke which 
 straddles the joint at the top of the legs, is 
 indispensable for facilitating the manipulation 
 of the compass. 
 
 The pen, pencil, and needle-point legs should 
 be provided with flexible jomts, designed ac- 
 cording to the specifications given for corre- 
 sponding joints in the compass-legs; and also, 
 the joints should be as near to the working 
 points as practicable. 
 
 The pen should be designed and cared for in 
 the same manner as specified above for the 
 ruling-pen. 
 
 The pencil should be of a material described 
 above in "Substances Apphed, etc.," and of 
 nothing softer than a hhhhhh grade. It 
 should be so sharpened that the point has a 
 very flat elliptical section. 
 
 The needle-points should be made of the best 
 tempered steel with one end conical, and the 
 other end with a very short, sharp, and fine 
 point, terminated by a square shoulder. 
 
 The needle-point and lead should be a good 
 fit in a split socket, and held in place with a 
 clamping-screw.- The device for securing a 
 needle-point by the point of a screw should be 
 shunned. ^ 
 
62 
 
 Use of Needle 
 Point. 
 
 Care of Iteedle 
 Point. 
 
 Lubricate Screws. 
 
 Distance Taken by 
 Compass. 
 
 Drawing a Large 
 Circle. 
 
 A needle-point should not be screwed into 
 the socket. 
 
 The shoulder end of the needle-point should 
 always be used when drawing circular arcs, and 
 should be adjusted so that both the shoulder and 
 pencil- or pen-points touch the drawing when 
 they are perpendicular to the plane of the paper. 
 
 The needle-point should be occasionally 
 ground on the oilstone until it is sharp enough 
 to enter the drawing-paper, when a pressure due 
 solely to the weight of the compass is applied. 
 
 If a screw in the compass or bow instruments 
 works hard or becomes rusty, a little graphite 
 rubbed off the drawing-pencil will lubricate it. 
 
 A distance should always be taken by the 
 compass directly from the scale, which is ac- 
 plished by holding the compass level with the 
 surface of the scale, and applying the compass 
 so that the shoulder of the needle-point and 
 the end of the pencU- or pen-point just touch 
 the edge of the scale. 
 
 When a large circle is being drawn with the 
 lengthening-bar inserted, the compass should 
 never be steadied by taking hold of one of the 
 legs, but it should be gripped, as before, by 
 the cylindrical handle at the yoke, and very 
 slightly inclined in the direction to which the 
 compass is moving, which direction should al- 
 ways be right-handed or clockwise. 
 
64 
 
 Materials for Tram- 
 mel Poiuts. 
 
 Attachments. 
 
 Beam. 
 
 Fastening Tram- 
 mels. 
 
 Tubular Beam. 
 
 Spring Wheel At- 
 tachment. 
 
 Beam Compass. 
 
 The beam-compass is used for striking large 
 circular arcs. 
 
 The trammel-points and their attachments 
 should be made of materials used for similar 
 purposes in the compass, and cared for after 
 the same manner as prescribed for the regular 
 compass. 
 
 The needle-point leg should be fixed, but 
 the pen- and pencil-legs should be interchange- 
 able; and the compass should be provided with 
 a micrometer-adjustment attachment. 
 
 The beam should be designed for stiffness 
 and to permit of smooth running of the tram- 
 mels along its length. 
 
 The trammels should be provided with a 
 strong and rigid fastening device. 
 
 The metal tubular beam with a split socket 
 on the trammels for binding is recommended. 
 
 When an arc of long radius is drawn a spring 
 wheel attachment should be used close up to 
 the pencil- or pen-point. 
 
 Dividers. 
 
 The dividers should be made of materials 
 which are used for similar purposes in the com- 
 pass, and should be cared for after the same 
 manner as prescribed for the regular compass. 
 
66 
 
 Legs. One leg should be without a joint, and the 
 
 other leg should be provided with only a hair- 
 spring adjustment. 
 
 Needle Points. The needle-poiuts should be conical. 
 
 Laying off an Exact If an exact length is to be laid off with the 
 
 *°^ ■ dividers, a large multiple of that length should 
 
 be laid off first directly with the scale on a 
 
 right line, and then exactly sub-divided into 
 
 the desired exact length by the dividers. 
 
 Bow Instruments. 
 
 The bow-instruments consist of the spacers, 
 
 pencil, and pen. They should be made of the 
 
 best tempered steel, with a metal handle and a 
 
 central adjusting-screw. 
 
 Use and Care of Bow The spacers, pencil, and pen are used and 
 
 Instruments. . 
 
 cared for m the same manner as prescribed for 
 the dividers and compass, but they are dis- 
 tinctly designed for short lines and arcs of short 
 radii. 
 "Drop" Bow Pen. The so-called "self-adjusting needle-point" 
 or "drop" bow-pen has the particular advan- 
 tage of requiring no adjustment of a needle- 
 point to suit the length of the pen or pencil; 
 but the needle-point end should be made with 
 a shoulder, and not conical as is usually done. 
 Pricker Point. 
 The pricker-point is used for marking off dis- 
 tances more accurately from the scale than 
 can be done with the drawing-pencil. 
 
To Make a Pricker 
 Point. 
 
 Pricker Point in 
 Pen Handle. 
 
 Pocket Case. 
 
 Bulging End. 
 
 Coarse Pen. 
 
 Fine Pens. 
 
 A fine sewing-needle, with the eye end firmly 
 driven into a non-cylindrical handle, makes a 
 desirable pricker-point. 
 
 A ruling-pen with the pricker-point inserted 
 
 in the handle can be purchased for a few cents 
 
 extra. 
 
 Case for Instruments. 
 
 A case should be procured for the ruling-pen, 
 compass and attachments, dividers, and bow 
 instruments. 
 
 The folding pocket-case is undoubtedly the 
 most convenient, but a good case can be made 
 of chamois-skin by sewing pockets into it; and 
 the chamois-skin would be incidentally useful 
 for cleaning the instruments, which should be 
 done every time the instruments are used and 
 laid aside. 
 
 Writing Pen and Staff. 
 
 The writing-pen and staff are essential and 
 important in a draftsman's outfit, for letter- 
 ing, etc. 
 
 The pen-staff should have a bulging cork end 
 where the pen is inserted, and should be gripped 
 close to the pen when it is used for printing. 
 
 The pen should be comparatively coarse with 
 a ball point for holding ink. 
 
 "Crow-quill" and "Falcon" pens should 
 usually be rarities in a commercial mechani- 
 cal draftsman's outfit. 
 
70 
 
 Selection of Pens. Care and common sense must be exercised 
 in the selection of the writing-pen for the differ- 
 ent grades of work. 
 
 Pressure on Pen. No more pressure should be applied to the 
 writing-pen than to the ruhng-pen; and the 
 erroneous belief that a fine flexible point when 
 worked under pressure is the proper pen, is as 
 puerile as wetting the pencil-point in the mouth. 
 
 Pen Wiper, A good wipiug-rag is an essential. It should 
 
 be free from lint; and a good one is usually 
 found wrapped around the bottle of the pre- 
 pared drawing-ink. 
 
 Tracing-cloth when soaked free from the 
 glazing makes a very desirable wiper. 
 
 Mechanical Point- 
 ers. 
 
 Pencil Pointer. 
 
 A good pencU-pointer is found in a steel file 
 or a sandpaper pad. 
 
 There are several good devices for sharpening 
 pencils mechanically, which should be selected 
 with scrutinizing care and judgment. 
 
 A jack-knife should never be used for finish- 
 ing the point of a drawing-pencil. 
 
 Pencil Eraser. 
 
 A pencil-eraser should be of open rubber and 
 not the usual velvet type. It should clean the 
 surface of a drawing with very little rubbing 
 and leave it perfectly smooth. 
 
72 
 
 Sponge Rubber. A sponge rubber is found convenient for clean- 
 
 ing the surface of a drawing without obliterat- 
 ing the pencil-lines. 
 
 Breadcrumb. Fine crumbs from stale bread effectually 
 
 clean a drawing. 
 
 Ink Eraser. 
 
 An ink-eraser should be made of a fine abra- 
 sive substance which is quick-cutting and non- 
 heating; it should leave the surface of the 
 drawing perfectly smooth. 
 
 Pumice stone. Fine pulverized pumice-stone will very effect- 
 
 ually take out ink lines when rubbed on a 
 drawing. 
 
 steel Eraser. A steel eraser is indispensable in the hands 
 
 of a skilful draftsman; and a pocket-knife is 
 no proper substitute for it. It should be made 
 of the best-tempered steel, have a wooden 
 handle, and its edge must be kept keen. 
 
 When a steel eraser is used the ink should 
 be just taken off the drawing and no more. 
 
 To Erase Ink. ^^ is much better for the unskilled person to 
 
 take off only a part of the ink with the steel 
 eraser and finish with the ink-eraser. 
 
 Erase Thoroughly. When lines are erased from a tracing they 
 should be thoroughly rubbed off, to avoid vague- 
 ness on the print as to what was intended on 
 the drawing. 
 
74 
 
 Eraser Shield of 
 Tin, etc. 
 
 Drawing Paper 
 Shield. 
 
 Eraser Shield. 
 
 An eraser-shield is sometimes found useful 
 where only a particular and very small part 
 of the drawing is to be rubbed. 
 
 An eraser-shield can be made by slitting a 
 piece of sheet tin, brass, or celluloid. 
 
 The straight edge of a piece of brown draw- 
 ing-paper also answers very well for a shield. 
 
 Oilstone. 
 
 An Arkansas knife-oilstone should always 
 be found in a draftsman's kit, and should be 
 used when necessary. It is always an index 
 of a good workman when his tools are sharp 
 and in prime condition. 
 
 Tacks. 
 
 The tacks for holding down drawings should 
 have small heads. 
 
 Copper Tacks. The 1-ounce copper tack is recommended; but 
 
 the 1-ounce iron carpet-tack is an eternal nui- 
 sance. Its head breaks easily and leaves the 
 point in the drawing-board to be picked out 
 before the board can be planed off, as is often 
 done when it is repaired. 
 
 Thumb Tacks. Thumb-tacks should have a small flat head 
 
 rounded on the edge and a sharp point. 
 
76 
 
 Tack Lifter, 
 
 The tack-lifter is a convenience and not a lux- 
 ury. It will doubtless preserve the original 
 shape of the blade-point of the pocket-knife, 
 which is so often resorted to as a tack-lifter. 
 A piece of i" or -^" steel wire, three or four 
 inches long, with one end flattened to an edge 
 and bent into a claw shape, will serve as a tack- 
 lifter. 
 
 Machinist Scale and Caliper. 
 
 A six-inch machinist scale and a six-inch re- 
 versible inside and outside caliper are often 
 found convenient in taking measurements when 
 a draftsman is required to sketch a piece of 
 mechanism that is already made. 
 
 Folding Rule. 
 
