I'm about to buy like my 4th or 5th 7/16th drill bit. Is there a relatively inexpensive machine to sharpen bits? I've heard of the drill dr. but it only does the little bits then you have to buy an adapter to fit up to 1/2". I'd like something that will sharpen up to 5/8s. I'm not too grinder savy on sharpening and feel I'd do more damage than good by trying this route. Any help as always is appreciated.