TS 600 .R5 Copy 1 ammmmmmmmmnifnua ilnmm TINSMITHING AMERICAN SCHOOT, OF CORRFSPONi^FNCF, ARMOUR INSTlTUTFv OF TECHNOLOGY CHICAGO :>I3 ti^mttmmmmtitmti^'aitiimfmmtmtm'mmmatMijaaimimiummu' TINSMITHING I N S T R IT C T I O N PAPER PREPARED BY "WlIvLIAM Neubeckek Instkuctor Sheet Metal Department of New York Trade School FoRMEKLY Superintendent Forester Co. 1903 AMERICAN SCHOO.Iv OF CORRESPONDENCE AT ARMOUR INSTITUTE OF TECHNOLOGY CHICAGO ILLINOIS U. S. A. THE LIBRARY OF CONGRESS, Two Copjet Rec«lveif JUL 16 1903 U Cup/iiijht bntty lussr H XXc. No. COPY B. J- Copyright 1903 by American Schooi. of Correspondence o TINSMITH ING. An important j)art of the technical education of those con- nected with tinsmiths' work is a knowledcre of laying out patterns. When making the various forms of tinware, or, as they are com- monly called, housefurnishing goods, the greatest care must be taken in developing the patterns, for if a mistake of but one point is made, the pattern will be useless. There are general geometri- cal principles which are applied to this w^ork which, when thor- oughly understood, make that part plain and simple, which would otherwise appear intricate. These principles enable the student to lay out different patterns for various pieces of tinware where the methods of construction are simila:-. Fig. 1. Fig. 2. Construction. Before laying out the pattern for any piece of tinware, the method of construction should be known. Knowino- this, the first thought should be: Can the pattern be developed and cut from one piece of metal to advantage, as shown in Fio-. 1, or will it cut to waste, as shown in Fig. 2 ? Will the articles have soldered, grooved or riveted seams, as shown respectively by A, B and C, in Fig. 3 ? Also, will the edges be wired or have hem edges at the top, as shown respectively by A and B, in Fig. 4 '^ Some- times the pattern can be laid out in such a way that the article may be made up of two or more pieces, so that the patterns may be laid in one another, as shown in Fig. 5, thereby saving material. This is a plan that should always be followed if possible, AVhen the patterns are developed, tin plate should be obtained of such size as to have as little waste as possible. By means of the table on pages 45-47 tin plate may be ordered TINSMITHING which will cut to advaiitat'-e, lV)r there is nothincf worse in a tin- shop than to see a lot ot" waste plate under the benches, whereas a little foresioht in orderino- stt)ck would have saved nuiterial. Capacity of Vessels. k^t)nietinies the tinsmith is reijuired to make a piece of tinware which will hold a given quantity of li(]uid. The methods of lindincp the dimensions are given in Arithmetic and Mensuration, which subiects should be reviewed before beoin- nincr this work. CD Shop Tools. The most im])ortant hand tools required by the tinsmith are: hauimer, shears, mallet, scratch awl, dividers and soldering coppers. The other tinsmith tools and machines will be explained as we proceed. c Fig. 3. F\cr. 4. Fii Various Methods of Obtaining Patterns. The pattern draft- intr for this course is divided into two classes: 1. Patterns which are developed by means of parallel lines. 2. Patterns which are developed by means of radial lines. The princij)les which follow are fundamental in the art of pattern cutting and their a])plication is universal in tinsmiths' work. INTERSECTIONS AND DEVELOPMENTS. The layincr out of i)atterns in tinsmiths' work belono-s to tliat department of descriptive geometry, known as development of sur- faces, Mhich means the laying out Hat of the surfaces of the solids, the fiat surfaces in this case being the tinplate. In Fig. () is shown one of the most simple forms to be developed by parallel lines, that of an octagonal j)rism. This problem explains certain fixed rules to be observed in the development of all |>arallel foi-ms, which are as follows: 1. There must be a j>/(ni, chDnttoii or other view of the article to be made, showing the line of joint or intersection, and TINSMITIllNG in line witli which imist l)t' drawn a Hection or prolih' of the article. Thus, AIJCD shows the view of the artich'. A L tlic liiu' of joint or intersection, and E the ])rotile or section of the article. '2. Tile Pmflc or section (if curved) must he divided into e(]ual spaces (the more spaces emjtloyed the more accurate will Ix^ the ])attei'n ), from which lines are drawn ])arallel to the lines of the article intersectino; the line of joint or intersection. Thus from the corners numbered 1 to 8 in the ]irotile E, lines are drawn H-'' B 1 H e ^ ^ rrr::^ ^___. ____, i- H or— :t^^ z o h < > Id _l UJ 1' 2' 3' 4' 5' 6' 7' 6' D c J F PUAN Fig. 6. [tarallel to the line of the article, intersectin»»; the line of joint AL from 1" to 8". In Fi^. 7, where the section A is curved, this is divided into equal spaces. 3. A ,'/(t line (showini£ the amount of material the article will require) is next drawn at right angles to the line of the article, upoji which is placed each space contained in the section or profile. Thus JE, in Eig. 6, is the stretchout line, which con- tains the true amount required to enclose the profile E. 4. At right angles to the stretchout line, and from the inter- sections thereon, draw lines called the iiht/surnif/ JiiivK. Thus, from the intersections 1' to S' on JF lines are drawn at right angles to the stretchout line JE, which are called measuring lines. 5. Erom the intersections on the line of joint draw lines in- tersecting similarly numbered measuring lines, which will result in the pattern shape. Thus lines drawn from the intersections on -G TINSMITHIXG the line AL at right angles to BC intersect similarly numbered measiirincp lines as shown. Then JIIiF will be the development for an octagonal prism intersected by the line AL in elevation. This simple problem shows the fundamental ])rinciples in all parallel-line developments. AVhat we have just done is similar to taking the prism and rolling it out on a flat surface. Let the student imagine the prism before him with the corners blackened B i 1 1 1 1 1 1 Fig. 7. and starting with corner 1 turn the j)rism on a sheet of white paper until the point 1 is again reached, when the result will cor- respond to the development shown. Bearing these sim])le rules in mind, the student should have no difliculty in laying out or developing the forms which will follow. Fig. 7 shows the development of a cylinder, and also shows the j)rinciples which are applied in spacing circular sections or pro- flies, as explained for parallel developments. A shows the proflle or section. B the elevation, and CD the stretchout line or the amount of material retjuired to go around the circle. By drawing the measurinu- lines C"F and DE and connectintr them by the line FE, we obtain CDEF, which is the development of the cylinder. Fig. 8 shows how to obtain the development of the surfaces of an intersected hexaooual prism, the angle of intersection being 45°. First draw the elevation ABCD and the section E in its proper position below. Number the corners in the section 1, 2 and 3, as shown, from which erect perpendicular lines intersecting the TlNSMITllLXd plane AB, as shown bv 1\ 2^ and S\ Bisect the lines 1 — 1 and 3 — 3 in phm obtainincr the points F and 11 ivsj)ectively, and draw the line Fll. This line will be used to obtain dimensions with which to construct the developed surface on the plane AB. At ricrht ano-les to AB and from the intersections 1\ 2' and 3 draw lines as shown. Parallel to AB draw the line F^ H^. Now, iiieasurino- in each instance from the line FH in E. take the dis- tances to 1, 2 and 3. and ])lace them on similarly numbered lines drawn from the plane AB, measurintr in each instance from the A **/ /'j\ \ \, >3' / e-A^ '°"' ^^-^-.a/^' / \ / / / / / M ^ B n C K I ^ i" 5' 1 ' 1 Z Fig. 8. line F^ 11^ on either side, thus obtainino- the points 1'. 