patternmaking foundry

7/28/2019 Patternmaking Foundry

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pj-L . H.HAND .


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Pattern MakingAND

Foundry PracticeA PLAIN STATEMENT OF THE METHODS OF WOOD PATTERNMAKING, AS PRACTICED IN MODERN PATTERN SHOPS, WITH COM-PLETE INSTRUCTIONS FOR SWEEP WORK AND NOTES ON FOUNDRYPRACTICE, TOGETHER WITH NUMEROUS DRAWINGS TAKEN FROMACTUAL PATTERNS WHICH HAVE BEEN SELECTED AT RANDOMBY THE AUTHOR FROM A MODERN PATTERN ROOM WITH AVIEW TO ILLUSTRATE THE PROCESSES OF THE CRAFT AND THEINSTRUCTIONS CONTAINED IN THIS WORK.

NOTE The majority of the problems in this book hwve beensolved^ the ivork performed directly under the super-vision ofthe author.

ByL. H. HAND, M.E

3(lllu0trateD

FREDERICK J. DRAKE & CO.PUBLISHERS CHICAGO

1905


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B8ARY of OONQRSSIwo Oopies riiscMvociSEP. 5 J9U5^Oopvrmnx cuiry

COPT 8.

COPYRIGHT, 1905BY

FREDERICK J. DRAKE & CO.CHICAGO

6-^Wl


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PREFACEMy purpose in writing this book will be ap-

parent from its great usefulness, which, I amquite sure, will be conceded by intelligent andthoughtful readers.

For many years I have been employed in rail-road and construction shops and have observedthat the principles of pattern making were lessunderstood than any other branch of woodwork. I have frequently noticed, in railroadshops especially, that the workmen who could"make a pattern" commanded a better positionand were in greater demand than those whocould not. In large shops from one to a greatmany pattern makers are regularly employed,and work is systematically arranged; but in thesmaller shops it is very important to have aworkman in the cabinet or carpenter shop whois competent to make a correct pattern and whomay be called upon at any time to perform thisduty, thereby being instrumental in saving muchmoney for his employers.

For a term of years I was employed as gen-3


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4 PREFACEeral foreman of the wood working departmentof a factory near one of the large cities on LakeMichigan. This factory, from a very modeststart, advanced rapidly in wealth and impor-tance, until its employes were numbered by thehundreds. In the beginning the pattern shopwas only a branch of, or rather a bench in, thecabinet shop. For about three years the growthof the pattern shop kept pace with the growthof the plant, until eventually it became a depart-ment of itself and passed out from under mysupervision.During my term as foreman of the patternshop, I observed that workmen who were con-sidered pattern makers were entirely ignorant ofsome of the simplest problems in pattern mak-ing, while others were expert in every detail ofthe business. I also discovered that there was agreat scarcity of literature upon the subject ofpattern making, and such as was obtainable wasnot generally read by the members of the trade.Having become much interested in the variousproblems with which I was confronted fromtime to time, I consulted frequently with theintelligent and expert members of the craft, untilI became thoroughly familiar with the business


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PREFACE 6in all its details and quite skillful in the actualworkshop practice of the art. Being ambitiousto become a master of the science, I took greatpride in working out difficult problems at thelathe and the bench, and by assiduous andpersistent application I soon acquired a sub-stantial reputation as a pattern maker.Not being engaged in active business lastwinter, I devoted my leisure time to the prepa-ration of this work, feeling assured that it wouldconfer a lasting benefit upon those of my fellowworkmen of the craft, who will study the expla-nations and illustrations which it contains withthe same care and earnestness which I havedevoted to their elaboration. The subjectstreated relate mainly to patterns which came,from time to time, to my bench or which fellunder my observation while I was general fore-man of the wood working department in thefactory.A wide and varied experience in the employ

of railroads and car shops generally, has con-vinced me that even the professional patternmaker is ignorant of many comparatively simpleproblems, while to many careful and close woodworkmen the simplest rules are unknown. As


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6 PREFACEevidence corroborating this statement, I will citean instance of the ignorance of a professionalpattern maker whom I once knew. This work-man cut up about six dollars' worth of lumberand spent two days' time making a large corebox. Later on this core box needed some alter-ations, and another pattern maker, who hadbeen employed subsequently, was called upon tomake the changes. He looked the box over andseemed much amused. Then he picked upsome large scraps and four strips of wood ofthe desired length, and in about thirty minuteshe made a skeleton box, at a cost of about thirtyor forty cents, which answered all purposes,thereby demonstrating the fact that "knowledgeis power," and that the serving of a given timein a pattern shop does not always develop pro-ficiency to its highest plane of usefulness.

Should this work be the means of improvingthe condition or advancing the wages of any ofmy fellow laborers, I shall be pleased to hearfrom them, and their letters will be carefullyfiled away as the tokens of some fellowmen'sburdens which have been made a little lighterthrough my efforts.

The Author.


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PATTERN MAKING ANDFOUNDRY PRACTICEPRELIMINARY REMARKS

While the catalogues of publishing houses,dealing in scientific works, abound with hand-books published in the interest of the progressivewood worker who desires to learn all he canabout the possibilities of wood construction, andwhile we may find books devoted to the use ofthe steel square, building construction, superin-

tendence, different rules and methods for esti-mating and contracting, forms of specificationsand contracts, rules for laying out arches instraight and circular walls, different systems ofhand railing and stair building, rules andformulas for determining the strength of mate-rials and estimating the natural strains to whichsuch materials are subject, hopper bevels, hipand valley roof framing, groined ceilings, rakemouldings, roof and bridge trusses and their


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8 PATTERN MAKINGjoints and strength, yet it seems that the par-ticular branch of the art of wood working, whichpertains to the making of wood patterns for themoulder's use in making cast metal forms of thevarious kinds, shapes and dimensions requiredby the numerous and ever-increasing demands ofmodern construction, has not been given muchattention, as very little literature on this subjectexists, and that which does is not read to anyextent by the craft, the bulk of information onall technical points being, as it were, carried bytradition from foreman to apprentice. In viewof this fact, it occurred to me that an exhaustiveand comprehensive work on this subject, givingthe results of years of practical experience, eluci-dated by clear and concise instructions and illus-trated by drawings, cannot fail to supply anurgent want in the ever-growing complexity ofthis masterful era of mechanical progress.

This work is destined not only to aid the welltrained and skillful artisan by simplifying manydiflScult and seemingly impossible tasks, but itwill become an indispensable source of educa-tional advantage to the inexperienced mechanicand apprentice.

There is absolutely nothing known as to the


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AND FOUNDRY PRACTICE 9origin of the process of casting metal forms fromwood patterns. Among the reUcs of prehistoricman there are weapons, implements and vesselsof bronze which, by inevitable inference, wemust concede were cast in moulds made byembedding either a pattern of wood or othermaterial in sand or earth. The very discoveryof metal, in all probability, owes its origin tothe accidental fusing of some kind of ore, andthe form of the cavity in the earth in which ithas cooled suggested to the mind of primitiveman the wonderful process of moulding, whichhas been so great a factor in the marvelousdevelopment of the human race. Patientscientific research has revealed incontrovertibleevidence that the art of moulding in earth is oneof high antiquity, and this justifies the deduc-tion that pattern making also as a craft, thoughno doubt struggling through long periods of timein a state of primitive crudity, is of almostequally remote origin, as the conception andnecessity of a pattern to construct the mouldwould most naturally follow the discovery of thefusion of ores into the various forms given tothe cooled metal by the accidents of its positionin earth or sand.


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10 PATTERN MAKINGIn the early history of pattern making the art

was not separated from ordinary wood working.It was a branch of the millwright or wheelwrighttrade, and answered all the purposes and wantsof that period; but the demands of modernmanufacture are so multitudinous and exactingthat the highest order of skill has become animperative necessity in every department of thewood worker's trade.The wonderful improvement in machinery

during the past century has created a demandfor forms in casting, so numerous in their end-less variety, that the vocation of the modernpattern maker has become a specialized art requir-ing scientific knowledge highly developed, andcoupled with the ability to apply this knowledgepractically to the requirements of modern me-chanical discovery and invention.

It is therefore of the utmost importance thatevery mechanic who selects for his vocation inlife that of the pattern maker, should thoroughlymaster all the technical knowledge of the art,not only for his own temporal interests, but forthat still higher motive which actuates all zealousworkers in every department of human endeavorand who reap as their reward, in addition to


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A>D ForyBRY practice: ii

tioiL, and tbtmqthat the patterrand no* made, y--

wcMbf experierto the effioenc;indnsinr in tlie :Xambered &: j : ~i= a

young man wt^.great cities anbrass foandry .Talves, checks, z .from the time h'r ^foveman of th-^poatkm foi' years. A:-a farmer, made his -for a grain birthe straw. TLbut the introcsc^ed the prohtwo la^ge Imic b had his inren-tion under ecu larmed andjcMned the gecK : binder,cansi^ a V-^^ _ : al! his


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12 PATTERN MAKINGlabor on the machine. These two instances,however, of rapid success and utter failure, rep-resent the extremes of good and bad fortunerather than the average medium of success whichalways attends assiduous application and per-sistent endeavor in the aggregate.The principal aim of the pattern maker should

be to make himself so absolute a master of hiswork that the solution of all problems with whichhe may be confronted can be quickly obtainedand with the least possible expense. The mod-ern pattern maker should be thoroughly familiarwith all the rules for draft shrinkage, etc., andready to apply them at a moment's notice.

