Those of you that follow this NG closely may know I grow apples for a
living...

I use the "Limb Lopper" brand pruner to prune my orchard. This is the
Cadillac of pruners. Like all too many quality made in USA products, it has
been judged too expensive and now you can only get inferior products made
off shore. The pruner is out of production and parts will soon not be
available.

The shear and hook part of the pruner are wear items that must be
re-sharpened every few hundred trees. After 10,000 or so trees you need to
replace them. My son is writing up a CNC program to machine the parts after
scanning in a coordinate measuring machine.

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