2' and 8'. Connect these points by lines as shown; then J will be the true development or section on AB. For the development of the prism, draw the stretchout line KI at ricrht anoles to AD. upon which place the stretchout of the section E. as shown by similar numbered intersections on Kl, From these intersections, at rij^ht angles to KI, draw the measur- incr lines shown, which intersect with lines drawn from similar numbered intersections on the plan AB, at rioht angles to B(\ Throuo-h the intersections thus obtained, draw the lines from L to TINSMITIIING M. Then KLMI will be the pattern or development of the inter- sected prism. Fig. 9 shows the development of an intersected cylinder. A is the elevation and B the profile or plan. As each half of the develo])ment will be symmetrical, divide the profile B into a num- ber of equal parts, numbering each half from 1 to 5, as shown. From these points perpendicular lines are erected, intersecting the plane 1^ — 5^ at 1^ , 2^ , 3^ , 4^ and 5^ . A stretchout is now made of the profile B and placed on the horizontal stretchout line CD, the points being shown by 5', 4', 8', 2', 1', 2", 3", 4" and 5". From Fig. 9. these ix)ints measuring lines are erected and intersected by similar numbered lines drawn from the plane 1^' — 5^ at right angles to the line of the cylinder. A line traced through points thus obtained will be the development of the intersected cylinder. In this case the butting edge or joint line of the cylinder is on its shortest side. If the l)uttiniT edge were desired on its lonwst side, it would be necessary to change only the figures on the stretchout line CD, making 1' start at 5' and end at 5". Where two j)risms intersect each other, as shown in Hg. 10, it is necessary to find the points of intersection before the surfaces can be develo])ed. Thus we have two unequal quadrangular TINSMITHING 9 prisms interset'tinii; cliao;()nalIy at right ancrles to each othei-. We hrst draw the section of the horizontal prisms as shown by B in the end view, from whicli the side view A is projected as shown. P'rom the corner T in the section B erect the perpendicuhir line T(\ and above in its ])roper ])()sition draw the section L) of the vertical |)rism, and number the corners 1, 2, H and 4. From the corners 1 and 3 drop vertical lines intersecting the profile J3 at 1' and 3', T representing the points 2' and 4' obtained from 2 and 4 in T). From the points 1' and 3' in B, draw a horizontal line through the side view, and locate the center of the vertical prism as 3", from which erect the perpendicular line 3" — 1. Now take a duplicate of the section D and place it as shown by F, allowing it to make a quarter turn (-H) ); in other words, if we view the vertical prism from the end view, the point 1 in section I) faces the left, ^\hile if we stood on the ritrht side of the end view the point 1 would point ahead in the direction of the arrow. The side view therefore represents a view standing to the right of the end view, and therefore the section F makes a quarter turn, brino-ino- the corner 1 toward the top. From points 2 and 4 in section F drop vertical lines intersecting the line drawn from the corner 2' — 4' in B, thus obtaining the intersections 2" — 4" in the side view. Draw a line from 4" to 3" to 2", which represents the intersection between the tM^o prisms. To develop the vertical prism, draw the horizontal stretchout line HI, and upon it place the stretchout of the profile D as shown by similar figures on III. Draw the measuring lines from the points 1, 2, 3, 4, 1, at right angles to III, which intersects with lines drawn at right angles to the line of the vertical prism from intersections having similar numbers on B. A line traced throuo-h the points thus obtained, as shown by HILJ will be the develop- ment of the vertical prism. The development of the horizontal prism with the opening cut into it to admit the joining of the vertical prism is shown in Fig. 11, and is drawn as follows: Draw any vertical line O^ P^, and on this line place the stretchout of the upper half of section B in Fig. 10, as shown by similar letters and figures in Fig. 11. From these points at right anoles to ()v pv di-aw lines equal in length to the side view in Fig. 10. Draw a line from U to T in Fig. 11. Now, measurincr from the line RS in side view in P'ig. 10, take the various distances to points of in- 10 TlNSMlTHOG -iH TmSMITIIIX(; It tersections 4", 8". 1" and 2", and place them in FiV. H on lines having similar numbers, measuriiitr fr(»m the line O^ P^ thus re- sultiiio; in the intersections 1 , 2 . H and 4. ( 'oniuH'tiiitj; theso points by lines as shown, then O^UTP^" will be the half develop- ment of the t()|) of the horizontal prism. The bottom half will he similar without the onenino-. ilavino; described the ])rincij)les relatin^r to j)arallel forms, the next subject will be the princijdes relatino; to taperintr forms. These forms include oidy the solid titrures that have for a base the circle, or any of the rei^ular jiolycrons. also ii<^ures of uiu'iinal sides which can be inscribed in a circle, the lines drawn from the cor- ners of which terminate in an apex, directly over the center of the base. The forms with which the tinsmith has to deal are more frequently frustums of these tiirures. and the method used in developino; these surfaces is simply to develop the surface of the entire cone or ])yramid. and then by simple measurements cut off ]iart of the liouro, leavintr the desired frustum. Thus in the well- known forms of the dipper, coffee ])ot, colander, strainer, wash boM'l, bucket, funnel, measure, pan. etc.. we have the frustums of cones above referred to. In speakinir; here of metal plate articles as ])ortions of cones, it must be remembered that all patterns are of surfaces, and as we are dealing with tinplate, these patterns when formed are not solids, but nierel}^ shells. In works upon Solid Geometry the right cone is delined as a solid with a circidar base, generated by the revolution of a right-antrle triangle about its vertical side called the axis. This is more clearly shown in Fig. 12, in which is shown a right cone, which contains the ])rinci[)les applicable to all frustums of ])yramids and cones. APC represents the elevation of the cone; the horizontal section on the line EC being shown by (tDEF, which is spaced into a number of e(jual ])arts, as shown by the small tigures 1 to 10. As the center or apex of the cone is directly over the center <( of the circle, then the length of each of the lines draM'n from the small h'gures 1 to 10 to the center <( will be equal both in plan and t'levation. Therefore to obtain the t'nveloi)e or development, use AB or AC as radius, and with A in Fig. 18 as center, describe the arc 1- 1'. From 1 draw a line to A and start- ing from the point 1, set off on the arc 1-1' the stretchout or num- 12 TIN SMITHING ber of spaces contained in the circle DEFG in Fig. 12, as sliown by similar figures in Fig. 18. From 1' draw a line to A. Then A- 1-7-1' will be the development of the right cone of Fig. 12. Suppose that a frustum of the cone is desired as shown by HICB, Fig. 12; then the opening at the top will be .equal to the small circle in plan, and the radius for the pattern will be equal to AT. Now usino- A in Fio-. 