Thread: Lapping Shapton w/ DMT D8C

I got my shapton stones the other day and tried lapping them today. I bought a 1k, 4k, 8k and 16k shapton ceramic on tempered glass. I lapped the 16k and 1k today on my DMT D8C. The lapping went fine but took some time as the glass is a lot harder than a coticule or a norton stone. I did the lapping in the sink and used my DMT holder in the bottom of the sink to hold the DMT so I could lap the shapton on top of it, I think it took me around an hour or a little more to lap the two stones with the DMT, but I was able to get both of them lapped so that after applying grid-lines with a pencil they come off almost immediately when lapped for a few seconds on the DMT.

I did try holding the two stones together in my hands at first under running water like I would with the norton or a coticule but that was taking a long time and starting to get a little hard as I had to hold up the DMT. I didn't keep the water running the entire time while lapping these with the DMT in the holder though. I ended up just running the water to clean off the DMT and shapton often and to reapply a bunch of water to the DMT surface so it would move freely across the surface.

Any of you that have the shapton GDLP have the experience go faster or does it still take some time? I was reading on the shapton webpage that the DRLP only takes around under a minute to lap a shapton stone. At $500 or so new and $325 for a remanf. one or $289 for the GDLP I think I'll stick with my DMT that I only paid $120 for a set with the D8C, D8F and D8E and a holder for them though, I don't think I'll end up needing to lap them enough to really justify the purchase. Also I think after the initial lapping and with their use solely for straight razors subsequent lappings of these will probably be pretty quick. Now I just have to lap the 4k and 8k stones but I'll leave that for another day or maybe later today.

I just got a couple Shaptons and a GDLP yesterday. Today I lapped an 8000 and a 16000 (along with two coticules and a small Escher). The Shaptons took longer than the natural stones but still only required a few minutes to get them flat. I have a DMT, but haven't had the inclination to compare its speed with the GDLP. Shapton recommends the GDLP over the more costly DRLP for razor hones. I was told that the GDLP is the flattest of their lapping plates.

Well my 4k and 8k are lapped now. It took about an hour to do both, a little less than 30 minutes on each. I noticed the high and low areas on all four shaptons were in pretty much the same spots. I rotated the shapton a few times during the process as well.

Just curious did you use grid lines when you lapped your stones?

Yes, I used pencil grids before and after.

I have the 1K, 4K, 8K, and the 16K. All were lapped with a sheet of 600 grit wet or dry paper on a piece of glass and none took more than a few minutes. I don't see where you are having problems??

Fred

Hmm... duno, well they're all done now. The grid-lines went away fairly quick in a few spots on the shaptons but in other spots it took longer. It was pretty similar for all four of them as far as the high and low spots. I made sure it wasn't the way I was lapping it by rotating the shapton 180 degrees with the DMT staying still.

The reason Shaptons are so exceptional is the diamond composite and that they're so flat to begin with and that's what you're really paying for with that stone. I have used a GDLP on Shaptons as that's part of the Shapton system. When you have something that flat, a rock solid holder is necessary to keep it flat and the lapping stone should be consistent with the technology. The Shaptons start out two orders of magnitude flatter than a DMT which is +-.001" across the surface. The Shapton is .001mm which is a whole heck of a lot flatter. I've been playing with Shaptons (with Harrelson Stanley) lately as I'm going to be carrying them in a couple of weeks.

Really.. hmm when I was lapping them I noticed that I could look at the shapton from the side and see a low spot near the middle where it curved downward.

Originally Posted by Howard

The reason Shaptons are so exceptional is the diamond composite and that they're so flat to begin with and that's what you're really paying for with that stone. I have used a GDLP on Shaptons as that's part of the Shapton system. When you have something that flat, a rock solid holder is necessary to keep it flat and the lapping stone should be consistent with the technology. The Shaptons start out two orders of magnitude flatter than a DMT which is +-.001" across the surface. The Shapton is .001mm which is a whole heck of a lot flatter. I've been playing with Shaptons (with Harrelson Stanley) lately as I'm going to be carrying them in a couple of weeks.

Ah ha! So Howard's been bit by the Shapton bug as well. As Christian (Kaptain Zero) says...resistance to Shaptons IS futile!

Originally Posted by bevansmw

Really.. hmm when I was lapping them I noticed that I could look at the shapton from the side and see a low spot near the middle where it curved downward.

What Howard means is the Shapton GDLP lapping plate is .001mm flat across its surface. The Shapton ceramic on glass stones are not pre-lapped and vary in factory flatness or lack thereof. Don't worry about how long it took you. You're there and can enjoy the stones. It depends on how much pressure you use when lapping. On a few of my Shapton ceramics I laid them on my GDLP and literally just used the weight of the stone to lap. It took as long or longer than it did for you.

Now when I touch up (which I do for each stone before each lapping session, I just rub the stone and GDLP together lightly under running water for 10-20 circles to remove the steel swarf. It only takes less than 30 seconds.

Enjoy those Shaptons!

Chris L

That makes sense. So the DMT is about .025mm (= .001") flatness and GDLP .001mm, so the question is 24 thousandths of a mm really perceptible?

Edit: Maybe makes more sense in terms of micrometers, 25 micrometers flatness vs. 1 micrometer. I don't think that is much noticable, though 25 times greater it's still exceedingly flat.