. Railway mechanical engineer . g tool, thinner tools can be used, thus re-ducing the amount of metal wasted. In addition to this,there is a considerable saving in the time required to makethe rings. March, 1918 RAILWAY MECHANICAL ENGINEER 171 MAKING COLD CHISELS BY G. J. BRUNELLEAssistant Blacksmith Foremao, Boston & Maine. North Billerica. Ma There should be no more guesswork in the making of goodchisels than in the making of good taps, reamers, millingcutters, etc. In the first place, a suitable steel must be pro-cured, and manufacturers usually carry on hand a special85 to 9S-point carbon
. Railway mechanical engineer . g tool, thinner tools can be used, thus re-ducing the amount of metal wasted. In addition to this,there is a considerable saving in the time required to makethe rings. March, 1918 RAILWAY MECHANICAL ENGINEER 171 MAKING COLD CHISELS BY G. J. BRUNELLEAssistant Blacksmith Foremao, Boston & Maine. North Billerica. Ma There should be no more guesswork in the making of goodchisels than in the making of good taps, reamers, millingcutters, etc. In the first place, a suitable steel must be pro-cured, and manufacturers usually carry on hand a special85 to 9S-point carbon steel for this purpose. It is rathercoarse grained in the annealed bar, yet capable of refining atthe critical point when forged and hardened at tlie properheat, and is ver)- tough. It is important to know that carbon,while imparting hardness to steel, also increases its brittle-ness, and a chisel made of steel with too high a percentageof carbon is dangerous to use. Should one of the alloy or high-speed steels be Fig. 1—A 5/16-in. Cape Chisel Driven Through ^ Stock it must be plainl} marked, for the method of treatment isentirely different from that of carbon steel, and the tool-maker should be able to tell at a glance with just what kindof steel he is working. After securing a good steel, the next requisite is a goodtoolmaker, and it is a mistake to give the work to a cheapman. novice or apprentice. The excuse is generally madethat the job is good practice for beginners, as the chisel isone of the cheapest tools. This is true enough if the chiselsare being made to give a man experience, but if they arerequired for use they should be made by the most experiencedworkman available, because a man can employ with profit asmuch skill in making a good chisel as in making a goodlathe tool. Good chisels, like those illustrated in Figs. 1and 2, do not break with fair usage nor require frequentgrinding, and are highly prized by good mechanics. Uniform practice in worki
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
