Thread: DMT NEW PROBLEM.

Not taking sides or trying to **** anyone off, but I have run into this a number of times the last few months. This may just be this companies’ policy. I can’t find it on any DMT sites.

Extra-Extra Coarse diamond (XX) - (120 micron / 120 mesh) for extreme removal of material and edge repair. They are well suited for flattening conventional and water stones such as those made by King and Norton. Using grits finer than this to flatten waterstones may damage the plate and is not covered by warranty.

Here is where I got this little gem.
DMT Dia-Sharp 8x3x3/8 in. Diamond Plates

I haven't had any problems while using a DMT D8C to lap everything up to 16k, including the hard "white" Spydercos. I'm also careful to avoid much slurry build up. The only thing I've lapped with the E 1200, except for breaking it in, is barber hones.

Thanks guys. The limitations of the DMT hones are now starting to fill in.
Good stuff to know.

On the low grit DMTs I imagine the "peaks" of the diamonds extend far above the hone's surface. This helps to keep whatever it is you are lapping off of the DMT base plate (nickel, did someone say?). Thus you get effective cutting and lapping of the waterstone, and no impact to the DMT plate.

When you get down to a 3um plate, that means the waterstone is very close to the DMT base plate, and as the 3um diamonds cut into the material to be lapped, the material to be lapped (in this case an abrasive hone itself) is busy lapping the nickel on the DMT base plate as well, undercutting the material that is holding the diamonds in place. It will thus errode the material, and the diamonds will be lost.


That's my understanding of the dynamic.

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.

My thought is that the nickel surface on the higher grit DMT's is closer to the waterstones by enough to allow the waterstone's slurry to cut into the nickel. I'm guessing.

Please let us know what the DMT rep says,

Well, crap. That would certainly explain the "well broken in" response I've had from my 8E, as it's been my primary Shapton lapper. There are a few areas on the surface of the 8E that now look like the underside, if that makes sense... on the underside of the DMT, the metal plate is not covered by nickel and diamonds (obviously) and looks alot different than the top. Well, the top of my plate is now starting to look like the bottom.

Guess I'll switch to 2k automotive wet/dry paper on granite to lap the shaptons now, while I still have some DMT left.

Thanks hi_bud_gl for starting this thread.. you just saved my DMT 8E and 8EE.

This is REALLY good to know, I definitely would have tried lapping on my D8EE after my D8C if I hadn't read this

My DMT 325 xtra coarse has never been the same since lapping a couple of translucent arkansas stones. Still usable, but acts like a much finer plate now.

Regards,
Neil

Originally Posted by FloorPizza

Well, crap. That would certainly explain the "well broken in" response I've had from my 8E, as it's been my primary Shapton lapper. There are a few areas on the surface of the 8E that now look like the underside, if that makes sense... on the underside of the DMT, the metal plate is not covered by nickel and diamonds (obviously) and looks alot different than the top. Well, the top of my plate is now starting to look like the bottom.

you look at dmt straight under the light it will be shiny spots.that means that spots doesn't have diamonds anymore=my understanding.
more shiny then opposite side of the dmt

You can often 'recharge' your DMT with a plastic kitchen dishbrush or scotchbrite pad and some dishwashing soap. It really cleans the swarf off. If you use a drop of dishwashing soap while honing and/or lapping, the buildup is greatly reduced.

Originally Posted by kelbro

You can often 'recharge' your DMT with a plastic kitchen dishbrush or scotchbrite pad and some dishwashing soap. It really cleans the swarf off. If you use a drop of dishwashing soap while honing and/or lapping, the buildup is greatly reduced.

Yeah, but unfortunately, what we're talking about is the reduction of the nickel surface containing the diamonds themselves. Brushing cleans between the diamonds, but it doesn't help if the diamonds aren't there (of course).

My Shapton ceramics have been wearing away the DMT's nickel surface to where there are a few points along the edge where there is no nickel/diamonds remaining at all.