I’ve always preferred diamond plates for flattening my waterstones and oilstones. Though a coarse or extra-coarse diamond stone does a fine job, the sharpening stones are pretty hard on the diamond impregnated surface, wearing the diamond plate prematurely, according to engineers at DMT.
I’m not a big fan, however, of the stone-based flattening systems I’ve used. I have yet to use one that stays flat enough. I have purchased two of the Norton flattening stones. Both were warped to the point of being unusable. After I flattened them (with a diamond plate!), they went out of flat after only a few uses.
I like Norton products. Lots. But not this one.
So I decided to flatten the product one more time.
Back in January, the president of DMT sent me a prototype of a flattening plate called Dia-Flat that is impregnated with diamonds at 120 microns. The diamonds are bonded to the plate using a proprietary technology called DMT Hardcoat Technology. They asked me to use the heck out of it and report back.