Dertermining Rc?

[Eodjuggernaut]

I am not a knife maker. Maybe someday it certainly is something that I would like to try in the near future. My question is how is steel hardness determined by most custom knife makers? I know there are Rockwell hardness testers but they can be expensive. I can't imagine all blades are tested but maybe a percentage or just belief in their HT? I imagine if your steel supplier is consistent in their manufacturing that there should be little doubt that your HT process would vary once you nail it down. This is just conjecture on my part and I'm sure experience is the biggest factor here but I would be interested in hearing from the experts out there.

Thanks

 

[Stacy E. Apelt - Bladesmith]

You are correct that most makers just guess the final Rc by what they expect it to be from their HT methods and past results.

Most full time makers, and many of the hobby makers have a tester, but even then, most blades are not tested.

The other way the Rc is known is by having the HT done professionally. The blades are tested individually by the HTer and are at the target hardness requested. This is a big plus for those who sell their blades.

 

[Eodjuggernaut]

You are correct that most makers just guess the final Rc by what they expect it to be from their HT methods and past results.

Most full time makers, and many of the hobby makers have a tester, but even then, most blades are not tested.

The other way the Rc is known is by having the HT done professionally. The blades are tested individually by the HTer and are at the target hardness requested. This is a big plus for those who sell their blades.

Thanks for the answer. This helps. I may be overthinking it but it seems like a difficult process to perfect especially if you use several different alloys.

 

[NYMet]

If you have a consistent and repeatable heat treat process you are fine. The problem is; how do you know your process is good without knowing the hardness? They go hand in hand. I consider not checking hardness like driving at night and turning your lights off. As long as nothing changes you will be ok, but one slight change and it's in the ditch you go.

 

[Stacy E. Apelt - Bladesmith]

One simple way of checking the approximate hardness is purchasing a set of hardness files. If they are used occasionally, and properly, they will last a while.