Thread: Buying a DMT lapper, please help

I am about to buy a DMT for lapping and heavy duty work. My main question is, should I get one with or without holes?

Also is the 10x4 worth it compared to the 8x2.75?

From reading I have gathered:
With holes- far less stiction and swarfs up less quickly, but has fewer diamonds/area
without holes- more stiction, swarfs quickly, but has more diamonds per area.

Any advice? Any thoughts on the blade catching on a hole? I will not need a low grit hone frequently, so if its just that I should be careful, that is okay by me. I just want to know if its a very likely danger.

Between the four options price is not really an issue (I know there are big price jumps but all are in my budget I would like the best of the 4)

Also for what its worth I'm leaning towards the big combo holey one. Seems like while it has less diamonds/area, the decreased stiction and less swarfing would make it a more efficient lapper.

IME the continuous DMTC 325 in 8x3 works very well. I also have the XX 120 which eats barber hones. I've not tried the one with the holes so I can't speak to that but I have read posts by members who use them with no problems. Any of them should be used under running water according to DMT and nothing above a 325 for lapping waterstones.

For size, it's really a question of how much you are willing to spend, and how heavy a plate you feel like having...

I've never used one with holes, but if they don't scratch hones, I would think they should be fine to hone on. Personally, I bought one without holes because I figured it would lap faster with more diamonds and put less wear on the diamonds (cause there are more of them). Mine has held up just fine, and I'm happy with it. (I have a 6c)

Two here just like Jimmy has the 8x3 325 and 120 ..... The 325 is by far the one, if you get only one... The 120 is more for pre-lapping hard Naturals, and Barber's hones...IME

I've got an 8x3 continuous XC (Damned cheap ~$45 at amazon). It laps everything I want. Leaves some scuffs on some hones but they don't have any impact on use and wear off after a few uses on my naturals, a few passes on my synthetics.

For my Swaty I found myself wanting the XXC, but that's the only hone that's been "slow" to lap on this thing. Those Swaty's are monstrously hard.

Thanks for the responses guys. Any reason you guys chose the 8 inch over the ten inch?

I have some Nani's, a couple barber hones, a jnat and a thury. Are any of those "hard" (besides the barber hones which are... duh)

On a side note I lapped four (!) Swaty's to date using only 220 grit sandpaper and a tile... holy mother of god that was a pain. I am sick of it which is why I am getting the DMT. Would having the x-coarse be welcome/necessary, or does the 325 get it done easily? (and I mean very easily)

I voted for the 8 because I use a 6 and have no issues with the size, so I can't imagine spending the extra money for the 10 over the 8. But that's just me.

It did take me a while to lap Swatys, but they got there. If you want something faster, by all means go for it; you can always rub out the scratch marks the XC leaves with a lapped Swaty; I used to use my Swaty to rub out scratches from my C, and I use a Spyderco Medium pocket hone now that I no longer have any Swatys.

I like an 8 because I want a plate that is at least as long as most of my hones. I have lapped longer hones with the 8 and all went well but for the extra few bucks I think it is worth it to get the 8. YMMV.

So where is wet dry paper on a flat (counter, glass, wood)

+1 on what Holli said.

8x3 is perfect for everything I've put it too so far. Unless you're getting stones WIDER than 3", I wouldn't even consider going to the 10x4, unless it's only a few dollars more. I find that stones an inch or two longer than my DMT are still no problem to lap... I can imagine wider ones being a bit more awkward (and a longer and wider one would definitely be a pain).

I didn't lap my Jnat (very hard stone)... except when I make slurry it gets briefly lapped with my EF (1200 grit)... it came lapped (at least it was totally flat the first time (and indeed every time) I slurried it). I recall a couple of the more experienced guys had suggested that I may not want to lap it, though I can't recall why.

For my barber hones, well my swaty took a long time... one other took forever... and was a waste as it turned out to be a grit level that I didn't need as well as a very irregular grit. Then there's my Dimo-grit razor hone and my King Icebear stone. Both took seconds to lap. Soooo soft. All the naturals I've done have been somewhere in between (though I hear the hard black and translucent arkansas are even harder than the swaty).

I'm sure if you search Naniwa and Lapping you can find some reports on them, I seem to recall reviewers saying they aren't especially hard, so should lap up pretty easy. There's probably similar info for Thurigians, though you may want to search "hardness" with them, as I recall some people discussing their hardness when trying to identify stones.


If you plan to lap a lot of swaty's I'd go as course as you can. For reference. I lapped one with 600grit. It took about 2 hrs in 15 minute shifts. I lapped another with 220grit. It took about 30 minutes in 10 minute shifts. Neither were visibly uneven (until I started lapping and the wear pattern became evident).

A DMT is about as fast as Paper when you first put it down... and the XC is 220 grit. So imagine if your paper never got worn and that's about how long lapping will take on the XC. Maybe you could get the XXC plate and then a few sheets of 400 or 600 and just use the paper to get the scratches from the XXC gone (let the plate do the actual leveling).