Under the old regime, the millwright hewedthe timber, framed his building and made thepatterns for boxing, gear wheels, etc. He thenset up the machinery, officiating practically asmillwright, machinist, pattern maker and car-penter; in fact, he was a veritable mechanicalfactotum; and yet, although the millwright iscredited with the ability to figure out the speedof gears, pulleys, etc., and to set up machinery,he may be totally ignorant of the simplest rulesfor shrinkage, draft, etc. Hence the importanceof specialized labor in the vast number of de-


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AND FOUNDRY PRACTICE 13partments which have been created by the neces-sities of the gigantic industrial world of moderntimes, as better results are obtained and timeand money saved. Living as we do in this ageof high pressure and quick results, it is incum-bent upon every worker to do his part with aslittle expenditure of time, energy and money aspossible, or the procession will pass him by andhe will be consigned to the rear in the ranks ofthat great army of those who are unfit to con-tinue the fierce struggle of existence under mod-ern industrial conditions.The old time buggy maker, who was black-

smith and wheelwright, body maker, trimmerand painter, was wont to build a few vehicleslike the famed "one hoss shay," but they wereso expensive that only a very few people, excep-tionally fortunate could afford to own them. Inthese days half a dozen smiths make as manydifferent parts of the gear, while the man whowelds the tires could not in all probability forgethe simplest part of the gear, and the curtainmaker may never see the top of the buggy.The gear may be made in Grand Rapids, theshafts in Indianapolis, the body wherever theleast money will buy the largest box, and the


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14 PATTERN MAKINGparts assembled in Chicago. Then the finishedproduct is put on the market at a price solow that the barefooted boy in the country cantake his grist to mill in a buggy. In fact, bug-gies have become so cheap that, driving alongalmost any country road, one will often pass abuggy wreck piled up in a fence corner or in aside ditch. These wrecked vehicles are notentirely worn out, but the price of a new buggyis so low that it is cheaper to buy one than toincur the expense of repairs upon the old one.A thorouo^h division of labor, while it forces amechanic to become, as it were, a cog in the

wheel of some great machine, which grinds thesame round from day to day and month tomonth, also cheapens the product of every me-chanic's labor, so that now people of small meansare not denied the products of mill, loom andfactory, which half a century ago were onlyobtainable by the very rich. With the ever-increasing demand for cheaper production, pat-tern making is destined to become more andmore a trade to be desired. The destruction ofthe forests and the presence of the iron moun-tain in Missouri are two fixed facts, indicatingwhere we will be forced in the near future to


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AND FOUNDRY PRACTICE 15seek our raw material which heretofore the greatforests have suppHed. With the disappearance ofthe timber, iron is slowly and almost imper-ceptibly but surely taking its place. I haveheard old men bewail the condition of the coun-try when the supply of rail timber becomes ex-hausted, and yet what farmer would split therails now if he were given free of cost the tim-ber? The wooden fence post is rapidly makingway for cast iron or a block of concrete with arolled sheet iron standard. The wooden railroadbridge has almost disappeared, and even countryroad bridges are now nearly all built of iron.Wooden buildings now only exist because theforests have not entirely disappeared, and woodin its first cost is yet cheaper than other andbetter material for construction. The railroadcross tie is yet a perplexing problem; nevertheless,when the timber for its manufacture is entirelyexhausted, necessity will give birth to someingenious device or substitute in iron, glass, con-crete or paper, which will supersede the presentwooden cross tie, and will in all probability proveso far superior to it that those of a generation orso to come will contemplate with amusement theprimitive methods employed by their fathers in


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16 PATTERN MAKINGthe construction of roadbed, just as we of thisgeneration look with jocose good nature upon theoW wooden plow of our ancestors.It should not be inferred that any arbitrary setof rules can be devised governing the making ofevery description of pattern which the workmanmay be called upon to produce. The nearestapproach to an unerring guide, covering thewidest range of the subject, is the classificationof certain forms of patterns with drawings illus-trating each class, with concise and lucid expla-nations by which the well-informed and intelligentmechanic can work out problems in whateverclass they may appear. This is what the authorhas done in this work, and in a manner to insurethe certain accomplishment of his purpose, andyet the hope is nowhere excited throughout thisv/ork, either by direct statement or implication,that any self-educational facilities afforded by thestudy of this work will supply the deficiency ofnatural mechanical talent which must primarilybe possessed by any person who may hope toexcel in any department of mechanical science.

In a factory which employed over one hun-dred carpenters and cabinetmakers, I do notthink there were more than three or four who


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AND FOUNDRY PRACTICE 17could or ever did turn anything on the woodlathe, and whenever many of the others at-tempted to do so a complete failure was theresult, notwithstanding the most explicit verbalinstructions as to the holding of the tools and thepractical demonstration by the instructor takingthe tools himself and performing the operationfor the students.

In the preparation of this work it has been myaim to simplify and present all problems in alight so clear that the principles at least will bethoroughly understood by any reader of ordinaryintelligence; but the practical and successfulapplication of the principles expounded willdepend wholly upon the innate ability and care-ful execution of the operator. Even with nativetalent of the highest order, rough and carelesswork will not promote success nor obtain for theworkman any creditable reputation.The work of a pattern maker is clean and

pleasant, but requires a very high grade of skillto properly execute, even under the direction ofa skillful foreman. The cutting tools should bethe very best that the market affords, with edgessmooth and keen at all times. To the foremanof the shop every new job is "another problem


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18 PATTERN MAKINGto solve." There is no precedent for manyjobsno beaten path to follow. Often after ajob is completed a better way has been discov-ered, by which the job could have been done togreater advantage. There have been instancesof capable pattern makers widely differing intheir views of how certain patterns should bemade; each one maintaining vehemently that hismethod was the only right and proper one.


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FOUNDRY PRACTICEBefore entering into the details of pattern

making, let us first consider the customary wayof making castings; for if we are ignorant of themanner in which the moulder obtains the propercavity in the sand by the use of the wood pat-tern, it would be impossible to make the patternto the best advantage. I say this advisedly, andI believe that a first-class moulder can takenearly any object for a pattern and get it out ofthe sand, leaving the mould perfect, and make asuccessful casting. It has been authenticallyrelated of a certain moulder that he could mouldthe pronged horns of an antlered buck from thenatural pattern as it grew on the animal's head.I remember an instance of a farmer who broughtto a small foundry the fire bowl of a heatingstove, which was broken in seven pieces. A newbowl was moulded from the pieces, a feat ofmoulding which suggests a strong argument tothe pattern maker and which should convincehim that a knowledge of foundry practice is a

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20 PATTERN MAKINGmost powerful auxiliary to his trade, enablinghim always to make his patterns.

Castings are usually made in a flask. This iscomposed of two or more rough boxes, so con-structed, by the use of dowels or other devices,as to retain their relative positions at all timeswhen in use. This is absolutely necessary, asotherwise the casting would be one-sided orwould show a jog at the joint or parting.When more than two boxes are used, this flask

is called a compound flask. Usually only twoboxes are used, and this arrangement is called atwo-part flask. The upper box is called thecope, and the lower box the drag. The heaviestportions of a casting are usually left in the drag,which naturally retains its shape, thereby mini-mizing the risk of agitating the sand, whereasthe cope has to be lifted and moved around,which has a great tendency to disturb the sandin it and break and destroy the mould. Toovercome this danger, it is customary to put rodsor wooden bars, or both, across the cope,through the sand, v/herever they can be placedwithout interfering wath the pattern. Then barsand rods hold the sand in shape so that they canbe lifted to remove the pattern and replaced to


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AND FOUNDRY PRACTICE 21make the finished mould. Where it is possibleto do so, it is best to make a parting in thewooden pattern at the point where the sand inthe cope and drag divide on a straight Hne.This done, that part of the pattern which is tobe left in the drag is placed on a flat board orbench, with the parting down. The drag isplaced in an inverted position on the same boardor bench and "rammed up"; that is to say,filled and tamped solidly with moulding sand.The drag is then placed right side up on thefoundry floor and the upper part of the patternis put on. A parting is then made with fine dryparting sand and the cope is secured in placeand rammed up. Holes are then made downthrough the cope to the pattern, for the purposeof pouring the metal into the mould and also toallow the air to escape. The flask is then takenapart and the wooden pattern removed, leavingthe two halves of the mould, which are thenplaced in their proper positions, making a com-plete and finished mould. In ordinary work aboard, which is the size of the flask and is calleda "follow board," is used for parting. For somespecial work, a special follow board is used, asin cases when the parting would describe a


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22 PATTERN MAKINGcurve. In other cases a follow board is madefor a single piece pattern, like the hand wheelfor a car break, by bedding the pattern one-halfits depth in plaster of Paris, thus bringing theparting to the center of the pattern without anyparting in the wooden pattern and without theuse of the trowel. All these things are done forconvenience to the moulder, so that he can maketime in getting out his work.The first thing to be considered in looking at

a pattern is how it will best draw out of thesand. Every complicated form of casting pre-sents a partially new problem to the patternmaker. If a piece will readily draw out of thesand except one or more small projections, theycan sometimes be left on a dovetail slide, whichwill allow the pattern to be drawn, leaving apart in the sand to be removed later on; or if itbe a cavity, it must be cored out.