 A six-foot folding rule is found very useful 
 in many ways. It is often a suitable accom- 
 paniment to the caliper for getting the ap- 
 proximate dimensions of a piece of mechanism 
 which is being sketched. 
 
78 
 
 LIST OF DRAWING INSTRUMENTS. 
 
 A list of drawing-instruments is given below 
 which every machine draftsman should have 
 for a first-class and fairly complete equipment: 
 
 One 24" and one 42" mahogany T square, 
 bead fixed with five screws, ebony-lined head 
 and blade, and with working edge of blade 
 beveled. 
 
 A 10"-30'^X60° transparent triangle. 
 
 A 7"-45° transparent triangle. 
 
 Three 12" nickel-plated sheet-steel Brown & 
 Sharpe scales with graduations conveniently 
 distributed on them as follows: i", i", -f", |", 
 i", 1", li", and 3" to the foot, tV and ^''. 
 
 A 5" first-quality and first-class designed, 
 hinged or quick-opening ruling-pen, with in- 
 serted pricker-point in handle. 
 
 A 5 J" compass of the first-quality with jointed 
 and fixed leg for needle-point, detachable 
 jointed pencil- and pen-legs, and lengthening 
 bar. 
 
 Bow-pen, pencil and spacers, with central 
 adjusting-screw, for scribing not over 1^". 
 
 A pair of 5" dividers with hair-spring ad- 
 justment. 
 
 A pocket-case or chamois-skin with pockets 
 for protecting the usual case instruments. 
 A good nickel-plated steel protractor. 
 
80 
 
 A good beam-compass with trammel-points, 
 and with three beams of two-feet, four-feet, and 
 six-feet lengths. 
 
 One HHHH and one hhhhhh Hardmuth Koh- 
 i-noor grade drawing-pencil. 
 
 A set of Hardmuth's Koh-i-noor grade 
 HHHHHH lead for compass. 
 
 A good pencil-pointer. 
 
 A good steel eraser. 
 
 An ink-eraser — Faber's. 
 
 A pencil-eraser — Tower's Multiplex. 
 
 An eraser-shield. 
 
 A six-foot folding rule. 
 
 A package of 1-ounce copper tacks. 
 
 An Arkansas knife-oilstone. 
 
 A pen-staff and writingr-pens. 
 ' A bottle of black water-proof drawing-ink. 
 
PART II. 
 
 COMMERCIAL MECHANICAL DRAWINGS. 
 
 Before defining a commercial mechanical 
 drawing it may be well to anticipate the con- 
 fusion which may arise as to the technical mean- 
 ing of the phrase "Mechanical Drawing," since 
 it has two distinct meanings. The phrase 
 "Mechanical Drawing" may be interpreted as 
 any drawing in general that is not made free-, 
 hand; or, as a drawing that particularly per- 
 tains and is incident to machine construction. 
 The latter interpretation is the one used in the 
 definition given in the succeeding paragraph. 
 
 A Commercial Mechanical Drawing is fully 
 defined when such conventions are present as 
 to enable the manufacturer or builder in me- 
 chanical lines to erect his buildings, to select 
 and arrange his equipment for most economical 
 production, or to produce, by means of the draw- 
 ing, and with the greatest facility, that which 
 has utility and a commercial value. 
 
 Commercial Mechanical Drawings can be 
 divided into three general types which will be 
 
 82 
 
84 
 
 termed: General Plans, Machine Drawings, and 
 Patent Office Drawings. 
 
 General Plans would include such drawings 
 as : Layout Drawings, Foundation Drawings, 
 Piping Drawings, etc. 
 
 Machine Drawings would include: Working 
 Sketches, Scheming Sheets, Detail Drawings, 
 Assembly Drawings, and Diagram Drawings 
 of Machines. 
 
 Patent Office Drawings are in a class by them- 
 selves, and are essentially such drawings as are 
 required by the United States Patent Office when 
 a claim for a patent on a mechanical invention 
 is presented. 
 
 GENERAL PLANS. 
 Drawing plans of buildings intended for me- 
 chanical purposes are often made with nothing 
 more on them than a section of the walls, with 
 the doors, windows, and supporting piers for 
 columns located, an^ sometimes a very gen- 
 eral arrangement of the inside equipment shown 
 in part or the whole. 
 
 Layout Drawing. 
 Fig. I. A layout drawing is often a plan of a floor 
 
 of a building with the positions of different 
 parts of the equipment located to scale. It is 
 also, sometimes, a preliminary drawing of a part 
 or a whole of a machine, and serves the same 
 
86 
 
 purpose as the scheming-sheet which is defined 
 below. The former sense, however, will be 
 accepted in this Manual. 
 Locating Machines. In locating a large number of machines or 
 other equipment in a plant, they should be 
 drawn first to scale on a sheet of fairly stiff 
 drawing-paper, cut out, and then moved on the 
 proposed drawing until they are satisfactorily 
 arranged; after which they can be drawn to 
 scale. 
 
 Piping Drawing. 
 
 A piping drawing shows the arrangement of 
 the piping separately from other equipment in 
 the building. 
 
 If there are several kinds of piping, as steam- 
 pipes, hydraulic-pressure pipes, water-service 
 pipes, etc., and they are to interpass each other, 
 they should be all drawn on one sheet to show 
 their relation, and then each class by itself can 
 be drawn on a separate sheet for the use of the 
 piper. 
 
 In laying out piping drawings, no attempt 
 must be made to draw elaborate views of 
 the fittings, but simple and conventional lines 
 should represent them. All valves,, unions, 
 tees, and important connections must be 
 plainly indicated. 
 
 Do not locate pipes too closely together, but 
 leave a little leeway for the piper. 
 
 Several Kinds of 
 Piping. 
 
 Simple Lines, 
 Fig. 2. 
 
 Do Not Crowd 
 Pipes. 
 
88 
 
 Pipes along Walls, 
 etc. 
 
 Fig. 3. 
 
 Templet Drawing. 
 
 Brick Work. 
 
 Boiler Settings. 
 
 Always show an outline of the walls, machines, 
 etc., along which the pipes run and with which 
 they are connected. 
 
 Foundation Drawings. 
 
 Foundation drawings should show the nature 
 of the foundation upon which a machine or 
 building stands, whether it is in wood, stone, 
 concrete, or brick; also, the position of the 
 anchor-bolts, with their attached caps, anchor- 
 plates, washers, and nuts, and also the main 
 outlines of the machines which set on them. 
 
 A templet drawing usually shows a templet 
 made of boards which are nailed together, and 
 with holes bored in them, which have the rela- 
 tive dimensions between them that are required 
 for locating the anchor-bolts in the foundation. 
 
 If brickwork is shown in a foundation, a con- 
 tinuous right line and not the corbeling should 
 show the outline of the foundation. 
 
 Drawings of boiler-settings would be in- 
 cluded under the head of foundation drawings. 
 
 MACHINE DRAWINGS. 
 
 When a new machine or any of its parts has 
 been conceived, the next step is to develop it on 
 drawings. 
 
 Naturally, the most simple drawings will be 
 made first, and will be followed in logical se- 
 quence by more complete drawings. 
 
90 
 
 A machine drawing must be made simple, 
 clear, and direct. Any attempt to imitate the 
 product of the camera, or to display impracti- 
 cal rudimentary knowledge, is foreign to the 
 practice in the United States at present, and 
 must be eliminated in order to harmonize with 
 the existing state of affairs. 
 
 Descriptive Geometry, which is the founda- 
 tion on which all mechanical drawing (used in 
 a general sense) has been built, should be, practi- 
 cally, theoretical drawing applied; and, as such, 
 it will mean a radical revision in the text as 
 found within the covers of the current text- 
 books, which are used, and fuUj^ intended, as a 
 vorspiel to all mechanical drawing, whether or 
 not such drawings are along the lines of stereot- 
 omy, architecture, or mechanical drawing. 
 
 Thus it is, that the draftsman must apply his 
 knowledge of Descriptive Geometry in such a 
 manner as to harmonize with methods and rules 
 of procedure current in the modern practice of 
 making machine drawings. 
 
 To make a machine drawing properly and 
 most intelligently, the draftsman has no other 
 recourse than to be a thorough mechanic him- 
 seK; which implies a working knowledge of 
 pattern-making, molding, forging, and machin- 
 ing. 
 
92 
 
 Save Sketches. 
 
 Several Sketches of 
 Same Thing. 
 
 Cross Section Paper 
 for Sketching. 
 
 Copying Pencil 
 Sketches. 
 
 SKETCHES. 
 
 Preliminary free-hand sketches should be 
 made with a soft black pencil, and only the 
 essential outlines of the proposed piece are 
 needed. 
 
 Several sketches may be required before one 
 is satisfactory; and all sketches ' made should 
 invariably be saved for possible future refer- 
 ence. 
 
 It is a rule frequently followed by designers 
 and inventors to make several sketches of the 
 same thing; and it often happens that they re- 
 turn to and use the first sketch made. 
 
 Cross-section paper is invaluable for sketch- 
 ing, as proportion is secured without the use of 
 the scale. 
 
 Copying-pencil sketches are frequently made 
 to serve the purpose of a small drawing or blue- 
 print. They should be made with a copying- 
 pencil on checked paper, and duplicated by 
 means of a damp cloth and a letter-press. 
 Scheming Sheet. 
 
 A scheming sheet is made up of the accepted 
 free-hand sketches drawn to scale and with 
 somewhat more detail shown. 
 
 They should be drawn in with a hhh or 
 HHHH grade drawing-pencil on drawing-paper, 
 and no elaboration to completeness is usually 
 needed. 
 
94 
 
 The Workman's 
 Drawing. 
 
 Projections, etc., 
 Secondkry. 
 
 ITumber of Parts 
 Detailed. 
 
 Detail Drawings. 
 
 Detail drawings are undoubtedly the most 
 important, and surely the most extensively 
 used, drawings. 
 
 The details in the execution of a properly 
 made detail drawing are a complete history 
 and exposition of the art of machine drawing. 
 Therefore what has been written in the para- 
 graph directly under the heading "Machine 
 Drawings " distinctly applies to detaU drawings 
 and must be strictly adhered to. 
 
 After the parts on the scheming sheet have 
 been made in a general drawing, they are then 
 completely detailed for the various departments 
 of the shop. Consequently, a detailed drawing 
 is the workman's drawing; and, as such, it is 
 his official order for doing the assigned work. 
 He should be held responsible only for failure 
 to work to the figures and the Anglo-Saxon 
 notes on the drawings. 
 
 The projections and conventions are second- 
 ary and only serve as illustrations to interpret 
 what the figures and notes stand for. 
 
 The number of parts of a machine detailed 
 on a drawing may depend on the methods used 
 in doing the work, or upon the number of men 
 who are to work from the drawing, or upon both. 
 
