Short Method of Pattern Development

Pu'blished by

THE AMERICAN ROLLING MILL COMPANY MIDDLETOWN. OHIO

Short Method of PATTERN DEVELOPMENT

PRICE THIRTY CENTS

COPYRIGHT 1940 T HE A MERI CA N ROLLING MILL COMPA NY

SHORT METHOD OF PAT T ERN DEVELOPMENT

ARMCO Sheet Metal Products

FOR

The Building Industry

Galvanized ARMCO Ingot Iron Galvanized ARMCO Ingot Iron is a highly-refined metal

especially noted for its easy-working qualities and long life.

Strong yet ductile, it solders easily and can be worked on

ordinary shop equipment with both speed and accuracy. Once

you've mastered the Short Method of Pattern Development

you'll be surprised how quickly you can transform fiat, accur

ately-sheared ARMCO Ingot Iron sheets into neat craftsman

like fittings. The familiar blue ARMCO triangle trademark

stenciled three times on every sheet assures quick, positive

identification.

USES: AIR DUCT S • CORNICES • MARQUISES • TANKS •

GUTT ERS • DOWNSPOUTS • FLASHING • ROOFING • SIDIN G

Galvanized ARMCO PAINTGRIP ARM CO P AINT GRIP is an improved galvanized sheet especially

Bonderized at the mill to take and hol d paint. Weathering and

acid etching are unnecessary when it is used. The work can

be painted as soon as it is up. P AINT GRIP sheets are produced

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S H O R T M E T H OD O F PATT E R N DEVE L OPM E N T

III a base of easy-working ARMCO Ingot Iron, or if desired,

plain or copper-bearing steel made by ARMCO.

USE S: AIR DUCTS • FURNACE CASINGS • MARQUISES •

CORNICES • GU TTERS • DOWNSPOUTS • FLASHING • ROOFING

SIDING • SIGNS • STORE FRONTS

ARMCO Stainless Steel

ARMCO Stainless Steel ranks high in surface finish, corrosion

resistance, workability and tensile strength. You'll find it ideal

for applications where durability, attractiveness or utmost

sanitation are important. ARM CO Stainless Steel is produced

in different types and surface finishes, some polished, some not.

USE S: GU TTERS • DOWNSPOUTS • FLASHING • ORNAMENTAL

WORK • MARQUISES • SIGNS • EXTERIOR TRIM • STORE

FRONTS • KITCHEN EQU IPMENT • KICK PLATES

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H O R T M E T H O D O F P AT T E R N D E V E L O P M E N T

INTRODUCTIO'N A S an exclu ive service to heet metal craft men, The

American Rol ling Mill ompany pre ents here in com

plete form for the first time A Short Method of PatteTn Development. This unique, time-saving layout method wil l be welcomed by heet metal worker everywhere. It fol lows ARMCO's other popular service , Fundamentals of Pattern Dl'afting and Blue P'rint Reading and Simplified 1J.·tem of Co·t A ccounting.

A few old timer may recognize the hort Method by another name-the "rollation" method of layout. For year it was an important "trick of the trade" passed only from father to on or from shop-owner to apprentice. Now, through the able assistance of Ralph W. Poe, sheet metal contractor of Canton, Illinois, this "short cut" comes to you in textbook form.

Layout men wil l be pleased to find the Short Method requires a knowledge of neither geometry, draftsmanship nor mathe

matics. Al l the craftsman needs to know is the size and shape of the fitting he wishes to make. Patterns for even the mo t intricate form can be developed in a surprisingly hort time.

hould you find difficulty with any pha e of the Short Method, or if que tion arise which you would like to have an wered, write The Market Development Division, The American

Rolling Mill Company, Middletov. n, hio.

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S H O R T M E T H O D O F P A T T E R N D E V E L O P M E N T

C H A PT E R O N E

Two Funnel Patterns

THE fu ndamentals of the hort Method of Pattern Development are founded upon the basic pri nci ple of geometry

a they relate to the surfaces of solids. Yet i nterestingly, the Short Method requires neither complicated i nstruments nor an exhaustive knowledge of mathematics. Mastering this method wi l l make it possible for you to lay out-with comparative ease-even complicated and odd- haped piece . You wil l sa ve t ime on every pattern .

Although the Short Method of Pattern Development is not intended to replace methods now used in factory drafting rooms, it is by no means a "hit or miss" formu la. It is based upon ound geometrical principles which fortunately do not ha ve to be understood to be applied.

Described and i l lustrated in this first chapter are two comparatively s imple funnel forms : the conventional shape and another with one side at a right angle to the l arge end . However, before attempti ng even such simple patterns as funnels, it is i mperative that the basic principles of the method be understood. Remember first, all heet metal forms

View I showing pattern for conventional shape funnel.

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S H O R T M E T HO D O F P A TTE R N D E VELOP M E N T

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PLATE ONE ' SHORT METHOD PATTERN DEVELOPMENT ' RALPH W. POL

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PLATE TWO ' SHORT METHOD PATTERN DEVELOPMENT • """PH w·PO[

HORT METHOD OF PATTERN DEVELOPMENT

may be con idered merely as the u rfaces of ol id . A funnel, for example, is the out. ide of a cone, and a pipe the urface of a cyl inder.

If either or the e forms is cut th rough the center, i t is immediately apparent that rolli ng the hal f over a piece of paper, and tracing the path of the edge , will produce an accurate pattern for half the object.

At the extreme left of View I is half a wooden cone. Two of these would form a solid cone identical to the funnel appearing at the extreme right of the arne view.

Roll ing the wooden form on a piece of paper and tracing the path of the edges would produce a pattern for half the funnel. Two of these "half pattern " placed together, as shown in the foreground, would make a pattern for the complete funnel.

In the center of the first view is a metal form whi ch hereafter wil l be cal led a "template." It was used to draw the pattern appearing di rectly below it. The solid lines on the one

ide were made by roll ing the template over the paper. The other half of the pattern, which is dotted, wa made by turning the first pattern over and matching the two straight ides .

No dimen ion have been indicated, a the only knowledge

View II showing template, pattern and fun nel.

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SH O R T M E T H O D O F P A T T E R N D E VE L O P M E N T

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PLATE THREE ' SHORT METHOD PATTERN DEVELOPMENT ' RAVH w. po�

View III showing pattern for the spout and the completed fun nel.

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necessary to the pattern maker i the size and shape of the piece he wishes to make.

At the left in Plate One i a cross section of the funnel B, with circles above and below corresponding to the diameters of the small and large ends, A and C.

The center drawing in Plate One shows how the template is laid out preparatory to rolling the pattern. The cross section of the funnel, it can be een, has been reproduced actual size on a piece of sheet metal with half the small and large circles A' and C' added at each end.

The template now is complete except for bending the half circles at the top and bottom, A" and C", at right angles to area B", representing the cross section. At the extreme right of Plate One is a side view of the finished template, with the ends bent at right angles.

