Pattern making and foundry practice; a plain statement of the methods of wood pattern making, as practiced in modern pattern shops, with complete instructions for sweep work and notes on foundry practice, together with numerous drawings taken from actual patterns .. . nd the pattern until a perfect V/eTf cartel core -|j|fw:r:r7:^^^^r3^g-^l^:- A .^^*; SnUonal view of mould foT Fig 6 Wio\¥mff pattem m 9and parting 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
Pattern making and foundry practice; a plain statement of the methods of wood pattern making, as practiced in modern pattern shops, with complete instructions for sweep work and notes on foundry practice, together with numerous drawings taken from actual patterns .. . nd the pattern until a perfect V/eTf cartel core -|j|fw:r:r7:^^^^r3^g-^l^:- A .^^*; SnUonal view of mould foT Fig 6 Wio\¥mff pattem m 9and parting 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 30 PATTERN MAKING as 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 iTirongh fire etlitigmsJter tcp & ntoiilci 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 AND FOUNDRY PRACTICE 31 beveled; , 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 thewoo
Size: 2500px × 1000px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherchicagofjdrakeco
