Quote Originally Posted by prodigy View Post
If you think it's the diamonds getting "worn" I'd like to understand how and why with evidence. Diamonds are the hardest material known to man and I really don't think rubbing them on a stone is wearing them one bit. Now the steel plate holding the diamonds might be wearing out, and losing its hold on the diamonds, but the diamonds themselves are not being "worn".
To put it bluntly, you are wrong. Diamond is the hardest natural substance we know of. This doesn't make it invincible. Everything wears, including diamond. The wear mechanism differs, from small fractures to flattening and rounding off of the diamond abrasive particles. Any machinist who uses diamond points to dress grinding wheels (mostly aluminum oxide, the same abrasive used in most synthetic hones) can give you firsthand knowledge of that fact, which is why it's standard practice to rotate a diamond dresser with every few uses to prevent a flat forming.

It happens faster with powered grinding wheels, sure, but it happens with hand lapping very hard stones just the same. For instance, my Atoma 400 will flatten my SG20k if it's not very far out of flat, but it takes quite a while and quite a bit of pressure as well. When the Atoma was new it would rip that hone down in a minute flat. Using it to lap very hard natural stones like Arks & c. dulled it down pretty quick. It will still cut steel pretty fast, but hard hones not so much.