OCR Text |
Show !heat drill evenly j TO WORK ON STEEL ; In preparing a drill to be used on hard l steel, the drill should be heated to an I even red heat, the scale removed and ! the top of the drill be touched to a drop ' of quicksilver and then be quenched in I water. After this treat mem the drill j will so through the hardest steel with-: with-: out trouble. A simple method of tem-I tem-I per in? small tools quickly is to heat 1 them red hot and then thrust them into I a potato, after which they should be j drawn to the correct temper to rcmuve 1 britlleness. |