In preparing this work I have begun with thesimplest forms and kinds of patterns, progressinggradually through the more difficult features ofthe work, and for illustrations I have used prin-cipally patterns which may be found in duplicatein the pattern loft of the Hicks Locomotive andCar Works, near Chicago. These patterns have


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AND FOUNDRY PRACTICE 23been made by different pattern makers and havebeen selected with a view to properly illustrateideas and demonstrate such peculiarities of con-structions as are treated in this work.The very simplest form of pattern is repre-

sented by the cast iron washer, Fig. 1. Thispattern, being straight on one side, lies entirelybelow the parting and is consequently entirely inthe drag. When a great many pieces of anyarticle of this class are required, it is customaryto make whatis called"gated pattern," which , ^ =rosi section throvjih a ca^t Washer*consists of anumber of patterns made exactly alike andfastened together with small strips let into thestraight side, level with its face. Then smallstrips lying on the follow board leave littlegrooves in the sand which allow the molten metalto pass freely into all the moulds, which areeasily broken apart when the metal cools. Thismanner of moulding this kind of pattern issimilar to that previously described, except thatthe cope is simply placed on the drag and filledwith sand, as there is no part of the pattern


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24 PATTERN MAKINGprojecting up into it. A better understanding ofthis may be derived by a study of A-1, Fig 2,wliich shows a cross-section through the drag,the pattern, the follow board and the sandrammed up. Fig. 2 shows the cross-section ofthe entire box and its contents ready to be in-verted and placed on the foundry floor, when thefollow board is removed and the cope secured in

''


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AND FOUNDRY PRACTICE 25shape as to render the moulding of the castingmore convenient when it is entirely up in thecope. If executed otherwise, the sand in the

ssfiiiay

Cro53 section through finisheci inould

cope would make it heavy and clumsy and verydifficult to handle and the cope would have atendency to drop off and ruin the mould/ In

^ It should be borne in mind that the manner of mak-ing the mould depends entirely upon the nature of thework and the purpose for which it is to be used.

Thus it will be found that all, or nearly all, stove cast-ings are made in a manner exactly the reverse from thatwhich is employed in the moulding of ordinary castings.The hollow or concave parts are usually made down inthe drag, and the sand in the cope is strengthened bycross bars of wood fitted in such a manner as to come asnear the metal as is practicable, and these bars are drivenfull of nails or made with other projections in order toprevent the sand falling out. By this means a smoothcasting on the outer surface is obtained, as the metal,being heavier than the dross or other foreign substances,


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26 PATTERN MAKINGthis case the pattern, which is assumed to behollow or of cup shape (see Fig. 4), should be

placed onthe followboard withthe cupor hollowdownward.Over thisshould beplaced that

part of the flask which is to be used for thecope, and it should then be rammed up in the

Tig ^


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AND FOUNDRY TRACTICE 27usual manner, after which the proper vents toreceive the moulten metal should be made/

The cope should then be turned over, the followboard removed and the drag placed in positionand rammed up. Then the flask (cope and(cope and drag). This clamp is slipped on the flask andthen crowded into a slightly diagonal position with ashort bar or chisel, used as a pry, and which holds theboxes firmly together. For small work the flask ishinged together on one side with an iron hinge so designedas to be readily slipped apart.

^ The vents or holes down through the cope for pour-ing the metal, are called gates, and are made by placingtapered pins or wedges of proper size in the cope andtouching the wood pattern. These, being withdrawn,leave the desired gates or ways for the molten metal topass into the mould in the sand.


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28 PATTERN MAKINGdrag) should again be turned over, taken apartand the wood pattern removed, leaving the fin-ished mould as shown in cross-section, Fig. 5.In many instances it is customary to part thesand entirely by the use of the moulder's trowel,especially where the pattern is of some simpleform, or where only a few pieces are required,as, for example, the small connecting rod shownin Fig. 6. In this case a flask is filled with sandand smoothed off, after which the pattern or

patterns are pushed down into the sand abouthalf of their depth, or to such a point as willmost readily permit their withdrawal from eitherway. The moulder then smoothes the sanddown and packs it thoroughly around the pat-tern with his trowel. Then a parting is madevv^ich dry sand and the cope is placed in positionand rammed up as previously described. SeeFig. 7, which shows a cross-section through thesame pattern in the sand. Many other forms of


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AND FOUNDRY PRACTICE 29castings are parted in this manner where theparting, instead of being on a plane with theparting in the flask, is curved or has suddencrooks and offsets. In such cases the sand ispacked in the drag to conform as nearly as pos-sible to the crooks in the parting. The patternis then placed in position and bedded firmly inthe sand. The moulder then packs and trowelsdown the sand around the pattern until a perfect

V/eTf' cartel core

-|j|fw:r:r7:^^^^r3^g-^l^:- 'A'.'-v.-f-^^*;

SnUonal view of mould foT Fig 6 Wio\mff pattem m 9andparting is made, sometimes cutting deep cavitiesaround portions which otherwise would tearout the sand in drawing the pattern. In thismanner an expert moulder will get out formswhich at first glance look to be impossible. Butprimarily it is the duty of the pattern maker so toconstruct his patterns as to reduce to a minimumof intricacy all of these difficult problems withwhich the moulder may be confronted. As aninstance of the value of a correctly-made pattern


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30 PATTERN MAKINGas an initial desideratum, see Fig. 7a, whichillustrates a small fire extinguisher top andwhich, at a cursory glance, appears very diffi-cult, but which in reality is readily drawn out ofthe sand. This is a cup-shaped brass castingwith round, projecting handles serving to screwand unscrew it. A cross-section of this is shownin the sand in Fig. la. The heavy lines show

113. 7 **^Toss SfCtton i Tirongh fire e tlitigmsJter tcp & ntoii'lci

the parting in the flask and the dotted lines showthe parting in the sand.

It is of the greatest importance that a patternshould have draft; that is to say, it must be ofsuch a shape that it will begin to loosen fromthe sand the moment a move is made to draw itout. To facilitate a ready loosening and suc-cessful withdrawal from the sand, all patternwork should be slightly out of square or slightly


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AND FOUNDRY PRACTICE 31beveled; i.e., it should be a trifle smaller at theportions which are embedded the deepest in thesand. Then again, the moulder often raps somepatterns very heavily to get them out. That isto say, a pointed iron, which is driven into thewood pattern for the purpose, is smartly struckin all directions, causing the mould to becomelarger than the pattern. Some patterns areso shaped that they cannot be drawn outof the sand, as they may be hollow and ofirregular form, or contain cavities or projectingparts which would tear out or loosen the sand.In all such cases it becomes necessary to usecores, to prepare which boxes or moulds aremade of the proper shape. Into these boxes ormoulds a preparation of sand with flour andmolasses is packed, and the forms or cores somade are balced in an oven. After beingthoroughly baked, these cores become firmenough to stand handling and will support theirown weight across a considerable space. Forcertain purposes cores are sometimes madeby substituting linseed oil, rosin, etc., forflour and molasses, and these are consideredsuperior, as they make a smoother and strongercasting.


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32 PATTERN MAKINGIn some instances the required cavity in the

casting will be of such a form, or may be com-plicated in such a manner, as to render it verydifficult to mould the desired core in a singlebox, and therefore in many instances two ormore cores are made and glued together. Thecores for some of the parts of improved pneu-matic tools in use in modern boiler shops havebeen made up of from twenty to thirty pieceswhere the desired cavity was so complicated asto be impossible of construction in a single corebox. It is also frequently desirable to use coreson work which could be drawn in the ordinarymanner, and this is when the casting is hollowand thin enough to spring easily. In all caseswhere cores are used, the pattern, instead ofbeing the shape of the desired casting alone,should have certain projections, termed "coreprints," added to it. These core prints leavetheir impression in the sand, thus forming acavity to hold the projecting ends of the core.In such cases it is necessary that the patternmaker should construct his core boxes in such amanner as to produce a core of the exact shaperequired by the cavity in the casting, togetherwith such projecting parts as will exactly fill the


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AND FOUNDRY PRACTICE 33cavities in the sand left by the core prints on thepattern. To illustrate this idea, a stake pocket,such as may be seen on the sides of a gondolaflat or coal car, has been selected, the pocketitself being of the form shown in Fig. 8. Thiswill readily draw out of the sand and it is fre-quently cast in this manner; but on account of

F/> eits thinness it is more apt to spring out of shapethan if it were cast with a core, as shown inFig. 9.

