Thread: DMT Duosharp as lapping plate

So fellas I haven't really seen a thread to this effect but I know I and a few others have had questions about this. Yesterday I got my 10 inch duosharp x/c- the one with the holes. I want to start off by saying that I don't own any other DMT, just the one I am going to discuss. I have seen/used/felt a DMT8C though.

Today I took a couple rocks that have potential for being good hones and lapped them. As in heavy duty grindin'. I figured this would test its mettle and also break it in on something other than my expensive hones and razors.

Here are my thoughts:
First off I wanna say WOW to the 10x4 in size. WOOOOOOOW.
It is a significant improvement and if you can afford the upgrade, do so. (diasharp/continuous also comes in the big size now) I am not sure about the diasharp model which is entirely metal, but the duosharp is not too heavy in the big size (plastic core). Besides, I found the best use was as a "washboard"- I propped it on one end, held the other and "scrubbed" the rocks on it under a faucet.

Next, I really liked the benefit of two grits. While I only have the x/c model (220/325) not the xx (120), even the 220 really helps for heavily dished rocks, and was still fast on everything but barber hones (which I don't even think a 30 grit dmt would be good enough for) and even then the 220 was a big help (vs the 325).

With regard to cutting speed (the argument that the holes mean less usable cutting surface) I cannot really comment as I don't own a comparable continuous plate to compare the same hone on the different plates but I will say it is very fast- definitely fast enough.

Next, the HOLES! It is hard to describe the feeling. Swarf is not an issue at all, and I can only attribute this to the holes. Previously I have lapped on wet/dry and films stuck to a flat surface, and it seems to clog up or cause the hone to "hydroplane" and thus not lap well. No problem here. When the hone gets "there" it does still stick to the plate (I imagine the little holes are like little suction cups lol), but once again it doesn't have that feeling of hydroplaning on a thin film of water- the water and swarf get caught by the holes ensuring what feels like great stone to plate contact.

Flatness- In my limited test environment this hone is certainly good enough. Dunno if it is perfectly flat but vs. a drafting straight edge, a known flat hone, and a marble tile it is flat.

In summary, I find there is absolutely no problem using these as lapping plates, ESPECIALLY in the big model. Hope this helps.

PS: Just wanna add that I am not saying they are better than continuous (diasharps) but I am just giving them a thumbs up as lappers.

I think for lapping, they might be a good choice. I have the small ones for honing knives and they are excellent.

I know the continuous ones are flat to a pretty nice degree, but not sure how flat the others are. I'm sure it would be flat enough for our purposes though.

Personally, I think I'll stick to the continuous ones. No sense in having 2 hones of the same grit right now...saves on money

Not saying they're better, just giving it sort of a review, and putting info/answers out there that I couldn't easily find a week ago when I looked.

I understand, wasn't saying one way or another, just my thoughts jumped out to my fingers haha

I'd love to know how well it laps compared to the continuous ones. I think it would be better for removing the slurry with the holes in the metal plate like that.

Maybe someone will let you borrow one to compare the 2

Interesting!

I use the continuous D8C and I have been very satisfied. I have wondered, though, how well the DMT's are with the swarf holes. Does it leave scratch marks? Does it leave the surface nice and smooth?

Thanks,

Steve

From what I can see the scratch marks are a little finer than the grit equivalent in sandpaper- so I guess yes it leaves scratch marks but off the 325/coarse they are not bad. The Naniwas didn't need any more and because I am obsessive I took my jnat all the way up to 1000 but it would've been fine after the 325.

I also noticed that on the D8C I have the marks are not as "coarse" as the sandpaper equivalent.

Lapping my 1k Norton actually leaves the surface FEELING too smooth, but once you put steel to it, you can feel the abrasion. Could it possibly be that the diamonds are coarse, but they are so much smaller and closer together than on sandpaper that it leaves the surface looking and feeling smoother?

I know that makes no sense but it's the only thing that comes to mind right now.

I have two concerns with using them for lapping. One: I was told that when they are used in a stone holder with some force they may flex a little. Second: I used one and noticed it made a stripe pattern on the surface of a Naniwa and also on a Spyderco UF.

Hmmm. Not sure what stripe pattern you are talking about. Do you have pics? I have not seen this.

Not saying they can't be used for lapping. I just have these concerns. Here is the (poor quality) photo. Look very closely and you can see dark stripes. May not be important, but I didn't like this result.