18 as a center with x\I as radius, describe the arc II I, intersecting the lines 1 A and Al' at II and I respective- ly. Then II — I- 1' -7 — 1 Mill l>e the develo])ment for the frustum of the- cone. When a right cone is cut by a plane passed other than parallel to its base, the method of development is somewhat different. This A Fie?. 13. is exj)lained in connection with Fig. 14, in which A is the right cone, intersected by the plane represented by the line DE, B re])re- sents the plan of the base of the cone, whose circumference is divided into e(]ual spaces. As the intersection of both halves of the cone are symmetrical, it will l)e necessary to divide only half of plan B as shown by the small figures 1 to 7. From these ])oints, erect lines parallel to the axis of the cone, intersecting the l)ase line of the cone. From these points draw lines to apex F, intersecting the line DE as shown. From the intersections thus obtained on the line DE and at ripht anoles to the axis, draw lines as shown, inter- sectinoj the side of the cone FE, Now using F as center and FIl , as a radius, describe the arc 7-7'. From 7 draw a line to F, and TINSMITIIING 13 startino; from the point 7 set off on the arc 7-7', the stretcliout of the circle B as shown by the small figures 7-1-7'. From these points draw radial lines to the center point F, and intersect them by arcs struck from the center F. with radii e(jual to similarly num- bered intersections on the side FIl, and partly shown by ])()ints 7^-1^-7. Trace a line through the]H)ints of intersections thus obtained; then 7"- 7^- 7-7' will be the desired development. These same principles are applicable no matter at what angle the cone is intersected. For the section on the line DE, see the explanation in Mechanical Draw- ing Part III. Fig. 15 shows the principles applicable to the developments of pyramids having a base of any shape. In this case, w^e have a square pyramid, intersected by the line DE. First draw the elevation of the pyramid as shown by ABC and in its proper position the plan view as shown by 1, 2, 3, 4. Draw the two diagonal lines 1-3 and 2-4 intersecting each other at A'. The length of the line AC repre- sents the true length on K'<\ but is not the correct radius with which to strike the development. A true length must be ob- tained on the line A'4 as follows: At right angles to 3-4 from the center A' draw the line A'E' and using A' as center and A'4 as radius, describe the arc 4E' intersecting A'E' at E'. From E' erect the perpendicular line E'l^ intersecting the base line BC ex- tended at 1^. From 1^ draw a straight line to A, which will be the true length on A'4 and the radius with which to strike the de- velopment. (See also Part III, Mechanical Drawing) Now with A as center and A-1^ as radius, describe the arc 1^-3^-1^. Starting Fig. 14. 14 TINSMlTIlI^Ti from 1^' set off the stretchout of 1 - 2 - 3-4- 1 in pkn, as shown by 1^-2^-8^-4^-1^ on the arc 1^-1^ (1^-2^ being equal to 1-2, etc.), and from these points draw lines to the apex A and con- nect points by straioht lines as shown from 1^ to 2\ 2^ to 8^ 8^ to 4^ and 4^ to 1^". Then Al^ 8^ 1^ will be the development of the square j)yramid. To obtain the cut. in the development of the intersected plane DE, which represents respectively the points 3' -4' and l'-2\ draw at right angles to the center line, the lines I)- D" and E-1 , iHtersecting the true length Al^ at 1>" and 1". Using A as center and radii equal to A-D" and A- 1" intersect similarly numbered radial lines in the development. Connect these points as shown TINSMITHING 15 from 1" to 2", 2' to 3", 3" to 4" aiuU" tol". Then 1" -l^-3v_lv_ l"-3" will be the develo])iiient of the intersected square pyramid. To dnuv DE in plan droj) perjjendieuliirs from 1) and E in- tersectinir the diagonal lines in plan at h c and d a. Connect lines as shown at a, h, c and d. To obtain the true section of the plane DE, take the length of DE and place it, as shown in ])lan from /' to /; through /draw the vertical Wwa j,n which is inter- sected by horizontal lines drawn from ])oints . The notches of the allowance 1) and E should be cut at a small angle, as shown. Transferring Patterns. After the ])attern has been de- veloped on manilla })aper, which is generally used in the shop, it is placed on the tin plate and a few weights laid on top of the paper; then with a sharp scratch awl or ])rick punch and hammer, slight prick -punch marks are made, larger dots in- dicating a bend. The paper is then removed and lines scribed on the plate, using the scratch i k-l Fig. 18. awl for marking the straight lines, and a lead pencil for the curved lines. After laps are added as required, it is ready to be cut out with the shears. PRACTICAL PROBLEMS. In ])resenting the twelve problems which follow, particular attention has been given to those problems which arise in shop practice. These problems should be practiced on cheap manilla paper, scaling them to the most convenient size, and then prov- ing them by cutting the patterns from thin card board, and bend- ing or forming up the models. This wnll prove both instructive and interesting. Pail. The first piece of tinware for which the pattern will be developed is that known as the flaring bucket, or pail, shown in Fig. 20. First draw the center line AB, Fig. 21, upon which place the height of the pail, as shown by CD. On either side of the center line place the half diameters CE of the top and DF of the bottom. Then EFFE will be the elevation of the pail. Ex- tend the lines EF until they meet the center line at E, which will Fig. 19. 18 TINSMITHING be the center point with which to describe the pattern. Now, with C as center and C'E as radius, describe the semi-circle CAE, and divide it into equal spaces, as shown. This semi -circle will represent the half sec- tion of the top of the pail. <^i Bi|'r Fig. 21. For the pattern proceed as follows: With B as center and radii equal to BF and BE, describe the arcs Gil and IJ. Draw a line from G to B. JStartino- from the point G lay off on the arc Gil, the stretchout of the semi-circle EAE, as shown by similar figures on Gil. From II draw a line to B, intersecting the arc IJ at J. Then GHJI will be the half pattern for the pail, to which laps must be added for seamintr and wirino- as shown by the dotted lines. TIXSMITIIING 19 Funnel and Spout. In Fio-. 22 is shown a funnel and spout, wliic'h is notliino- luori' than two frustums of coiu^s joined toovther. Fio;. 