Thread: grit, grade, mesh, micron & finish

I have seen the comparison chart posted here, on ameritech, two from Pam, on sharpening supplies, and some random lapidary and microfinishing sites - I have been wondering about this because the Norton 4K/8K seems pretty popular, and also because of the usage of the EE DMT hones. These stones use mesh grading, not grit, so are they comparable to JIS grit in the finish created? Norton 4K is 6 micron, because the US mesh grade of 4000 is a 6 micron mesh. But, new Japanese Industrial Standard (JIS) - that it seems most Japanese waterstones use, puts 6 micron as somewhere in the range of 2500, and 4000 grit is 3 micron. Likewise, 8000 mesh is 3 micron, and 8K JIS is 1.2 micron. Both Norton and DMT have an 8K stone, but neither is 8K grit, they are 8K mesh.

It seems that some people think that the stones are assigned certain numbers because the abrasive breaks down, or is a certain shape that gives a certain finish. But to me the numbers advertised just aren't the same scale, or even trying to approximate each other. Like, maybe DMT didn't say, 'hey, this 3 micron plate gives a finish like an 1.84 micron glasstone, coticule with slurry, 1.2 micron King, etc.' They just used US mesh grade and not 'grit'. I am guessing this is the same thing Norton did... but if this is the case, is anyone getting near/shaving edges off a 4K/3 micron abrasive of another manufacturer?

Also, does anyone try to get a shaving edge from 2000 grit sandpaper? On the US CAMI scale, that is 1 micron, around 8K JIS. Or F1500 FEPA from Europe? And is 0.5 micron chromium oxide or diamond generally referred to as 30,000 or 60,000 (mesh)?