Like spyder said, DMT makes good diamond stones. They have a double sided one with coarse and fine, and that, really, is all a person needs. I think they sell a little base for the stone as well, or you can make one to hold the operation steady. The nice thing about them is you can use them without water or oil, but of course it works better with a little lubrication, and it doesn't take near as much work to put an edge on your tools. The downside to diamond stones is that they grind a lot more metal off the edge if you're not careful.