*What do you flatten your stones with? I've been using one of the flatteners with the deep diagonal grooves in it. Recently I got a DMT diasharp course plate. It worked well at first, but seems to be losing its grit fairly rapidly. And the original flattener I had doesn't seem to be as course as when I first got it as well. I was thinking about getting the extra course DMT plate, but I just got the one I have only a few months ago. In my research on the plate, I did read that sometimes you may get one that has some spots that have little to no grit. I found that to be true. However, not so much that it should affect flattening a stone. Shouldn't the flattening device outlive the stone???