2H sliows how the jKitteras are developed. In this tiuure the full elevation is drawn, hut in praetiee it is necessary to draw only onedialf of the elevation, as shown on either side o\' the eenter Fig. 22. Fig. 23. line IW. Extend the contour lines until they intersect the center line at (' and A. Now, using A' as a center, with radii eipial to AF' and AE, descrihe the arcs F'F- and E'E-' respectively. On the arc F]'E- lay off twice the number of spaces contained in the semi-circle B, then draw radial lines from E' and E' to A', inter- secting the inner arc at F^'F", which completes the outline for ihe 20 TINSMITIIING pattern. Laps imist be allowed for wiring and seaming. For the pattern for the spout use C as a center, and with radii equal to ( 'G and CP" describe the arcs F'l" and (t'GI On F'F" lay off twice the amount of s])aces contained in the semi-circle D, and draw radial lines from F' and F' to ('. Then F'F'G'G- will be the pat- tern for the spout. The dotted lines show the edges allowed. Hand Scoop. In Fig. 24 is shown a perspective view of a hand scoop, in the development of which the parallel and radial line dev(ilopments are employed. Thus A and B represent inter- sected cylinders, while C represents an intersected right cone. The method of obtaining the patterns for the hand scoop is clearly shown in Fig, 25; these principles are applicable to any form of hand scoop. First draw the side view of the scoop as shown, inline with u'hich place the half section ; divide this into a number of equal spaces as shown by the figures 1 to 7. From these points draw horizontal lines intersectinc; Fig. 24. the curve of the scoop. In line with the back of the scoop draw the vertical line I'-l', upon which ])lace the stretchout of twice the number of spaces contained in the half section, as shown by similar numbers on the stretchout line. From these points on the stretchout line draw horizontal lines, which intersect lines drawn from similarly numbered points on the curve of the scoop parallel to the stretchout line. Trace a line through points thus obtained, which will give the outline for the pattern for the scoop, to which edo-es must be allowed as shown by the dotted line. The pattern for the back of the scoop is simply a flat disc of the required diameter, to which edges for seaming are allowed. When drawing the handle, first locate tho point at which the center line of the handle is to intersect the back of the scoop, as at 2". Through this point, at its proper or re(juired angle, draw the center line 2 2^. Establish the length of the handle, and with any point on the center line as center, draw the section TINSMITH I N(l 21 PATTERN FOR CONICAL BOSS Fig. 25. TINSMITIIING as shown by 1^, 2^3^, and 2^=, and divide tbe circumference into equal spaces, in this case four. (^In practical work it would be better to use more than four). Parallel to the center line and from these four divisions draw lines as shown iutersectinp; the back of the scoop at 1 , 2 and IV. For the ])attern draw any horizontal line in 8. as 1"3"1". upon which place the stretchout of the section of the handle as shown by 1" 2" 8" 2" 1" on the stretchout line. From these points at right antjles to the line of the stretchout, draw lines as shown. Take the various distances measuring from the line }io in side view to points 1\ 2^ and 3\ and place them on lines drawn from similar numbers in 8, measuring from the line 1"3"1". A line traced through these points of intersection will be the pattern for the handle, laps being indicated by dotted lines. To close the top of the handle i/o, a small raised metal button is usually employed, which is double-seamed to the handle. To draw the conical boss in side view, lirst locate the ])oints /' and r, through which draw a line intersecting the center line of the handle at /'. At right angles to Fit?. 26. the center line, draw the line // re])resenting the top opening of the boss. In similar numner, at right angles to the center line, draw a line from e as shown by fv/, intersecting the center line at (/. Now make caces contained in the send circle kcc in side view, as shown by similar letters in diagram u). From these ])oints TINSMITHING 23 draw radial lines to the center/''. Now usino; /* in w as a center describe the arc /'/'. In similar manner, using as radii /r^',f^',/r', pV and fe in side view, and /' in m as center, describe arcs inter- sectinpr radial lines having similar letters as shown. A line traced through points thus obtained forms the pattern for the conical boss. Fig. 27. Drip Pan. Fig. 26 shows a view of a drip pan M'ith beveled sides. The special feature of this pan is that the corners (( and h are folded to give the required bevel and at the same time have the folded metal come directly under the wired edge of the pan. A pan folded in this way gives a water tight joint without any sol- dering. Fig. 27 shows the method of obtaining the pattern when the four sides of the pan have the same bevel. P'irst draw the side elevation having a bevel indicated at <(^1. Now draw ABCD, a rectangle representing the bottom of the pan. Take the distance of the slant 1-2 in elevation and add it to each side of the rect- angular l)ottom as shown by 1', 1", 1'" and 1"". Throuo-h these points draw lines ])arallel to" the sides of the bottom as shown. Now extend the lines of the bottom AB, B(\ CD and DA inter- secting the lines just drawn. Take the pi-ojection of the bevel 24 TINSMITHING a to 1 in side elevation and place it on each corner of the pan, as, for example, from a' to 1'. Draw a line from 1' to B. By pro- ceeding in this manner for all the corners, we will have the bntt miters, if the corners were to be soldered raw edge. AVhere the bevels are equal on all four sides, the angle l^Bl' is bisected as 1" r' I Fig. 28. follows: With B as center and any radius draw the arc ff inter- sectincr the sides of the bottom as shown. Then with a radius greater than one half of ;^'*, with yand /"' respectively as centers, draw arcs which intersect each other at v. Draw a line through the intersection / and corner B, extending it outward toward y. Now with 1' as center, and radius less than one-half of I'-l^, draw arc (l-(\ intersecting the line 1' B at h^ and intersectincr the line Vd' at c Then with h as center and he as radius, intersect the arc vd at e. Draw a line from 1' to e^ intersecting the line /;' at //. From // draw a line to 1^. Transfer this cut to each of the corners, which will complete the pattern desired. Dotted lines indicate the wire allowance. Sometimes a drip pan is required whose ends have a different TIXSMITIII^'G flare from those of the sides, and in one case th^ f^U j to be Wnt toward the end, while it ,„ v Z^^^'^uT "*' "ers be folded towards the side The ,„h„-i!, „ f """ eases, but as the .nethod of app^i :;:';, ::i:;:' '"'•''' '"''' little dirticit, Fi,. ,,S has bee,! 'p-P-ed :h • f i:;; T,: apphcation of these prim-iples. ^i" expl,„„ the First draw the side elevation, showin.r the of the pan as follows: Take the distan e'l 0° e.thei s de by 1 - ,> . t„„„larly take the distance H-i in end eleva ™, a,K, place ,t on the sides of the botton. as shown on eitl!: ^ byJ-i Through the point 2' and 4' draw lines parallel to the e.ds and s.des of the bot.on, as shown, which interseet'lines dr pped from the end and side views respectively. /„■// represent the I Ut m.ters wh,ch should be placed on all corners.' If these ntrs We r BTrrh'^'I'l','': ''"'''' *™'" '' 'o.