Tools & Gear Drills Centrebore

3871-SET 6 Pce 3-10mm 180 Degree Counterbore Drill Set Bright finish HSS-Co5 (Cobalt) for extreme tool life. Use to enlarge the top of an existing hole to create a cylindrical-shaped opening with a flat bottom that acts as a seat for the head of a screw or wood plug. Ideal for use with standard cap screws or socket head screws.