Speaking of annealing/heat treating- - - -Here's an old gunsmiths' trick I learned in a blacksmithing seminar some time ago. When heat treating a piece of oil-hardening drill rod, etc., heat the part cherry red, quench it in an oil bath with lots of stirring/agitation, then put the part in a shallow pan with some 30 weight non-detergent motor oil. Use a Propane torch to light off the oil and let it burn away, then repeat the process a second time. The burning oil "draws" the metal to the proper temperature to make it tough, not brittle like the heat/quench procedure does. After tempering, bury the part in a pile of sand for a slow cool-down.
Jerry