For the template to produce a perfect pattern, it is important that the angles be accurate. It is recommended that templates for larger pattern be strengthened with metal braces, or with blocks of wood.

The pattern itself is produced by chalking the edges of the template and then rolling it over a sheet of soft, black building paper. * A distinct white line is the result. View I shows the template, the chalk pattern, and the completed funnel.

Any experienced sheet metal worker will understand, of course, that some allowance must be made for seams. The pattern transferred from the template represents only the actual surface of the object, in this case a funnel.

View II shows a template, pattern and completed funnel, where one side is at a right angle to the large end. This pattern, as with the one for the conventional shaped funnel, was made by rolling the chalked template over a piece of black building paper.

Plate Two shows the steps necessary in laying out the template. At the extreme left is a cross section, B, with circles at the top and bottom, A and C, corresponding to the size of the funnel ends.

In the center of Plate Two the cross section is laid out actual size on a piece of sheet metal, adding half of each circle A' and C' for the two ends. At the extreme right is a side view of the finished template with ends A" and C" bent at right angles to area B", the cross section.

The complete template appears at the left in View II. Below

• An alternate method is to dip the edges of the template in oil and then roll it over paper. The lines are transferred readily.

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S H O R T M E T H O D O F P A T T E R N D E V E LO P M E N T

it i een the pattern which was produced by chalking the edges, and rolling the template over black paper.

Here again, it should be noted that the solid line was made by rolling the chalked template and the dotted l ine drawn by reversing the solid l i nes.

Only a tapered cyl inder, to be soldered on the mall ends, is needed to complete the funnel . While any competent workman could guess at the size and pattern for thi part of the j ob, it would be well to lay it out with the arne hort Method principles if accuracy is desired.

Plate Three i llustrates steps i n layi ng out the tapered cyl inder : (1) Finding the size of the cross section ; ( 2 ) determining the diameters of the circles at either end ; and (3) adding half of each c ircle to the ends of the cro s section. The center drawing shows the template laid out, while the right show a side view of the fi n ished template, with the half c ircles bent at right angles.

At the left of View I I I is hown the finished template with the pattern below. The center show the graduated cyl inder after it has been cut and joined together. Again, bear in mind that the pattern does not allow for seams. At the right i the completed funnel, with tapered cylinder attached.

If there is any question whatever in the mind of the Short Method tudent on the material presented in thi article, he would do well to experiment with the two funnel models, going through the entire process from laying out the template to cutting the finished pattern and formi ng the pieces.

This cannot be too strongly emphasized, as other forms to be described i n the chapters that follow are based on the arne fundamental principles : consideTing each piece a the sUTface of a olid, and making a metal fOTm to duplicate the exact outline of the hape de i1"ed.

C H A PT E R TW O

Square To Round Transition

H ERE we are concerned with one of the mo t common littings encountered i n warm air heating work, restaurant

installations, and in making special funnels for oil tation and industrial plants. It is the "Uni form quare to Round Tran-

ition," a funnel-type fitting in which the large and small end are of d ifferent shapes.

The i llustr�ted transition is one with the large end square and the small end rou nd. From the shape of the pattern i n View I V, i t may b e seen that the fitting would be practically

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View IV showing round to squore transition.

impossible to lay out by the "trial and error" method. And it would be plenty hard by triangulation. But following the Short Method, it's a simple task.

Plate Four shows the steps necessary to make a template for rolling the pattern . No dimensions are given, as the process is the same regardless of the size of either the large or small ends, or the height.

At the left of Plate Four is a cross section of the transition B in which the lower line indicates the size of the large end. The upper line indicates the diameter of the small end.

The exact diameter of the small end i seen at A, the cross section at B, and the shape of the large end appears at C. I n the center of the plate, cross section B' is laid out (on heet metal, in practice ) with half of ection A' and C' added above and below. When you have progre sed to thi point, your plate i ready to cut.

At the extreme right of Plate Four i an "edge" view with half circle A" at the top and half section C" at the bottom bent at right angles to the cross section BU.

For laying out the pattern of a large transition, as in a piece designed for a hood over a stove or team table in a restaurant, it is obvious that a template of 24 or 26-gage metal

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SHOR T M E T H O D O F P A T T E R N D E V E LO P M E N T

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PLATE FOUR - SHORT METHOD PATTERN DEVELOPMENT ' RALPH W. POE

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PLATE FIVE . SHORT METHOD PATTERN DEVELOPMENT' Rt.LPH W. POE

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would bend, e pecially when pressed down on building paper to make the pattern .

o again , a in the first chapter, it seems well to emphasize the importance of the right angle where the ides A" and C" j oin cross section B". Any deviation from a right angle at the e j oint means that when the template is rolled there will be a corre ponding irregularity in the actual pattern .

To eliminate any such possibilities in large patterns, the entire template should be strengthened. Braces may be soldered or riveted from both ends to the center ection . Where the template still bends, a brace may be extended from A" to C" and fastened to the center of section B".

Some workmen prefer to cut wooden braces to fit between the two ends and thus strengthen the center section. The metal of the template may be fastened to the wood brace with tack , mall nail or screws.

The pattern is rolled by the same process as u ed for the two funnels described in chapter one. The edges of the template are rubbed with chalk ; then it is rolled firmly over a piece of soft black building paper. The line that re ult form hal f the finished pattern.

To complete the pattern, turn over and rever e the fir t

View V showing squore to round eccentric transition.

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S H O R T M E T H O D O F P A T T E R N DEVE L O P M E N T

pattern and join the straight sides. Then, and this is important, be sure to add an al lowance for earn , a the pattern i for the exact surface only.

At the left of view IV i the completed template, with the pattern it produces below. The left half of the pattern is the original made by roll i ng the template. The right half, shown by dotted l ines, was made by turning over and outlining the first pattern . Together they form the complete pattern .

Square To Round Eccentric Transition

Occasionally an installation wil l be encountered in which the small connection m ust be made i n a corner, while the full size of the large end m ust be retained .

This is an awkward pattern to lay out even where both ends are square. The problem is further complicated when the smal l end is round, and particu larly when ide of the large end are as long as 36 inches.

Forming the template for this pattern is illustrated in Plate Five with a d iagrammatic sketch at the extreme left . As i n previous fitti ngs, the circle a t the top represents the diameter of the small end, and the square at the bottom represents the

ize and shape of the large end.

In the center figure, Plate Five, halves of each of the end A' and C' have been added to cro ection B'. This completes the template except for bending parts A" and C" at right angles, as i llustrated in the figure at the extreme right.

The fin ished template, braced where necessary and chalked, i rolled over black bui lding paper to produce the pattern i l lustrated in the lower part of View V. Above and to the left is the completed template. The finished transition fitting, shaped and soldered, is at the right .