 Detail drawings are usually penciled on light- 
 brown drawing-paper and traced on tracing- 
 
96 
 
 cloth, or penciled and inked on bond paper and 
 printed on blue-print paper in the order given. 
 For convenience of analysis the considera- 
 tions, methods, and technic involved in the com- 
 plete execution of a detail drawing will be dis- 
 cussed \mder separate headings. 
 
 Types of Detail Drawings. 
 
 The number of parts of a machine detailed 
 on a drawing should be according to the nature 
 of the work and the methods of doing it. If a 
 shop is manufacturing machines in lots, where 
 six or more are built exactly alike and at the 
 same time, not so many parts would be detailed 
 on one drawing, and the work would be dis- 
 tributed among a larger number of men. 
 
 Individual Draw- It is the practice with some firms, and the 
 "^^^' growing tendency with others, to make indi- 
 
 vidual or separate drawings of a great many of 
 the parts. 
 
 Casting and Forging It has been the custom of some firms to place 
 the casting details and forging details on sepa- 
 rate drawings; and that scheme would be par- 
 ticularly advantageous to firms which build. 
 
 Assembly Detail When a Single uew machine, or a section of it, 
 
 Fig. ^40^'°^ is built for the first time, it is often advisable 
 
 to show the parts in partial assembly and fully 
 detailed on the drawing. Such an arrange- 
 ment assists the mechanic to make his allow- 
 
98 
 
 Fig. S- 
 
 Fig- 5- 
 
 Omitting Border 
 Liues. 
 
 Border Lines One 
 Half Inch from 
 Edge. 
 
 ance for proper fits and adjustments. This 
 type of drawing might serve as an assembly or 
 general drawing, and, perhaps, it is more prop- 
 erly called an assembly detail drawing. 
 
 Sizes of Drawings. 
 
 The size of the detail drawing is dependent 
 on the type of drawing, the size or sizes of the 
 part or parts detailed, and the scale to which 
 they are drawn. 
 
 The following sizes are good average ones, 
 
 as they can be cut very economically from 
 
 the commercial widths of drawing-paper : 6 X 9, 
 
 9X12, 12X18, 18X24, 24X36, 36X48, and 
 
 48X72. 
 
 Border Lines. 
 
 Border lines are of no material assistance to 
 the mechanic or to any one else, except possi- 
 bly to the draftsman, who may comfort himself 
 with a doubtful fact that the appearance of the 
 drawing is enhanced. 
 
 The writer believes it to be the growing ten- 
 dency to leave off all border lines; but when] 
 they are used, they should not be over one thirty- 
 second of an inch wide and have no fancy or 
 elaborate corners. 
 
 The border line should be placed one half inch 
 from the edges of the sheet; it is the first thinj 
 to be drawn in a pencil drawing, and the last 
 thing in an inked drawing. 
 
100 
 
 Match Lines. 
 
 Fig. 4. Short lines drawn with the T-square on each 
 
 side of the drawing are convenient for resetting 
 a drawing after it has been removed from or 
 accidentally shifted on the drawing-board. 
 
 Titles. 
 
 Fig. s. A title is an essential part of any drawing, 
 
 and a particular . and invariable place on the 
 drawing must always be provided for it. 
 
 Place for Title. ^ place at the lower right-hand corner of the 
 
 drawing should be blocked out for the title, and 
 directly after the match-lines are drawn. 
 
 Parts of Title. The title should comprehend: first, the type 
 
 ^'S- s- of drawing, as a sketch, assembly, or detail ; 
 
 second, the name of the machine drawn, or the 
 part thereof, or both; third, the name of the firm 
 which builds the machine; fourth, the address 
 of the firm; fifth, the scale or scales used on the 
 drawing; sixth, the name or initials of the per- 
 son or persons who are responsible for the fin- 
 ished drawing, — which includes every one, from 
 the penciling draftsman, through the tracer 
 and checker, to the approving engineer, — and 
 also the date on which the drawing is finished. 
 
 Additional, Parts of In addition to the above there is occasionally 
 placed along with the title the shop order num- 
 ber, the sheet number, the number of the draw- 
 ing in the case where the drawings are stored, 
 
 Title. 
 
PROPERTY 
 
 DEPARTMENT 
 MACHINE DESIGN 
 
 SIBLEY SCHOOL 
 CORNELL UNIVERSITY 
 
 RECEIVED 
 
102 
 
 Size of Letters. 
 Fig. 4. 
 
 Fig. 4. 
 
 Scale Terms. 
 Fig. 4. 
 
 Size of Letters for 
 
 Name. 
 Fig 4. 
 
 Symmetry of Title. 
 Fig. 4. 
 
 Stamp for Title. 
 
 and the lot number — provided the machine is 
 manufactured in large lots. 
 
 The words indicating the name of the ma- 
 chine must be in larger letters than the rest, 
 since it should be the first or chief thing seen in 
 a title. 
 
 The words indicating the type of drawing, 
 the name of the firm, the address, and the scale 
 should be composed of letters of the same size, 
 but they must be smaller than the letters in 
 the words which indicate the name of the ma- 
 chine. 
 
 The words used to indicate the relative sizes 
 to the true size of the objects as drawn should 
 be expressed, preferably, in the terms of a scale ; 
 as, so many inches to the foot, or so many milli- 
 meters to the meter; or, if not, a proportionate 
 size should be given; as, full size, one-half size, 
 etc., etc. 
 
 The date and the names or initials of the per- 
 sons responsible for the drawing should be in 
 very small letters. 
 
 All lines in the title must be arranged sym- 
 metrically with reference to a center line. 
 
 The title is occasionally put in with a stamp,* 
 which usually stamps the tracing in red ink; 
 after which it is filled in with black drawing- 
 
 * The title or border lines, or both, are sometimes printed on in 
 black with an ordinary printing-press before the drawing is begun. 
 
104 
 
 Place for Size of 
 Sheet and Serial 
 Number. 
 
 Fig. S- 
 
 Sizes of Sheets. 
 
 ink. The black drawing-ink should be applied 
 while the red ink is still wet. 
 
 In the lower left-hand corner there should bp 
 placed a letter and number which correspond 
 with the size of sheet and serial number of the 
 drawing respectively ; as, for example, A-2 will 
 indicate that the sheet is 36X48 and is the 
 second consecutive drawing that has been made. 
 V The letters which should be used, with the 
 corresponding sizes of sheets, are as follows: 
 A, 36X48; B, 24X36; C, 18X24; D, 12X18; 
 E, 9X12; and F, 6X9. 
 
 Place for Bill of Ma- 
 terial. 
 Fig- S- 
 
 Every Piece on Bill 
 of Material. 
 
 Columns of Bill of 
 
 Material. 
 Fig. 5- 
 
 Bill of Material. 
 
 Every detail drawing should have a bill of 
 material which should be placed directly above 
 the title; and it is a good plan to block out a 
 space for it immediately after the title has been 
 allowed for. 
 
 Eveiy piece in a machine or its parts, or in 
 any structure, should be accounted for on the 
 bill of material, so that any clerk in the office 
 can order from it independently of anything else. 
 
 In the table of the bill of material, the first 
 column should contain an identifying mark 
 which is exactly the same as the one placed on 
 the view of the piece as shown on the drawing, 
 and may be a letter or a number. The second 
 column should contain the name of the piece. 
 
106 
 
 Common Terms. 
 
 Pattern Number. 
 
 Only Necessary- 
 Views. 
 
 Most Comprehen- 
 sive Views. 
 
 The third column should contain the number 
 wanted of the same piece for one machine, or 
 for one composite structure of any; sort. The 
 fourth column should contain the name of the 
 material of which the piece is made. And the 
 last column should contain any further neces- 
 sary description of the piece, which may be, for 
 example, the pattern niimber, the dimensions 
 of the rough stock from which it is made, the 
 method of casting, etc.; and, in fact, the last 
 column should provide for any description of 
 the piece not found in the first four coltmms 
 and which would be essential for completeness 
 in the order for the stock. 
 
 The name of the piece in the bill of material 
 should be a common shop-term used by the 
 mechanics; and if there is none, a simple and 
 suggestive one must be used. 
 
 Every piece that is cast from a pattern should 
 be given a pattern number in the column under 
 the head of " Remarks." 
 
 Views. 
 
 The number of views is determined by that 
 judgment which serves common sense. 
 
 All the views necessary and no more should 
 be drawn. 
 
 The selection of a view or views which shows 
 the piece in the most comprehensive manner 
 should always be made. 
 
108 
 
 Simple Pieces. In simple and symmetrical pieces, as a round 
 
 ^^' * shaft, bolt and nut, plain gears, etc., one view 
 
 is sufficient. 
 Symmetrical Pieces. If an object is Symmetrical in every respect 
 
 Pigr, 14, ■ ' 
 
 and it is required to show some little irregu- 
 larity, it is sometimes only necessary to show a 
 part of a view. 
 Crooked Pieces. j^ a verv crooked piece several views may 
 
 Fig. ^5. . •" ^ 
 
 be quite necessary. 
 Sectional View. A sectional view is often clearer than an out- 
 
 Fig- 5, ' D-" gj[(jg view to the mechanic who works from the 
 
 drawing, but it should not be made unless clear- 
 ness obtains. 
 Combined Outside If an object is Symmetrical, it is often better 
 
 and Sectional , , , . i ■ i . , , 
 
 View. shown by makmg a combined outside and sec- 
 
 ^'^" ^- tional view; usually making the division at the 
 
 center line. 
 Develop Plates and All bent and unusual-shaped plates must 
 Fig.X^ have their surfaces developed, if it is necessary, 
 
 to show proper spacing of rivets, bolt-holes, 
 
 outline of cams, etc. 
 Full Size Section It is sometiuies essential that an object which 
 
 Reduced Scale. ^^ drawu on reduced scale should have some 
 ^^g- 7- important section of it shown full size. 
 
 One View for Rights When there are two pieces that are exactly 
 
 alike in every respect except that, they are of 
 
 opposite hands, one should be drawn in all of its 
 
 views, and a note should be added to indicate 
 
 that they are rights and lefts. 
 
 and Lefts. 
 
110 
 
 Concentric Circles. 
 Fig. 38. 
 
 Flat Surface on 
 Body of Screw, 
 etc. 
 
 Fig. 16. 
 
 Bearings on a 
 
 Round Shaft. 
 Fig. 17. 
 
 Knurled Piece. 
 Fig. 5, " M." 
 
 Square Bolt Heads, 
 etc. 
 
 Hexagonal Bolt 
 
 Heads, etc. 
 Fig. s,"C." 
 Fig. 4°. 
 Distance of Holes 
 
 on a Circle from 
 
 the Axis. 
 Fig. 5, " H." 
 
 Washers and Collars 
 
 Attached. 
 Fig. 5, " G.» 
 
 Keys Attached. 
 Fig. S, " C." 
 
 Side Views of Con- 
 ventional Thd's. 
 Fig. 18. 
 
 In any view where there are a number of 
 concentric circles, show only a few; as they are 
 practically worthless for conveying any idea, 
 and only useful to fill space. 
 
