Lock parts...heat treatment?

[Tenn Hills Guy]

I have only one old rifle..a Golcher back action, half stock, set triggers German silver furniture.  The barrel is pretty well shot out, but the action and triggers are still solid.  I've scratch built a few locks and wondering what the proper heat treatment is for the parts.  I'm thinking, e.g., lock plate, bridle, tumbler, sear, cock, maybe stirrup, frizzen and springs self evident....I guess.  Bill

[jerrywh]

 It depends on what kind of steel the components are made of.  Most of those old guns were made of mild steel or even wrought iron. In that case the thing to do is to pack case harden them and then draw to about 600° for about 20 minutes. That may seem a little soft but better than too hard. To hard leads to stuff like the sear nose breaking off etc. I think Chambers draws his internals to about 600°. Maybe he will chime in. You will probably get 50 different opinions. Bob Roller is a good source of info. 

[rich pierce]

Lock plates are seldom hardened though case hardening helps function. In general springs have their own steel requirements and tempering, tumblers and sear and fly will be much harder, and frizzen faces hardest of all. Simplest procedure is to use mild steel or wrought iron for everything but springs then case harden everything but the springs. Then temper the frizzen face the least, sear and tumbler more, and frizzen toe and screws even more.

Add in using different steels for different parts and you need a worksheet to plan hardening and tempering.