A t this point i t should be explained that the shapes of either the top or bottom openings do not i n any way complicate pattern drafting under the Short Method.

The small end could be laid out in the hape of an oval, and the large end the shape of a rectangle i nstead of a square. The finished pattern would result in a piece of precisely the shape a indicated i n the first layout.

To gai n proficiency in the Short Method of Pattern Development, the sheet metal worker or student wi l l find it well to spend an hou r practicing one of the transitions i ndicated here, or a variation which might occur to him . The possibi l i tie of the Short Method are practically unlimited.

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S H O R T M E T H O D O F P A T T ER N DEVE L O P M E N T

CH A PT E R TH R E E

Oval To Round Fittings

HURRY-UP call on furnace, stove and heater job are a familiar occurrence around every heet metal shop. And

more often than not, the fitting required on the e h urry-up job are tough one to lay out. One that has cau ed many headaches is the "oval to round" tran ition frequently neces-ary to con nect the oval collar on a furnace to the round moke pipe.

Almost always there is a difference in the size of the two ends. Smoke pipes a small as four inches in diameter are common, while furnace sometimes come equipped with smoke collars as large as two feet across . Such a variation means a difficult problem for a sheet metal layout man ; and even more of a problem for the h urried shop worker with perhaps j ust a few hours to lay out a fitting, seam it, and make the installation. That is, un less he has a thorough working knowledge of the Short Method of Pattern Development.

View VI showing regular round to oval transition.

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SH O R T M E T H O D O F P A T T E R N D E V E L O P M E N T

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Illu trated in Plate Six are the step necessary for laying out the ordinary oval to round transition. Note the cross

ection of the fitting at the extreme left. If the reader has carefully studied the two preceding chapter , he will understand without further explanation that cross ection B is laid out actual size on a piece of sheet metal .

To this cross section are added half of the two end areas, the round top A' and the oval bottom C', as illustrated in the center drawing, Plate Six . At the extreme right is the finished template, with half circle A" at the top, and half oval C" at the bottom, bent at right angles. The template now is ready to be chalked and rolled over black building paper, as explained in preceding chapters.

The lower right-hand corner of Plate Six ill ustrates the pattern produced by rolling the finished template over building paper. Hereafter, as patterns in the booklet become more intricate, they will be illustrated in the plates as well as in the view . In transferring the e patterns to heet metal, be sure to make allowance for seams. This is important.

View V I illustrates, left, the finished template ; center, the oval to round transition after it has been formed and seamed ; and right, arne fitting with collars added .

View VII showing off-center round to ovol transition.

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S H O R T M E T H O D O F PA T T E R N D E V E L O P M E N T

Affixing collars to the two ends is a simple operation of adding bands of the desi red width. Since no involved calculations are necessary, this operation has not been included in the plate, but appear in the View V I at the right.

If now you surmi e that the oval to round fitting is just another funnel pattern, you are correct. In sheet metal work there are three forms used more frequently than any other : funnels, cylinder , and quare or rectangular box-like pieces with straight side . Most fitti ngs are a combination of these.

Often a job wil l be encountered where the furnace ha been placed flu h with one side of the chimney i nstead of being centered . As a result the round pi pe is off center with the oval collar.

If because of a low ceiling or close wal l there isn't room to take up this difference with elbows, the only sati factory solution is an oval to round transition with th round pening on one ide of the center l ine.

The shape of thi fitting wi l l become clearer by studying the drawing at the left of Plate Seven, which illustrates a eros ection with a large oval opening below, and a small round opening above. ize of t he small opening i indicated by A and ize and shape of the large opening is represented by The cross section i labeled B.

Center drawing shows the familiar operation of laying out the cross section B' and adding hal f of each of the end areas A' and G. The completed template, with A" and C" bent at right angles, appears at the extreme right.

Learn Basic Forms

In the lower right of Plate Seven is hown the pattern produced by the template. The left half is the original rol l-out pattern and the right half, shown with dotted lines, was made by reversing the original .

View V I I shows the same three steps a s described i n detai l in the fi rst part of this chapter. At the left i the finished tem plate. The completed fitting, formed and seamed, appears in the center. At the right it is shown with a col lar added to each end.

Of course, for off-center transition, collar' may not be needed at both ends. Most i mportant, learn to lay out the basic forms. Any artisan can add a band without working himself into a stew figuring out how to cut it.

By now it hould be apparent that either regular or "offcenter" pieces can be laid out easily by a workman who possesses average skill and ability, provided he has enough i magi-

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S H O R T M E T H O D O F PA T T E R N D E V E L O P M E N T

nation to vi ualize the piece as i t wi l l appear when finished. Remember, fiTst, determi ne the cross section of the fitting ;

second, determine the exact ize and shape of the two end ; then follow the ShOTt Method formula.

Although the fittings thus far in this text have been comparatively sim ple, they' are by no means unimportant. Each ha a definite place in the chapters that fol low. No heet metal man can be said to understand the Short Method of Pattern Development until he is able to lay out several fittings without con ulting the text. Master the principles in each ucceedi ng chapter and you wi l l be well on you r way to proficiency.

C H A P T ER F OUR

Rectangular To Round Fittings

M EN work ing on forced air heati ng and summer eooling in ta llations often ru n into job where trunk l i nes are

rectangular and branch l ines rou nd. Wherever a branch l i ne joi ns a main trunk, there m ust be a rectangular to rou nd transition . And when the intersection is at an angle, a "plenty tough" layout problem pre ent itself.

Ill u,trated in Plate Eight are the three fam i liar teps ior ma king the tem plate-and the pattern resulting.

View VIII showing template, rough and completed fittings for rectangular to round transition.

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A t the left is a diagrammatic ketch of the cro ection in which you'l l note the i des are not parallel. The top i quite a bit narrower than the bottom. This fact alone would precl ude any gue work at making the pattern. But to make it sti l l more d ifficu lt, there i the oblique intersection angle at the bottom.

The circle "A" above the left cross section shows the ize of the small opening where the round pipe connection is made. The lower opening " C" is rectangular and designed to fit a trunk l ine uch as would be found on rna t forced a ir heati ng or venti lati ng ystems.

The center drawing, Plate Eight, shows cross section B' with hal f c ircle A' added to the mall end, and half-rectangle C' added to the large end.

The lower part of Plate Eight il lustrate the pattern produced by chalking the edges of the template and then roll i ng it over black build ing paper. The left half, sol id, i s the original pattern ; and the right half, dotted, was obtained by rever i ng the origi nal pattern and matching the straight sides.

This pattern di ffers sl ightly from preceding pattern , for poi nts of bending are not as clearly indicated . Poi nt "D" on the pattern is one of the corners of the finished rectangular open i ng. It is located where the point of the template touche

View IX showing templote ond simple ovol to round tronsition.

