I had picked up a couple of rasp in a lot of old files.  I planned on making a couple of matching blades.  As is my SOP (standard operating procedure) with an unknown file I heated the tang, quenched in water then tried to break it.  As you can see, one broke clean the other bent (case hardened). 

Another perfect reason to shop test unknown materials. Good call! What is the brand name on the case hardened file for our future reference. Thanks for sharing this info! 

 

Darren

That case hardened rasp was a Bellota, made in Spain.

Bellota's are the best rasps I have used... (for Farrier work.) Good to know.

I did the heat quench break test on Bellota rasps and it broke clean.  No bend.  But still did not harden.