I'm very interested in the outcome of this.My Fuller countersinks are getting a little dull and burning up. I've cleaned them, but is there a way to sharpen them so I don't have to buy another set? I don't have a grinder, but I do have diamond stones if there is a way.
I would not do that. Think of running the blade out on a plane and dragging it backwards on a stone…Might be a crazy idea but what if you chucked the countersink in a drill and then ran it in reverse while holding a stone against it (lightly)? I don't have any of these so can't comment on whether the angle is right for doing this sort of thing.
I thought you sharpened the "faces" of the countersink (at least I always have)I would not do that. Think of running the blade out on a plane and dragging it backwards on a stone…