 A flat surface on the body of a screw, stud, or 
 shaft is occasionally indicated, when there is 
 only one view, by a rectangle with its inter- 
 secting diagonals. 
 
 Rectangles, with their intersecting diagonals, 
 are often used for indicating the bearings on a 
 round shaft, as a line-shaft, crank-shaft, etc. 
 
 A knurled or milled piece should be shown 
 conventionally in a view. 
 
 In the side views of square bolt-heads and 
 nuts, show only one side. 
 
 In the side views of hexagonal bolt-heads 
 and nuts, show three sides. 
 
 In a sectional side view of a cylindrical piece, 
 if there is one hole or more in it parallel to 
 their axis, they should be shown at their true 
 scale distance from the center as measured each 
 side of the center line. 
 
 Washers and coUars should generally be 
 shown in section on the piece to which they 
 belong. 
 
 Keys should be shown in the piece into which 
 they are driven. 
 
 The side view of a Seller's V-thread, pipe- 
 thread, square-thread, bastard or acme stand- 
 
112 
 
 Threaded Piece 
 Sectioned. 
 
 Fig. 19. 
 
 End Views of 
 Screws, etc. 
 
 Fig. 20. 
 
 FiUster Head 
 
 Screw. 
 Fig. 21. 
 
 Regular 
 
 PuUey. 
 
 Fig. 10. 
 
 
 Fig. 5, ' 
 
 'D." 
 
 Fig. 8. 
 
 
 Fig. 9. 
 
 
 Cast Gears. 
 
 Arrangement of 
 
 Views. 
 Fig. S. 
 
 ard-thread, knuckle-thread, buttress-thread, and 
 wood-screw thread are conventionally shown 
 by the figures in their respective order. 
 
 If a threaded piece is sectioned nothing but 
 the Vs should represent the thread. 
 
 The end views of a screw and tapped hole are 
 conventionally shown by the figures in their 
 respective order. 
 
 A filister-head screw should show, in all views 
 of the end, its slot making an angle of 45° 
 with the horizontal; and the slot should show, 
 in the side views, a true projection of the end 
 views. 
 
 A regular pulley is shown by the conventions 
 in the figure. 
 
 Spur-, bevel-, and worm-gears are shown de- 
 tailed as by the conventions in the figure. 
 
 Cast gears made from a pattern should have, 
 in addition to an ordinary view, one tooth 
 completely detailed and the number of teeth 
 specified. 
 
 The arrangement of views on the drawing 
 demands, for the sake of clearness, system, and 
 convenience; first, that they should not be 
 crowded; second, that all views of the same 
 piece should not be separated any further than 
 necessary to show outside dimensions and notes 
 clearly; third, that all views of different pieces 
 be sufficiently separated to prevent any confu- 
 
114 
 
 sion as to their proper relations to views of 
 other pieces; fourth, as far as possible, aU pieces 
 of a machine must be shown on the drawing in 
 their natural relative positions in the machine 
 and to each other. 
 Section Views at Sectional views can be placed, if convenience 
 
 One Side. 
 
 Fig. 38. demands it, at any place on the sheet provided 
 
 they are properly noted. 
 Arranging Views of 'j'q cover the drawing sheet properly with 
 
 Pieces on Sheets. _ . . 
 
 views, it is sometimes convenient to approxi- 
 mately pre-arrange the location of all views by 
 enclosing them in a rectangle which is suffi- 
 ciently large to include the outside dimensions 
 and notes to the view. At other times it is not 
 . necessary to do much planning, but commence 
 at the upper left-hand corner and work across 
 and down the sheet. This order of working 
 across the sheet should always be followed. 
 Third Angle Projec- The relation of views to each other must al- 
 
 tion. 11. 
 
 Fig. s. ways be what is technically called third-angle 
 
 projection; which, interpreted, means: that 
 when there is a definite and natural top to an 
 object, its projection should be the top view, 
 which is often called the plan; that the views of 
 the elevation should be shown below the top 
 view; and that, in addition, every projection 
 must be shown as the near side of the adjacent 
 view from which it is projected. 
 
 Sectional View. . i. •> 
 
 Fig. 5. In a sectional view the portion of the object 
 
116 
 
 Fig. II. 
 
 Round Corner. 
 Fig. 10. 
 
 To Draw a Hexag- 
 onal Figure. 
 
 Distance Across 
 Flats and Cor- 
 ners of Hexago- 
 nal Bolt Heads. 
 
 Curves of Intersec- 
 tion. 
 Fig. 10. 
 Ellipse. 
 Fig. 22. 
 
 which is cut away and nearest the view is re- 
 moved, and what is left is shown in the sectional 
 
 view. 
 
 Lines of Projection. 
 
 A visible edge of a solid should be represented 
 by a full line, clean-cut, comparatively wide, to 
 make them stand out in a bold effect, and of 
 uniform width throughout their length. 
 
 Where a corner is not sharp but rounded, it 
 is admissible by convention to represent it in 
 all views, if any clearness is gained thereby.* 
 
 Always show filleted or rounded corners 
 when finished adjoining surfaces do not forbid. 
 
 All lines bounding a hexagonal figure should 
 be drawn in tangent to a circle whose diameter 
 is equal to the distance between parallel sides 
 of the hexagon, and by means of the triangles 
 and T square. 
 
 When the three faces of a standard hexagonal 
 bolt or nut are shown, make the distance between 
 the outside lines equal to twice the diameter 
 of the body of the screw, and the distance be- 
 tween the inside lines a trifle less than the diam- 
 eter of the body of the screw. 
 
 Curves of intersection should be put in as 
 circular arcs when possible.* 
 
 An ellipse in projection which is not very 
 flat may be shown, by convention, by a circle. 
 
 * See curve of intersection of pulley-arm with bead on rim. 
 
118 
 
 Chamfers on Bolts, 
 etc. 
 
 Oil Holes and Chan- 
 nels. 
 
 Spacing of V Thread 
 
 Lines. 
 Fig.5,"C." 
 
 Spacing of Thread 
 Lines Except 
 V Threads. 
 
 Sectioned Nuts. 
 Fig. 19. 
 
 Long Screw. 
 Fig. S, " F." 
 
 Invisible Edge. 
 Fig. II. 
 
 Invisible Lines. 
 Fig. 5- 
 
 Make the chamfers on bolts, studs, shafts, 
 etc., 45° lines. 
 
 Oil-holes and channels are usually not shown, 
 unless they are to be made in an unusual man- 
 ner. 
 
 The spacing of V-thread lines, and their pitch, 
 may not be absolutely exact; but a fine thread 
 naturally has its lines close together and has less 
 pitch than a coarse thread. 
 
 The spacing of all thread lines, except V- 
 threads, should be approximately close and 
 always done by marking off distances directly 
 from the scale. 
 
 Remember that nuts, when sectioned, theo- 
 retically show the pitch of the threads in reverse 
 order to those on the screw which fits it. 
 
 When a screw is of considerable length four 
 or five threads should be drawn at the ends only, 
 leaving the intervening length blank. 
 
 An invisible edge of a solid should be repre- 
 sented by a broken line which is clean-cut and 
 composed of comparatively short dashes of 
 equal lengths. The dashes should be drawn 
 as close together as possible, and not quite so 
 wide as the visible lines of projection. 
 
 An invisible line, composed of more than one 
 dash, should always begin and end on the ter- 
 minating lines which include it. 
 
120 
 
 Short Invisible 
 
 Lines. 
 Fig. 23. 
 
 Adjacent Part Line. 
 Fig. 3. 
 
 Broken Edges. 
 Fig. II. 
 
 Alternate Position 
 
 Lines. 
 Fig. II. 
 Fig. 24. 
 
 If an invisible line is shown by one dash only, 
 it should not begin or end at the terminating 
 lines, but a short space should be allowed be- 
 tween the dash and terminating hnes. 
 
 An adjacent-part line is a line in another ob- 
 ject which is adjacent to the one regularly 
 shown on the drawing, and simply serves the 
 purpose of indicating, for some particular rea- 
 son, what is attached to the piece shown on the 
 drawing. Therefore it should be a main out- 
 line, of sufficient length to indicate what is 
 attached. It should be a fine, broken, clean- 
 cut line composed of alternating dashes of one 
 eighth of an inch and three eighths of an inch 
 lengths respectively, drawn as close together 
 as possible. 
 
 A broken line represents the visible and in- 
 visible edges of the part of a solid of a structure 
 that is broken off. The width of this line 
 should correspond to the width of the projec- 
 tion line adjacent which represents the edge of 
 a surface. 
 
 An alternate position line is used for repre- 
 senting a limiting or important position of a 
 moving part, other than is shown regularly on 
 the drawing. An alternate position is some- 
 times represented by drawing the bare outlines 
 of the object, or by a center line. If the bare 
 outhnes are drawn, they should be fine, broken, 
 
122 
 
 Fig. 7. 
 Fig. 38. 
 
 Section Lines. 
 Fig. 5- 
 
 Angles of Hatch 
 
 Lines. 
 Fig. 5- 
 
 Spacing of Section 
 Lines. 
 
 Fig- S- 
 
 clean-cut lines, composed of alternating dashes 
 of one-eighth of an inch and three-eighths of an 
 inch lengths respectively, drawn as close to- 
 gether as possible. 
 
 Sectioning. 
 
 Where there is a section view, the trace of the 
 cutting plane shown on the view of the object 
 that is cut should be represented by a fine hne 
 whose character is that of a center line. The 
 line is also to be notated at each end, and the 
 corresponding notation must be suitably placed 
 and referred to under that view which shows 
 the section. 
 
 Section-lines, which are sometimes called 
 hatch-lines, are oblique parallel lines at equal 
 distances from each other. They are used to 
 represent a surface which has been cut. 
 
 Usually hatch-lines make an angle of 45° with 
 the horizontal; but it is not criminal, but even 
 sometimes desirable, to use 30° and 60° lines if 
 the conditions warrant it. 
 
 The spacing of section-lines should be deter- 
 mined by the area of the sectioned surface on 
 the drawing and the kind of material which is 
 cut. But section-lines should not be over three 
 thirty-seconds of an inch apart ; and softer 
 material should be shown with section-lines 
 further apart than those that show harder 
 material. 
 
124 
 
 Sectioning Adja- 
 cent Pieces. 
 Fig. 8. 
 
 Hatching Penciled 
 Drawing. 
 
 Sectioning Large 
 
 Area. 
 
 Fig. 25. 
 
 Materials Cut. 
 Fig. 12. 
 
 Section Shown by 
 Soft Pencil 
 Shading. 
 
 Thin Pieces. 
 Fig. 10. 
 
 Solid Round Piece. 
 Fig. 40. 
 
 Turned Section. 
 Fig. 10. 
 
 Two pieces which are assembled and shown 
 in section must be hatched with lines in reverse 
 order. 
 
 All hatching should be done free-hand on 
 penciled drawings which are to be inked. 
 