^---™'^ -M «c „/, then use „ and /, as centers and ol>tain the intersection c through whtch draw the line ,/. Now assnn.e that the folded cor ner ,s to be turned towards the end view as shown by rS. Usin. /' as a center draw the arc (J. Then with I as ceLr and "a^ rad.us, ,n ersect the arc (; at «. Draw a line from /, through I meetmg the I,ne ,/at f, and draw a line fron, f to // .■ " t\i1'"^, corner were turned towards the side as shown by ' -~ m the s>de v,ew, b.sect the angle rV. as before, and use ., as I center and proceed as already explained. Note the difference i! the two corners. The only point to bear in , d is. that w^ , the eo^er ts to be folded towards the end, transfer the ancle h end n„ter; whde if the corner is to be turned towards^tL side rans er the angle of the side miter. If the corners were t. be folded towarf the ends of the pan, the cut shown in the right-hand orner won d be used on all four corners, while if the corners w'e ririitz" "^ ^"^^' ''' '•"' ''- °" '"« -^^-^-"^ -: Tea Pot. In Fig. 2!l is shown the well-known form of the tea or coffee pot, for which a short n.ethod of developing the pat- 26 TINSMITHING Fiff. 29. tern is shown in Fig. 30. This is one of the many cases where a short rule can be used to advantage over the geometrical method. While it is often advisable to use the true geometrical rule, the difference between that and the method here shown is hardly noticeable in practice. Of course, if the body A and spout B were larger than the ordinary tea pots in use, it would be necessary to use the true geometrical rule, which is thoroughly ex])lained for Plates I, II and III. The pattern for the body of the tea pot will not be shown, only the short rule for obtaining the opening in the body to admit the joining of the spout. The method of obtaining the pattern for the body is similar to the flaring vessels shown in previous problems. First draw the elevation of the body of the tea pot as shown at A. Assume the point a on the body and draw the center line of the spout at its proper angle as shown by 2/^. Establish the point 3 of the bottom of the spout against the body, also the point 3^ at the top and draw a line from 3 through 3^ intersecting the center line at h. At right angles to the center line and from 3 draw the line 3-1 and make el equal to (-3. From 1 draw a line to the center point and from 3^ draw a horizontal line until it intersects the opposite side of the spout at 1". Then l'-l"-3^-3 will be the side view of the spout. Now with c as a center draw the half section 1-2-3 and divide it into equal spaces; in this case but two (in practical work more spaces should be employed). From these points and at ricrht angles to 1 - 3 draw lines intersectincr the base of the spout as shown, and draw lines from these points to the center h. Thus line \h intersects the body at 1' and the top of the spout at 1"; line 2/^ intersects the body at a and the top of the spout as shown, while line %h cuts at 3 and the top of spout at 3^. From these intersections at right angles to the center line ((f>^ draw lines intersecting the side of the spout at 3, 2", 1^ at the bottorn and 1^, 2^, 3^^ at the top. Now with h as center and h^ as radius, describe the arc 3' - 3" upon which place the stretchout of twice TlNSMITIllNG 27 the number of spaces contained in the half section 1-2-3, as shown by similar tioriires on 8" -8"; from these points draw radial lines to the center /». and intersect them l)v arcs drawn with h as a center and radii eipial to the intersections contained on the side of the spout 3-8^. To form the pattern, trace a line through points thus obtained and make the necessary allowance for edues. It should be understood that in thus developing the spout, the fact that the spout intersects a round surface has not been considered; it was assumed to intersect a plane surface. As already stated the difference in the pattern is so slight that it will not be noticeable 28 TINiSMITIlING in practice. Had we developed the pattern according to the true* geometrical rule, it would ])resent a problem of two cones of unequal diameter intersecting each other, at other than at ri upon mIucIi lay off the stretchout of E as shown by similar figures. Through these points draw lines which intersect with lines drawn from similar intersections in the curve D |)arallel to ah. Trace a line through the points thus obtained as shown at F. Foot Bath. In Fig. 32 is shown an oval foot bath; the princi- ples used in obtaining the pattern of which are apjilicable to any Fig. 31. TINSAIlTlllNG 29 form of tlarino- vessels of whicli the section is elli])tic'al or struck from more than two centers. In this connection it may be well to ex- plain how to construct an ellipse, so that a set of centers can be obtained with \vhich to strike the arcs desired. Flo-. 88 shows the method of drawing an a])proximate ellipse, if the dimensions are oriven. Let AB represent the lenoth of the foot bath and ('D its width. On BA measure BE e(pial to CD. JVow divide the dis- tance EA into three e(pial parts as shown by 1 and 2. Take two of these ])arts as a radius, or E2, and with () as center, describe arcs in- tersectino- the line BA at X and X'. Then with XX' as a radius and using X and X' as centers describe arcs intersecting each other at C and D. Draw lines from C to X and X' and extend them toward F and G respectively. Similarly from D draw lines through X and X', extending them towards I and II respectively. Now with X and X' as centers, and XA and X'B as radii describe arcs intersectino- the lines ID, FC, GC and HI) at J, K, L and M, respectively. In similar manner A R B Fis. 32. Fiff. 33 with D and C as centers and DC and CD as radii describe arcs which must meet the arcs already drawn at J, M, L and K, respect- ively, forming an ap])roxinuite elli])se. In Fig. 84 let AIX'D repre- sent the side elevation of the pan, whose vertical height is equal to lie. In precisely the same nuinnei- as described in Fig. 88 draw 80 TI^'iSMITlllNG the plan as showu, in correct relation to the elevation, letting EFGIl be the plan of the top of the pan, and JKLI the plan of the bottom, struck from the centers, 0,M,P and K. The next step is to obtain the radii with which to strike the ])attern. Draw a horizontal line RE in Fig. 85 equal in length to NE in plan in Fig 84. Take the vertical height RC in elevation, and place it as shown by RC in Fig. 35 on a line drawn at right angles to RE. Parallel to RE and from the point C, draw the line CJ equal to NJ in Fig. 84. Fig. 35. Now draw a line from Eto J in Ficr. 85, extendinirit until it meets the line RC produced. Then OJ and OE wall be the radii with which to make the pattern for that part of the pan or foot bath shown in plan in Fig. 84 bj EFKJ and GIIIL. To obtain the I'adii with which to strike the smaller curves in plan, place distances PF and PK on the lines RE and CJ in Fig. 85 as shown by RF and C^Iv. Draw a line from F through K un- til it meets the line RO at P. Then PK and PF will be the radii with which to strike the pattern, for that part shown in plan in Fig. 84 by KFGL and IHEJ. Now divide the curve from G to II and II to E (Fig. 84) into a number of etpial