Thread: Service life of DMT 3xx grit plate

'Recently bought the dmt, and lapped a norton 1k/4k flat, then a chineze 12k, and tried to take the bow out of an old translucent arkansas stone. The dmt feels pretty smooth now. Anyone know how fast they can be worn out? I realize usage is key, but it seems like a short life so far.

Which DMT, and how did you lap? Using a coarse or coarser DMT under running water and rinse it now and then, it should be no problem. It will break in a bit, but still work just fine. IF you use a finer DMT or don't lap under running water and rinse it off now and then, the slurry and/or hone you are lapping can rip the diamonds out of the nickle substrate that bonds them to the steel, wearing out the DMT. If used properly, they'll last years. If not, well, they'll wear out fast.

The C12k was no doubt hard on it; a transleucent arkansas will kill a DMT pretty quickly...

I don't know what you mean by the DMT "3XX." The DMT XX is the 120 grit plate and it is the only one that DMT recommends for lapping. DMT says that the DMT X and C (220 and 320 grit) can be used for lapping but only for waterstones.

The Chinese hone and Arkansas hone should not be lapped with anything but the DMT XX. You MIGHT get away with using one of the higher grit plates, but you risk destroying your plate. The diamonds are hard, but the surface that holds the diamonds is not. If you lap a natural hone with one of those finer grit DMTs, you risk undercutting the diamonds causing their release. That will lead to a smooth ruined plate.

One & all, thank you for your kind help.

The arkansas stone took alot of lapping, and stopped progressing, so I gave up. The 12k came in easily (was new). It may be I have to get another plate.
Again, Thank you so much.

Ok from the title of your second post you've clarified which DMT you have, the C which is 320 grit. As I already indicated, that one is only meant for water stones, but on the bright side it is unlikely that you will need to lap your Arkansas or Chinese hone ever again! That means if you buy another DMT it should last much longer if you treat it better.

Since you said the Arkansas "stopped progressing," what you can do is put some low grit (around 180) wet dry sandpaper on the flat DMT plate (it still has a purpose!) and continue lapping with that.

Utopian, your help is great. I sure appreciate it!