 When the surface covers a large area the 
 hatch-lines should be short and placed along 
 the edges only. 
 
 There are conventional lines to represent the 
 different materials that are cut; but they are 
 often unintelligible to the mechanic, and 
 their relegation to oblivion is strongly recom- 
 mended. 
 
 A soft drawing- or crayon-pencil is often 
 rubbed on the surface of the drawing to repre- 
 sent the section, but a blue crayon-pencil should 
 never be used for the purpose when a print is to 
 be taken from it. 
 
 A rib, an arm of a pulley, or any compara- 
 tively thin piece should not be shown in section 
 when the cutting plane is taken parallel to its 
 largest bounding surfaces. 
 
 A solid round piece should not be shown in 
 section when a cutting plane is taken through 
 its axis. 
 
 A turned section placed on a view is conven- 
 ient, more direct, and often clearer than when 
 placed off at one side. 
 
126 
 
 Key Way. A kevwav in a hole should not, as a rule, be 
 
 Fig! 10. ' sectioned, but should be shown by an invisible 
 
 line. 
 Broken Pieces. Pieces that are broken at the ends are shown 
 
 ^'s- 13. conventionally in the figures. 
 
 Center Lines. 
 
 Fig. 5- A center line is used to indicate symmetry, and 
 
 any configuration which has a natural axis or 
 
 axes, has a center fine or lines to represent it or 
 
 them. A circle, for instance, should have two 
 
 center lines at right angles to each other. 
 
 Circles along a Cir- When circles are evenly spaced along a cir- 
 
 yjg g^ .< H." cumf erence on the surface of a disc, as bolt- 
 
 ^'s- 40. circles on a fiange, a circular arc and radial lines 
 
 passing through the bolt-hole centers, are used 
 
 as the center lines. 
 
 Character of Center ^ center line should be a fine, broken, clean- 
 
 Lrne. 
 
 Fig. II. cut line, composed of alternating dashes of one- 
 
 eighth of an inch and three-eighths of an inch 
 lengths respectively, evenly spaced and not too 
 close together. A short center line may consist 
 of one dash. 
 
 Penciled Center Penciled center lines that are to be inked or 
 
 traced over should be a full line. 
 
 Lines having Pre- Luies of projection, \n^hich show visible and 
 
 cedenceoverCen- ...,,,. . i . , i » , i 
 
 ter Lines. invisible Imes 01 an object, and surface shade- 
 
 lines, have precedence over center lines in case 
 there is coincidence. 
 
128 
 
 Character of Di- 
 mension Lines. 
 Fig. II. 
 
 Arrow Heads. 
 Fig. II. 
 
 Radius Dimension. 
 
 Character of Arrow 
 
 Heads. . 
 Pig. 5, "K.» 
 
 Fig. 5, "K." 
 
 Position of Dimen- 
 sion Line. 
 
 Dimensions. 
 There is nothing on the whole drawing so im- 
 portant as the dimensions. 
 
 A dimension-Une is used for indicating a 
 dimension between certain Umits, and it is 
 broken at some convenient place between its 
 limits (preferably midway) to allow for the di- 
 mension. 
 
 The character of a dimension-line should be 
 a fine, broken, clean-cut line, composed of equal 
 dashes, equally spaced from each other. 
 
 All dimension-lines, excepting those repre- 
 senting radii of circular arcs, are terminated 
 by arrow-heads at both ends. 
 
 A dimension-line which indicates a radius is 
 terminated by an arrow-head at the arc only; 
 and if there are no intersecting center lines at 
 the center from which the arc is struck, a small 
 cross should indicate it. Rad. should be placed 
 after the dimension. 
 
 The arrow-head should make a small acute 
 angle with the dimension line, and should be 
 made in short arcs with the same writing-pen 
 which is used for the figures and letters on the 
 drawing. 
 
 All dimensions should be given with refer- 
 ence to main lines or center lines or both. 
 
 The position of the dimension-line is deter- 
 mined by judgment. It should be placed on 
 
130 
 
 that view which shows the most, and in such a 
 manner as to indicate most clearly and directly 
 what the dimension between the extremities 
 of the line stands for. 
 Distribution of Di- j^ jg ^gU to distribute the dimensions of a 
 
 mensions. . . . •<. i • • i i 
 
 Fig. 5, "K." piece over its views, it clearness is gained by so 
 
 doing. 
 
 Dimensions on One Dimensions of any particular configuration 
 
 Pig'g^.'.H." of a view, as that of a circle, rib, rectangular 
 
 surface, etc., should be shown on one view if 
 possible, and not on several views. 
 
 Dimensions on the A dimension is more clear and direct when 
 lew se . placed on the view itself, provided it does not 
 cause a confusion of lines so as to impair clear- 
 ness ; and also provided there is sufficient 
 space, withoiat crowding, for the figures be- 
 tween. 
 
 Dimensions off the The dimensions, however, may be placed off 
 
 Pig „' the view, and a curved witness-line drawn from 
 
 it to the usual place for the figures at the di-" 
 mension-line. 
 
 Do not Crowd Di- Dimcnsion-lines should not be placed so close 
 
 mension Lines. i i- , • • i 
 
 to other lines as to impair clearness. 
 Groups of Parallel When dimensions are grouped in parallel 
 Fig. 8. ' lines the shortest dimension is inside, and the 
 
 others are graded to the longest dimension on 
 
 the outside. 
 Arrow Heads Out- jf one or the two ends of a dimension-fine 
 
 side of Lines. . . ... . n i v 
 
 Fig. 26. terminate m the vicmity of two parallel lines;« 
 
133 
 
 Fig. S, "L." 
 
 Whole of Dimen- 
 sion Line Not 
 Shown. 
 
 Fig. 27. 
 
 Sub Dimensions. 
 Fig. 28. 
 
 Dimensions in Feet 
 and Inches. 
 
 which are close together, and confusion is 
 caused thereby as to which one of the parallel 
 lines limits the dimension-line; and if the di- 
 mension is limited by the outside line or lines, 
 additional short dimension-lines with arrow- 
 heads should be placed in a line with the di- 
 mension-line, outside of the line or lines and 
 with their arrow-heads just touching the limit- 
 ing line. 
 
 A short dimension can be shown by placing 
 the dimension-lines with their arrow-heads on 
 the outside of the limiting-lines, and the dimen- 
 sion can be placed inside. 
 
 If one end of a dimension-line cannot be 
 shown joining the limiting line, the usual full 
 dimension is given, and the dimension should 
 be placed as usual between the lines. 
 
 A line of sub-dimensions should always com- 
 mence at the finished surface; and if there is 
 an unfinished surface on the opposite side, the . 
 last sub-dimension should be omitted; and, 
 also, an over-all dimension should be given from 
 surface to surface. 
 
 The common two-foot rule has undoubtedly 
 been generally adopted for a standard when 
 dimensions are given in feet and inches. There- 
 fore all dimensions must be given in inches, in- 
 cluding twenty-four inches and below. Dimen- 
 
134 
 
 sions above twenty-four inches must be given 
 in feet and inches. 
 
 Fig. 5, " F." When dimensions are given in feet and inches, 
 
 a dash one eighth of an inch long shoiild sepa- 
 rate them. Foot- and inch-marks not less than 
 one sixteenth of an inch long should be used 
 for accents. If there is a fractional number 
 less than an inch, when the dimension is ex- 
 pressed in feet and inches, the figure zero should 
 be placed before it. A fraction must never 
 have a diagonal division-line, and the figures 
 must be a little smaller than the integer which 
 precedes it. 
 
 Dimensions in Dec- When dimensions are given in decimals, the 
 
 Fig. s, "K." inch-marks should be placed between the whole 
 
 number and fraction. If the decimal dimension 
 is less than an inch, the figure zero should pre- 
 cede it and the decimal-point, and the inch- 
 marks should be placed as indicated above. 
 
 Outside Diameter jf the outside diameter of a gear is a fraction, 
 
 of a Gear. . i i i i i « . 
 
 Fig. 5, " G." it should be stated as a common fraction. 
 
 Reading Dimen- All dimensions should read from the bottom 
 
 Fig.°s!' ^^'^ right-hand side of drawing. If dimensions 
 
 are at an angle with the edges of the sheet, 
 they should read from bottom side of the 
 drawing. 
 
 Mark Over Dimen- jf a dimension is not to the same scale as 
 
 sion Not to , . . -. 
 
 Scale. others on the view, indicate it by a dash above 
 
 Fig. 5, ' K." ^YiQ dimension. 
 
136 
 
 Full Dimensions. 
 Fig. 5- 
 
 Final Dimensions. 
 
 Radii or Diam- 
 eters. 
 Fig. 5, "H." 
 
 Never Cross a Di- 
 mension. 
 
 Small Rounds. 
 Circles. 
 
 Rounded End of 
 
 Screw. 
 Fig. S, "C." 
 
 .Standard Bolts, etc. 
 
 Dimensions on a drawing should indicate 
 the full dimensions independent of the scale of 
 the drawing. 
 
 All the dimensions given on a piece indicate 
 the final dimensions of the piece when it is com- 
 plete; and no allowance should be made for 
 the shrinkage of casting, etc. 
 
 Care and judgment musi be exercised as to 
 whether the radii or diameters are the dimen- 
 sions needed for the mechanic: e.g., a bolt circle 
 should have its radius given; a bored hole, its 
 diameter given; a turned piece, its diameter 
 given, etc. 
 
 A dimension should never be placed on a cen- 
 ter line. 
 
 It is an inviolable rule to never cross a di- 
 mension with a line. 
 
 Small rounds on corners, or fillets, are not 
 usually dimensioned. 
 
 Circles which do not indicate clearly their 
 relation to the piece shown in the view should 
 never be dimensioned. 
 
 If the end of a screw, stud, etc., is rounded, 
 the dimensions should be given to the corner 
 and not to the extreme end. 
 
 If bolts and screws are drawn, and every- 
 thing is standard except their lengths, only 
 the diameters of their bodies, the lengths under 
 
138 
 
 Bolt Hea;ls, etc, 
 Fig. 29. 
 
 Rolled Structural 
 Steel. 
 
 Rivet Holes, etc, 
 Fig. 30. 
 
 the heads, and their lengths of thread, are 
 shown in the dimensions. 
 
 Bolt-heads and nuts (when not standard), 
 and square and hexagonal figures, should be 
 dimensioned across fiats and not across diago- 
 nals. 
 
 Rolled structural steel should be dimensioned 
 in the commercial sizes and not in every 
 detail. 
 
 Where a number of rivet- or small bolt-holes 
 are in a right line, the usual dimensions should 
 be given in a note on the dimension-line between 
 the first hole and the last hole. The note should 
 give their number, size, distance apart, and the 
 total distance from the first to the last hole. 
 The dimension from one of the end holes to the 
 end of the piece should be regularly given. 
 
