On 2008-04-26, Richard J Kinch wrote:
Ignoramus3107 writes:

I know that these are useful for wheel dressing, but is there any
other use of them?

Relative hardness testing. Make a dimple with it using a force on an
unknown sample and compare the same force dimple made in various known
samples.

The standard diamond for that purpose is polished to a specific
angle cone, with a specific radius tip. And the usual practice is to
apply 5kg of force, zero the penetration meter, increase the force to a
specific value (which varies depending on the scale used), and then back
the force back down to 5kg and measure how far into the test sample the
point has moved. This is for several of the Rockwell hardness tests,
including the Rockwell C test.

there are some of the Rockwell tests which use a ball bearing of
a specific diameter instead, but the principle of use is similar. This
is more likely to be used for testing brass or something similar instead
of steel.

So -- if your diamonds are sharpened to a cone shape, with a
radiused tip, then they are probably used for such testing (but these
usually have a shoulder some distance behind the tip, while the stone
dressing ones don't, and are not likely to have nice smooth cones,
either. But they still could be used for comparative tests, even so.
And you can buy hardness standards used for checking the calibration
of the Rockwell hardness testers.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---