76 



PATTERN MAKING 



tern from the sand, we find that it must be moulded on its side, 

 and that the moulder may not lose time in cutting away the sand 

 (see Figs. 113 and 114, Part I) the pattern must be parted, or made 

 in two halves. 



For finish on this small pattern -jV inch will be sufficient, and 

 draft will be required only on the ends of the pattern, and on the 

 ends of the core prints, which in this case, should be not less than 

 1 inch long. This is necessary, because the core-print moulds must 

 sustain the weight of the dry-sand core. 



Fig. 149. Fig. 150. 



The pattern 'for this casting is represented by Fig. 150, in 

 which it is seen that, unlike Fig. 140, the body and core prints are 

 perfectly straight, a slight draft -^ inch to 12 inches being giver 

 to the ends of the pattern and to the ends of the core prints only. 

 A slight curve of yV inch radius should also be made at the inter- 

 section of the body of the pattern, and the inside of the flange 

 at , <i. 



The wrnxl in being prepared for this pattern should be cut 2^ 

 inches longer than the finished pattern. The dimensions of the 



