Steve Voigt
Bill, I mean soft compared to a hard or trans ark. Compared to those, an India stone will cut much faster, dish more quickly, and gouge more easily. And as I mentioned, metal can get embedded, which doesn't happen with the harder stones.

The names of India stones are misleading. There's very little difference between medium and fine, and both are what I'd call coarse, aggressive stones--very effective as the first stone after hollow grinding.

For those who don't have a grinder, something coarser would be needed for bulk metal removal. A waterstone or a Norton Crystolon will work. I have had bad luck with what Norton calls a coarse India stone, and do not recommend them. They don't seem to like being resurfaced the way a medium or fine does.

Regarding SiC and glass, that is a standard way of flattening oil stones and it works very well. Yes, the SiC breaks down, but you just sprinkle a little more on. You can also stick PSA laminate sheet down to the glass, which saves the glass. Lee Valley sells them.

I bought a pound of the SiC on Ebay years ago. I think it was $4.25 plus shipping and I'll never have to buy more--a little goes a long way. But there's no doubt a diamond plate works better and is way more convenient.