Thread: DMT NEW PROBLEM.

JimmyHAD's link to DMT under #18 does warn about slurry. In a quote from there: "Make sure there is plenty of water to flood the surfaces of the stones when flattening to wash away the slurry made by the flattening process."

Nickel has been a component of many steels for over a hundred years. We use slurry to cut steel... I never allow much slurry to build up while lapping, anyway. More slurry = faster cutting.

Once you think about it, it's easy to see how slurry can cut nickel. When lapping anything that makes much slurry, I'm going to start using a lot more water now.

hi_bud_gl: from your first post, it seems that slurry from your Charnley forest stone was cutting very little of the nickel from the 1200, but a lot from the 8000. Interesting cut-off point.

Good point Steven. FWIW, I use my DMT 325 ....or the GDLP in the kitchen sink with a steady stream of water running on the work. I stop frequently to clear the slurry. I have used these for months and lap often with no problem. I recently bought a DMT600 grit to further smooth out the hones that I lap with the 325. Both DMTs are holding up fine so far.

I have lapped such toughies as the Swaty and the Charnley Forest as well as the Chinese 12K with no visible or perceptible damage to the 325. I hold the stone in one hand and the plate in the other and do a kind of x pattern frequently flipping the stone end for end to try and keep the pressure even.

Originally Posted by Sticky

hi_bud_gl: from your first post, it seems that slurry from your Charnley forest stone was cutting very little of the nickel from the 1200, but a lot from the 8000. Interesting cut-off point.

when i use 325 and 1200 slurry was coming out from charnley but when i go 8000 slurry changed to black color =this was dmt's color not charnley's slurry.i mean now slurry was coming out from dmt odd

Originally Posted by hi_bud_gl

when i use 325 and 1200 slurry was coming out from charnley but when i go 8000 slurry changed to black color =this was dmt's color not charnley's slurry.i mean now slurry was coming out from dmt odd

The diamond particles in the 8000 are probably too small to protect the nickel from the abrasive in the stone/slurry.

Originally Posted by Sticky

This excerpt is from Craftsman Studio - Blog · Sharpening - Diamond Products (my highlighting)

• Flattening Waterstones: Customers often ask if it is appropriate to use DMT DiaSharp 8” diamond plates to flatten waterstones. On the surface this seems like a good idea, but in practical application, only the DMT Dia-Sharp D8XX 8×3x3/8 in. Diamond Plate is suitable for some waterstones. This is because the diamonds are large enough to create an “air break” between the surfaces of the waterstone and diamond plate so the two don’t stick together due to the surface attraction of the water. It should also be noted that waterstones will quickly remove the nickel holding the diamonds in place on finer DMT plates.

Oh this is annoying. I've read in SOOOO many places about using DMTs to flatten Nortons and the like, but never read of this problem before. And yes I think I've done it too. Got my DMT 8E a few days ago, read about the need to break it in so I just kept grabbing things to use on it. Bit of steel pipe - no problem. Norton flattening stone - no problem (I think). Norton 4/8K - Seemed OK at first but reached a stage where it was just gliding, didn't seem to be cutting much. I thought (and still hope) that this was because the Norton was aquaplaning because the surfaces were so smooth and wet. I had to do some funny things to make it "bite" at all. Oddly, trying to pull the Norton up from the DMT helped it drag more, especially if I lifted at one end. (The suction between them meant I could lift either one just by holding the other.)

I guess this explains why my Norton looked like this after using it on the DMT:


Funny thing is I've honed a razor on the DMT since then. I thought it was working, but I better test it to see if it is broken in or just plain broken.

I'd be interested in the resolution to this as well. I've used DMTs to lap Charnley Forest stones but never got a milky slurry so much as a gray/green slurry. I use the DMT 325 to lap stones and don't go finer as they load up too quickly and the surface left by the 325 is velvety and fine for honing my razors. I doubt you've hurt your DMT8EE (their 8000 grit waterstone) as a Charnley is just not that hard. If you'd said Arkansas black translucent or Arkansas White, I'd say there was a possibility. Interesting! Thank you for sharing.

This really sucks! Luckely I haven't ordered my D8E yet.I have sent an email to Howard and asked him if he would recomend that use of the D8E, I know he recomends using the D8C as a lapper.If this turns out to be a general problem, I'm getting the shapton 1k instead! Is there anyone out there who has used the D8E as a beve lsetter/lapper over a longer period of time? I just don't find the surface left by my D8C smooth enough at the higher grit hones, and I'm sick of using sandpaper!

Thanks Kristoffer

Although personal preference does rule in basically all things shaving, I have to say that if Howard laps everything with a D8C and says it works fine, I pretty much take that as fact. Now obviously if you prefer the stone to feel smoother - maybe it helps you get a more consistent stroke or somesuch - that's perfectly fine. I just wouldn't worry that the D8C will leave too rough of a hone surface to get the ultimate sharpness. Howard's business isn't called the Perfect Edge by mistake!

Okay, you just posted before me Howard.Then I guess what i wrote don't make any sence

Originally Posted by KingOfMalkier

Although personal preference does rule in basically all things shaving, I have to say that if Howard laps everything with a D8C and says it works fine, I pretty much take that as fact. Now obviously if you prefer the stone to feel smoother - maybe it helps you get a more consistent stroke or somesuch - that's perfectly fine. I just wouldn't worry that the D8C will leave too rough of a hone surface to get the ultimate sharpness. Howard's business isn't called the Perfect Edge by mistake!

Good point sir, but there are very experienced honers out there ( like Randy ) that recomends using at least a 1000 grit to finish a hone.I have myself noticed a large differense.Also shapton doesn't recomend using anything less than 400 grit on their glass hones.But I will admit that I'm a bit confused

Kristoffer