Patterns are painted in such a way as to showwhich portions are iron, and the core prints areleft white or painted of a light color. Usuallycolored shellac is used for the black portions anduncolored for the core prints. By this means


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34 PATTERN MAKINGthe moulder can tell at a glance the moment hetakes up the pattern just how to make the cast-ing. Recently, through the carelessness or ig-norance of a pattern maker, over two hundredpounds of cast fittings in the Frisco R. R. shopsat Cape Girardeau, Mo., were cast solid instead ofhollow, because of the entire piece having beenpainted black, when the core print should have

jF\y 9been left light. In moulding patterns of the classshown in Figs. 9 and 10, the process is much thesame as has already been described. The lugs"a" "a", Fig. 10, are made removable, andwhen removed the pattern. Fig. 9, is laid flat onthe follow board. The drag is then placed inposition and rammed up; then it is turned overand the lugs "a" and "a" inserted, the cope se-cured in its proper position, the parting made


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AND FOUNDRY PRACTICE 35and the cope rammed up, as heretofore described.The flask is then separated and the wood pat-tern. Fig. 9, is removed and in its place the coreis laid J making the complete mould, as shownin Fig. 10.

Small patterns are often gated together, aspreviously mentioned, or a flask is leveled off anda quantity of tliem stuck around here and there,

///

{gcftoytCT? vt'gw o mould for /yy's a flf ^ ^howin^ paiicrn itt_ sangwhile in other cases the pattern will be almosttoo large to be put in a flask at all. In suchcases it is customary to dig a pit in the floor ofthe foundry to answer for the drag, and in thecase of large castings, such as flywheels, enginebeds, etc., the pattern itself is so heavy that itcan be handled only by the use of a power hoistor crane.


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PATTERN SHOP PRACTICEIt is customary in pattern shops to furnish the

pattern maker with a mechanical drawing or blueprint of the part to be made. This is very im-portant, in fact almost an indispensable part ofthe work, and yet often this drawing falls farshort as a reliable guide to the pattern maker;for wliile it may indicate clearly enough the styleof casting desired, it may contain no directionsor suggestions which will govern or assist thepattern maker in the construction of the pattern.Although the office drawing may be a perfectrepresentation of the casting itself, the patternmaker's drawing should show not only thecasting, but also the cores, core prints, etc.,etc., and where practicable the pattern maker'sdrawing should be full size, in order that thedimensions may be taken directly from the draw-ing with the dividers. Some shops may onlyemploy a rough sketch with figured dimensions,and this is especially true of large repair shops,the foremen of which will send a man fifty or a37


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38 PATTERN MAKINGhundred miles down the road to repair enginesor cars which have become temporarily disabled.This man will frequently find a cracked or wornout casting or a burned out set of grate bars, inwhich event the number and date of the enginewill be noted and every effort will be made tosecure a correct description of the broken part inorder that the blue prints of the engine may beconsulted and the part located exactly. It oftenoccurs, however, that the blue prints of adamaged engine have been mislaid ; consequentlythe pattern maker is instructed to make, say, agate bar for the engine and have it ready for theengine immediately upon its arrival at the shop.Having failed to find the blue prints of theengine, the foreman, as a last resource, carriesto the pattern shop a memorandum sketch takenfrom the notebook of the mechanic who had beensent to repair the engine, and from this crudedrawing (see Fig. 00) the pattern maker is re-quired, at very short notice, to make a patternwhich will give satisfactory results. Any oldemploye of a railroad shop will recognize thischaracter of drawing (Fig. 00). It is apparent,therefore, that the pattern maker should under-stand mechanical drawing, at least to an extent


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AND FOUNDRY PRACTICE 39sufficient to enable him to make full size workingdrawings of any piece of pattern work which hecontemplates producing.

Drawing is the art of representing objects on aplain surface by the use of lines and shadows.Mechanical drawings are further illustrated andexplained by the use of dotted lines, figures, let-ters, etc. For certain purposes mechanical draw-ings are sometimes made in perspective; but forpattern shop uses perspective effect is neveremployed. Two or more views of any object

Fig. 00

treated should be given in a mechanical drawing.The art of drawing in a very high state of prac-tical usefulness is now taught by several cor-respondence schools, and it ma.y be readilyacquired by any ambitious person.

Ordinary drawings for most patterns may bemade with a lead pencil, a pair of dividers with


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40 PATTERN MAKINGa pencil point, a pair of beam compasses ortrammel points and a steel square. Many oldpattern makers use no other tools and maketheir drawings on the surface of a smooth plank,which only needs planing off to be ready for thenext job. A much better way, however, for animportant job is to make the drawing on heavymanila paper, which can be filed away for futurereference. Where paper drawino-s are to be used

ris tt

it will be found very convenient to have a fewregular drawing instruments. The drawingboard should be of any convenient size andmade of well-seasoned, clear, soft pine, perfectlystraight and square, with hardwood cleatsdriven snugly into dovetail gains or groovesacross the back of the board, as shown in Fig.11. The T-square is used for drawing parallellines, either way, across the board, and is made


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AND FOUNDRY PRACTICE 41of any hard, straight-grained wood. Pear woodis excellent for this purpose; mahogany, cherryand maple also being used. A most excellentT-square is made for the trade with a trans-parent celluloid edge. A proper T-square forpattern shop use should have a blade at least

y^rT^

three feet long, S'X^y'X^^", and slightlybeveled toward the edges, with a head 2i''Xi"fastened securely at right angles to the blade.The most approved form of joint for a T-squareis shown at a 6, Fig. 13, A tapered dovetailedwedge is glued to the blade of the square with>-- Dove, tail we^j9-

-I 1^ . E

ri3 IS

the grain of the parts running at right angles toeach other. A corresponding notch or mortise ismade across the head of the square, which allowsthe blade to be taken out of the head and truedup. The joint can be better secured by the useof a few round-head screws, if desired. The


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42 PATTERN MAKINGset squares or angles are used to draw parallellines, at right angles to the blade of theT-square; or to draw such angles as appear inthe corner of the set squares (see Fig. 14). Thefirst of these set squares contains an angle of 45in two corners and an angle of 90 or a rightangle in the other. This is used to lay out octa-gons, or to bisect the right angle, producing a

Fi^ i


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AND FOUiNDRY PRACTICE 43squares are yet in use for certain purposes; butfor general use the modern celluloid or amberoidinstruments are so far superior, on account oftheir transparency, that the wooden ones havefallen into disuse.A set of mathematical instruments may be

bought for from $2.00 to $25.00 or more, accord-ing to the fancy of the purchaser. The very

Tin /sr

cheap ones are not desirable, and in buyinginstruments or tools it is always advisable toprovide the very best that one's means will per-mit. An indifferent mechanic can never do goodwork with inferior tools and a good one will notuse them when he can possibly avoid it. Theset shown in Fig. 15 has fairly good points and


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44 PATTERN MAKINGwill answer very well for persons of limitedmeans. A set of this kind retails for about$6.00 and will answer every purpose for the classof drawings required in the pattern shop.

In making up the working drawings for shopuse it is preferable to trace the outlines faintlywith a sharp, hard lead pencil. After this hasbeen done the drawing can be brought out withink or a soft, black lead peacil. When the draw-ing has been plainly brought out, some drafts-men give the cores or core prints a yellow tintand darken the parts which are to be metal.This not only improves the appearance of thedrawing, but has additional advantages, espe-cially if some workman other than the draftsmanis to work from the drawing, in which event thecoloring of the drawing obviates the risk of anymisconception of what the finished pattern is tobe, thereby preventing what might otherwiseresult in awkward mistakes. Mechanical draw-ing, being a scientific subject in itself and onewhich for an elaborate elucidation would involvea voluminous treatise, can only be cursorily re-ferred to in a book of this nature, and it musttherefore be assumed that the reader is suffi-cieutly familiar with the principles and practice


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A^D FOUNDRY PRACTICE 45of mechanical drawing to readily understand theinstructions pertaining to the subject-matter ofthis work.The pattern shop should always contain suffi-

cient space to provide for the free and comfort-able execution of its greatest volume of productionand should be arranged with a view to affordample room for the advantageous distribution andlocation of machinery, benches, trestles, clamps,tools, etc. The light should be as nearly perfectas it is possible to obtain and preferably derivedthrough skylights which direct the rays verticallyupon the work, thereby escaping the shadowsthrown upon it by light which strikes it horizontallyfrom the side. The room should be so arrangedthat a proper temperature can be maintained inwinter to insure the successful gluing of work, ascold destroys the adhesive quality of glue and isdeti-imental to good work in many ways. Thework bench is usually made of three-inch plank,in order to keep the top true. The vise shouldbe of modern construction, capable of beingused either as a high or low vise, and should beequipped with an adjustable jaw for taperedwork, and so arranged as to hold the workfirmly without bruising it. The shop should be


