Hardening Piston Pins

Q-How can small pieces such as piston pins be hardened?

First secure a cast iron pan or similar vessel. Fill this half full of cyanide and place on fire until it is about to boil. Then place metal parts in cyanide and heat until they have a cherry red color. Remove from cyanide with tongs and quench in water. If you want the parts glass hard, quench in sperm oil. This can be bought from most any oil dealer. If only a slight degree of hardness is desired, this may be applied quickly by heating the part to a red heat and sprinkling with a little cyanide, then plunge into water.

Parts can also be hardened in pieces of pipe when they are packed in hardening compound. If more than one piece is hardened they should not touch each other or the pipe. When packed both ends of the pipe should be sealed with clay. Heat to bright red for several hours and then plunge.

Motor Query Encyclopedia, 1922