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SHORT METHOD OF PATTERN DEVELOPMENT

the paper. If not di tinguishable a the template is rolled, it hould be marked. It wil l be needed later in ben ding the pat

tern into correct shape. Point "E" is clearly indicated, 0 it hould need no further

attention . A line from "D" to " E" form the long ide of the rectangle. With the e point clearly marked, forming the joint should present little difficu lty to any sheet metal craft man.

View VIII at the left how the fini hed template. In the center i the completed fitting, formed and seamed, and at the right, the same fitting with collars added . Again no directions have been given for making the collar as they present no pattern problem.

This rectangular to round fitting, it will be seen, can be used equally wel l to con nect a small round pipe to rectangular ducts or to the body of a hot air register extending through the floor. Of course, for the latter, it would be necessary to add col lars.

Oval To Round

The second fitting in this chapter, il lustrated in Plate Nine, wil l not be used nearly as often as the fir t. However, since it is laid out in exactly the same manner as the rectangular to round, it is included here with the pos ibility that everal uses may be seen.

The steps for laying it out are identical with those of the rectangular to round fitting-determining the size and hape of cross section "E" and the two openings "A" and "C".

The large opening i oval in shape, as shown in the lower projection of the diagram at the left in Plate Nine. The center drawing il lustrates the end areas added to the cross section. At the right appears an "edge" view of the finished template.

View IX illustrates both the template and the finished fitting. Addition of collars to the end would make the piece identical with the rectangular to round, except for the hape of the large opening.

CH A PT ER FIV E

Square To Round Elbow

ALL fittings described and illustrated in preceding chapters have been comparatively simple and formed from only

a single piece of metal. Now we take up m ulti-section fittings . Men who do gravity furnace instal lation work often run

into jobs where rectangular to round elbow fitting are re-

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S H O R T M E T H O D O F P A T T E R N D EVE L OP M E N T

View X showing Short Method steps for developing 3-section

rectangular to round elbow fitting_

quired to connect cold a ir registers. Such fitti ngs are usually large elbows made up of three or more sections. Using conventional layout methods, developing, forming and matching the sections is a long, tiring task for even the most experienced draft man.

The Short Method of Pattern Development now takes up thi important layout problem. Masteri ng the s imple steps laid down here wil l mean a saving i n time whenever you need a multi-section elbow. It might be for a cold air return, a hot air register, a venti lating outlet, a hopper in a grain elevator, a blower on a threshing separator, or any of a dozen other places where uch a fitting m ight be needed.

Plate Ten at the upper left shows a cross section of the complete elbow. Size and shape of the end openi ng are indicated by the rectangle and circle projected at the top and bottom.

At this point the fitting is divided into three distinct sections, "X", "Y" and "Z". Section "X" will need little explanation . It can be een that in both View X and in the drawing in Plate Ten, i t i a simple rectangular form . The side are hown actual size, and the top and bottom are i dentical in length with the ide of the rectangle projected at the left.

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H O R T M E T H O D OF P A T T E R N D E V E L O P M E N T

PATTERN FOR X

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PLATE ELEVEN . SHORT METHOD PATTERN DEVELOPMENT UL'H w. pot:

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SH O R T M E T H O D O F P A T T ER N DEV E L O P M E N T

A pattern could be laid out using a template, but since there are no curves of obscure dimensions it wou ld be j ust as easy and probably quicker to use conventional methods. The pattern for section "X" appears at the lower left of Plate Ten and is i dentified as "X".

N ext is the shaded area "Y" which appears i n Plate Ten and forms the center section of the elbow. Those fami l iar with preceding chapters wil l readily u nderstand that areas A and C projected at the ends of cross ection B are i dentical with the openi ngs of the fin ished piece . B, as in preceding instal lments, represents the cross section of the fitting.

The next drawing, i mmediately to the right, shows how half of areas A' and C' are added to cross section B'. Note that the lower opening C' is oval, a transition from the rectangle A'.

Step three, as i l lustrated at the extreme right of Plate Ten, is bending the end areas A" and C" at right angles to cross section BU. A m uch clearer picture of the finished template is shown i n View X, where separate sections "X", "Y", and "Z" a re shown along with the templates for "Y" and "Z".

Section "Z", next to be described, is indicated by the shaded area in Plate Eleven. The same layout steps are fol lowed as i n a l l preceding forms.

Above and below cross section B are areas A and C representi ng end openings of the finished piece. Immediately to the right, half of these areas A' and C' are added.

In the final step, end areas A" and C" are bent at right angles to give the correct template for section "Z". Then, as explained in preceding chapters, the template i chalked and careful ly rolled on black bui lding paper.

Templates for large fittings, such as cold air return elbows, had best be braced as explained i n Chapter One. Again it should be made clear that templates produce only a halfpattern. Two halves matched and joined, as indicated by the dotted l ines, form the complete pattern.

View X i l lustrates the three sections of the finished elbow, "X", "Y" and "Z" as they appear after being shaped and seamed, but before being joined together to form the complete elbow.

To clearly i l lustrate the shape of the pieces and avoid complicating the patterns, they have been cut without allowance for seams between sections. A nyone who has closely followed the Short Method wil l readily u nderstand that allowance m ust be made for seam , and also for soldering ends of a fitting to adjoin ing parts.

[ 25 ]

H O R T M E T H O D O F PA T T E R N D EVE L O P M E N T

In studying the pictu re of the fin i hed elbow, View X , you wi l l see at the extreme right how the open ends might be varied. Template for quare or oval rectangular open i ng could be made ju t as easily as the rectangular and round given in thi example.

In u i ng the hort Method the metal worker mu t picture the finished fitti ng clearly in hi mind, then go to the drawing board and translate hi picture. If thi proced ure is fol lowed, and al l measurements are made accurately, the completed fitti ng wi l l dupl icate the drafting board de ign to a fraction of an i nch, and u ually at a great saving in time.

CH A PT E R SIX

"Y" Fittings

M EN who make a specialty of instal l ing dust- and fumecol lecting systems, and those who do gravity furnace

work, often run into j obs where "Y" fittings must be u ed. Invariably the e mu lti- ection tran ition represent a tough layout job. Even the most proficient draftsman u i ng triangulation or geometrical methods often takes several hou r for

uch a j ob.

View XI showing template, seamed branches and completed "Y" fitting.

r 26 1


With the Short Method i t's a different tory. By fol lowing the simple steps outl ined here you can cut layout time to less than half on your next Y -fitting.

The pattern for an ordinary "Y" fitting, shown in the lower part of Plate Twelve, appears complicated enough to require con iderable k i l l , no matter what layout method is used. Yet with the hort Method only the abil ity to visual ize the completed fitting is e sential .

At thi point we want to remind readers that at no time have we claimed the Short Method of Pattern Development more accurate than other methods. We've merely stated that, in the hands of a workman who understands fundamentals, the template system of layout is m uch faster than other methods ; enough so that it effects an i mportant saving in time.