spaces. To describe the pattern draw any vertical line E'O^ {^^'^^' '■^'^) ^'^^ with O' as center and radii eipial to OJ and OE in the diagram Y, describe the arcs J'K' and E'F^ as shown. On the arc E'F' lay off the stretch- TINSMITHING 31 out of GH in plan in Fig. 34 as shown by similar figures in Fig. 35. From the point 6 on the arc E'F^ draw a line to O' intersect- ing the curve J'K'. Now with PF in diagram Y as radius and F' as a center describe an arc intersecting the line F'O' at P'. Then using P' as a center and witli radii equal to P'lv' and P'P'' describe the arcs K'L' and ¥W as shown. On the arc F'G' starting from point 6 lay off the stretchout of HE, Fig. 34. From 11 draw a line to P* intersecting the arc K'L' at L'. Then E'F'G'L'K'J^ will be the Fig. 36. half pattern, the allowance for wiring and seaming being shown by the dotted lines. Should the article be desired in four sections, two pieces of F^K'L'G^ would be. required. The pattern for the bottom of the pan is shown by the inner elli])se in Fig. 34 to which of course edges must be allowed for double seaming. Wash Boiler. In Fig. 36 is shown a perspective view of a wash boiler to which little attention need be given, except to the raised cover. First draw the plan of the cover B, Fig. 37, which shows straight sides with semi-circular ends. Inline with the plan draw the elevation A, giving the required rise as at C. Let C rep- resent the apex in elevation, and C the apex in plan. As both 32 TINSMITHING halves of the cover are symmetrical, the pattern will be developed for one half only. Divide the semi-circle 1-3-1 into a number of equal spaces as shown by the small licrures 1. 2, 3, 2 and 1. From these points draw radial lines to the apex C, and throuoh C draw the perpendicular aa. C3" in elevation represents the true length of C'3 in plan, and to obtain the true length of (''2, C"l and CV^ it will be necessary to construct a diao-ram of triangles as follows: AVith (" as center, and CV/, C'l and C''3 as radii, descril)e arcs intersecting the center line in plan at a\ 1' and 2'. From these points at right angle to 3(" erect lines inter- secting the base line of the elevation at a'\ 1", 2" and 3", from which draw lines to the apex C, as shown. Xow, with radii equal to 03", C2", 01" and O'/", and 0' as center describe arcs 3^,2^2^, 1^1^ and a^(t^. From 0" erect the perpendicu- lar intersecting the arc 3^ at 3^. Now set the dividers equal to the spaces 3 to 2 to 1 to a in plan, and starting from 3^^ step off to similar numbered arcs, thus obtainino; the intersections oxjx^^x. from o'^ draw lines to C^, and trace a line a^^^a^ to get the half pattern for the cover. Allow edges for seam in o-. The body of the boiler re(]uires no ])attern, as that is simply the recjuired height, by the stretchout of the outline shown in ]ilan. The handles shown on the body and cover in Fig. 36 are plain strips of metal to which wired or hem edo-es have been allowed. Measure. Pig. 38 shows a flaring-lipped measure with han- dle attached. Care should be taken in laying out the patterns for these measures, that when the measure is made uj) it will hold a given quantity. While there are various proportions used in making up the size of the measure, the following table gives good proportions : Fi"-. 38. Quantity. Bottom Diameter in inches. Top Diameter in inches. Height. 1 Gill. 1^ Pint. 1 Pint. 1 Quart. i^jGallon. 1 Gallon. 2.06 2.60 3.27 4.12 5.18 6.55 1.37 1.75 2.18 2.75 3.45 4.35 3.10 3. -89 4.90 6.18 7.78 9.80 TINSMITIIING 33 Fig. 39 shows the method of laying out the pattern for the measure and lip. . First draw the elevation A to the desired size Fiff. 39. and assume the flare of the lip B, as shown by (I.. From ' draw a line through 7" to e which is a chosen point, and draw a Ime from G to (I. Draw the handle C of the desired shape. Now extend contour lines of the measure until they intersect at a, and draw 34 TTNSMITIimG the half section of the bottom of the measure as shown at J); divide this semi-circle into equal parts as shows. Now, with a as a center, and a 7 and «7" as radii, describe the arcs as shown. From any point (as 1') draw a radial line to a, and starting at 1' set off the number of spaces contained in the half section D, as shown by the small figures 1' to 7'. From 7' draw a radial line to a. Allow edges for wiring and seaming. E represents the half pattern for the body of the measure. We find that lip B is simply an intersected frustum of a right cone, w^hich can be developed as shown in the pattern for conical boss of Fig. 25. There is, however, a shorter method which serves the purpose just as well; this is shown at F, Fig. 39. First draw the half sec- tion of the bottom of the lip, which will also be the half section of the top of the measure, as shown by the figures 1" to 7". Now, with radii equal to J-1", or h-l" and h' in F as center, describe the arc 7^7^. From b' drop a vertical line intersecting the arc at 1^. Starting from the point 1^, set off the spaces contained in the half section l"-4"-7", as shown by the figures 1^ to 7^. From ?/ draw lines through the intersections 7^7^, extendino; them as shown. Now take the distance from 1" to d of the front of the lip and place it as shown by l^d' in F. In similar manner take the dis- tance from 7" to c of the back of the lip and place it as shown in F from 7^ to c' on both sides. Draw a line from c' to d', and bi- sect it to obtain the center e. From e, at right angles to c'd', draw a line" intersecting the line Jj'd' aty. Then using /as center, with radius equal to /?/', draw the arc c'd'c', as shown. Adding laps for seaming and wiring wdll complete the pattern for the lips. The pattern for the handle and grasp C is obtained as shown in Figs. 30 and 31. Scale Scoop. Fig. 40 shows a scale scoop, wired along the top edges and soldered or seamed in the center. The pattern is made as shown in Fig. 41. First draw the elevation of the scoop as shown by ABCD. (In practice the half elevation, BDC, is all that is necessary.) At right angles to BD and from the point C, draw the indefinite straight line CE, on w^hich a true section is to be drawn. Therefore, at right angles to CE, from points C and E, draw the lines CC and EE'. From E' erect a perpendicular as E'C, on which at a convenient point locate the center F; with TINSMITHING 35 FE' as radius, describe the arc IIE'I. Then IIE'I will be the true section on CE in elevation. Divide the section into a number of equal parts as shown by the figures 1 to 7; through these points, parallel to the line of the scale BD, draw lines intersecting B(J and CD as showUo At rio;ht ang-les to BD draw the stretchout line 1-7 and place upon it the stretch- out of the section as shown by similar figures. At right angles to 1 - 7 draw lines which intersect lines drawn at right angles to BD, from intersections on BC and DC having similar numbers. Trace a line through these Fig. 40. Fifif. 