Quote Originally Posted by Derek Cohen View Post
Raf, I am not disputing what you do here, but have a question about the use of the finer grit …

It has long been a puzzle for me why some recommend coarse grits to flatten stones at the coarser end of the spectrum, and finer grits for stones at the finer end of the spectrum. The point is, as I believe, the result in honing comes from the grit in the stone and not the surface treatment of the stone.

I use the same coarser grit (140 diamond stone) to maintain all my waterstones. In the case of these oil stones I would use the 90 grit SIC powder or the diamond equivalent.
The coarser grit will cut more aggressively, so the process is faster with them. The grit breaks down fairly quickly, so even if you start coarse, one ends with a finer slurry until you refresh it with fresh grit.

I suppose finer grits are preferred with finer stones because otherwise the surface would be left all scratched up. I should point out that on softer stones than a typical washita, using the coarse (around 90x) grit leaves a very rough unusable surface, in my case they were a slate, and some waterstones. After the coarse grit, I used finer grits until a uniform surface was achieved.

I have about a couple dozen sharpening stones, mostly washitas. The fine ones are Arkansas (Dan's and Norton) and those came my way in good shape, so I didn't need to lap them. Some of the washitas, indias, crystolons arrived in need of some lapping. The infrequent need to flatten and trying to wear them evenly is one of the reasons I prefer the washitas and the Indias over water stones.

Maintaining oilstones or waterstones with a diamond stone should work, the amount to remove is small compared to what's needed when they're dished or clogged. It's in that case where the coarse grit saves you time.

There's one last point to be made. Once you start using a relatively low wear oilstone like an India, washita or an arkansas, the roughness left from the manufacturer's lapping or your own refurbishing lapping wears off. I think they say that the stone "has settled". It's around that cutting power that one works with when using these stones, not their behavior freshly lapped. One could rough them up with a coarse stone, but that just adds time to the process and may not be needed.