Tinker

The steel is O1 oil hardened at 1500 degrees, and drawn at 575 degrees for 2 hours. This (for me) makes an extremely tough and durable part.

The above is what I do for this part. It works for me, and my gear. It may or may not work for anyone else, and is for information purposes only. (I have to cover my hindquarters here). There are so many variables, such as; steel batch/manufacturer; oil type, temperature and agitation technique; furnace temperature accuracy/control; scale control, and other things. You have to experiment to find what works.

As for a hardness tester, I don't have one. I do what works from experience. Rockwell numbers are a guide to get you close. And different heat treatment processes can yield the same number, but instill vastly different properties, strengthwise, in the steel.