So i just finished the temper on my first forged knife. The steel is 1080. So my question is after tempering at 400 for an hour twice i tried drilling a small hole in the tang just to see how hard it was and the drill bit in and drilled a simple then stopped and just skated. Also with a file if i really tried with the edge of the file i could start a smalle file mark it wasnt easy but i was possible. Im just checking to see if this sounds right or if the ht is junk. Thanks bill
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Heat treat test
- Thread starter Blitt
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afishhunter
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Don't they make a special file set to test for various hardnesses/tempers?
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You'll have some amount of decarbed steel, depending on how long it was at heat. Since it was your first one, it was probably longer than optimal. So you may have say .020" of material on each side that won't reach full hardness. That would explain why your bit started the stopped.
As for the file, that just proves your file is harder than your blade, and it should be. Your blade should be in the 58-60HRC range. An average file would be a few points harder at least. The decarb would also be present at the edge, so you may get the same effect as the drill, starts to cut but then hits harder material.
Without a hardness tester, your best test is to sharpen it and use it some. I think it's probably ok.
As for the file, that just proves your file is harder than your blade, and it should be. Your blade should be in the 58-60HRC range. An average file would be a few points harder at least. The decarb would also be present at the edge, so you may get the same effect as the drill, starts to cut but then hits harder material.
Without a hardness tester, your best test is to sharpen it and use it some. I think it's probably ok.
Stacy E. Apelt - Bladesmith
ilmarinen - MODERATOR
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Your description sound normal. Grind/sand the knife down past the decarb and put an edge on it and I am sure all will be fine.
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Yes, it could be. The decarbed steel will be deeper than just the outer layer of scale.
Stacy E. Apelt - Bladesmith
ilmarinen - MODERATOR
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I am saying your file testing sound like a normal result for a hardened and tempered blade. Without knowing more about the method of hardening/tempering and equipment used, it is hard to say much more.
A file is around Rc67, a drill bit is around Rc60. Both will make a mark on a hardened blade. The drill will only make a small divot and then get dulled. The file will saw a small notch before the teeth start to round. Skating a file down the edge is fairly reliable, but you are looking for the sound and feel of the test. Obviously, if you can file away any amount of the edge then it is too soft.
A file is around Rc67, a drill bit is around Rc60. Both will make a mark on a hardened blade. The drill will only make a small divot and then get dulled. The file will saw a small notch before the teeth start to round. Skating a file down the edge is fairly reliable, but you are looking for the sound and feel of the test. Obviously, if you can file away any amount of the edge then it is too soft.