Profile: Desco Tools Co. is a distributor of drills, taps & dies, cutting blades, hole saws, screw extractors, and hand tools & accessories. Our high speed steel drill bits are the most widely used of all metal cutting tools. Taps are used to cut threads on the inside of a hole, as in a nut. One end of the tap is square, so it can be turned with a tap wrench. As the tap turns, it bites into the metal, removing material which flows into the flutes.