Heat Treatment Of Milling Cutters Drills Reamers Etc

: HIGH-SPEED STEEL
: The Working Of Steel

THE FIRE.--Gas and electric furnaces designed for high heats are

now made for treating high-speed steels. We recommend them for

treating all kinds of Blue Chip tools and particularly the above

class. After tools reach a yellow heat in the forge fire they must

not be allowed to touch the fuel or come in contact with the blast

or surrounding air.



HEATING.--Tools of this kind should be heated to a mellow whi
e

heat, or as hot as possible without injuring the cutting edges

(2,000 to 2,200 deg.F.). For most work the higher the heat the better

the tool. Where furnaces are used, we recommend preheating the

tools to a red heat in one furnace before putting them in a white

hot furnace.



COOLING.--We recommend quenching all of the above tools in oil

when taken from the fire. We have found fish oil, cottonseed oil,

Houghton's No. 2 soluble oil and linseed oil satisfactory. The

high heat is the important thing in hardening Blue Chip tools.

If a white hot tool is allowed to cool in the open air it will be

hard, but the air scales the tool.



DRAWING THE TEMPER.--Tools of this class should be drawn considerably

more than water-hardening steel for the same purpose.



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