Nope, I don't sharpen them beyond the factory edge. I've found that a knife edge doesn't last more than a few minutes and if I hit twigs or the ocassional stone, a knife edge can actually roll over and be damaged more than if it was slightly dull. Yeah, I know there aren't supposed to be stones in the lawn, but in my neck of the woods, a new crop comes up every spring from ground frost pushing them around. Our soil is basically filler for the spaces between the rocks and stones.