I think you are trying too hard to find the same metal. Do a Rockwell
hardness test and then pick some steel that is easy to heat treat to
the same hardness. Or maybe a steel as stressproof that is already
that hardness.

When in doubt start with O-1 Medium wear, medium toughness, medium
distorsion in heat treat, and high machinability. Normal range of
hardness C 58 to 62.

Dan


Karl Townsend wrote:

These two parts are made out of a tool steel with incredible properties. The
material is as resistant to being bent as the best quality wrenches. I have
never broke or bent a hook and shear. Yet, the steel is soft enough to be
sharpened with a file.

I need to determine exactly what this material is and its likely heat
treatment. I want to get this exactly right, not just guess. How would I go
about finding out what material to use?

Karl