Quote Originally Posted by bth88 View Post
You would not mill one of these [hone]. You would grind it on a surface grinder using a diamond wheel (or maybe even less). I've never trued a hone but a shop I worked for did true granite check blocks in a similar fashion (these have to be incredibly precise as they are used to take measurements off. usually within .00005").
You would not hunk right into the stone (that would cause it to break/crack and could destroy the wheel. very expensive to replace $$$) with the grinder. You would take several light passes that each would take off less than a hair width. Most likely they would marker the top surface were you can see at which point the stone is level (I would), then do an a final pass for shits and grins. I used to do the same technique to level carbide stamp tools. Carbide is also very brittle.

If my math is correct, that would be flat to within 1.27 microns! Thats pretty flat!

How much would this cost, do you think?