Hi!
I am trying to better understand polishing (enamel/ glass), polishing compounds, grit, mesh, microns, etc...and came across this comparison chart that I thought might be of interest to some.
It compares grit mesh micron.
here is the link:
https://www.gemsociety.org/article/just-ask-jeff-how-are-gritmeshmicron-related-and-what-is-what/
all the best,
Julie
***edit***
(here is somewhat different information, from a page in rio grande catalog...)
http://www.riogrande.com/Product/Rubber-Mandrel/337234
30 microns = approx. 400-grit
15 microns = approx. 600-grit