Anyone know about heat treating knives?

[MACV]

I was wondering if a person can heat treat bayonet or cheap stainless steel to harden it up some.

[K. Funk]

You gotta know the grade of steel. The 18-8 austenitic stainless used in butter knives will not get hard no matter how you treat it. Cutlery grade martensitic stainless, usually Type 420 or 440C is probably already at the desireable hardness level. If you try to re-do the heat teatment, you will most likely either break it or make it so it won't hold an edge. It's a pretty fine line with that stuff. If it is carbon or alloy steel, you have to know the carbon content in order to know what tempering temperature to use to get the best balance of hardness and toughness.

So, the answer to your question is "Maybe", but you have to know what you are starting with.

krf