Thread: Can I use the "Perforated" DMT Duo-sharp for lapping Norton 4k/8k, and Naniwa 12K?

My dad just picked up the DMT Duo-Sharp diamond plate, with one side 220 grit, and the other side 600 grit. It has perforations, or holes across the entire surface, which is different than the diamond plate most people recommend on this side, the DMT D8C. I just got a Naniwa 12k for Christmas, and I need to lap it. Can I use this diamond plate for this purpose? Is the 220 going to be to rough for the 12k stone (or the Norton 4K, or 8K), or could I first use the 220, and then move to the 600 grit to smooth it out a bit?

Will those perforated holes in the surface of the diamond plate not be good for a lapping plate(damage my hones)?

Also, can I use this same plate to lap a Norton 4k/8k?

Lastly, I know the 600 grit is not normally used as a lapping plate since there is risk of damage to the diamond plate. But if I did the majority of the lapping with the 220 side and then just did a quick touch up with the 600 side of the diamond plate to smooth over the honing surface, would this carry much of a risk with it to the diamond plate?

Thanks!

yes, the perforation does not matter

I don't know about the rosk to the 600 side (I've never lapped, no matter how little, with one), but the interruptions in the surface are no problem at all. They help remove the slurry buildup from between the plate and hone, and therefore should help protect the plate.

An interrupted surface is as Holli mentioned designed to let the material removed fall away and keep it from interfering with the diamonds. They are all recessed, so they have no way of damaging anything you hone on it.

I lap with a 220 and find the surface of pretty much everything lapped on 220 evens itself out after a few passes with a razor. Lapping is imho there to make a stone FLAT not smooth... Smoothness is what whetstones will naturally tend towards. Flatness is what we've got to maintain. Lapping with high grits is used to smooth surfaces that don't wear (metal)... it's unnecessary for surfaces that do wear. Possibly with very high grit, VERY hard stones you may want to lap... but as far as a swaty (very hard synthetic barber hone), it is mirror smooth only a few seconds of use after lapping with 220. The only time I lap any stone to smooth it is when a razor edge catches and creates a deep scratch, then I lap to remove the scratch... these scratches are much, MUCH larger than anything a low grit lapping would leave behind however.

Originally Posted by IanS

but as far as a swaty (very hard synthetic barber hone), it is mirror smooth only a few seconds of use after lapping with 220.

Out of curiosity, which Swaty do you have and what were you lapping with? I found that all three that I've had (two lines of text, three lines of text, and long with two lines of text) had scratches from my DMT C (325 mesh) that were visible when looking at the hone dry, but not while the hone was wet. If we both have the same Swatys, what you are lapping with may be better than a DMT... unless it's slow or the grit is rated by a different system and is actually finer than the DMT C.

I have two 3 lines, one very old one (or abused) lapped on a dmt 600grit and one much more recent one lapped on the dmt 220. It had scratches immediately after lapping, but a few passes with the razor I used on it first and they were gone.

The perforated DMT's are not as rigid as the steel plate versions, so you would need to allow for that. Also, I used one to lap a hard stone (black ark) and it somehow created shallow grooves that matched the dot pattern in the DMT. But no harm in trying it on your Naniwa and it might work just fine.

I know the pattern you're talking about. It's appears as a shiny dull stripe pattern on razors you use a straight polish on too. It's not actually any (significant) difference in depth, not one noticeable under 200x looking head on anyway. And there actually is no part of the stone/razor that is not contacting diamond unless you are moving them less than a centimeter along the plate (if you take a good look at the pattern you'll notice the interruptions are perfectly offset to each previous row). That appears to be caused by the fine lines of the hone which are NOT interrupted (couple mm gaps between interruptions) providing more or less polish effect than the interrupted strips. It is removed from razors by just doing a couple extra passes on my 4k stone before my final polish, so it's really a very insignificant difference in my experience, and shouldn't really impact the performance of a whetstone. I don't notice it even happening on my hard stones (every stone other than my 4k), and on the one it does happen on, they are gone completely after a single use and have no detectable impact on performance. On a stone like a hard arkansas, it would likely take longer, if it bothers you I'd expect a few high pressure passes along the entire length with anything flat and metal or another lapped stone could take them out quite quickly.

Maybe make circular motions and straight back and forth motions while lapping hones? I usually go in circles anyway because it removes material faster and therefore reduces the time to lap.

Yep, that may be why the swaty I did on my 600 (it's interrupted) , never had those marks. I didn't think of that. It was done in a variety of motions. My 4k king was done back and forth because it was almost as big as the 600 was, it got them, but they went away almost immediately upon use.