41. points and thus obtain the desired pattern, shows the lap and wire allowance. The dotted outline 86 TlNSMITHmG In Fig. 42 is shown a perspective view of a dust pan witli»a tapering handle passing through the back of the pan and soldered to the bottom. The lirst step is to draw the plan and elevation which is shown in Fig. 43. Let ABC be the side view of the pan. Directly below it, in its proper position, draw the bottom DEFG. From the point C in elevation draw a line d'd indefinitely. Now bisect the anMe EFG. Through c and F draw the line ccL in- tersecting the line dd' at d. From d draw a line to G. In the same manner obtain E^/'D on the opposite side, which PATTERN FOR RAN t y^. -^ Fig. 42. Fiff. 44. will complete the plan view of the pan. Now locate the point A in side view, through which the center line of the handle shall pass, and draw the line m. Through m, the end of the handle, draw the line 7io at right angles to Im^ and assume o the half width at the top and j the point where the contour line of the handle shall meet the back of the pan, and draw a line from o through y, inter- secting the center line Ini at /. Make inn equal to mo and draw a line from n to /, intersecting the back of the pan at x^ Through h at right angles to the center line draw ij'\ giving the diameter of the handle at that point to be used later. This coni- ])letes the elevation of the handle; the plan view is shown by dotted lines and similar letters, but is not required in developing the pattern. For the pattern of the pan proceed as is shown in Fig. 44, in which DEFG is a reproduction of similar letters of Fig. 43. Take the distance of 130 in side view, Fig. 43, and place it as shown by TINSMITHING 37 B(^ in Ficr. 44 and throutrli C draw a line parallel to EF as shown. At right anoles to and from EF draw Er and ¥/', then take the VIEW distance from r to (7 In plan in Fig. 43 and place it as shown from /■ to d on both sides in Fig. 44. Draw the lines dF and r/E. Now using E as D center, and radius equal to Er/ des- cribe the arc sf. Then with td as radius and s as cen- ter, intersect the arc st at d'. Draw a line from d' to D. Insimilarman- ner obtain ^'G on g the opposite side, which will com- plete the pattern for the pan. Allow laps for wiring and edging. The opening in the back of the pan to allow the handle to pass through is obtain- ed by first drawing a center line ef, then take the dis- tances from / to k and h to x in Fig 43, noting tha<" j comes directly on the bend B, and place it in Fig. 44 on the line ef Fig. 43. Fisr. 45. 38 TINSMITHING from j to ?i to 'X, placing,; on the bend as shown. Now take the dis- tance from h to i or h to j" in side view in Fig. 43 and place it 14 Fig. 44 from h to i on either side; on a line drawn through the points jid draw an ellipse shown. Fig. 45 shows the method of drawing the pattern for the tapering handle. From the ligiire we lind that we have a frustum of a right cone. To illustrate each step the handle has been slightly enlarged, n, o,^;, J' represents 71, oJJ' in Fig. 43. Draw the half section in Fig. 45 as shown, and divide it into equal parts; drop perpendiculars as shown to the line rto, and from these points draw lines to the apex 7^, which is obtained by extending the lines nj' and oj until they Fig. 47. Fig. 46. meet at h. Where the radial lines intersect the line jf draw lines at right angles to the center line 3b, intersectincr the side of the handle o h at 1', 2', 3', 4' and 5'. Now with J as a center and ho as a radius, describe the arc 1-1, upon w^hich place twice the number of spaces contained in the half section a. From these points on 1-1 draw radial lines to h and cut them with arcs struck from h as center and radii equal to }A\ h1\ h^\ JA' and hi)'. Trace a line through points thus obtained to complete the pattern. Colander. Fig. 46 shows another well-known form of tin ware, known as a colander. The top and bottom are wired and the foot and body seamed together, the handles of tinned malleable iron being riveted to the body. In Fig. 47 is shown how to lay out the patterns. Draw the elevation of the body A and foot B and extend the sides of the body and foot until they meet respec- TINSMITHING 39 tively at C and 1) on the center line aJ). Draw the liaif section on the line 1-7 and divide it into equal parts as shown. For the body use C as a center and describe the arcs shown, laying off the stretchout on the lower arc, allowing edges in the usual manner. Then E will be the half pattern for the body. In the usual man- ner obtain the pattern for the foot shown at F, the pattern being struck from D' as center, with radii obtained from the elevation Dl and Dc. PLATES. In preparing the plates, the student should practice on other paper, and then send finished drawings for examination. The plates of this instruction paper should be laid out in the same manner and of the same size as the plates in Mechanical Drawincr Parts I, II and III. PLATE I. On this plate, the intersection between two right cones is shown. This problem arises in the manufacture of tinware in such instances as the intersections between the spout and body as in a teapot, watering pot, kerosene-oil can, dipper handle and body, and other articles. It is one of the most complicated prob- lems arising in tinsmith work. The problem should be drawn in the center of the sheet making the diameter of the base A 4 inches and the height of the cone B 4i inches. The distance from X to Y should be 1 inch. From the point F measure down on the side of the cone a distance of 3|^ inches and locate the point C, from which draw the axis of the smaller cone at an angle of 45° to the axis of the larger cone. From C measure on CL 1§ inches locating the point 6'; through this point, at right angles to the axis, draw ED ecpial to \\ inches. From the point 4' on the base of the cone, measure up on the side of the cone a distance of i inch as indicated by o, and draw a line from o to E, extending it, until it intersects the axis LC at L. From L draw a line through D extending it until it intersects the larger cone at E will represent the outline of the frustum of the smaller cone in elevation. The next step is to obtain the line of intersection between the two cones, but before this can be accomplished, horizontal 40 TlJil SMITHING sections must be made through various planes of the smaller cone cuttincf into the larcrer. As the intersection of each half of the in o smaller cone with the larger one is symetrical, and as the small cone will not intersect the larger one to a depth greater than the point 1 in plan, divide only one-quarter of the plan into a number of equal spaces as shown by figures 1 to 4; from these points draw radial lines to the center F' as shown. Also from points 1, 2, 3 and 4 erect vertical lines intersecting the base of the cone at 1', 2', 3' and 4' respectively, from which points draw radial lines to the apex F. Now with 6' on the line ED as a center describe the circle shown, which represents the true section on ED. Divide each semi-circle into the same number of divisions as shown by the small figures D, 5, 6, 7, and E on either side. From these points at right angles to ED draw lines intersecting the center line ED at 5 , 6' and 7'. From the apex L draw lines through the intersection 5', 6 and 7', and extend them until they intersect the axis of the large cone at e and the base line at h and n. The student may naturally ask why the radial lines in the small cone are drawn to these points. As it is not known how far the smaller cone will intersect the larger one, we obtain such