 The sizes of pipes must be stated in their 
 nominal inside diameters. 
 Pipe Tapped Holes. Pipe-tapped holes must be indicated by the 
 size of pipe-tap required, and all other data re- 
 garding the hole are useless and should not be 
 stated. 
 
 In giving board dimensions remember that 
 the thicknesses of stock boards are more likely 
 to be in fractional than in even inches; as, a 
 seven-eighths of an inch instead of a one-inch 
 board, and one and three-fourths inches instead 
 of a two-inch board, etc. 
 
 Sizes of Pipes. 
 
 Board Dimensions. 
 
140 
 
 Brick Dimensions. 
 Fig. 31. 
 
 Windows and 
 
 Doors. 
 Fig. 8. 
 
 Dimensioning 
 
 Angles. 
 Fig. 8. 
 
 Dimensions in Co- 
 ordinates. 
 Fig. 32. 
 
 Size of Dimension 
 Figures. 
 
 Extension Lines. 
 Fig. 5- 
 Fig. II. 
 
 Short Extension 
 Lines. 
 
 Brick dimensions should be given in multi- 
 ples of four. 
 
 Windows in brick walls should be dimen- 
 sioned to their centers, and doors should be 
 dimensioned for the width of opening. 
 
 When anglies are given in degrees and minutes 
 the usual degree and minute accents should be 
 used, and a curved dimension-line should re- 
 place the usual right line. Otherwise the di- 
 mension-line conforms to the same rules as are 
 observed for all dimension-lines. 
 
 Dimensions of angles on a drawing intended 
 for pattern-makers are often more convenient 
 when given in coordinates from a given refer- 
 ence line or point, than when given in degrees 
 and minutes. 
 
 As a rule the dimension-figures should be 
 put in with as wide a line as the projection-lines. 
 
 Extension-lines are limiting lines that are 
 used when a dimension is placed off the view, 
 and must have the included distance between 
 them equal to the same distance as referred to 
 on the view. They should be fine, broken, 
 parallel lines, composed of equal dashes spaced 
 at equal distances, and no extension-Une should 
 join a projection-line. 
 
 Short extension-lines of one dash only can 
 sometimes be used. 
 
142 
 
 Note in Horizontal 
 
 Line. 
 Fig. S- 
 
 Uniform Lettering. 
 Fig- 5- 
 
 Initial Letter. 
 
 Size of Letters. 
 
 Guide Lines. 
 
 Written on Pencil 
 Drawing. 
 
 Short and Concise. 
 
 Fig. 5, "A." 
 
 Notes. 
 
 Notes should be placed on a drawing so that 
 they can be read easily and quickly. 
 
 If convenience admits of it and there are 
 several words in the note, they are more quickly 
 read when placed in a horizontal line. 
 
 All letters used in notes on drawings must be 
 of the most simple type, j)lain, of uniform height, 
 and composed of lines of vmiform width to 
 match the projection-lines of the object. 
 
 The initial letter of every word, excepting 
 prepositions, should be taller than the others. 
 
 All the letters in a word should be close to- 
 gether and not less than one sixteenth of an 
 inch nor more than one eighth of an inch in 
 height. 
 
 Draw parallel guide-lines in pencil before 
 printing words. All words shoidd be sufficiently 
 separated for clearness. 
 
 All notes should be written on pencil draw- 
 ings which are to be traced, and printed on inked 
 or finished pencil drawings. 
 
 Notes must not be too abbreviated. 
 
 All notes must be in short sentences, exphcit 
 and concise. 
 
 Castings and rough forgings are occasionally 
 not finished all over; as a consequence, the cus- 
 tom in practice is to note the surfaces on each 
 piece which are finished. 
 
144 
 
 /Mark. 
 Fig. s, "A." 
 
 Fin. All Over Mark. 
 Fig.s, "H." 
 
 Marking Lines of 
 Finished Sur- 
 faces. 
 
 Fig. as- 
 
 State Kind of 
 
 Finish. 
 Fig.5, «K." 
 
 Omit Finish Notes. 
 Fig. S. "C." 
 
 Steel Casting. 
 
 Surface Partially 
 
 Finished. 
 Fig, 34. 
 
 Fixture or Jig Used. 
 
 When a surface is machined or finished an 
 / mark should be placed on that line of the view 
 which represents it, and not on the view where 
 the blank surface only is shown. 
 
 If a casting is finished all over, the several / 
 marks should be left off, and the words fin. all 
 over should be printed under or near the view^. 
 
 When there are two lines representing the 
 edges of surfaces and one or both of them rep- 
 resent finished surfaces, the / marks should be 
 placed outside and a curved dimension-line 
 should be drawn from it to the finished surface. 
 
 It is sometimes clearer, or necessary, to state 
 the kind of finish or machining a piece should 
 have, as file-finish, grind, plane, bore, etc. 
 
 Pieces which are made from rolled or wrought 
 steel bars, as spindles, shafts, studs, etc., are 
 usually finished all. over, and it is the custom 
 to omit the finish notes. 
 
 If a steel casting is wanted, do not confound 
 it with cast steel, but call it a steel casting every- 
 where on the drawing. 
 
 A large surface that is partially finished 
 should be indicated to instruct the pattern- 
 maker as to where the extra metal on the cast- 
 ing should be allowed. 
 
 , If, in machining, a fixture or jig is used for any 
 interchangeable part in a machine, it should be in- 
 dicated by note on or near the view of the piece. 
 
146 
 
 Threads Noted. 
 Fig. S, "F." 
 
 Taper on Shafts. 
 Fig. 35. 
 
 Springs. 
 Fig. s, "N." 
 
 Wire. 
 
 Forced Fits. 
 
 Inclination. 
 Fig. 36- 
 
 Identifying Letter. 
 
 Threads should be noted in number per inch, 
 unless they are U. S. Standard; in which case 
 they should be indicated as such. 
 
 Tapers on shafts should be given in inches 
 per foot. 
 
 Springs are described in detail by giving gage 
 size of wire in a coil, the number of free coils to 
 the inch, and the inside or outside dimensions 
 of the body of the spring. 
 
 The mesh of wire in screens is indicated by 
 the size of wire to gage used, and the nunlber 
 per inch or the amount of opening between the 
 wires.. 
 
 Forced fits should be indicated by the total 
 pressure required. 
 
 The inclination of a pipe or a roof should be 
 given as the pitch or slope. 
 
 Every piece shown on a drawing must have 
 an identifying letter, which should be a capital 
 letter somewhat larger than the initial letters 
 in the other notes on the drawing, and must be 
 the same letter as used in the bill of material 
 for the same piece. The letters I and J 
 must not be used; and when the letters in the 
 alphabet are exhausted, small capitals should 
 be used along with and at the side of the large 
 capitals. 
 
148 
 
 Fig. 40. 
 
 Outline Shading. 
 
 Shade Line. 
 Fig. 40. 
 
 Shading, 
 
 Shade-lines, for outline shading, are sometimes 
 used on edges and surfaces of views which con- 
 ventionally cast shadows. , They should not 
 be used too freely, for they are a convention 
 which adds to the work of the draftsman; but 
 occasionally they make clearer the configura- 
 tion of an intricate piece which is shown on a 
 drawing, provided that the mechanic under- 
 stands the convention as well as the draftsman 
 who uses it. They are occasionally used for 
 the purpose of display, which, at its best, in de- 
 tail drawing is very much out of place. If, 
 however, they are used on the views of one piece, 
 they should be used on all the views of all the 
 pieces which are shown on that one drawing, 
 in order to conform to that fundamental rule 
 of imif ormity which should obtain in all draw- 
 ings. 
 
 Outline shading should be done by drawing 
 a second adjoining projection-line on and not 
 outside that part of the view which represents 
 the surface of the material. By drawing a shade- 
 line, then, on the surface of the piece, it cannot 
 be considered as a litie in the shadow which is 
 cast by an edge of an object, as it is often in- 
 terpreted. 
 
 By considering as a shade-line a line in the 
 shade of the piece and not as a shadow cast 
 
150 
 
 Circle Shaded. 
 
 Round Piece. 
 
 Unsectioned Round 
 Piece. 
 
 V Thread Screw. 
 Fig. 37- 
 
 Sectional V Thread 
 
 Nut. 
 Kg. 37. 
 
 by it, the actual dimensions from edge to edge 
 are kept to scale; and it follows that the lower 
 and right-hand outside edges of a piece and the 
 upper and left-hand edges of holes would have 
 shade-lines. 
 
 AVhen a circle is shaded the set of the com- 
 pass which strikes the circle should not be 
 changed, but another center should be taken, 
 up and along a line which makes 45° with the 
 horizontal. The eccentric arc which is then 
 struck with the new center to represent the 
 shade- line should just join the original circle at 
 the end of the 45° line, and it is then continued 
 until it just merges with the original circle. 
 
 In the side view of a round piece there is 
 theoretically no outline shade-line on the round 
 edge, but, by convention, a shade-line should be 
 used. 
 
 An unsectioned round piece in a bushing that 
 is sectioned by a. meridian plane has conven- 
 tionally an outline shade-line. 
 
 In a V-thread screw, by convention, the short 
 conventional thread-line is shown as a shade- 
 line. 
 
 In a sectional V-thread nut, by convention, 
 the long conventional thread-line is shown as a 
 shade-line. 
 
 Pencil- drawings that are to be inked or traced 
 over should never be outline-shaded. 
 
152 
 
 Surface Shading. The views of the surfaces of pieces which are 
 
 in the shade are occasionally shade-lined. Sur- 
 face shading should be done to a very limited 
 extent on commercial mechanical drawings, 
 and only where it is quite necessary to make 
 clear or stand out some surface which would 
 otherwise be wholly confused in the view of an 
 intricate piece. 
 
 Ho Surface Shading As a rule no surf ace shading should be used 
 
 on Detail. i , m i 
 
 on any detail drawing. 
 
 Penciled Drawings. 
 
 When penciling a drawing, each piece, with 
 all its views, should be completed before another 
 is begun; and the penciling should be done in 
 the following order: 
 
 1. Draw border-lines. 
 
 2. Draw match-lines. 
 
 3. Block out space for title. 
 
 4. Block out space for bill of material, if there 
 is one. 
 
 5. Draw main center lines of object in all its 
 views. 
 
 6. Draw projections of the ttiain lines of the 
 object. 
 
 7. Draw projections of the small and inside 
 lines of the object, commencing with that view 
 which shows the most essential features, if there 
 is a choice. 
 
154 
 
 Free Hand Arcs. 
 
 Appearance of 
 Drawing. 
 
 8. Put in dimensions and necessary notes. 
 
 As large arcs as possible should be put in free- 
 hand. 
 
 It is an art to make a finished pencil draw- 
 ing neatly, quickly, and properly. With some 
 draftsmen it appears to be a gift, but with others 
 it must be acquired. 
 Pencu Completely. A drawing which is to be traced or inked 
 should usually be completely penciled. It is 
 an Undesirable habit to form, and an unneces- 
 sary tax on the mind, when a draftsman leaves 
 a large share of the details in his mind for inking, 
 instead of penciling them on the drawing- 
 paper. 
 
