Ditto what KMOT said. I bougt a drill doctor to sharpen my most used sets. While getting all my drills sharpened was never the plan, the few I needed to sharpen constantly went so fast & acurate that I had to do them all. Like KMOT, I have over 300 drills as I was a mechanic for a school system for 30 yrs, & had a business at home that I also had just as many drills & sets. I got tired of taking it back & forth & not having it were I needed it, so 6 months later I bought second one for the home. When the first one was bought, (1996 or 97) I got an extra stone for it cause I didnt know how fast it would dull up. Well, both machines still have there original stones in them & they still work great. Sorry for sounding like a comercial for them, but they are great. No mess, no fuss, always on center, & sharp as new. Bill