sections on the planes just drawn, as -we think will be required to determine the depth of the intersection. Thus the radial line drawn through 5' intersects the radial lines through 4', 8', 2' and 1' in the larger cone, at Z*, c, d and e respectively. The radial line through 6' intersects radial lines in the larger cone Sii f,h, i,j and the base line at k, while the radial line drawn through the point 7', intersects the radial lines of the larger cone at I and m and the base at ti. We know that the line Da and E^ of the smaller cone intersect the larger cone at points a and o re- spectively, and determine the true points of intersection ; these are shown in plan by a' and o', and therefore no horizontal sections are required on these two planes. For the horizontal section on the plane h e,- drop vertical lines from the intersections 7j, e and cl on the radial lines, intersecting radial lines having similar num- bers in plan as shown by l\ c' and d' . To obtain the point of in- tersection in plan of e in elevation, draw from the point c a hori- zontal line intersecting the side of the cone at e^^ from which point drop a perpendicuUr line intersecting the center line in plan at e^. TIN SMITH I IS' G 41 Then using F^e^ as radius, deserilte an arc intersecting the radial line 1 at e'. Through the points c', in elevation onto the line E^ F^ in plan. Through the points thus obtained, draw the curved line «', S'^, 6-"^, 7^, <>' which will represent the plan view of one-half of the inter- section between the two cones, the other half being similar. Now from the intersections 5'^, ^^ and 7-'^ on the section lines J' 6'',y' /■' and 7' 7?' respectively, erect perpendicular lines inter- secting similar section lines in elevation b e^fk and In q,s shown respectively by points 5°, 6° and 7°. A curved line traced through «, 5°, 6°, 7° and o will represent the line of intersection between the two cones in elevation. At right angles to the axis of the smaller cone and from the inter- sections «, 5^, 6'' and 7° draw lines intersecting the side of the cone E o at D'^ 5^ 6^ and 7^. For the pattern of the smaller cone proceed as is shown in the following plate: PLATE III. On this plate the two patterns should be placed in the center of the sheet. Take the radius of LD in Plate II and with L in Fig. 1 of Plate III as center describe the arc DD. From L drop a vertical line as shown by L E*^. Upon the arc DD meas- uring from either side of the point E, lay off the stretchout of the semi-circle E, 7, 6, 5, D in Plate Has shown by similar letters and figures on DD in Fig. 1 Plate III. From the apex L and through these points draw radial lines as shown and intersect them by arcs whose radii are equal to L D^, L S'^, L 6^, L 7^ and L E-^ in Plate II, as shown by similar letters and figures in Plate III. Trace a line through points thus obtained, and D, E, D, D^, E^, D-^, D will be the pattern for the small cone. As the pattern for the larger cone is obtained in the usual manner, we will only show how to obtain the opening to be cut into one side of the larger TINSMITHING 43 cone to admit the intersection of the smaller. We must now again refer to Plate 11. From the intersections a, 5°, 6^, 7", and o in elevation draw lines at right angles to the line of the axis, intersecting the side of the cone at 4^, 5^, G^^, 7^ and 4^. Also in addition to the spaces 1, 2, 3 and 4 'in the plan view, it wnll be necessary to obtain the points of intersection on the base line in plan, where the radial lines would intersect drawn from the apex F^ through the points of intersections between the tw^o cones. This is accomplished by drawing lines from F^ through 5^ 6^ and 7^ until they intersect the base line in plan at 5, and 7. All these points form the basis with which to develop the pattern shown in Fig. 2 of Plate III, in which draw the vertical line F 4, and with F as a center and radii equal to FY, and F P in Plate II draw the arcs YY and PP in Fig. 2 of Plate III as shown. Now starting from the point 4 on the arc PP on either side, lay ofif the stretchout of 1, 6, 5, 7 and 4 in plan in Plate II as shown by similar numbers in Fig. 2 of Plate III. From the points 6, 5, 7 and 4 on either side draw radial lines to the apex F, which will be used to obtain the pattern for the opening. Now with F as center and radii equal to F 4^, F 5^, F 6^^, F 7^ and F 4^ in Plate II, describe arcs intersecting radial lines having similar numbers in Fig. 2 of Plate III as shown by intersections having similar numbers. A line traced through these points will be the required opening to be cut out of the pattern of the larger cone, one-half of which is shown by drawing radial lines from the points 1 and 1 to the apex F. PLATE IV. In drawing this plate, the same size paper and border lines should be used as for the preceding plates. The subject for this plate is an oil tank resting on inclined wooden racks. The prob- lem involves patterns in parallel and radial-line developments. The drawing can be made to any convenient scale until the prob- lems are understood and should be proven by paste-board models. It should be drawn to a convenient scale, placing the pattern to fill the sheet and make a neat appearance. The section, stretch- out lines, construction lines, and developments should be num- bered or lettered, so as to prove the thorough understanding of the problem, and then sent to the School for correction. The var- 44 TINSMITHING ious parts in the elevation and patterns have similar letters. A represents the tank body, the pattern being shown by A^, B shows the bottom, the pattern being shown by B^ The cone top and inlet D are shown developed by (J^ and D^ respectively, while the outlet E and opening F in elevation are shown developed by E^ and F^ in the bottom B^ EXAMINATION PLATES. Drawing Plates I to IV inclusive constitute the examination for this Instruction Paper. The student should draw these plates in ink and send them to the School for correction and criticism. The construction lines and points should be clearly shown. The date, student's name and address, and plate number should be lettered on each plate in Gothic capitals. Table of standard or regular tin plates. Size and Kind of Plates, Number and Weight of Sheets in a Box, and Wire Quage Thickness, of Every Kind and Size. Size. Grade. • Sheets Pounds Wire ill Box. in Box. Guage. 10x10 IC 225 80 29 u IX 225 100 27 u IXX 225 115 26 (( IXXX 225 130 25 (( IXXXX 225 145 24 1-2 10x14 IC 225 112 29 a IX 225 140 27 (( IXX 225 161 26 a IXXX 225 182 25 a IXXXX 225 203 24 1-2 u IXXXXX 225 224 24 C( IXXXXXX 225 245 23 1-2 10x20 IC 225 160 29 (k IX 225 200 27 11x11 IC 225 95 29 a IX 225 121 27 a IXX 225 139 26 (( IXXX 225 157 25 u IXXXX 225 175 24 1-2 11x15 SDC 200 168 26 u SDX 200 189 25 u SDXX 200 210 24 12 11x15 SDXXX 200 230 24 12x12 IC 225 112 29 a IX 225 140 27 (( IXX 225 161 20 ii IXXX 225 182 25 ■ (( IXXXX 225 203 24 1-2 « IXXXXX 225 224 24 a IXXXXXX 225 245 23 1-2 12 1-2x17 DC 100 98 28 a DX 100 126 26 (( DXX 100 147 24 (( DXXX 100 168 23 (( DXXXX 100 189 22 u DXXXXX 100 210 21 13x13 IC 225 135 29 a IX 225 169 27 u IXX 225 194 26 « IXXX 225 220 25 u IXXXX 225 245 24 1-2 13x17 IXX 225 254 26 13x18 IX 225 234 27 li IXX 225 269 26 14x14 IC 225 157 29 (C IX 225 196 27