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46 PATTERN MAKINGequipped with a band saw or at least a jig^ saw,a pattern lathe and suitable clamps for gluingup material. In large shops a rip saw and woodworker will be found very useful. The highestgrade of glued work, such as piano and organcases, sleeping car bunks and fine furnituregenerally, is made by using hot glue applied towood which has been heated to receive it; thework being done in a room heated for the pur-pose. Work glued up in this manner is verystrong and better for many purposes than solidtimber; but unless special arrangements havebeen made for this work, ordinary glue is liableto become chilled and lose its strength. Thereare several preparations of liquid glue v4iich arevaluable substitutes in many classes of workwhere conditions are not favorable to the use ofhot glue. These liquid glues, being very slow toset, allow plenty of time to work over a piecewhere the assembling .of the parts is tedious,and the result is far better than that which isobtained by clamping hot glue between two coldsurfaces, the effect of which is to convert the glueinto a jelly, with little or no adhesive qualities.The workman, however, will have to decide forhimself which kind of glue is best suited to the


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AND FOUNDRY PRACTICE 47specific conditions of the shop in which he isemployed. In shops where the general conditionsfor gluing are bad, liquid glue promises the bestresults, when nails, screws or wood dowel pinsare used to add such strength to the parts as thenature of the work may demand.


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TOOLSIt is highly impracticable to attempt the

enumeration of any exhaustive list of tools forpattern making, as the field covers such a widerange of work that unless it were limited to somecertain branch of the trade, it would tax theingenuity of the most resourceful inventor to con-ceive of such a tool that the wood worker mightnot at some time meet with a situation requiringits use. To the workman engaged entirely inthe making of stove castings, his carving toolsare the most important of his kit; while if hiswork were confined to the making of patterns forheavy machinery, the need of carving toolsmight never be felt. The making of wood pat-terns, while the principles involved are much thesame in all cases, covers the widest range ofwork of any branch of the wood worker's artand embraces castings from the size of door keysand windov/ latches to the ponderous parts ofthe giant engines which supply the water togreat cities, turn the v/heels of mammoth fac-tories and propel the iron-ribbed reindeers of the

49


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50 PATTERN MAKINGsea, hurling them plunging through the greensurges of the sea. Most pattern makers carry avery complete assortment of cabinet maker'stools, including their lathe tools or turningchisels, gouges, etc., and also a set of longstraight gouges, called pattern maker's gouges,with a set of carving tools for some classes ofwork. The special tools for pattern making,independent of those in general use, are shownfrom Fig. 16 to Fig. 22.

Fig. 16 represents the pattern maker's gouge,which is made in all sizes from J to 2 inches.This tool is used for making core boxes and forparing out all kinds of convex surfaces. It isindispensable to the pattern maker. Fig. 17represents the turning gouge, about three sizesof which are usually considered sufficient for allpractical purposes. This tool is used for rough-ing out work in the lathe, and for turning andfinishing the concave portions of the work.

Fig. 18 represents a paring tool, of which notmore than two sizes are usually needed. Thistool is used to finish the work in the lathe afterit has been roughly formed by the gouge. Theflat chisel. Fig. 19, is used for turning beads,ovals, etc., and for sizing particular work as


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AND FOUNDRY PRACTICE 51indicated by the calipers. In such cases it isused much in the same manner as a scraper.^

Ttg 1Th9 pattern 'mahn ,^ugo

Tia Itf'","f*

^Tig /The: flal rhhel

"The pari t Itq toot

' itili itoseci cAist?

The parting tool, Fig. 20, is used for cuttingdeep grooves and for cutting off work in thelathe. The diamond point. Fig. 21, and the


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52 PATTERN MAKINGbull-nosed chisel. Fig. 22, are used for turningboth the outside and inside surfaces of hollowpatterns, such as the piece shown in cross-sectionin Fig. 23.

Figs. 15, 16 and 17 can be procured at hard-

Ti^ 23

ware stores generally. The rest can be had fromlarge supply houses, or from dealers in toolspecialties, or they can be made by a first-classsmith. In addition to the tools heretofore men-tioned, the pattern maker will sometimes find it


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AND FOUNDRY PRACTICE 53convenient to have special tools of a peculiardesign for some special work.

The shrinkage rule is a measure designedespecially for pattern making, and is intended tomake the proper allowance for the contractionof metal in cooling. However, it is not possibleto accurately figure the contraction or shrinkageof metal, as a thick casting will shrink morethan a thin one. Some shapes shrink more thanothers or more in some parts of the same piecethan in other parts. A large cylinder, if cast onend, will shrink more at the bottom than at thetop. Castings are calculated to shrink from one-tenth to one-eighth of an inch to the foot; but,as nearly all machine castings are either turnedor planed to an accurate size, the determina-tion of the exact amount of shrinkage is ina great measure immaterial. Then again,in cases where the moulder raps the pat-tern heavily, in order to withdraw it fromthe sand, the casting will show but little ifany shrinkage.The lathe is perhaps the most important of all

the pattern maker's tools. A lathe suitable forordinary pattern work should have a swing of atleast twelve inches over the bed and it should be


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54 PATTERN MAKINGso arranged as to allow a face plate for work oflarge size to be swung off over the end of thebed, as shown in cross-section in Fig. 23. Aheavy cast iron tripod of sufficient weight to re-main steady when in use, is employed to holdthe rest for this lathe.The art of wood turning has by tradition

always been and is at the present time classifiedas a trade to itself, properly appertaining to thecabinet shop and planing mill; for the art, whenapplied to pattern making, differs so materiallyfrom that of ordinary cabinet and planing millwork, that it cannot be considered in the samecategory.The wood turner, working by gauges or marks

on the lathe rest representing his measurements,depends almost entirely upon the accuracy of hiseye and skill of his hand to obtain the requiredform and size of the piece; as the compensationfor such work is often determined by a fixed rateper thousand pieces, the operator soon acquiresa peculiar sleight for getting out a great quantityof material in a given length of time, which, ifdisplayed in regular rows, presents an appear-ance sufficiently uniform to answer all the pur-poses for which the finished work is intended,


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AND FOUNDRY PRACTICE 55although it could not stand the test of rule andcalipers.

The pattern maker, on the contrary, worksfrom a drawing of some part of a machine orother device, showing the figured dimensions ofall its parts. Every figure bears an importantrelation to the finished work and each part isrequired to correspond with mathematical pre-cision to some other part already completed orin process of completion in another departmentof the same factory, or mayhap in some distantcity. The loss of only the sixteenth of an inchof material in any part may mean the loss of theentire piece. Hence the paramount necessitythat the maker should exercise the most scrupu-lous care during the process of work, stoppingfrequently as he proceeds to test his accuracywith rule or calipers or both, for only painstakingvigilance will assure to even the most adroitmechanic a perfect duplicate in its minutest de-tail of the part represented in the drawing.Manifestly, then, the art of the wood turner con-sists in turning out great quantities of pieceswhich bear to one another sufficient resemblanceto answer the purposes for which they are de-signed, whilst the science of lathe turning, for


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56 PATTERN MAKINGpattern making, lies wholly in the accuracy andperfection, and not in the volume of work per-formed.

In operating the pattern lathe to turn out hol-low forms it is customary to fasten discs of woodto the iron face plates of the lathe with heavywooden screws. The work to be turned is thensecured to the face of these discs with otherwooden screws passing through the woodendiscs into the back of the piece to be turned.See Fig. 23. When a pattern is to be screwedon the face plate, these wooden discs are markedwith the point of the turning tool at the outsideor inside of the piece, and it can then be turnedover and fastened true to center.To formulate any set of rules which will

apply to the production of all kinds of patternsor to the solution of every problem in patternmaking which may arise would involve adegree of knowledge and a gift of propheticvision which cannot be expected to fall to thelot of any observer, however patient may havebeen his research or broad his experience;therefore, in the treatment of this work, I haveavailed myself only of such forms of patterns ashave been successfully made under my own


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AND FOUNDRY PRACTICE 57supervision and observation ; using these forms asobject lessons to illustrate the subject and impartto the student a practical knowledge of the essen-tial principles of pattern making, in order thathe may be well preparedassuming, of course,the possession of natural talentto grapple withevery new and perplexing problem with whichthe interminable intricacies of the craft may con-front him in any hour of his career. And inci-dentally I have introduced into this work a fewproblems submitted to me by workmen famiHarwith foundry work in all its details, and whilst Ihave not seen these problems demonstrated byactual practice, my certainty as to the correctnessof their illustrations enables me to present themto the reader with the utmost confidence in theirpractical value.


