RC testing ?

rodriguez7

Gila wilderness knife works
Joined
Feb 1, 2009
Messages
1,428
just wondering, can I rc test a blade right out of quench? I would imagine it could crack!
 
It shouldn't crack but you would need to test on a fully hardened area that is flat/parallel and that has had the decarb layer removed. It is better if you can work out the HT and do hardness testing on sample pieces first then HT the blade knowing what you can expect.
 
I hardness test all my blades after the quench. I clean up a small area on the tang and test. I have never cracked a blade. Not saying it can’t happen but it has not happened to me.
 
It can definitely happen, but as long as you've got a nice, flat/parallel spot, it's not super likely. Don't do it anywhere that's not flat on both side where you're sitting it on the tester's anvil, and of course, make sure you clean up enough to compensate for decarb if you want an accurate reading.
 
Tried it last night on 2 different batches. Now I can dial in heat treat much better. All my blades were lower hardness after quench than what I expected. Aeb-l tested around 62 rc after a dry ice acetone bath. Which is lower than I expected. The weirdest one was a batch of 8670. They consistently tested right at 60 after quench, after the dry ice. I ground it down on the tang to remove any de carb. All 4 tested 60-61. The weird part, is I went ahead and tempered them anyway, starting at 300 degrees. After the first one hour temper, with a dunk in water, they all tested around 63-64. Any clue why the hardness would bump up after the first temper?
 
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