 Inked Drawings. 
 
 All drawings must be inked in with black 
 water-proof drawing-ink. 
 To Ink a Drawing. The different parts of a drawing should be 
 inked in the following order: first, all the lines 
 of projection which are represented by the small 
 arcs, the large arcs, and right lines taken in 
 their respective order — and if there is any out- 
 line shading, it should be done at the same time; 
 second, all auxiliary lines excepting hatch-lines; 
 third, dimension-lines, arrow-heads, and notes; 
 fourth, hatch-lines; fifth, surface shade-lines, 
 if there are any; sixth, bill of material; seventh, 
 title; eighth, border-lines. 
 
156 
 
 Ink by Sections. 
 
 Trace by Sections. 
 
 Work Across and 
 Down. 
 
 Wide Line. 
 
 Narrow Sections. 
 Fig. 38. 
 
 Short Hatch Lines. 
 Fig. I. 
 
 Uniformity. 
 
 It is sometimes well to ink only a section of 
 a drawing at a time, particularly, if the drawing 
 is not to be finished the same day that it is 
 begun. 
 
 It is rather imperative that tracing-cloth 
 should be inked in sections, as change of atmos- 
 pheric conditions has a marked effect on ' the 
 surface of tracing-cloth. 
 
 Always commence the inking at the top and 
 left-hand side, and work across and down the 
 sheet. 
 
 Any line which is over one thirty-second of an 
 inch wide and drawn with a medium-size ruling- 
 pen should be made with more than one Stroke 
 of the pen. 
 
 When inking in the sections of very narrow 
 walls in building plans or like sections, draw 
 heavy parallel lines to represent their outlines, 
 and fill in with the writing-pen or, preferably, 
 a large ruling-pen. 
 
 Hatch-lines which are three sixteenths of an 
 inch long or less, should be put in with the 
 writing-pen. 
 
 That which makes an inked drawing look well 
 is uniformity in every detail, to wit, all figures, 
 letters, lines, etc., that are used for like pur- 
 poses should be of the same height, same width 
 of line,, and same style. 
 
ing. 
 
 168 
 
 Checking Drawings. 
 
 Everything on a drawing must be thoroughly 
 checked by at least two persons before it is 
 allowed ta pass into the shops. 
 
 Check by Steps. A draftsman should check his drawing by 
 
 methodical steps, and should not try to check 
 it by taking a bird's-eye view of what he has 
 done. 
 
 To Check a Draw- The following steps are to be observed in 
 checking a detail drawing: 
 
 1. Identify every piece in its relation to the 
 machine, and note if it is of proper form and that 
 none are missing. 
 
 2. Check every view for correct and neces- 
 sarily complete projections. 
 
 3. Note if there are any required dimensions 
 or working notes missing. 
 
 4. Scale every dimension, and note if it agrees 
 with the one given on the drawing. 
 
 5. Check the main dimensions of the pieces 
 in detail and assembly and note if they agree. 
 
 6. Check the arrow-heads to see if there are 
 any missing. . 
 
 7. Check the accents to figures, as inch- 
 marks, foot-marks, and degree-marks. 
 
 8. Check the center lines. 
 
 9. Check the supplementary notes and marks 
 to see if they are correct and none missing. 
 
160 
 
 Fig. 38. 
 
 Outline, Section 
 
 Lined. 
 Fig. 39- 
 
 Lines Near 
 Together. 
 Fig. 38. 
 
 Elevations. 
 
 Minor Details. 
 
 Over All and Main 
 Dimensions. 
 
 Structural Steel 
 
 Parts. 
 Fig. 13. 
 
 Bolts. 
 Fig. 40. 
 
 Assembly Drawings. 
 
 The function of an assembly drawing is to 
 show the arrangement of its principal parts in 
 the most simple, direct, and comprehensive 
 manner. 
 
 An arrangement of parts is sometimes clearer 
 when the main part has its outline fringed with 
 a dotted section-line. That scheme, however, 
 is not common at the present time. 
 
 On a small scale it sometimes happens that 
 several lines in true projection would be close 
 together, and even merge if inked in. If such 
 is the case, the line should be spaced a httle 
 farther apart or now and then one left out. 
 
 In assembly drawings show elevations in a 
 line, if possible. 
 
 Minor details, as, nuts, keys, set-screws, etc., 
 can be left off the assembly drawing when they 
 are evident without drawing. 
 
 Over-all and important main dimensions are 
 the most that are needed in an assembly draw- 
 ing. 
 
 Structural steel parts, when they are shown 
 on such a reduced scale as to make a section one 
 eighth of an inch or less in width, should be 
 blacked in. 
 
 When there are four or more bolts in a piece, 
 they should generally be shown, in a side view. 
 
162 
 
 at their true scale distance from the center as 
 measured each side of the center line. 
 
 Diagram Drawings. 
 
 Fig. 41. If merely an outline of a machine or the kine- 
 
 Fig. 42. matic relation of some of, its parts is desired, 
 
 a diagram drawing is made which is composed 
 of the main lines of the machine with the usual 
 center lines, or with heavy center line to show 
 the kinematic relation of some of its parts. 
 
 In some intricate types of machinery, as 
 shoe machinery, textile machinery, etc., and 
 especially in textile machinery, it is often quite 
 impossible to show, for an assembly drawing, 
 anything more than a diagram drawing. 
 
 Fig. 43. 
 
 PATENT OFFICE DRAWINGS. 
 
 A Patent-Office drawing must be made to 
 certain specifications which are given verbatim 
 as published in the official "Rules of Practice" 
 in the United States Patent Office: ■ 
 
 When the invention consists of an improve- 
 ment on an old machine the drawing must ex- 
 hibit, in one or more views, the invention itself 
 disconnected from the old structure, and also, 
 in another view, so much only of the old struc- 
 ture as will suffice to show the connection of 
 the invention therewith. 
 
164 
 
 Drawings must be made upon pure white 
 paper of a thickness corresponding to three- 
 sheet Bristol board. The surface of the paper 
 must be calendered and smooth. India ink 
 alone must be used to secure perfectly black and 
 solid lines. 
 
 The size of a sheet on which a drawing is 
 made must be exactly 10X15 inches. One 
 inch from its edge a single marginal line is to be 
 drawn, leaving the "sight" precisely 8x13 
 inches. Within this margin all work and signa- 
 tures must be included. One of the shorter 
 sides of the sheet is regarded as its top, and, 
 measuring downwardly from the marginal line, 
 a space of not less than IJ inches is to be left 
 blank for the heading of the title, name, num- 
 ber, and date. 
 
 All drawings must be made with the pen only. 
 Every line and letter (signatures included) must 
 be absolutely black. This direction applies 
 to all lines, however fine, to shading, and to 
 lines representing cut surfaces in sectional views. 
 All lines must be clean, sharp, and solid, and 
 they must not be too fine or crowded. Sur- 
 face shading, when used, should be open. 
 Sectional shading should be made by obhque 
 parallel lines, which may be about one twen- 
 tieth of an inch apart. Solid black should not 
 be used for sectional or surface shading. 
 
166 
 
 Scale of Drawing. 
 
 Letters of Refer- 
 ence. 
 
 Drawings should be made with the fewest 
 lines possible consistent with clearness. By 
 the observance of this rule the effectiveness of 
 the work after reduction will be much increased. 
 Shading (except on sectional views) should be 
 used only on convex and concave surfaces, 
 where it should be used sparingly, and may be 
 even there dispensed with if the drawing is 
 otherwise well executed. The plane upon which 
 a sectional view is taken should be indicated on 
 the general view by a broken or dotted line. 
 Heavy lines on the shade sides of objects should 
 be used, except when they tend to thicken the 
 the work and obscure letters of reference. The 
 light is always supposed to come from the upper 
 left-hand comer at an angle of forty-five degrees. 
 Imitations of wood or surface graining should 
 not be attempted. 
 
 The scale to. which a drawing is made ought 
 to be large enough to show the mechanism with- 
 out crowding, and two or more sheets should be 
 used if one does not give sufficient room to ac- 
 complish this end; but the number of sheets 
 must never be more than is absolutely neces- 
 sary. 
 
 The different views should be consecutively 
 numbered. Letters and figures of reference 
 must be carefully formed. They should, if 
 possible, measure at least one-eighth of an inch 
 
168 
 
 in height, so that they may bear reduction to 
 one twenty-fourth of an inch, and they may be 
 much larger when there is sufficient room. 
 They must be so placed in the close and com- 
 plex parts of drawings as not to interfere with 
 a thorough comprehension of the same, and 
 therefore should rarely cross or mingle with the 
 lines. When necessarily grouped around a cer- 
 tain part they should be placed at a little dis- 
 tance where there is available space, and con- 
 nected by short broken lines with the parts to 
 which they refer. They must never appear 
 upon shaded surfaces, and when it is difficult 
 to avoid this a blank space must be left in the 
 shading where the letter occurs, so that it shall 
 appear perfectly distinct and separate from the 
 work. If the same part of an invention appears 
 in more than one view of the drawing, it must 
 always be represented by the same character, 
 and the same character must never be used to 
 designate different parts. 
 
 Signature of inven- The signature of the inventor should be 
 tor and Wit- placed at the lower right-hand corner of each 
 sheet, and the signatures of the witnesses at 
 the lower left-hand corner, all within the mar- 
 ginal line, but in no instance should they tres- 
 
 Titie. pass \ipon the drawings. The title should be 
 
 written with pencil on the back of the sheet. 
 The permanent names and title will be sup- 
 
170 
 
 plied subsequently by the office in uniform 
 style. 
 Large Views. When views are longer than the width of the 
 
 sheet, the sheet should be turned on its side, 
 and the heading will be placed at the right and 
 the signatures at the left, occupying the same 
 space and position as in upright views, and 
 being horizontal when the sheet is held in an 
 upright position; and all views on the same 
 sheet must stand in the same direction. 
 
 As a rule, one view only of each invention can 
 be shown in the Gazette illustrations. The 
 selection of that portion of a drawing best cal- 
 culated to explain the nature of the specific im- 
 provement would be facilitated and ^he final 
 result improved by the judicious execution of 
 a figure with express reference to the Gazette, 
 but which might at the same time serve as one 
 of the figures referred to in the specification. 
 For this purpose the figure may be a plan, ele- 
 vation, section, or perspective view, according 
 to the judgment of the draftsman. It must 
 not cover a space exceeding 16 square inches. 
 All its parts should be open and distinct, with 
 very little or no shading, and it must illustrate 
 the invention claimed only, to the exclusion of 
 all other details. When well executed it will 
 be used without curtailment or change, but any 
 excessive fineness, or crowding, or unnecessary 
 
172 
 
 elaborateness, of detail will necessitate its ex- 
 clusion from the Gazette. 
 
