Countersink Bit Wood (Various Sizes)

A countersink is a conical hole cut into a manufactured object. The same term is used for the cutter used to cut such a hole.

Common uses:
COUNTERSINK CARB.STEEL 1/2″A common use is to allow the head of a countersunk bolt or screw, when placed in the hole, to sit flush with or below the surface of the surrounding material. A countersink may also be used to remove the burr left from a drilling or tapping operation thereby improving the finish of the product and removing any hazardous sharp edges.
Drawing of countersunk hole
Regardless of the name given to the cutter, the surface being generated may be a conical chamfer (plunging applications) or a beveled corner for the intersection of two planes (traversing applications).

These Tork Craft carbon countersinks are referred to as fluted countersinks and mainly suitable for wood