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Old January 27, 2013, 07:44 PM   #21
Hellgate
Senior Member
 
Join Date: November 18, 2010
Location: Orygun
Posts: 533
Doc,
I actually found the original post that I plagerized:

LEAD HARDNESS TESTING USING ART PENCILS
The following is a short version of a method commonly used to test the
hardness of paint films, and your library can give you a full description if
you ask them for "The American Standard Test Method (ASTM) for Pencil
Hardness."
In brief, you can go to an art supply store and get a set of pencils
whose core varies in hardness from "9B" to "9H". The actual range runs from[softest] 9B,>>>1B, HB, F, 1H, >>>9H [hardest]. The harder pencils can be used to test some aluminum alloys, and are much too hard for lead alloys. Leadwill run about 4B or 5B, depending on purity, and linotype will run about HB or F. So a dozen pencils will cover the entire range.
To use, you shave the wood away with a penknife to expose the lead
core of the pencil, but without cutting into it with the knife. I cut close
and peel the thin wood away with my fingernail, leaving about 1/8 to 1/4"
exposed. You can also get mechanical pencils with seperate cores that
eliminate the problem, but it's not necessary. Once you have some exposed
core, you hold it vertical and sand the end to a flat wadcutter shape, with
sharp edges. Use about 400 grit sandpaper, and wipe the graphite dust off soit won't act as a lubricant.
Now hold the pencil in an ordinary writting position, and try to push
the lower edge into the lead surface. If the graphite core is harder than thealloy, it will cut into the metal, or at least leave some serious s 6cratches in it. But if the metal is as hard or harder than the graphite core, it will not be able to gouge. The hardness is ranked as the hardest graphite core thatwill NOT cut in. If your bullet is resistant to pencils from 6B through 2B,but a B scratches it, or peels up a small shaving, the hardness is 2B.
This isn't as precise as Brinnell numbers, but it doesn't take
thousands of dollars of testing equipment to do the job, either. And it lets
you reproduce the hardness of different alloys with considerable confidence. If a batch of metal that tested "B" 5 years ago is all gone, you can blend anyother combination of metals to get a "B" and rest assured that it will performin a very similar manner to the long gone metal in your handload, even though it may not have the same castability, cost, etc.
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