MODERN BLACKSMITHING 45 



TWIST DRILLS 



Twist drills are not easy to make by hand, as they 

 should be turned to be true, but a twist drill can be 

 made this way. Take a piece of tool steel roimd and 

 the size of the chuck hole in your drill press. Flatten 

 it down to the size wanted, heat, put the shank in the 

 vise, take with the tongs over the end and give one 

 turn to the whole length, turn to the left. When 

 finished be sure that it is not thicker up than it is at 

 point, and straight. Now harden, heat to a low cherry 

 red, cool off in luke-warm water — salt water, if 

 you have it — brighten it and hold over a hot bar of 

 iron to draw temper, cool off when brown, the whole 

 length of the twist should be tempered. 



Another way to make a drill is to just flatten the 

 steel and shape to a diamond point and bend the 

 shares forward. This is a simple but good idea and 

 such drills cut easy. In cooling for hardening turn 

 the drill in the water so that the edge or shares are 

 cooled in proportion to point, or the shares will be 

 too soft and the point of such a drill too hard. Our 

 trade journals, in giving receipts for hardening drills, 

 often get watch-makers receipts. This is misleading: 

 watch-makers heat their drills to a white heat. Now, 

 remember, as I have already said, when your drill or 

 tool of this kind is heated to this heat the best thing 

 to do is to cut that part off. It is different with watch- 

 makers, they do not look for strength, but hardness. 

 They run their drills with a high speed, cut chips that 

 cannot be discerned with the naked eye, and must 



