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 .. . 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 hollow or concave parts are usually made down inthe d
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 .. . 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 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, 26 PATTERN MAKING this case the pattern, which is assumed to behollow or of cup shape (see Fig. 4), should be placed onthe followboard withthe cupor thisshould beplaced that part of the flask which is to be used for thecope, and it should then be rammed up in the. Tig ^<^ro55 5€ction through cup settles to the bottom of the mould and shows a perfectlysmooth surface, while the imperfections float to the topor inside of the sheet. In small shops where repair workis done, the ingenuity of the flask maker is often taxedto devise means for making flasks perform work for whichthey were not intended, for the reason that in cases whereonly one piece of casting is required, the cost of makinga special flask would be more than the value of the cast-ing. In factories such as stove works, etc., where a greatnumber of similar pieces are required, many flasks aremade for particular pieces, such for instance as ovendoors, fire-backs, etc. In these cases the flasks are spe-cially designed wit
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License: Licensed
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherchicagofjdrakeco
