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?

The professional-use Drill Doctor 750X sharpens standard twist and masonry bits from 3/32” to ¾”. The custom point angles can easily be set anywhere from 115 to 140 degrees.The adjustable material ...

Dull drill bits are not usually a type of tool that's worth buying used, unless you can sharpen them yourself. Many companies that sharpen drill bits use precision grinding machines, but there are ...