Problems with my Atoma 400 diamond stone

[overland]

I recently asked for advice about flattening my Shapton Pro water stones. I was having trouble. Someone suggested I check the flatness of my Atoma, which I had never bothered to do. Sure enough, it's not flat--there's a slight crown in the center. (My EZE laps, on the other hand, are perfectly flat.) I've had the Atoma for 2 years old and so it's too late to send it back, but I wonder if the problem lies in the thin steel diamond-impregnated sheet that attaches with some kind of adhesive to the thick aluminum block. It can be replaced. Indeed, the other side of the aluminum plate is perfectly flat. What should I do?

[Steve Friedman]

Unless you've abused it, the plate should stay flat and I would expect most of the sellers to honor that. Maybe one of the metal guys will have a way to flatten it.

You can buy replacement Atoma sheets, but it's not appreciably cheaper than buying a new stone. If you get it from Stu at Tools from Japan, the difference in cost between a new sheet and a new stone is only around $12. A little more with shipping.

I like my Atoma stones and would replace them if they wore out.

Next time keep it away from steel.

Steve

[overland]

I think you're right: I should have kept steel away from it. I did use it for some flattening of chisels and plane irons. But over two years I didn't really use it that much--I'm a very part-time woodworker-- and yet apart from the problem of unevenness, it no longer cuts very well. That's pretty surprising to me. I expected it to be more durable.

[Bibliophile 13]

That's odd. If it were a wear problem, I'd expect it to be dished rather than crowned in the center.

Diamond stones do lose their initial aggressiveness after the first few uses. That's to be expected. It is certainly possible to wear one out, but usually excessive wear is visible--the nickel plating will be missing, and you'll see patches of bare steel.

[Steve Friedman]

Bibliophile 13 said:

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That's odd. If it were a wear problem, I'd expect it to be dished rather than crowned in the center.

Diamond stones do lose their initial aggressiveness after the first few uses. That's to be expected. It is certainly possible to wear one out, but usually excessive wear is visible--the nickel plating will be missing, and you'll see patches of bare steel.

---

Steve,

I agree with you completely that using the Atoma on steel probably had no affect on the flatness of the plate. I just meant that if I got a brand new Atoma, I would want it to retain it's abrasiveness as long as possible, which means keeping it away from blade flattening duties. The Atoma's flatten stones quickly and I wouldn't want to do anything to it that might make that process take longer.

Lots of other (cheaper) options for flattening plane and chisel backs. My favorite is still 80 grit PSA sandpaper on granite. I have 150 and 250 grit barely-used EZ laps and they mostly just gather dust.

Steve

[overland]

Steve & Steve---
This is all good to know. The Atoma was my first. I bought it for its reputation but had no experience with it. Now I do.

[ranger29]

I have used the Atoma 400 over a few years with absolutely no problems. I have used it to flatten the backs of a couple of chisels but primarily use it to flatten stones. To date, it still works extremely well.