Thread: Lapping a Nakayama

There's simply no reason not to lap a natural hone. IIRC, OLD_SCHOOL's reason for not lapping was to extend the life of the hone. If a hone is dished, it is because the maximum wear is on the lowest point. The lowest point is what defines the useful life of the hone, so lapping down to the lowest point doesn't shorten the life of the hone in any way.

Originally Posted by Chimensch

There's simply no reason not to lap a natural hone. IIRC, OLD_SCHOOL's reason for not lapping was to extend the life of the hone. If a hone is dished, it is because the maximum wear is on the lowest point. The lowest point is what defines the useful life of the hone, so lapping down to the lowest point doesn't shorten the life of the hone in any way.

Very interesting point!

FWIW, I lap both of my nakayamas. I honestly think I get better results, at least in the feedback and feel when honing, after lapping. And I'm pretty sure it's not just in my head I will say that my kiita with nashiji is very soft, which may be why it requires more lapping (it actually raises a very very light slurry on it's own), and I haven't had the karasu very long, but it is significantly harder and may not require lapping as often, if at all.

I guess there is a fine line between a glazed hone
and a hone with a grit that you create
by lapping with coarser materials than the hone actually is.

Originally Posted by 0livia

I guess there is a fine line between a glazed hone
and a hone with a grit that you create
by lapping with coarser materials than the hone actually is.

If what you're saying is that there's nothing fine enough to lap a japanese hone without lowering its fineness, I have to disagree.

I finish lapping my coticules and Charnley Forest hones on 1000 grit abrasive paper even though they are finer than 1000 grit and they don't drop down in fineness because of that. The reason is that the fineness of the hone depends on the fineness of its own abrasive particles. I think the 1000-grit scratches that might theoretically be left on the surface of the stone have very little effect. Besides, if there are any scratches left from the abrasive paper, the first razor you hone on it will quickly smooth them down by removing them.

What I'm saying is that this fine line has to be met.

Originally Posted by 0livia

I guess there is a fine line between a glazed hone
and a hone with a grit that you create
by lapping with coarser materials than the hone actually is.

Originally Posted by 0livia

What I'm saying is that this fine line has to be met.

I'm not understanding what your point is ... we always lap hones with coarser materials and they don't "create a grit". On the face of it, what you're saying makes no sense. A hone consists of abrasive particles in a softer media or "carrier" that is worn away, releasing the abrasive particles. If you remove the media or carrier with a coarser material, there is no way that you are changing the grit of the hone because you are only removing the carrier to make a flat surface from which the abrasive particles are released.

I should have quoted, I guess.
Someone wrote that his hone felt coarser after lapping it.
Thats what I've experienced with one of my Frankonians as well
but it was a surface I've created and had nothing to do with the hone.

An option in this case, where the lapping leaves the
stone feeling a bit coarse, is to simply use a slurry
stone of the same material. Finer grit sandpaper is
probably feasible as well, but I've never used it.

- Scott

I have two and they have been lapped once when new but the next time they will be honed is when I can see or feel they need it and that will be a very long time I imagine.
Not to hurt anyone's feelings but I think at times we are a little to picky about keeping our hones 100% flat all the time.

On the subject of lapping nakayama:
So Yamashi.ta -arguably one of the most experienced experts on Japanese hones in the world- told me to use a diamond plate to lap my hones. 600 or 1000 grit is what he uses. It keeps the honing surface flat and fresh.

He laps before each honing session. I lap every couple of honing sessions, since my honing is less intensive than his. Lapping is -not- a waste of stone if you just lap until it is flat again. Because the material that is removed is typically on the surface that you don't use. If you would, then it would wear down the same as the middle of the stone.