Quote Originally Posted by Hirlau View Post
I've used it quite a bit, but really cannot give a good guess. Your 15 to 25 is a good size gap, but it is probably closer to the 25,,,,. The problem with me is, I'm used to man made hones with a factory rating,,,though I have several natural finishers, their grit ratings are a mystery to me.
25k sounds like a legit estimate but thanks for the guess.

Some guys. Go by the scratch marks under magnification

I just wondered what people would guesstimate.