I've been thinking about buying one of these but I don't know if they are just a gimmick. Also, if they genuinely work well how good do your bits need to be in the first place to be worth sharpening?

Close-up of unrecognizable craftsperson holding a hand drill and picking a drill bit from a set on a worktable. - Mixetto/Getty Images We may receive a commission on purchases made from links. A hand ...