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MAKING THE PATTERNMany patterns are of the simplest form and

require only a single piece of stuff > turned orcarved into a proper shape, finished with shellacand having proper draft and shrinkage. Thesesimple patterns are usually given to the appren-tice boys to make; for instance, the pattern of acast washer, such as is represented by Fig. 1.

Assuming this washer to be for a ij-inch rod,the diameter of the stock would be about 7inches and the thickness If inches. To makethis pattern, a disc is cut out of wood 7|XlJinches, one side is made true and straight and itis then secured in the center of the face plate.The pattern is then faced off with the diamondpoints and the center located with a pair of divi-ders as the piece runs in the lathe. Next a line islaid off for the center hole, a line for the edge ofthe O. G. and a hne for the outside. Now theoperator cuts straight into the face plate on theoutside line and with a very small gouge, turnedsideways, roughs out the O. G., taking care thatit does not jump back and tear up the work.59


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60 PATTERN MAKINGWhen the operator is not sufficiently expert withthe gouge to turn the O. G. it can be scraped toshape with the bull-nosed chisel. Next the holeis cut out with a small, stiff, flat chisel, leavingplenty of draft. When the pattern is turned itmust be sandpapered to a polish, taking extracare that the hole is left smooth. Next shellacof any desired color is applied, and when itbegins to set it is polished, while still revolving,with an old cloth and a few drops of linseed oil.

Fig. 6 represents the piece sawed out as nearto shape as possible and then carved or whittledand finished with sandpaper and shellac.

Passing on to another class of patterns, thestake pocket affords an apt illustration. Thispiece is easily cast from a form as shown inFig. 3. It has sometimes occurred that an oldstake pocket has been picked up in the yard,smoothed off a little, the sand holes puttied upand the piece shellacked and used for a patternfor other pockets. This method, however, wasonly resorted to when it was necessary to get carsready for service on very short notice. Theusual custom and the proper method is to castthis pattern with a core. The procedure for thisis as follows: First the working drawing (see


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AND FOUNDRY PRACTICE 61Fig. 24, a and h) should be made up full size bythe shrinkage rule. Next there should be laidout a pattern on a thin veneer of the cross sec-

CoT-e

TlQ 2ftion through the metal as it appears in the full-size working drawing, and the pattern cut outwith a sharp knife. Then this pattern shouldbe plainly marked with a pencil on both ends of


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62 PATTERN MAKINGa plank of sufficient thickness and length, cuttingaway all the surplus wood with ordinary hollowsand rounds, and this will leave a moulding of theexact dimensions of a cross-section through themetal forming the pocket. Now a block shouldbe made of the exact dimensions shown in theworking drawing and marked "Core" (see Fig.24, a and 6), and the prepared moulding shouldbe glued to this block as shown in Fig. 24. Asquare joint at the corner is proper for thiswork. When dry, the corners should besmoothed up, making all parts of the mould meetand match. Next four holes should be bored atc c c c, Fig. 24 6, making the tenons just largeenough to fit snugly into the holes. Then theentire work should be smoothed and polishedmaking the parts which are to be iron jet black,and leaving the core prints in the natural wood.Following this a core box is to be made,which should be exactly of the dimensions andshape inside as shown by the working drawing.Such a box is shown in Fig. 25 and may be opentop and bottom. In order to make a core in thisbox, the core maker puts the box together beforehim on the table. He then fills it with preparedsand and smoothes it off level with the top.


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AND FOUNDRY PRACTICE 63Core boxes are finished and polished on the

inside only.The next example is a casting which was made

for a pump of some description. It is a cylin-der which had a flange at one end and a pipethread at the other (see Fig. 26). As in theprevious example, the first thing required is the

Joi

working drawing, which, as has already beenstated, must show the casting, the core and thecore prints. Fig. 27 shows a cross-sectionthrough the casting and core; this being the onlydrawing needed for making the pattern. Thispattern was made by gluing together pieces ofmaterial of ordinary size, as a solid block sufii-


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64 PATTERN MAKINGciently large was not obtainable, and It was amatter of no little difficulty to secure a piece ofmaterial of sufficient diameter to turn up the

flange. It was also desirable that the patternshould be divided in the middle without rippingit through after turning it up. To accomplish

>

J'/y 37this the stock was prepared as shown In Fig. 28,and in cross-section in Fig. 29. The piecesa a were first doweled together and shorttenons, d d, made across the ends of the piece


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AND FOUNDRY PRACTICE 65and so fastened together in line with the joint.The gain for the flange piece, b 6, was thencut to the desired depth clear around the piece,

0:'i

3i!1i

hongiiudLincil sectioji ihroiicflt GfocTr for* Pzq SGand the flange pieces fitted in. The pieces, a a,were then taken apart and the flange pieces glued


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66 PATTERN MAKINGapart when completed. Then the parts wereput together again, grooves of proper size werethen cut in the blocks c c to engage the shorttenons d d and the blocks glued on to the endsof the work, as shown in Fig. 28. When thor-oughly dry, the ends of the prepared stock werecentered, the stock then put into the lathe andthe pattern turned up, leaving the projectingends, as shown in Fig. 27, for core prints,which come apart easily for the convenience ofthe moulder.

This pattern only requires half a core box, alongitudinal section of which is shown in Fig.27; the cross-section describing a semicircle.Two pieces are used to make the core. Manymoulders use ordinary flour paste to glue orcement their cores together. All such patternsshould be painted in the parting just as shownin the working drawing, in order that themoulder may see at a glance just which part isto be metal and which core.^

Fig. 30 shows a cast pipe fitting which was

'AH patterns should be painted so as to distinguishmetal from core. Patterns for iron should be dark withlight cores, and just the reverse for brass. All patternsare finished in shellac, rubbed to a polish.


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AND FOUNDRY PRACTICE 67used for steam heating. This fitting has beenselected on account of its peculiar shape, whichadmits of making the entire pattern and part ofthe core box on the lathe.

Fig. 31 shows the working drawing, the firstthing to be made in all cases before proceedingto make thepattern,reference

drawing it willbe seen thatthe straightparts a and hcan be madeby exactly thesame processas describedfor makingFig. 27, with the exception that no flangeis required. The circular portion c is turnedout of a disc of proper size secured to theface plate and turned to a true semicirclein cro.ss-scction, as shown in Fig. 31 J, which,being cut across through the line of itsdiameter and placed face to face, forms the

7^7^ J30


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68 PATTERN MAKINGhalf circular portion of the pattern c, Fig. 31.The only difficulty to be met with in makingthis pattern is the miter joint ^, which isfound by the intersection of parallel lines of equaldistance from each other on the straight side,with similar circular lines struck from the center

.^^^^^^^;^^^^^;^^^^^


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AND FOUNDRY PRACTICE 69mainder will have to be carved out with gougesand the finished core box made as shown in Fig.33. It will be observed that in this pattern afull core box is required, that is to say, two halfcore boxes,made right andleft, and dow-eled together.The next

pattern treatedis that of adouble - flangedwheel, for useon an overheadtraveling crane.Reference toFig. 34, a andb, which shows an elevation and cross-section,will afford a clear idea of this wheel.

There are so many ways to cast this wheelthat it makes a nice illustration. The first thingto be considered is how to get it out of the sand,which problem we think is best solved in themanner shown in the working drawing, Fig. 35,A and B. By this method almost the entirewheel is cored out; but it is by no means an

7^^ 3/r


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70 PATTERN MAKINGintricate task and is clearly illustrated in Fig. 36,which contains a sectional view of the finishedpattern.To make this pattern, cut out the discs a a.Fig. 36, of proper size for turning up. To these

T^a 7fCf oj tvrrnTto co-re "hote for Tiq 30

discs glue the band h in sections, and to one discthe core print c. Next attach the prepared discsto the lathe and turn up, as shown in cross-sec-tion, Fig. 36. Turn up two core prints, d d,and dowel the two halves together, making thefinished pattern.


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AND FOUNDRY PRACTICE 71Three core boxes are required for this pattern:

a plain half core for the center hole through thewheel, which has already been explained; a corebox representing all the cavity between the spokesof the wheel, Fig. 38, represented by the six

Qyte lidlf of cott lox for Tig 30

cores marked h 6, Fig. 35, B, and a circularcore box turned into the face of a plank (seeFig. 39, a and fe), which will mould half of thecore d shown in Fig. 35, B.A pattern for this wheel can be made without

coring out the flanges, by contriving the pattern


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72 PATTERN MAKINGto part near one side or at any place which willpermit the successful withdrawal of the half pat-tern. For a wheel cast after this pattern a three-part flask or a flask made of three boxes with aparting made between each box is employed.(See a a, Fig. 37.) It is possible to cast this

o^TJj 3^

pattern in a two-part flask without any corewhatever, and although this method is not recom-mended because of its greater cost and inferiorityto other ways of doing the work, it is well thatthe pattern maker should be familiar with theprocess. To make this pattern the wheel shouldbe made as shown in Fig. o34, with spokes and


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AND FOUNDRY PRACTICE 73hub complete. The center hole, the hub, bothsides of the rim and the spokes should have am-ple draft and the lower flange should be left looseso that the pattern will part at the line a b, Fig.o34.To mould this pattern, the cope is laid down

T75 3


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74 PATTERN MAKINGsand is then filled in to g-h and a second partingis made at c-g n-j. Now the drag is put in place

and rammed up. The flask is then inverted andthe vents made, when the pattern will appear asin Fig. o34. The cope, which should part along

C o 73 e. J. ... ' >.''"

