We have one in our shop. The old timers "eyeball sharpen" bits. I have been trying this for 50 years and still manage to sharpen a bit off center to where it cuts a bigger hole. I use the drill dr. However you do it, buying best quality American bits and re sharpening them is the best route to go. We also have one made by General that cost around $800. It is more complicated and no one ever uses it. It will sharpen very large bits, but the guys eye ball them.
