Hey John,
From the information and observation that I had while watching a fellow building locks for Chambers.., the heating is the key, first, the frizzen has to be quite hard, then followed by a proper tempering. He heats the frizzens quite hot, bright yellow, then uses a professional quenching oil. Then he heats them I think to 450 for an hour, not positive, followed by slow cooling..., I'd have to check with my buddy the lock-builder to be sure.
LD
From the information and observation that I had while watching a fellow building locks for Chambers.., the heating is the key, first, the frizzen has to be quite hard, then followed by a proper tempering. He heats the frizzens quite hot, bright yellow, then uses a professional quenching oil. Then he heats them I think to 450 for an hour, not positive, followed by slow cooling..., I'd have to check with my buddy the lock-builder to be sure.
LD