Important: Safety Warning
This page describes trade processes that use dangerously toxic materials such as cyanide solutions, mercury amalgams, or strong acids. These processes require training, equipment, and precautions far beyond what the text describes.
In addition, this page directs preparing a bath of molten lead and handling an engraving mixture containing vermilion. Molten lead causes severe burns and gives off poisonous fumes, and vermilion is a mercury compound.
This information has been left in for historical purposes but should not be acted upon.
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To Temper Mill Picks
After working the steel carefully, prepare a bath of lead heated to the boiling point, which will be indicated by a slight agitation of the surbox, covering the sawdust with ashes. Let face. In it place the end of the pick to the it stay until cold. For a larger quantity, and depth of 1½ inches, until heated to the temwhen it is required to be very soft, pack the perature of the lead, then plunge immediately steel with cast-iron (lathe or planer) chips in in clear cold water. The temper will be just an iron box, as follows: Having at least 1/2 or right, if the bath is at the temperature reinch in depth of chips in the bottom of box, quired. The principal requisities in making put in a layer of steel, then more chips to fill spaces between the steel, and also the or inch space between the sides of box and steel, then more steel; and, lastly, at least 1 inch in depth of chips, well rammed down on top of the steel. Heat to and keep at a red heat for from 2 to 4 hours. Do not disturb the box until cold. 3284. Engraving Mixture for Writing on Steel. Sulphate of copper, 1 ounce; sal-ammoniac, 1/2 ounce; pulverize separately, adding a little vermilion to color it, and mix with 1½ ounces vinegar. Rub the steel with soft soap and write with a clean hard pen, without a slit, dipped in the mixture.