I'd like to find a stone or stones to sharpen the inside conical part of my hollow mortise chisels. I thought I'd once read that Lee Valley had them. What I mean is a cone shaped stone with a small diameter shaft sticking out the end for attachment to a drill press. I went to the Lee Valley site and don't see anything like that.

What I don't want are the cone shaped bits of metal with a diamond coating. I got a pair from Rockler and the instant they touched the chisel the coating pulled away. They're totally useless.

Therefore, actual stones are what I think I want.

I have a Tormek, I've got the faces polished nicely, but the edges that do the cutting look pretty ragged, it seems obvious some cleanup of the interior conical surface is needed.

Where I can I get those conical stones I'm looking for?