Thread: DMT Extra Fine 1200

Hi, I've decided to buy a DMT 1200 plate for lapping.
My 325 plate is doing my head in, so to speak.
It leaves scratches in my hones. The sratches in my Shaptons i can live with but not the scratches left in my Jnat.
I have serious ware on the shank of my long screw driver, which has sorted out most of the protruding diamonds but not all.
What i wanna know is, will i have to break in the 1200 with my screw driver?
I dont wanna pay for the Shapton diamond lapper. Its extortion

Yes, you will. Not as much as the 325, but it still has a break-in period.

Does the 325 leave visible scratches in your hones? If so, it isn't broken in yet and still has protuding diamonds. Certainly, the 1200 will leave a smoother surface, but the 325 should do a good job.

My DMT has done its job as expected. I never formally broke it in, just lapped five new stones: Norton 220, 1000, 4000, 8000, and Naniwa 12000. I see no scratches in any and the last two feel smooth as glass. Could you contact DMT or retailer for replacement, maybe you just got a bad one?

On the Shaptons you have to angle them to the light to see the scratches, a touch with a nagura and they are gone but the scratches on the Jnat are clear and dont look good.
I have done about 6 session on the plate with a screw driver, wet + washing up liquid, until my thumbs hurt from applying pressure.
I've got rid of most if the awkward diamonds but its the last few that are still there.
I wont contact DMT , i cant be bothered but i definitely bought a dodgy one.

I just bought the Atoma 1200 for my lapping needs. After lapping the Norton 1 and 4k I realized that a large area of diamond grit was misplaced right in the center of the plate! The seller is returning the plate to the Atoma factory and sending me a new one. I'm considering only lapping 4k stones and above with this one. I'll have the learn more about what you call "breaking it in with a screw driver." At $90 I'm afraid to damage the dang thing.

Originally Posted by wyobarbershop

I just bought the Atoma 1200 for my lapping needs. After lapping the Norton 1 and 4k I realized that a large area of diamond grit was misplaced right in the center of the plate! The seller is returning the plate to the Atoma factory and sending me a new one. I'm considering only lapping 4k stones and above with this one. I'll have the learn more about what you call "breaking it in with a screw driver." At $90 I'm afraid to damage the dang thing.

That was the exact problem with mine, a cluster in the center that gauged the middle of my shaptons and made them very rough.
To break these plates in, take a long screwdriver and use the shank/stem. Run it up and down the plate (wet) to hopefully flatten any rogue diamonds, hit the edges too.
Thats one method.

I finally bought a DMT 325. Didn't like the idea of using a screwdriver to break it in. Had a broke razor, about half of the blade had snapped off, given to me. Put the broken piece to good use and ran that up and down the DMT till I lost count and consciousness. Lapped a newly acquired 12kish Chinese stone (with X pattern drawn on) and it flattened it evenly in no time.

Originally Posted by Hart

My DMT has done its job as expected. I never formally broke it in, just lapped five new stones: Norton 220, 1000, 4000, 8000, and Naniwa 12000. I see no scratches in any and the last two feel smooth as glass. Could you contact DMT or retailer for replacement, maybe you just got a bad one?

I would say you got lucky with the DMT then. Not every DMT plate does this but enough to be a recognized on this forum as a problem area. Mine did the same but was cured with the screwdriver shank treatment and been good since. I did drop little brown bricks when it first happened though.

Bob

I'm torn between a 1200 with potential breaking in problems and the Shapton Diamond Plate.
The Shapton plate dosnt even last forever , maybe a few years, i think.

Originally Posted by JOB15

I'm torn between a 1200 with potential breaking in problems and the Shapton Diamond Plate.
The Shapton plate dosnt even last forever , maybe a few years, i think.

I've got the DMT, Shapton GDLP, and the Atoma 1200. Go to the Dia-Sharp website (DMT) and you'll see in the FAQ, that they will not guarantee any plate used for lapping over 325. Even the 325 must be used under running water or you'll risk stripping the plate of the diamonds if you're lapping waterstones.

Unlike the DMT the Atoma 1200 is great for lapping. The method of mfg is different and the diamonds will stand up to the job. I believe the accuracy (flatness) of the Atoma is superior as well.

My GDLP is still good after maybe 6 years of use. Not as good as it was, somewhat worn, but I did a preliminary lapping with it the other day, and it delivered the goods. Of the 3 I would recommend the DMT if you are on a budget, or the Atoma if you are not. Whatever you do, don't go above 325 with the DMT if you are lapping waterstones and expect DMT to replace the plate if it is damaged.