&hoY/inq hoW I^rtjSt nrny levtoiildecl rn a It/opart

the line c d i e f, is now removed, as is also thepattern from the line a b upv/ards. The flaskshould then be put together and turned over,


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AND FOUNDRY PRACTICE 75removing the drag, which should part along theline c g hf, after which the flange is removed.The flask is now put together again and turnedover, which completes the work, and it is readyto receive the moulten metal. If the pattern isexactly right and the moulder is both expert andamiable, the casting can be made in this way,

Joi-n t

Tig ae

but this method is given more as an illustrationof what can be done than as a sample of goodpattern shop practice.Many difhcult or otherwise impossible formscan be cast by using a three-part flask. Thedouble-flanged gear wheel, Fig. 40, a and 6, is anillustration of work usually cast in a three-partflask. It can also be moulded in a two-part


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76 PATTERN MAKINGflask by making a double parting in the sand, asshown in Fig. 37. Or the gear can be coredinto the wheel.The next problem treated is that of an ordi-

nary brake wheel or hand wheel, such as is usedon freight cars, and which will serve more toillustrate wheel making in general than any

Tig 3

peculiarity in the construction of this particularpiece. In this pattern. Fig. 41, nothing is re-quired but a plain wooden wheel. The squarehole in the center, being tapered, makes its owncore.


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AND FOUNDRY PRACTICE 77When a great number of wheels arc wanted

the pattern is bedded half its depth in plaster of

Tf'q o3-yCraiJ jMfjoTi throtigh.nxoulot ^l^^y/a^ pattern -in tTtc sanB.

Paris and the plaster cast so obtained is used fora follow board. This arrangement brings the

ri^ -o

parting to the center of the patternwithout the

use of the trowel.


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78 PATTERN MAKINGTo make this pattern it is best to lay out on a

plain board the design or outline, as shown inFig. 41, dividing the rim into any number ofequal parts. In this case there are six equalparts. One of these parts is a suitable patternfrom which to saw out the rim, allowing a little

extra woodon both sidesfor turningup. Hav-ing roughlysawed outthe parts ofthe rim, fitthe jointstogether, onthe drawingor outline,

" taking carethat the parts of the rim are so fittedtogether that they will describe in the rough asnearly as possible a perfect circle. Then gluethe second layer on to the first, breaking jointswith the sections, so as to form a rough ring, asshown in Fig. 42. Next secure this preparedring to the face plate in proper position so that

Tis ^f


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AND FOUNDRY PRACTICE 79the tool will cut as nearly even all around as pos-sible and turn up the ring so that it will be incross-section, as shown in Fig. 43, using a thinwood or metal pattern to secure the desiredshape. (See Fig. 43.) Now, with the turningchisel, mark the face plate lightly as a guide, in

order that the ring may be turned over and yetbe secured to the face plate in its exact formerposition. Another way to maintain the ring inits proper position when turning it over is to tackfour httle blocks or brackets to the face plate sothat they will just touch the work to be turnedover on either the inside or outside of the circle.


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80 PATTERN MAKINGThese blocks or brackets always bring the workto its exact position in reversing. Now proceedin like manner with the reverse side of the pieceand the result will be a round ring, which will

be round alsoin cross-section.Then get outthe hub ofproper dimen-sions, mortise atapered squarehole in the cen-ter for the brakestaff, cut sixgains in the huband in the rimto receive theends of thespokes, and se-cure both huband rim in their

proper relative positions to the plank, usingthe working drawing as a guide to put theparts together. Provide six spokes of the de-sired form and fit them neatly into the gains.All the parts should be snug and tight enough in

-rig -^3


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AND FOUNDRY PRACTICE 81their adjustment to one another to require onlya light blow to drive them home. (See Fig. 44.)Lastly finish up the spokes as desired and coatwith black shellac varnish.The making of cog or gear wheels is one of

the most important features of the pattern

maker's trade, and although a drawing or blueprint is usually provided in repair shops, the oldcog wheel itself is sometimes given as a guide.A brief review of the principles of gear work andthe technical terms employed by mechanics inrelation to it will serve the purpose of this vol-ume, inasmuch as every pattern maker should


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82 PATTERN MAKING

A ' ' 1^

possess a reasonable knowledge of the principlesand practical operation of the machinery in com-mon use for which he may be at any time calledupon to produce patterns.

Gears are either straight or beveled. Straightgears are square on the face and transmit powerfrom one shaft to another one running parallel

to it. Beveled gears havetheir faces at an angle withthe line of the axis on whichthey revolve, and transmitpower from one shaft to an-other running at an angle,usually at a right angle, toitself. The pitch line of agear wheel is an imaginaryline running around the wheelthrough the cogs at a point

which is governed by the number and sizeof the teeth. The pitch diameter would bethe diameter of the wheel at tliis imaginaryline. This pitch line is located at the pointwhere the wheels would touch each other if,instead of being toothed or cogged, they wereplain friction wheels. The circular pitch ofa gear wheel is the distance from center to

-su.k--.

JTrj ^r


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AND FOUNDRY PRACTICE 83center of the cogs on the pitch Hne, and is foundby dividing the pitch line into as many spaces asthere are cogs in the wheel. All calculations inreference to gear wheels are made from the pitchline. Cogs are always .7 of the circular pitch inlength, of which .4 lies inside and .3 outside ofthe pitch line. The thickness of any cog isalways xVo of the circular pitch. (See Fig. 46.)

Let it be assumed of a gear wheel of any con-venient size, that it is 21 inches in diameter atthe pitch line, with any convenient number ofteeth, say 44. For all practical purposes anaccurate measurement of the circumference ofthis wheel would be accepted as G6 inches^ at thepitch Hne, and the pitch 66-^44=1.5 inches.

*The decimal is 65.9736.


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84 PATTERN MAKINGThe root of the tooththat part inside of thepitch Hnebeing .4 of the circular pitch, wouldgive 1.5''X.4=.6 of an inch inside of the pitchline as the base of the tooth. Now, as it is cus-tomary to make a gear wheel plain and then gluethe cogs to the face of the rim, it follows thatthe radius of the wheel would be the radius ofthe pitch line, minus the root of the tooth, or .6of an inch, making the wheel at the base of thetooth 1.2 of an inch (.64-.6= 1.2) less in diameterthan 21 inches, or 19.8 inches. Then the totallength of a cog, being .7 of the circular pitch,equals 1.5 X.7= 1.05 inches, which is the lengthof this particular tooth. Its thickness being .48of the circular pitch gives 1.5X.48=.72 inchesas the thickness of the tooth on the pitch line.Hence the solution of the problem calls for awheel 19.8 inches in diameter, to the outsidesurface of which, at regular intervals, determinedby accurate measurement, there should be gluedcogs or teeth which are 1.05 inches in length and.72 inches thick at the pitch line.

All wheels are more or less alike; therefore itwould be superfluous to treat the minor problemsof wheel patterns in this work, as every workmanwho understands the general principles involved


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AND FOUNDRY PRACTICE 85will use his own judgment and discretion in suchcases, especially as the nature of the work, thesize of the wheel, the strength of parts, etc., willalways be the controlling factor in the construc-tion.

Assuming that there has been constructed awheel which has been turned to exactly 19.8inches diameter by the shrinkage rule and theface of which has sufficient draft, the sur-face is divided into 44 equal parts by scribingsquare across the face of the work, with a pointedinstrument or penknife, and marking the scribeson the sides of the rim. The teeth are gottenout to approximately the proper shape and size.Then into a piece of thin hardwood a hole ismade exactly the shape of the desired tooth.The teeth should then be carefully finished withhand tools so that they will just pass throughthis hole, allowing a very little draft in each toothand marking the tooth in such manner as toeasily distinguish the allowance made when thework is being glued together, in order that thedraft may all be the right way. An exact centermark should be made on each end of the cog,matching exactly the marks on the rim of thewheel. Next the cogs should be glued to place,


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86 PATTERN MAKINGusing care that the center of each cog is exactlywith the dividing marks on the wheel. Smallbrads are used to hold the parts in place untilthe glue dries, and when thoroughly dry the workshould be dressed up with sandpaper and asmall fillet of beeswax run along both sides ofthe base of the tooth, pressing it in place with anirod rod which has been warmed over a spiritlamp. To finish, shellac varnish, as beforedescribed, is used.

Patterns of this class are usually parted by themoulder's trowel along the center of the spokeand at one edge of the rim.

