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Art, I assume that it's possible to get a idea of a materials hardness using a file and trying to file a groove in the metal.
Just for fun.
If you were going to develop some sort of standard, you would have to make certain that you used the exact same file for every test, or rather use a identical file that had been tested for it's own hardness, sharpness and tooth configuration and found to be identical.
Then the file(s) would have to be applied to the test object at the same angle, same pressure and same surface speed. At that point, you would have to have some sort of precise measurement of the groove that the file cut and the amount of metal that was removed.
After applying this test to numerous test objects made of various materials you could start to compare and correlate your findings into some sort of repeatable specification.
I have a hunch that I'm preaching to the choir here and that you already know a lot more than you let on about this subject.
The Rockwell Hardness Test that is widely used to test material hardness is simply this.....A (very small) super hard ball is pressed against the surface of the test material and the indention that is created is percisely measured and compared to a set of standards.
That's it in a nut shell.
Of course there was a lot more to building the first test instrument.
Such as designing the test apparatus, building a test frame that could withstand the enormous pressure exerted against the test ball without deflecting beyond a predictable amount, conceiving a repeatable way of measuring the deformity caused by the test ball and running a mountain of comparative tests on various materials and establishing a standard.
I'm sure that I've missed a lot in my description, I'm just describing the way that I would approach the problem if it were dropped in my lap.
I've always used a steel punch when I've wanted a idea of a materials hardness.
Of course, my testing has never been used to assure the preservation of life or limb, rather it's just a way of satisfying my own curosity about whether a metal is capable of meeting a prescribed specification.
Like you, I'm curious about a lot of things.
I have had materials professionally tested in the past if I really had to know.
There are several recognized methods of non-destructive testing for material hardness and all of them basically measure a surface deformity caused by a applied force....it's all comparative.
I'm a barnyard scientist who's also been a design engineer, and at this point in my life, I'm just curious about life and the way things really are.
I love owning and driving Volvo Bricks simply because the engineering that went into designing and building these cars was exceptional and infused with a whole lot of common sense.
Just blabbing
steve
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