Since we added the Atoma diamond plates for the Edge Pro to our website, people have been asking what the differences are between them and the DMT diamond plates. I thought that these microscope pictures of each series may help you choose which is best for your needs.
I will say that the only major difference is that the Atoma is available in a standard EP size – 1″x6″ while the DMT is only available in the 2″x6″ size. The standard 1″x6″ obviously makes things more consistent, but there are advantages to the 2″x6″ as well, especially with longer knives.
It is also quite obvious that the DMT diamonds are “sprinkled” into the matrix while the Atoma diamonds are precisely placed “clusters”. As with everything sharpening, arguments can be made for and against the merits of each, depending on specific situations. I will make my personal comments at the end of this post.
So on to the pictures :)
All photographs were taken with a Veho 400 USB microscope at 20x for macro and 400x for micro, and are approximately 13mm wide x 10mm high and 1mm x 1mm, respectively. The pictures have been re sized to fit the format on this blog, but no other alterations were made. Here are the links to the original photos for the Atoma and the DMT plates. All of the plates pictured are already broken in. Atoma does not have any official micron ratings as of this post, so all sizes are loosely compared to the JIS (Japanese) standard.
First up are the Atoma #140 and DMT Extra Coarse. These are not equivalent comparisons, as the the Extra Coarse is 60 microns or #220 grit, and the #140 Atoma is more closely related to the Extra-Extra Coarse (XXC) DMT, which is rated at 120 microns. You can easily see the major size difference. Nonetheless, these two are the coarsest of the bunch available for the Edge Pro.
The Extra Coarse diamonds at the micro level almost look like pebbles on a beach in comparison to the giant, almost 1mm wide cluster of diamonds in the Atoma (don’t forget – the Atoma is rated much coarser than the Extra Coarse DMT).
Next are the Atoma 400 and the DMT Coarse. These two plates are more closely matched in terms of micron sizes with the DMT Coarse being 45 microns (#320 grit), and the #400 Atoma falling into the JIS 400 range, which is 40 microns.
The DMT coarse clearly has a more even coating than the Extra Coarse DMT, and the Atoma #400 cluster is roughly half the size and height of the #140.
Onto the Atoma #600 and DMT Fine. The DMT Fine is 25 microns while the JIS 600 puts the Atoma #600 at around 29 microns.
At this level, the Atoma #600 ‘s cluster seems to have reached it’s smallest width, and the DMT Fine has a dense, even coating of diamonds.
Lastly, is the Atoma #1200 and the DMT Extra Fine. The DMT is rated at 9 microns, while the JIS standard loosely puts the #1200 Atoma at 13 microns.
As with all things sharpening, the answer to which is better is “it depends”. There is no doubt with my experiences that the DMT and Atoma diamond plates both deliver, they just do it differently.
The Atoma plates have a lot of positive things going for them: the #140 is certainly more aggressive than the Extra Coarse DMT, making it a better low end plate for profiling and chip removal. The systematic grid pattern of the Atoma plates make the diamonds less likely to “rip out” – for example, the knife may get between the spaces between diamonds on the DMT Extra Coarse. The Atoma plates also leave a very predictable scratch pattern at each level, which really appeals to my OCD and completely compliments the way my Shapton stones work. The clusters seem to ensure a longer lasting life of the plate, too.
But the Atoma plates come at a cost – literally. The labor in making the Atoma, while worth the cost IMO, may be a little over budget when compared to the price of the DMT plates.
Aside from the price factor, the DMT plates also have a larger surface area, which makes them better suited for working on longer knives, and even arguably faster since there are 2 inches worth of abrasives vs. 1 inch on the Atoma plates. The sheer density of the diamond coating on the Fine and Extra Fine DMT plates leave a very even finish and “smooth” scratch pattern, as well, which makes progressing to the next stone level easy.
So once again, I recommend getting them all and trying them for yourself :) One thing is for certain in all this – I don’t see either series getting much rest between performances :)