What I do is grind it till it has a slight edge then I take it to a diamond 'stone'. I move the blade in a circular motion till a burr forms across the entire edge, then I repeat the process on the otherside. After that, I switch to the fine side of the stone and slowly move the blade across it as if trying to cut a slice off. Once per side to make consistency of the angle easier-I do this several times. They're not as sharp as I like-but I probably should get a third grit stone to polish the edges.