Ive been using MDF with various polishing compounds this weekend. Just puttering with an old plane blade and my mark 2 jig to see if any of them took me beyond my shapton 6000. (I havent bought that 0.5 micron paste yet.) Bought some tripoli, red jewelers rouge and a yellow stick they said is for stainless steel. Only the yellow showed black streaks, so Im guessing it was the only one doing any cutting. Also bought valve grinding compound but didnt try it out. Like I said, I was bored and decided to putter a bit.
Got me to thinking though. Is there a way to compare the grit of sandpaper to that of my stones and also to the honing compounds? For example, is 2000 grit paper really coarser than my 6000 stone? Is that no-name stainless steel polish finer or coarser than that 6000 stone? Is there a credible way to compare these abrasives, or does each manufacturer use their own definition of grit?