PATTERN MAKING 



105' 



or a rag dipped in the hot water of the outer glue-pot and wrung 

 out nearly dry, care being taken not to wet any part of the pattern 

 more than can possibly be helped, after which it must at once be 

 wiped dry. 



These leather fillets will be found more pliable and more 

 easily placed and rubbed into position if the glue used is first 

 allowed to cool slightly. Very hot glue stiffens and crinkles the 

 leather, causing it to work hard. 



FACE PLATE. 



It is sometimes advisable to use cores even if it is quite possible 

 to construct the pattern so that it would core its own holes. This 

 is the case where it is desired that the faces of the casting and the 

 holes shall be smooth and as true as possible without expensive 



a. Fig. 182. b. 



machine work. The finished face-plate of an engine lathe illus- 

 trated in Fig. 182 is a good example of such work. 



It will be readily seen that the pattern for this casting could 

 be put in the sand and withdrawn from the mould, leavi-.g the sand 

 standing where the holes are located. 



The trouble that arises from this method is due to the fact that 

 when the metal is poured and allowed to flow about the fragile pro- 

 jections that are left to form the holes, the sand washes away, so 

 that the holes in the casting are irregular and much smaller than 