Your visualization of the completed fitting m ust first be put on paper as i l lustrated at the left in Plate Twelve. The cross section here has a circle above showing the exact d iameter of the single large opening, and two small c ircles below which have the same diameters as the two small ends.

It can be seen in the cross section that the branches are sl ightly tapered. This is done for two reasons: (1) to make a transition to small pipes ; and (2 ) to faci l itate joining the "Y" branche to extending pipe . With this slight taper in the

- '

PATTERN -"'/ (ENLARGED)

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PLATE. TWELV( . SHORT METHOD PATTE N DEVELOPMENT

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RAl.PH ""-/ POE

SH ORT METH OD OF PATTERN DEVEL OPMENT

View XII showing opplication of "Y" fitting as a pouring spout for on oil measure.

branches, it i po sible to fit the joint faster and with Ie s effort, even i f there is a sl ight i naccuracy i n the pattern. Making the branches longer than called for allows for seams, and for lapping in ca e of a difficult fit.

In examining the cros ection of the "Y" branch, you wil l note that the two prongs are identical . It i thu obviou that only one pattern wi l l be needed . To obtain thi s pattern, we shall take the right half of the "Y" branch through the nece -sary steps . Ob erve that it i shaded in the first cross section.

Area B, at the right of the complete section, show an edge view of a i ngle prong of the "Y". The half ci rcle above establ ishes the size and shape of the large opening, while circle C at the bottom shows the size of the small opening.

The next drawing shows cros section B' with the half circle A' added in two equal egment . At the bottom of the cross section half of circle C' i added.

At the extreme right of Plate Twelve an end-view of the template i hown . ince it true hape i not immediately apparent from thi worki ng drawi ng, i t ha been photographed and appears in View XI below the two fini hed branche .

The two quarter circles at the upper end of the template, as you wil l see in the i l lustration, have been bent at right

SH O R T M E T H O D O F P A T T E R N D E VE L O P M E N T

angles to cros ection B", bringing the points together and closing the end.

The fir t half of the pattern, which appear at the bottom of Plate Twelve ( identi fied by a sol id l ine ) , was created by roll ing the chalked template over black building paper. The second half of the pattern, shown by dotted l ines, was made by reversing the first. In examining thi pattern the reader wi l l note that the hape i symmetrical, 0 that the arne design will be produced, regardles of which ide is up.

A mentioned in preceding chapter , al lowance mu t be made for seaming the various sections. In order to show the exact hape of the eparate prong , and not confu e the reader, extra metal has not been left on the two branches, shown at the left of View XI .

However, for your layout, first make an allowance on the original pattern, and then in cutting make a second allowance for joining the two branches.

At the right in View XI is a finished "Y" branch with collar seamed to the large opening. Probably one of the most common appl ications of thi fitting is in dust-collect ing systems where two grinding wheels are placed as a unit and branches from a central pipe reach each wheel .

Pouring Breast

A further use of this fitting is seen in View XII . Here a single branch, made by the foregoing steps, has been attached to a cyl indrical can, forming a pouring breast as used on oil measures.

This piece i of the arne shape as those joined in the i l lustrated "Y" branch, except it has a more pronounced taper. The top opening is considerably smal ler, forming a more accurate pouring spout.

Remember, to derive the greatest pos ible value from the Short Method of Pattern Development the reader must thoroughly understand the problem outlined in each chapter. Probably the be t way to gain thi understanding is to make small model of the fitting that are i l lu trated. With the completion of each new model , useful variations of the same fitting are li kely to occur in one' mind.

C H A P T ER S E V E N

Oval To Round Elbow

HERE readers will learn sti l l further of how the Short Method can prove a great help in developing complex

multi- ection fittings.

[ 29 ]

S H O R T M E T H O D O F P ATT E R N D E VE L O P M E N T

'I'his chapter pre ent the various step for laying out and forming a three-piece oval to round gO-degree elbow. This tran ition, although not u ed as frequently as the rectangular to round fitti ng de cribed in chapter 5, nevertheless is mighty u eful . Time pent in mastering it wi l l not be wasted. Many sheet metal craftsmen know from experience that sometimes on difficult furnace in tallation jobs, the oval to round elbow is the only fitting that will solve the problem .

One of the mo t frequent applications i i n onnecting a heater or furnace moke collar to a chimney, or in the heet metal man's language, connecting the "boiler britchi ng" to the "stack." It is especially adaptable where furnaces are installed in corners, as often there isn't room for standard elbows and straight oval to round transitions.

In both de ign and method of layout, the f itti ng pre ented here i imilar to the one described in Chapter 5, " quare to Round Elbow ." However, in actual design, there is enough difference to j ustify eparate and thorough study of each.

Plate Thirteen i l lustrate a cros ection of the entire elbow, and shows at the left the diameter of the round openi ng and at the bottom the ize of the oval opening. First to be described wi l l be the upper egment " X " haded i n the complete drawing at the left in Plate Thirteen .

Immediately above i cro s section B with end area pro-

View XIII showing actual shape of the three templates,

the segments and the completed fitting.

[ 30 ]

S HO R T M E T H O D OF P A TTE RN D E V E LO P M E N T

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PATTERN

PL-'TE. THIRTEEN . SH OAT METHOD PAT TERN DEVELOPMEN T . �AL.H W. POE.

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PAT TE R N

PLATE FOURTEEN . SHORT METH OD PATTERN DEVELOPMe:"T . Rt.LPH W POE

[ 3 1 ]


jected . I n the next figure to the right, the standard short procedure is followed with half areas A and C added to cros ection B', giving the drawing A'B'C' . An end view of the

completed template A"B"C" appears at the extreme right. The pattern is shown below.

The process for making templates for the two remaining segments, "Y" and "Z",' i s exactly the same. Plate Fourteen, at the left, shows the middle piece "Y" of the full cro s section, whi le at the right are the succe sive steps necessary to develop the template. In the lower part the pattern is hown.

In Plate Fifteen the third, or lower egment, "Z" i s laid out. Again step by step procedure is given, showing exactly how the template is obtained, as well as the pattern it gives when chalked and rolled on black building paper. Shapes of the ends of each section are shown plainly in the projections, varying from round at the top to oval at the bottom.

Short Method students must bear these two thoughts in mind : First, end areas of each template must be bent accurately at right angles to the cross section . Second, each template produces only half a complete pattern.

The second point is i l lustrated clearly on every plate. The left half of each pattern, in sol id l i nes, is made by roll ing the template. The right half, dotted, is made by turning over the first pattern and matching the long sides.

c

PAT TE R N

PATTERN DEVELOPMENT ' RIILPH W POE .

[ 32 ]

c ..

S H ORT MET H O D OF P A T T ERN D E VEL OP MEN T

Each step for developing the working drawing of the elbow into individual template for the various egment i given in detail in the three plate accompanying thi chapter.

View X I I I show the actual shape of the templates, each below the piece for which it was made. At the left is the upper segment, formed and seamed together, with the center segment along side, and the lower egment at the right.

At the far right is the completed elbow, with the three segments seamed and soldered together. Patterns for each appear on the plates, so are not reproduced in the view.

To clearly i l lustrate the shape of the variou egments and avoid complicating the patterns, they have been cut without allowance for seams between sections. However, anyone who has fol lowed the Short Method of Pattern Development will readily understand that allowances must be made for seaming the various sections, and also for soldering ends of the completed fitting to adjoining part .

C H A PT E R EI G HT

Tee Joints

NOW readers will find the Short Method applicable to one of the most difficult of layout problems-the Tee joint.

As we have seen in preceding chapters, the more intricate the pattern problem at hand, the greater the aving in time.

There are two hort method for developing a standard Tee joint of the kind shown by diagram in Plate ixteen and by model in View X I V.

The fir t method to be explained, while not dead accurate, i very satisfactory in practice and a valuable hort-cut for ordinary job . The second method, described in part two of this chapter, gives a more accurate fitting, but requires considerably more time. Mastering the econd method, however, is important ; for it will prove a great help in grasping development to be introduced in the chapters that follow.

First Method

Exact ize and shape of the Tee joint required i indicated in the drawing in Plate Sixteen. The haded part is that for which a template and pattern wil l be required. No pattern will be needed for the main body of the joint ; the c ircular opening can simply be cut to fit.

Steps for the development of the template and pattern are similar to tho e for the l O y " branch fitting de cribed in Chapter ix . At the upper left in Plate ixteen i. a drawi ng of the


View XIV showing templote ond pattern for first method at the lower left, and for the

second method at the lower right. Above can be seen the two Tee joint segments, and

at the for riqht, the completed fittin q .

cross section of the branch, with openings indicated . At the top center, the template i laid out with hal f areas A ' and C' added to cross ection B'.

The reader will note that the radius of segment C' and e" is less than the length of the template angles . Since the two point of the segments must meet when bent, if they are to form an unbroken pattern, they have been extended as shown by areas outside the dotted l ines. Radius of the segments (R ) i s the same as the radi u of the circle or lower opening.

The pattern is produced by the usual method of chalking the edges of the template and then rol l ing it over black building paper. It will be found that the resulting pattern produces a sl ightly tapered branch in tead of a true cylinder of uniform diameter. However, thi is not a great di advantage. On most jobs, in fact, it actually faci l itates joining adjacent sections.

Then, in placing the completed branch over the main body of the Tee, the fit again wil l be found not quite accurate. But with j ust a l ittle trimming you will have a smooth, snug joint that easily can be soldered into a strong, lasting fitting.

[ 34 ]


A B

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Part Two

Fir t step for making the econd method template is i l lustrated in the lower left corner of Plate Seventeen, where the cross ection is shaded. Immediately above, at the upper left, is this same branch as visualized from an end view. Circles at the top and bottom indicate size of the openings.

The template for this method differ from the fi rst chiefly in that it is made from a cross section of the branch as seen ITom the end of the Tee joint ; not from the side.

To the right of the end view is an "edge" view of the half finished template, showing half of area A' added to cross section B' ; and C' formed around the main body of the Tee. Directly below is a perspective drawing showing the lower end of the unfin ished template formed around the main body of the Tee.

The next step is to cut C' to fit the shape of the opening required to join the branch to the main body.

A second perspective drawing hows this step completed . The elevation at each point on C" corre ponds to a similar point on A". This can be accompli hed by sketching the outline whi le sighting over the half circle A", or by guiding a square around the half circle and marking its course on C" to determine the shape.

It i important to remember that thi hould be done alte?' the template has been formed in the shape il l ustrated in the fi rst perspective drawi ng, at the left.

Second from the right, above, in Plate even teen, is the template as it would appear flat, howing half area A", the full cross section B", and the lower area C". At the extreme right, above, is an "edge" view of the finished template, and below the pattern it produces when chalked and rolled.

View XIV at the left shows actual sheet metal models of the branch and the main body of the Tee, before they have been joined together. At the right can be een the completed and soldered joint.

There is only one di fference between the two templates in actual u e. The first produce a l ightly tapered branch, while the fitting produced by the econd is a true cyl inder.

Either method will be uitable for the ordinary Tee joint8 you encounter in dust y tem and venti lating jobs. Understanding the second method, however, wil l prove of great valu to you in masteri ng the chapters that fol low.

r 6 1


C H A PT E R N I N E

Off-Center Tee

To the experienced sheet metal worker the model off-center Tee joining pipes of dissimi lar diameters in the upper right

of View XV will probably recal l several trying layout jobs. This extremely intricate fitting is often used to join branches to main trunk l ine in smoke, blow-pipe and dust-collecting installations where branches must be placed off-center to provide clearance.

Possibly you have used it elsewhere. Yet even if you have, you must have experienced difficulty in developing the pattern. I t's a tough one, sure enough. If you have never used it, a glance at the completed model will quickly reveal the complexity when using the ordinary square and compass method.

With the Short Method, development of the pattern is comparatively simple. Procedure differs from that of preceding chapters in this way : two templates are used instead of one, each producing only half the pattern. Instead of turning over or reversing the original pattern as in the past, the two half patterns are joined together. ( See Plate 1 9 ) . Keep this point in mind in studying the diagrams and in examining View XV.

The only part of the Tee for which a pattern wil l be needed

A

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C. � CN �. A B

-- PERSPECTIVES)

HALF PATTERN

[ 37 ]


A

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PERSPECTI VE S

FULL PAT TERN 'LATE NINE E�N • S HOAT METHOD PATTERN DEVELOPMENT ,

is the branch. Once completed, the branch can be placed over the larger pipe and an outline of the hole traced around it .

At the lower left in Plate 18 are both "side" and "end" working drawing of the Tee Joint, Then at the upper left, an identical "end" view is reproduced with an "edge" view of the template indicated by heavy lines.

A lso i l lustrated in Plate 18 are the steps necessary for making the template of the right half of the branch-that portion which extends down toward the center of the larger pipe. The template is developed as shown at the upper left, with area C formed around the large pipe. The procedure again is i l lustrated below and at the right in a perspective drawing.

At the top center of Plate 18 i a diagram showing the template as it would appear fiat, with half upper area A' added to cross ection B', Those who have closely followed the hort Method will find this a fami liar process by now.

Area C', as can be een, is bent to conform with the curve of the larger pi pe, 0 that the elevation at each point on C' corresponds to a similar point on A'. At the top right is an "edge" view of the finished template, and a perspective drawing below. Then at the lower right i the pattern produced by template No. 1 , which later must be joined to the pattern for the other half branch.

