I've got a diamond and rouge set of wheels on a grinder motor at home, and it's not possible to get a knife any sharper than you can with that set up. However, it also isn't necessary to have a knife edge worked up that fine, and for field work a $5 stone or a good carbide cross cutter is more than enough to get a desirable edge. I got the wheels because I can polish sharpen a 24" beat-to-hell machete in about 5 minutes. It does what it does with minimal effort and maximum results.