What is a Countersink Drill Bit? A countersink is a conical hole cut into a material, or the tool used to create such a hole, which allows the head of a countersunk screw, bolt, or rivet to sit flush with or below the surface of the surrounding material.

Cobalt Countersinks are suitable for soft and hard materials with cutting features that guarantee smooth results.

HSS Countersinks are often 90 degree drill bits that are extremely precise and suitable for use on iron, cast iron and plastic.