[ 38 ]

H O R T M E T H O D O F P A T T E R N D E V E L O P M E N T

Plate 1 9 shows development of the template for the second half of the branch, beginning at the upper left with an "end" dra wing of the Tee Joint . The section to be laid out is again indicated by heavy l ines.

At the top center the template is shown as it would appear flat, and at the extreme top right as i t would appear from either end . Forming the template is i l lustrated in the first perspective drawing at the left, while the right perspective shows the true shape of the finished template. Here also appears the pattern produced by template No. 2. Then at the lower right is the complete working pattern, combin ing the two half patterns produced by the templates.

Reference to the preceding chapter wil l explain two methods for obtain ing the c ircular shape of ends C. By the first method the outline for C is drawn while sighting over end A, or the half-ci rcle. This method is not "dead" accurate, but reasonably so for mo t practical work.

Where a more accurate pattern is required, the outline is obtained by guiding a square around the half c ircle A" and trac ing its course on the curved surface C/. ( See Chapter VIII ) .

Photograph XV at the bottom shows the two templates

View XV showing two templates, formed sections, and completed model

for intricate off-center Tee joint problem.

[ 39 ]

S H 0 R T M E T H O D 0 F P A T T E R N D E V E L 0 P M ' E N T

required to make the complete pattern ; at the center the t wo pieces before being joi ned ; at the right the fini hed off-center Tee joint.

Using ordinary care in marking the template will produce a close fit, and very l ittle trimming wiII be necessary.

Still, as explained before, the Short Method is not i ntended to replace drafting room methods now in use, especially i n shops where accurate fittings must be made from the same pattern day after day. Yet in the average shop, the Short Method is both fast and practical, especially where the pattern to be developed may be used on only one job.

C H A P T E R T E N

Angular Joints

T o the experienced sheet metal craft man, the model fitt ing in Views XVI and XVII will probably bring to mind layout

jobs that were real headaches. These models show a round tapering branch intersection at an angle-an intricate fitting often used in heating, ventilating and dust collecting systems where branches join main trunk l ines .

View XVI showing curvature of the template, and actual shape

of the segments and completed fitting.

[ 40 ]


Employing the Short Method of Pattern Development, the problem is rather simple. Plate Twenty i l lustrates the procedure, which differ from the la t chapter in this respect : only one template is needed . At the left above and below are side and end views of the intersection with heavy lines indicating the form of the template. At the right is a ide view of the template, and below a perspective drawing showing how area C is rolled around the large pipe to form the lower end of the template.

Second from the right, at the top, is the finished template, with half area A" added to cross section B'. Shape and size of C' are indicated i n the diagram and again in the perspective drawing below. At the extreme right, above, is an end view of the finished template, while the pattern it produces appears at the lower left.

Here as i n earlier chapters the pattern is made by roll ing the chalked template, reversing the original pattern and joini ng the long sides. The original pattern is identified by sol id l ines, and the pattern reversed by dotted l ines.

To complete the angular i ntersection, it is only necessary to place the finished branch against the larger pipe and outline the opening. Some trimming may be necessary, yet if care is taken with the template, a nearly perfect fit may be expected. View VXI reveals the template in the lower left corner, the two parts before join ing at the center and left, and the finished angle fitting at the right.

Part Two

Plate 21, the la t problem in this series, indicates a round tapering branch joining a larger pipe at an angle. The steps for making the template are similar to those described in Part One except that area "C" is i rregularly curved.

Just how this i rregular curve is obtained may be seen in both the working and perspective drawings, where area C' is rolled round the larger pipe. Plate 2 1 also includes an end view of the finished template, a perspective view of the template, and the pattern .

A in preceding chapters, the Short Method patterns il lu-trated here do not include an allowance for seams. The pat

terns represent only the actual urface of the object. You must make this seam allowance on one or more of the finished segments.

In concluding the example problems there are several points which seem of sufficient importance to merit repeating :

1. Where the template represent only half the finished

S I t OR '!' M E THOD OF P A TTERN D E VEL P MENT

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PLATE TWENTY • !MORT METHOD MTTIRN DRVCLAPMIlNT

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r 42 1

S J I OR T ME T HOD O F PA T T E R N D E VE LOP MEN T

piece, i t produces only half a pattern. To complete uch a pattern , reverse the original and match sides.

2. Mo t patterns are symmetrical 0 that either of two . ides may be joined. Where there is th is choice, you wi l l fi nd it best to join the long side . hort seam are ea ier to make.

3. While the Short Method can be used for developing almost every conceivable sheet metal fitting, not alway i it practical . In the many cases where it i , this method is such a time-saver that the average sheet metal craftsman cannot afford to be without at least a working knowledge of it .

The Short Method of Pattern Development as presented here wil l provide an excellent background for the man who has the imagination to fir t vi ualize the completed fitting and then develop his pattern . A thorough understanding of the model fittings that have been described and i l lustrated in this text will guarantee a good working knowledge of the method. Naturally it is important the reader understand that making patterns from prepared instructions and drawings is only a beginning. Once the journeyman has mastered the Short Method he should be able to make reasonably accurate working drawings and lay out hi own templates. After the template i s

View XVII showing a second method for developing

on angular branch intersection fitting .

r 4 ]


formed, making the pattern and haping the piece are only routine shop teps.

This booklet ha a much broader a p t than merely i l lutrating and expla ining a l im ited group of layout problems.

It was publi hed to give readers an alternate and shorter method of developing pat tern. for int ricate sheet metal fitti ngs.

C H A PT ER E L E V E N

Ad j ustable Tem plate Holder

ONE objection raised by men who have used the Short Method of Pattern Development is that often it requires

more time for them to form the template than would be needed to develop the arne pattern by triangulation . To overcome thi objection we offer an adj ustable template holder that simpli fie and speeds up the Short Pattern Method .

This holder i adj u table in length and take interchangeable templates. With it accurate patterns for all k inds of taper fitting can be turned out rapidly and ea i ly. No longer wil l

View XVIII illustrating how the inner slide o f the Ad justable Template Holder may be

reversed, a feature which makes the tool adaptable for short taper fittings.


A D J U ST A B L E T E M PLAr E HOL D E R M E T H O D O F U SI N G

E ) F l y I FI Y. A.

-E }-hl F I G 2. F I G. B

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TWEt-4 T V - TWO "o..J. TEMP HOLO£� St10IlT MElMOO SHEET MET,t.L PAT. O[V[LOPM£NT AA\.PH W. 90� lo/u/n

View XIX showing how the Ad justabl e Holder may be used for developing a simpl& square or rectangular to round transition.

[ 45 ]

S H O R T M � T H O D O � PA T T E R N D E V E L OP ME N T

i t be necessary to form separate and cumber orne templates for each layout. In tead a large as ortment of flat rna tel' templates can be de igned for the holder, making po ible a ready solution for mo t any problem.

