ANNEALING: the treating of a metal or alloy with heat and then cold – or the repeated process of heating and hammering to produce the desired shape. After casting metal, it may be necessary to further process it by cold working, hammering, and drawing the metal – either to produce hard cutting edges or to produce beaten sheet metal. Hammering makes the metal harder, though more brittle and subject to cracking, because it destroys its crystalline structure. Annealing, the reheating of the metal gently to a dull red heat and allowing it to cool, produces a new crystalline structure which can be hammered again. The process may be repeated as often as is necessary. The final edge on a weapon may be left unannealed as it will be harder and last longer.