PATTERN MAKING 



many of the softer metals it is as great as \ inch per foot. 

 Shrinkage rules, Fig. 82, are usually made of a single piece 



Pig. 79. 



V 



of boxwood or beech, those for cast iron being 24|; inches long, 

 for brass 24| inches long, and for other soft metals 24^ inches 



Pig. 80. 



in length. They can also be bought in ado of tempered steel 12 

 inches, 12-nf inches, and 12^ inches in length. Tn making use 



Fig. 81. 

 of the shrinkage rule, the workman will proceed just as though 



