ceramic bench stones

[nobody]

A few years ago, at a woodworking show, I bought a set of ceramic bench stones. I believe they are about 2 in. x 10 in. I found they cut quite well and the extra fine stone I believe is around 8000 grit which gives a pretty decent polish. The only problem with these stones is they have never been really flat and experienced sharpeners in this group will know how important this feature is, especially on plane irons.

Well, the other day I decided what the hell. Why not flatten them with new Duofast diamond stones. The diamond stone flatten them quickly but it left them with a sort of mottled effect. In other words, the initial glaze on the stones disappeared in places.

What I am wondering is exactly what this has done. I haven't really used them much since this operation but they seem to be cutting OK. I am just wondering about the experience others have had with ceramic bench stones and if anyone else has flattened one with a diamond stone?

[George]

As it is particle size which determines the amount of metal removed, shouldn't notice much of a difference.

As to perfect flatness being critical for plane irons, I thought the reason you moved them relative to the stone was to compensate and get the average. Think of lapping the stone, only your iron is flattened instead of the stone.

You didn't verify the diamond critically flat, did you?

[Australopithecus scobis]

You just ground off the glaze. The shiny spots probably don't cut as quickly. That's good.

When I put my ceramic stones on my brand new diamond plate they knocked all the rough off. The diamond was very aggressive out of the box. Now it's almost slippery. Next time I'll use loose grit on some MDF.