when I first read this post I thought we were talking about the back of the chisel, which I do like to hollow grind(with an angle grinder, horror of horrors).... I use the angle grinder(and a bucket of water) for most of my rough work like reshaping an old tool or mowing down the "back" of the bevel when there is a nick in the edge. After that I have an old water stone which I have worn down to around 18" in diameter. It turns quite slow and I keep water dripping on it so no trouble with heat. And after that I have sandpaper and glass and also waterstones. I always finish with the waterstones, hopefully with a hollow bevel and a hollow back.