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Hardness Testing Files


RedNeckLeftie

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Hey Folks,

 

I saw Jesus Hernandez mention hardness testing files in a very different recent thread, and wondered about their use. Specifically, how aggressive and when to do the test?

 

I think I have the same set of files (40-65HRC, 6 files), and have tested mostly polished and etched parts (#2000 wet/dry, ferric etch, then #2000 again--on chisel-like test "blanks"). What I typically find lately: A normal file skates on the hardened part (before polish). Then after polish the 65HRC file definitely bites and scrapes into the hardened part, and the 60HRC file will mar, but not bite into the hardened part. Does that mean I am done, and the answer is 60-65HRC? Or, do I need to go to the 55HRC file (which barely leaves any marring)? Or, am I doing it all wrong? It's the marring that has me cornfused. :wacko:

 

P.S. - The marrings would need repolishing, back to #900 EDM to clean up properly, and we're talkin' water-quenched 1060.

 

Thanks,

Brian K.

Brian K.

Rogue Amateur and Weekend Hobbyist

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A normal file skates on the hardened part (before polish). Then after polish the 65HRC file definitely bites and scrapes into the hardened part, and the 60HRC file will mar, but not bite into the hardened part. Does that mean I am done, and the answer is 60-65HRC?

Yes, you are done and the steel is somewhere in that range. A Rockwell hardness test will give you more accurate results but, only if the machine is properly calibrated.

 

~Bruce~

“All work is empty save when there is love, for work is love made visible.” Kahlil Gibran

"It is easier to fight for one's principles than to live up to them." - Alfred Adler

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Whew, thanks Bruce! That makes me feel a lot better. I was starting to see all kinds of "gray areas," with too much subjective guessing involved. One of these years, I may get a Rockwell tester, but I'd have to get a few real blades under my belt first.

 

Brian K.

Brian K.

Rogue Amateur and Weekend Hobbyist

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