Design of the adj u table holder is so simple that any student of the Short Method can make one in an hour or so. For best results the body should be made of 24-gage galvanized metal or heavier. hape and proportionate size of the different holder part are shown in Plate Twenty-Two, Figure 1 , 2 and

. The slide ( movable ection of the holder) shown in Figure 2 is cut and formed so that i t fit n ugly and evenly j ust i nside the body. This section m ust re t in such a way that i t may be moved back and forth ; and yet i t hould be tight enough to prevent side-play and l ipping of the holder.

The size of the holder hould vary according to the diameter of the tem plate u ed with it. For example, the i l lu trated holder measu res 24 " in length, 4" in width, and ha an 1 8" ' l ide. Thi i an i deal s ize for handl ing tem plates up to 1 2" in d iameter. For template mea uring more than 12" in diameter, the holder should be made of a heavier gage metal and have a wi der back for greater tabil ity.

U e of the Adj u table Holder are many. View XVI I I i l lustrates how the sl ide may be rever ed for laying out excep-

View XX i l lustrates how the Adjustable Holder can be greatl y ex :ended

for laying out most any kind of taper fittings.

[ 46 ]

H O R T M E T H O D OF P A T T E R N D E V E L O P M E N T

tionally short taper fitt ing ' . View X IX hows u 'e o f the holder i n developing a quare to round transition of the k ind often u ed in heating and blower jobs. I n Figure "A", " B" and "e" the reader ees how the holder may be used for both concentric and eccentric tapers and transitions.

As with other tools, certain cautions m ust be ob erved i n the u e o f the Adj ustable Holder. For example, the templates m ust be held tightly in place. If one l i ps after it has been careful ly centered in the pring cl i p there will be an error i n t h e fi nished pattern. An easy way t o guard agai nst uch error is to make a small punch mark i n the center at the ba e of all templates and then engage these in the mall holes centered at the c l ip ends of the body and sl ide.

Special care m ust be taken to see that these master templates are flat. Even sl ight variations make for serious errors. Equally important, master templates placed in the holder mu t be at right angles to the base. This poi n t has been tre ed i n preceding chapters a n d is important. Transfer o f the pattern to black bui ld ing paper is the same '.vith the adj ustable holder as with the formed templates described earlier in this text. Fi rst, edges of the i nserted template are chalked, then the complete unit i s rolled. This makes exactly half of the pattern . The second half i s obtai ned by inverting the first and matching l i ke sides.

To keep the adj ustable template holder always at your finger-tips, punch a 1.4 " hole in the body and hang it up alongside your other shop tools. Half c ircle master templates for all standard s izes should be made, labeled, and l ikewise h ung up. After a short t ime it i s l ikely that the Adj ustable Holder wil l become one of your best time-saver .

t i l l , with al l the t ime-saving possibi l it ies of the template method of layout, we em phasize that never ha it been our contention that the Short Method of Pattern Development wil l take the place of a thorough knowledge of mathematical pattern draft ing. However, it is hoped that publication of thi method in text-book form will be of u e to many craftsmen already proficient in pattern development. I t i also hoped that thi text will 't imulate inte re t in sheet metal pattern development among begin ners and apprentic , as wel l as ex pe rien ced c raft m e n .

[ 47 ]

Do You Have These Other Services ?

If t h i s hook i s i n tel'est i n g and h e l p f u l , you may wan t t he e other AR MCO serv ice :

Fun damentals of Pattern Drafting and Blue Print Reading

is a valuable guide for m a n y succes f u l metal worker .

I t brief, clear t reat men t of com p l i cated pattet'n d ra f t i n g p tOob l ems, a n d suggestion for read i n g blue prints, provide a handy and t i m e-savi ng reference. Many h 'ade chool

i nstructors have ado pted t h i s hook a ' a �tandal"( 1 text 1'01' t h ei t, sheet mctal classes. I t cost , only 20 ( 'cnt ' ,

Ut het' A R. M CO services incl ude t h e boo k , im plijietl Sys

tem, of Cost A ccounting alul Bookkeeping, a com pa n i on 'erv iee, How to Make and A lUllyze a Fin an cial Statement,

a n d a bi-m o n t h l y paper, Ingot Iron Shop News, w h i c h brings t h e l atest news of t h e t rade. Qual i fied heet metal cont racto rs may obtain t h ese servi ce free t h rough

A R MCO Distri butors.

Market Development Division

T H E A M E R I C A N R O L L I N G M I L L C O M P A N Y Middletown, Oh io

.:;::. 2500 1 1 -4 1

ARMCO P ro d u cts ALLOY COATED SHEETS • AUTOMOBILE SHEETS •

COLD ROLLED SHEETS AND STRIP • ELECTRICAL

SHEETS • ENAMEUNG mON SHEETS • FURNITURE

SHEETS � GALVANIZED ARMCO INGOT IRON SHEETS

• GALVANIZED COPPER-BEARING STEEL SHEETS •

GALVANIZED P AINTGRIP SHEETS • GALVANIZED

STEEL SHEETS • HOT AND COLD ROLLED COILS

• HEAVY BOT ROLLED SHEETS • HOT ROLLED

ANNEALED SHEETS • TERNE COATED SHEETS • HOT

ROLLED STRIP • STAINLESS STEEL SHEETS AND

STRIP • SPIRAL WELDED PIPE • PLATES • BILLETS

• ROOFING AND SIDING • WROUGHT STEEL WHEELS

• CASTINGS : PIG mON • COAL.

--------------��--------------

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1 . f l ' • ,I �' , ' \ ��Ie,S, ()fFices: Atldn�, Georg,ia ' � �rkeley,.'Coljfornia · 8ostqn� Mass. ··� ' Buffalo" ' [' 'Ne� ' 'York :e.' ChOtt��Q.' T��'n�e.e, , � , ' ChiC9'�O, IlIi�is , � Cinei�ncrli. ;Ohio,' t ,

'"� CleveIQ�d. Qhi� ', � ;:qoIUmb�s.' · O'h!p ., O�lIos, , ' Texas • Dayton, ' O�io ' �" D�s , Moi'nes .. " IQ�<:I ' " O,et".oi+. '''Michigdn ' • " rldiqri,QPoIJs, ' I"diana . ', Kansas' City. I, ' " . ':1 L "I • 'It ,I, , �" ,t .' ! f " : ' f: \' , j ' I .

, •

':M��ri � '� lOs Angeles�,Calif�rnici, ' . • Middlet�wn, Ohio • Mnwaukee, Wiscon�in .. MinneapOlis" Mirin�sota: , · 'New, Qrleans; ' .Lo.�i�iaria • , �ew York, ' Ne� York

. , , t J , l , ; . Pht1Odelphia. :Penri., , " ,' �ittsb"rgh, Penn • • ' Richmond, va. • St • . Loui

\�. ' Missouri.

Short Method of Pattern Development

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