 An agent's or attorney's stamp, or advertise- 
 ment, or written address wiU not be permitted 
 upon the face of a drawing, within or without 
 the marginal line. 
 
INDEX. 
 
 Adjacent part line, 130 
 Alterations on blue-print, 28 
 Alternate position lines, 120 
 Arrangement of views, 112, 114 
 Arrow-heads, 128, 130 i 
 Assembly drawings, 160 
 
 " detail drawings, 96 
 
 Beam compass, 64 
 
 Bearings on shaft, 110 
 
 Bill of material, 104 
 
 Black ink, 24 
 
 Black-print paper, 22 
 
 Blocking out parts of views, etc., on prints, 
 
 16 
 Blue-print cloth, 20 
 " paper, 18 
 " chemicals for sensitized surface, 
 
 26 
 Boiler settings, 88 
 Bolt-heads— hexagonal, 110, 116 
 
 " " —square, 110 
 Bond-paper, 6 
 Border lines, 98 
 Bow-instruments, 66 
 Broken edges of pieces, 120, 126 
 Brown-print paper, 22 
 
 Caliper, 76 
 
 Care of print-paper, 18 
 
 Case for instruments, 68 
 
 Celluloid lining T-square blade, 33 
 
 Celluloid— sheet, 14 
 
 Center lines, 126 
 
 Chamfers on belts, etc., 118 
 
 Character of arrow-heads, 128 
 " " Invisible lines, 118 
 " " adjacent part lines, 130 
 " " alternate position lines, 120 
 " " center lines, 126 
 " " dimension lines, 128 
 «• " " figures, 140 
 
 " " extension lines, 140 
 
 Character of section lines, 122 
 " " letters in notes, 142 
 " " " titles, 102 
 Checking drawings, 158 
 Circle — to draw a large, 62 
 Circular arcs— to draw, 63 
 Cleaning tracings, 14 
 Collars shown on shafts, etc., 110 
 Combined and sectional outside view, 108 
 Combining T-square and triangles, 36 
 Compass — description of, 58 
 Corrections on prints, 28 
 Cross-section paper, 8 
 Curved ruler, 48 
 
 Curves of intersection made with circular 
 arcs. 116 
 
 Dimension line— position of, 138 
 
 " —short, 133 
 Dimensions, 138 
 
 " of angles, 140 
 
 " boards, 138 
 " " brick work, 140 
 
 " " bolts (standard), 136 
 
 " bolts (not standard), 138 
 " in decimals, 134 
 
 " of end of screw, 136 
 
 in feet and inches, 133 
 —final, 136 
 " in parallel lines, 130 
 
 " of pipes, 138 
 
 " " pipe-tapped holes, 138 
 
 " " radii and diameters, 128, 136 
 
 " rivet-holes, etc., 138 
 " " rolled structural steel, 138 
 
 " " windows and doors, 140 
 
 " — sides of drawing read from, 
 
 134 
 Dividers, 64 
 Drawing-board, 30 
 " -paper, 4 
 
 " —bond, 6 
 " " — cross-section, 8 
 
 175 
 
176 
 
 Drawing-paper^— Duplex, 6 
 '< " —egg-shell, 6 
 
 " —Manilla, 6 
 " " — Whatman's hand-made, 6 
 
 " room — arrangement for lighting, 
 40 
 Drawings — assembly, 160 
 
 — " detail; 96 
 —detail, '94 
 " — diagram, 162 
 " —foundation, 88 
 " — layout, 84 
 " — ^machine, 88 
 
 —Patent Office, 162 
 " — piping. 86 
 " — serial number of, 104 
 
 —sizes of, 98, 104 
 " ' —templet, 88 
 
 Effect of moisture on tracing-cloth, 14 
 Egg-shell drawing-paper, 6 
 Ellipse shown by a circle, 116 
 Eraser— ink, 72 
 
 " —pencil, 70 
 
 " shield, 74 
 
 " — sponge-rubber, 72 
 
 " —steel, 72 
 Exposure of blue-print paper, 30 
 
 over-, 20 
 Extension lines, 140 
 
 Finish notes, 142, 144 
 Folding rule, 76 
 Foundation drawings, 88 
 
 Gears — spur, bevel and worm, 112 
 
 " — cast, 112 
 General plans, 84 
 Grade of pencil, 24 
 
 Hatch or section lines, 122 
 
 Identifying rhark, 146 
 Ink— black, 24 
 
 " eraser, 72 
 
 " —India, 34 
 
 " —red, 26 
 Inking a drawing, 154 
 Invisible lines, 118 
 
 Keys, 110 
 Kcyway, 136 
 
 Laying drawing-paper on board, 8 
 " off consecutive distances, 46 
 " " distances with dividers, 66 
 " " " on a right line, 46 
 
 Layout drawing, 84 
 
 Letters in title, 103 
 
 Limit of accuracy in scaling, 44 
 
 Lines — adjacent part, 120 
 
 " —alternate position, 120 
 
 '■ —border, 98 
 
 " —broken, 130 
 
 " —center, 126 
 
 " — dimension, 138 
 
 " — extension, 140 
 
 " —invisible, 118 
 
 " —match, 100 
 
 " — projection, 116 
 
 " — representing materials cut, 134 
 
 " — section or hatch, 123 
 List of drawing instruments, 78 
 Logarithmic spiral curve, 48 
 
 Machine drawings, 88 
 Machinist scale, 76 
 Manilla drawing-paper, 6 
 Marking off distances by scale, 43, 46 
 Match lines, 100 
 Milled piece — ^how shown, 110 
 Mounting drawings, 8 
 prints, 32 
 
 Needle-points, 60 
 
 " care of, 63 
 
 Notes, 143 
 
 " —finish, 143, 144 
 
 " — forced fits, 146 
 
 " — mesh of wire, 146 
 
 " — taper on shafts, 146 
 
 " —threads, 146 
 
 " — springs, 146 
 Nuts — sectioned, 118 
 
 Oil holes and channels, 118 
 Oilstone, 74 
 
 Parallel straight-edge, 34 
 Patent OflBce drawings, 163 
 Pen — ruling, 50 
 " — writing, 68 
 " wiper, 70 
 Pencils, 23 
 Pencil — Artist's, 50 
 " eraser, 70 
 " points, 48 
 " " on compass, 60 
 
 " pointer, 70 
 Penciling a drawing, 152 
 Piping drawing, 86 
 Place for bill of material, 104 
 
 " " title, 100 
 Preparing tracing-cloth for inking, 13 
 
177 
 
 Principle of printing, 16 
 Pricker-point, 66 
 Print-clotli, 20 
 " -paper, 14 
 
 " —blue. 18 
 " —black, 22 
 " " —brown, 22 
 
 " —quick blue, 20 
 " —white, 22 
 " " — exposure of, 20 
 Printing — general method, 14 
 
 " from bond and cross- section pa- 
 per, 20 
 Projection— lines of, 116 
 
 " — third angle, 114 
 Protractor-T-celluloid, 46 
 
 " — German silver, 46 
 " —steel, 46 
 Proving angles of triangles, 38 
 " T-square blade, 3d 
 head, 82 
 " scale, 44 
 
 " working-edge of drawing-board, 80 
 Pulley — regular, 112 
 
 Quick blue-print paper, 20 
 
 Red ink, 26 
 Ruling-pen, 50 
 
 " —care of, 52 
 " '" — medium size, 68 
 
 " —test of, 52 
 Rule— folding, 76 
 Ruler — curved, 48 
 
 Scale— flat boxwood, 42 
 " — triangular, 40 
 " — ^nickel-plated sheet-steel, 42 
 " guard, 40 
 " — machinist's, 76 
 " terms, 44, 102 
 Scheming sheet, 92 
 Screws — end view, 112 
 " — fllister head, 112 
 " —long, 118 
 " — side views, 110 
 Section or hatch lines, 122 
 " view of thin piece, 124 
 " " " solid round piece, 124 
 " " " turned piece, 124 
 Sectional view, 108, 116 
 
 " and outside view combined, 108 
 Sectionin ;• adjacent pieces, 124 
 
 " large area, 124 
 Selection of a view, 106 
 Serial number of drawings, 104 
 Shading, 148 
 
 Shading a circle, 150 
 —outline, 148 
 " —section, 124 
 " —surface, 153 
 " sectional V-thread screw, 150 
 " side view of round piece, 150 
 " unsectioned " " , 150 
 " V-thread screw, 150 
 
 Sheet celluloid, 14 
 
 Shrinkage of print-paper, 18 
 
 Side of tracing-cloth used, 12 
 
 Sizes of drawings, 98, 104 
 " " letters in title, 102 
 
 Sketches, 92 
 
 Smoothing a surface after rubbing, 26 
 
 Spacing of thread lines, 118 
 " " V-thread lines, 118 
 
 Sponge-rubber, 72 
 
 Straightedge on drawing-board, 80 
 " —parallel, 34 
 
 Stretching drawing-paper, 8 
 
 Sub-dimensions, 132 
 
 Surfaces developed, 108 
 
 Tacks, 74 
 
 Tack-lifter, 76 
 
 Taking distances with compass, 62 
 
 Templet drawing, 88 
 
 Test of ruling-pen, 52 
 
 Thin piece in section, 124 
 
 Third-angle projection, 114 
 
 Threads — spacing of lines, 118 
 
 " .—V-, etc., 118 
 Time of exposure of print-paper, 18 
 Titles, 100 
 Tracing-cloth, 10 
 " -paper, 10 
 Trammel points on beam-compass, 64 
 Triangles — combination, 36 
 
 " — hard-rubber, 34 
 
 " —nickel -plated steel, 36 
 
 " — pear- wood, 84 
 
 " — transparent, 84 
 —80° X 60°, 86 
 —45°, 36 
 T-square, 30 
 
 blade, 30 
 head, 32 ' 
 
 " — nickel-plated steel, 34 
 
 " — pear- wood, 32 
 Tubular beam, 64 
 Types of detail drawings, 96 
 
 Universal Drafting Machine, 46 
 Use of pencil, 50 
 " " ruling-pen, 56 
 
178 
 
 Varnishing drawings and prints, 8, 33, 36 
 Views of a drawing, 106 
 
 " bearings on a round shaft, 110 
 
 — combined outside and sectional, 108 
 of concentric circles, 110 
 
 " crooked pieces, 108 
 
 " conventional thi-eads, 110 
 
 " fllister head screw, 113 
 
 " flat surface on.body of screw, 110 
 
 " gears, 113 
 
 " hex. bolt-heads, 110 
 
 " holes on a circle, 110 
 
 Views of keys, 110 
 
 " " knurled or milled piece, 110 
 " " plates and cams, 108 
 —sectional, 108, 116 
 of " threaded pieces, 118 
 " simple pieces, 108 
 " square bolt-heads, 110 
 " symmetrical pieces, 108 
 
 Washers and collars, 110 
 Whatman's hand-made paper, 6 
 White print-paper, 33 
 

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