Thread: fast, cheap way to lap chinese 12k

I bought a chinese 12k that had really big saw marks left on it. I had a bunch of loose abrasives left over from a telescope mirror grinding project from a few years ago. I bought a granite floor tile (cost $4) and started with a slurry of 220 SiC grit, then 500 SiC, then 9 u Aluminum Oxide. The slurry cuts *really* fast (much, much faster than wet or dry sandpaper) and the AlOx left it really smooth. I have some 5u lying around but I'm not sure it would be that much of an improvement - the stone is really flat and smooth right now. One thing that is funny is that when you get to the fine abrasive, the stone really sticks to the tile!

I looked online and there is a place called gotgrits.com that sells these abrasives. A 1/4 lb of SiC 500 mesh is about 2 bucks, same of Al Oxide (I think) was about 1.75.

One other thing that seemed to work well - I started on the underside (unpolished side ) of the floor tile whose textured surface helps gather grit (it wears down with the 12k) then finished on the polished top side.

Anyway, just thought I would pass on the idea.

- Ian