266 



APPLIED SCIENCE 



Hot Chisel 



(c) Round Punch 

 Chisel 



There are several other forms of chisels used especially 

 by boiler-makers. Figure 125 shows four handle chisels, 

 so called because they are held by the wooden handle when 



used. A hot chisel (Fig. 

 125a) is used for trim- 

 ming or cutting hot 

 plates, etc. The cold 

 handle chisel, used for 

 general chipping on boiler 

 work as well as erecting 

 wort, is very similar, ex- 

 cept that the cutting edge 

 is not drawn so thin as 

 that of the hot chisel. 

 Figure 125c shows a 

 round punch used for 

 knocking off rivet heads 



(6) Square Punch (d) Side-Set 

 Chisel Chisel 



FIG. 125. Handle Chisels. 



and driving out stay- 

 bolts, rivets, etc. Figure 

 125b shows a square punch used for driving keys and 

 knocking off rivet heads. Figure 125d shows a side set 

 which is also used for cutting off rivet heads. All these 

 tools are made of tool steel. The hot chisel is tempered 

 to a dark straw color and the cold chisel to a blue color; 

 the set is also tempered slightly. It is customary not 

 to temper or harden punches since they would be apt to 

 break off. The handles in all these tools should fit loosely 

 and should be made of soft yielding wood so that the shock 

 or jar of a glancing blow will not hurt the hands. 



307. Kinds of Files. A file is a bar of high-grade crucible 

 steel, pointed at one end for a handle and having cutting edges 



