Thread: Lapping

I always envisaged the difference between the surfaces left by lapping grits (say 300 vs 1200) like the difference between the surfaces of a bitumen road and, say, a concrete path.

I guess the main difference with the analogy is that on hones the surface will smooth out with use. For example, you could always lap with 300 and then run a screwdriver shaft over the hone surface a few times - much like how some people suggest you "cure" a new DMT.

But I suppose the big question is: "just how different are the topology of the surfaces between a 325 and 1200 grit lapper?" The answer should be able to be worked out, to within acceptable margins of error and using some reasonable though generic (yet plausible) assumptions, based on grit geometry I would think. Anecdotal evidence suggests any topographical differences aren't overly worrisome when it comes to honing a razor, but it would be interesting to see a visualisation represented on the scale of the edge.

James.

If I had a USB microscope, I would try to figure it out & display it in photos.

Originally Posted by 1holegrouper

I have yet to really notice a difference on the razor edge from a hone lapped from DMT 1200 vs the DMT 325. That could merely be a function showing that I have yet to enter a zen state of honing prowess, lol. So, out of paranoia, on my part, I also lap my higher grit hones and naturals with a DMT 1200 after the 325, if for nothing else to raise a slurry. It would be interesting to see if someone could show a comparison of an edge via microscope, for example, on an edge off a Nani 12K lapped off of a 325 vs 1200 to see if there is a visible difference. Or, if that difference doesn't show visually, we could have a detailed description of shave feel from each method. My guess would be that most of the time the results from each are comparable but the odds for more keenness and smoothness are improved when you have lapped a finer surface on your hone since more of it can now have contact with your edge.

Yes that would be interesting, I'm all for anything that takes the guess work out of the equation. At this point i hope to just be able to repeat my last successful lappiing session.

Is there any situation with the stones/plates we've mentioned that i would have to worry about "grit" contamination from one to the other? For example: using the DMT325 to the 220 Norton or 4000 Norton to the 12,000 Nany if all surfaces are cleaned afterwards. When I starting out lappiing my 4000/8000 with the DMT i could see a couple of minute specks on the surface of the stone which i figured was small particles from the plate. I did condition the plate some before using. I was a little concerned after seeing that.