I purchased an older Thompson Contender frame recently that is in excellent shape, but is missing the hinge pin. I had another Contender and measured the hinge pin and turned a replacement; however, I'm not sure what the correct heat treatment would be for it. I have the knowledge and equipment to heat treat the pin if I know what the specs would be for it. I turned the replacement out of 01; however, I could easily make it out of mild steel and caseharden it if that would work. Any ideas?