Slash McCoy
I freehand dog rockets
Thank you for your very informative post! A nitpick - I don't think Norton uses ANSI grits to rate all of their stones, as ANSI 1500 grit has an average particle diameter of 3 microns whereas the Norton 8000 grit stone has an average particle size of 3 microns and the Norton 4000 grit stone has an average particle size of 5 microns.
I'm not sure the Japanese synthetic waterstone makers use JIS grits for their high grit stones either, as the particle sizes don't match each other (Suehiro Gokumyo calls a 0.5u stone 20k grit, Shapton calls a 0.49u stone 30k grit) or the JIS chart extrapolated to those numbers, or sometimes even the JIS chart at lower grits (Shapton 8k has an advertised 1.84 micron particle size and Shapton 12k is 1.2 micron, JIS 8000 is 1.2 micron).
Also, I would like to complain that every grit comparison chart that I've seen lists ANSI grit sizes a little differently.
Ah, thanks for that. Apparently I was wrongfully belaboring under a pre-misconceptualization.