Thread: DMT confusion causing much pain!

As a superior and more durable alternative to the Norton lapping stone, DMT has been recommended. Accross the web (and probably within this forum), the two most common references that I recall seeing for that purpose have been:
DMT D8C
DMT 325
What makes my brain hurt is that when I google under DMT D8C, Amazon shows what appears to be the dimensions of a Norton waterstone. DMT D8C 8-Inch Dia-Sharp Continuous Diamond Coarse - Amazon.com It resembles a waterstone in thickness, and is billed as (and appears to be) a "continuous diamond" surface, but unlike any waterstone it can be used dry. This is not what they call the "whetstone" (DMT 325), which by comparision looks very thin, and is described (as it appears to be) as a steel plate embedded with diamond. If this is steel, then I don't know if I would ever want to get it wet, therefore the name "whetstone" sounds rather mysterious. These appear to be very different products, although both are billed for "325 mesh". Perhaps it's the fact that both have that same grit pattern which is causing people to use DMT D8C and DMT 325 interchangeably.

Anyway, which is better for lapping with - is it the DMT D8C, or the DMT 325? Also, are they both about as durable?

Thanks.

I use the DMT 325 and it works very well. I use it under running water with the stone to be honed. When done I simply shake off the excess water, wipe it down with a towel and let it air dry. I've had no issues with it rusting at all.

Never any issues with rust on mine.I belive they are nickel plated

When lapping stones you do not want to use it dry, the build up of loose grit rubbed around on the DMT will eat the substrate that holds the diamonds.
All diamond hones and some ceramic too is more like "can be used dry".
It is very seldom good for them and since you get no lubrication from either water or oil, it's not so good for honing steel either.
I had some rust on my DMTs when I forgot to dry them and left them on the kitchen sink, any contact they have with a nobler metal will make them rust faster...

Originally Posted by Lemur

When lapping stones you do not want to use it dry, the build up of loose grit rubbed around on the DMT will eat the substrate that holds the diamonds.
All diamond hones and some ceramic too is more like "can be used dry".
It is very seldom good for them and since you get no lubrication from either water or oil, it's not so good for honing steel either.
I had some rust on my DMTs when I forgot to dry them and left them on the kitchen sink, any contact they have with a nobler metal will make them rust faster...

Is the D8C also good for lapping, and what issues should be expected with it?

Originally Posted by bluroot

Is the D8C also good for lapping, and what issues should be expected with it?

(C) Diamond - Coarse
Quickly sharpen a neglected edge (325 mesh, 45 micron)

It's more or less the standard for lapping by people here, but Atoma is a good alternative or any cheap Chinese coarse diamond hone if you feel lucky!
325 mesh is what I use together with a 220 for speed, always rub my finer hones with a similar stone, nagura, to get a fine surface.

Lots of water will keep your diamond hone alive longer, DMTs might rust and don't forget to chamfer the sides of your hone.

I've had 4 DMT 325 plates and only the first one showed any signs of rust.

Jerry

They are the same

D8C = Dia-Sharp "Coarse" C=325 grit 8 = 8 inches

D11C Dia-Sharp 325 grit 11 inches long

We often say specifically DMT 325 so there is no confusion on the grit


D8XXC
D8XC
D8C

These are all very close in name and it gets confusing but the grit is quite different XXC= 120 XC = 220 C=325


DMT also has 600,(D8F) 1200(D8E) and 8000(D8EE) but using them for lapping is not recommended by DMT


But to be VERY clear

D8C = DMT 325(8 inch size) same same

And no they do not rust easily, and I ABUSE mine..


Edit the 8 in the DMT names above designates the 8 inch hones which is what most of us use they could be a 6 or 11 also


ps; The dimensions on Amazon are wrong it is NOT 8.5 x 3.5 x 1.5 it is actually 8 x 3 x 5/16

Ive only seen rust on mine when I was doing a prebevel and didn't rinse off the steel that came off the blade. The steel filing or what have you will rust on the diamond plate. And very quickly.

I know their both rated 325. But do these two products look anything alike otherwise?
DMT D8C 8-Inch Dia-Sharp Continuous Diamond Coarse - Amazon.com
DMT 325 in Collectible Sharpeners for Knives, Swords, and Blades | eBay
Also, one is billed for (as I believe is shown) "continuous diamond", while the other is thin, with holes and color. This is what's confusing me! The bottom line for me is whether one or the other does better at lapping a big waterstone.

Originally Posted by gssixgun

They are the same

D8C = Dia-Sharp "Coarse" C=325 grit 8 = 8 inches

D11C Dia-Sharp 325 grit 11 inches long

We often say specifically DMT 325 so there is no confusion on the grit


D8XXC
D8XC
D8C

These are all very close in name and it gets confusing but the grit is quite different XXC= 120 XC = 220 C=325


DMT also has 600,(D8F) 1200(D8E) and 8000(D8EE) but using them for lapping is not recommended by DMT


But to be VERY clear

D8C = DMT 325(8 inch size) same same

And no they do not rust easily, and I ABUSE mine..


Edit the 8 in the DMT names above designates the 8 inch hones which is what most of us use they could be a 6 or 11 also


ps; The dimensions on Amazon are wrong it is NOT 8.5 x 3.5 x 1.5 it is actually 8 x 3 x 5/16