I found a knife in a ditch, more than likely left my some construction workers. She had many a chip in her edge, but I got them smoothed out.I have been sharpening her for two days, and she has come a long way, but I can't get her any sharper. I've been dragging her across the stone at a 30 degree angle, and after I finished, I smoothed her out. I want her to be sharp enough to shave with at least, so what angles would you recommend? Pic related, pulled it off the interweb, same model, same color.