Fig. 47 represents a pair of miter gear wheelsin mesh. Beveled gear work may be either amitered gear wheel as shown (in which case thepitch line is at an angle of 45 from the shaft, sucha gear transmitting power from one shaft to an-other at equal speed) ; or, in cases where a differentspeed is required, one wheel will be larger thanthe other (in which case it, the pitch line, willbe any angle which the nature of the casemay require). The making of a miter orbeveled gear pattern, while not necessarily avery difficult piece of work, requires persistentcare and skill. The. pitch of a beveled gear is


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AND FOUNDRY PRACTICE 87an imaginary line, a a. Fig. 47, which Hne repre-sents the surface of cones working as plain fric-tion wheels. Any variation in the relative sizesof these two cones would also change the angle

TVg -fV

of the pitch from the axis of the wheels. Tochange the angle of the axis from a right anglewould also determine the angle of the pitch line.To more fully illustrate the manner of laying outFig. 47, see Fig. 47^. Here a h and a c repre-


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88 PATTERN MAKINGsent the axis on which the gear revolves and a athe pitch Hne. Assuming, for convenience ofcalculation, that the pitch diameter d-e and d-fare 7 inches in length and the number of teeth22, the circumference at the pitch diameter


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AND FOUNDRY PRACTICE 89glued with accuracy and precision. The calcula-tion for both ends of the teeth should be madeby the rules given for gear work, i.e., turn up thecone and lay it off into 22 equal spaces, squareup for the centers of the teeth with the centeringtool (Fig. 48), glue the centers of the cogs to the

centers so established and finish in the usualmanner.

Fig. 49, showing an iron dome with projectingornament at the top and a handle at each side, ishere introduced as a sample of what may bedone with hollow cores. Assume that a roughform has been glued up as shown in cross-sectionin Fig. 50. Attach this form to the lathe andturn out the inside first, otherwise it will be im-


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90 PATTERN MAKINGpossible to turn that part. Reverse the patternand finish the outside, as shown by the shadedportion in Fig. 50, and attach square core prints

for the handles and finial. Make suitable coreboxes for these prints, which core boxes should

Ti^} so

be constructed so that the bottom of the box isthe center of the core. In this case the cores gotogether just the reverse of the ordinary way.


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AND FOUNDRY PRACTICE 91Next turn out the handles and finial of the de-sired form, rip them apart and fasten the halvesinto the bottom of the core boxes as in Fig. 52.A core moulded in one of these boxes will havean impression of half of this turned piece in theface, and when the two halves are pasted together

i1

Cron section ihraiiqjk flask ahaWiiig metaH Gc cores

a proper cavity is left to mould the desired form,which can then be put into the cavities in thesand left by the core prints on the pattern, andwhich will then appear as in Fig. 51. In thispattern it will be necessary to make special pro-visions for supporting the sand in the cope, other-wise it will have a tendency to fall off in han-


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92 PATTERN MAKINGdling. Iron kettles with flaring legs and roundears are cast in this manner. Others have theleg straight on one side so it will draw readily,and the ear is made in two pieces, which areloose from the pattern and remain in the sanduntil the pattern is withdrawn. It is well toremember that any projecting part of a castingwhich is of such a shape that it can of itself bedrawn out of the sand, may often be left loose

Tig S-SLCto^^ oectian ihroujh core lcK^forTi^ 9t

when on account of some angle it is preventedfrom being drawn with the pattern, in whichcase it remains in the sand until the pattern isdrawn, after which it is easily taken out.

There are many patterns which from somepeculiar formation are much easier to mould if aspecial follow board is made for them, and onaccount of a delicate form of construction aremuch easier to make by first making a followboard of the desired shape and then building


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AND FOUNDRY PRACTICE 93the pattern up piece by piece upon this form;for instance, the curved grates in stoves, the castbasket racks in passenger cars, etc., etc. Espe-cially is this true of small, curved open workcastings, where it would be tedious, not to sayimpossible, for the moulder to make a nice part-ing in the sand with the trowel. By the use ofa follow board, which exactly fits the plain side

TJ^ 53

of the casting, the parting is made without anytrouble. As an example of a pattern of thiskind the aisle end for a car seat has beenselected. This pattern was arranged in such amanner as to be divided in the middle, so thatthe upper portion is cast separate from the legand used for the wall end of the seat. (See Fig.53, a and 6.)


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94 PATTERN MAKINGThe first step in this case was to make up

the follow board (Fig. 54), on which the aisle

7V^ S-f

end was laid out full size, taking dimensionson a straight-edge and carrying them over

TJQ erg-37rO'v\'9 yrnisTn^ fnijitterrt -in place on faJfoW JocrcL

to the curved surface. In cases where the fin-ished pattern had to project below the face of


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AND FOUNDRY PRACTICE 95this follow board, as shown by the core printsa-a and the sockets for the seat rails 6 6 in Fig.55 y the wood was mortised out to the desireddepth. After this the pattern was gotten outpiece by piece, fitted to the board in its properplace and secured with small sprigs until theglue joints hardened, care being taken not toglue the pattern proper to the follow board. Inthis case it was necessary to allow the arm,which carried the back cushion from side to sidein reversing the seat, to pass behind the socketh by Fig. 55 y thus making it necessary to coreout a slot between the socket for the seat railand the aisle end, which was done as shownby the cores a a, Fig. 55. These are samples ofbalanced cores, which will be explained further on.

This pattern has a joint at ccc. Fig. 53, sothat it may be cast without the leg being madefast against the wall of the car.


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CASTING WITH PART PATTERNS,SWEEPS, OPEN SAND WORK, ETC.Castings are sometimes made without regular

patterns, or with only a portion of the pattern.Some castings are made by the use of straight-edges, curves, etc. Other castings are madewith sweeps. Many of these methods have comedown to us from periods of remote antiquity.

Recently in the foundry of atthe moulders were making a slab of iron 2 feetwide and 5 feet long, with a rim around theunder edge and V-shaped cross bars or ribs onthe under side at intervals of about 6 inches eachway. (See Fig. 56, a b.)

There was no pattern for this work at all; butinstead there were some 1X2 inch strips and astraight plank, v^^ith a V-shaped edge. To makethis mould, the floor of the foundry was leveledoff with the straight-edge, the grooves rubbedinto the sand with the V-shaped edge of theboard and the 1X2 inch strip laid down to formthe line of the outside of the casting. Againstthese the sand was packed level with their tops

97


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98 PATTERN MAKINGand smoothed off. The cope was made with astraight edge.

A very simple and useful "kink" was employedrecently in the case of a large piece of machinerywhich was damaged in shipping. It had a largecircular gear about 8 feet across without spokesor hub which was broken in two or three pieces.This was an old, out-of-dale machine and it was


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AND FOUNDRY PRACTICE 99To make the mould from this partial pattern,

level off the foundry floor with a straight-edge.

The center stake is then driven and left standingup above the floor the thickness of the casting.The partial pattern is next put on the center pinand rammed up, leaving both ends open. After

^IS 57

this it is lifted and moved, taking (jare that thelast cog on the pattern exactly fits the impressionin the sand. Ram this up again and move thepattern as before. Continue this until the com-plete circle is made, which will be an impressionof the complete gear. Since seeing this I have


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100 PATTERN MAKINGused the same plan for making mud rings forboilers with perfect success, thereby saving muchvaluable time and material. This method is notrecommended in general practice; but where asingle casting is all that will ever be needed, the

making of an entire pattern can and in somecases should be avoided.

Another problem of a similar nature is foundin making a large pulley or flywheel where thecost of making the pattern is not justified by thenumber of vdiecls required. To make the mouldfor such a pulley, first construct the form of theradius desired for the rim of the wheel (see Fig.


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AND FOUNDRY PRACTICE 10158), and in case of a belt wheel, make the rimof the shape desired to hold the belt centrally onthe face of the pulley. Now secure this form totwo arms so fixed as to cause it to swing around

Tig S9Core tor for. f\g /

a center stake at the proper radius. Make up acore box of exactly the shape of one-sixth of thewheel inside of the rim; that is, the radius of theoutside of tlie core box should be the thickness


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102 PATTERN MAKINGof the rim less than the radius of the form. Getout the rib, a-a. Fig. 59, and glue it in place.Turn up a hub one-half its length, cut it in sixparts and glue two of the pieces into the apex ofthe core box, as in c, Fig. 59, leaving a slot ormortise for withdrawing the spoke. Make onespoke and secure the joint with a dowel pin at6, Fig. 59. This will be better understood by a

1


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AND FOUNDRY TRACTICE 103center stake down level. Then put in a smalliron center pin and set the form (Fig. 58) on it.Bank the sand solidly against the outside of the

- cO

&7tcWrJrff y7io7/Jd w/M coyrtf in palacepattern, level with the top, moving the form andcontinuing the operation until a complete circularpit is formed of the depth of the pattern. Re-move the form and the center stake, leaving asmuch of the hole made by removing the stake as

patternmaking foundry

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