Looking for a set of durable and reliable counterbore drill bits? Look to this RS PRO six-piece counterbore bit set. It includes the most commonly used standard drill bits, including M3, M4, M5, M6, M8 and M10.
The drills are made from high-speed steel (HHS) which gives them excellent strength and a very high application temperature, so you can be sure they will have a long service life. You can use counterbore drill bits to create recessed holes that can receive screws or bolts sitting flush with the surface of your application material.
These counterbore bits are supplied with a metal indexing case for easy and safe storage. They comply with British (BS328) specifications for sizes of drills so the holes will have standard dimensions. You'll typically find counterbore fixings used to recess screws or bolts beneath the surface of a workpiece – this could be for aesthetic reasons or aerodynamic purposes in the aerospace industry.

• Kit contents include thread sizes M3, M4, M5, M6, M8 and M10
• Cutter diameter range of 6 to 18 mm
• HSS material
• Six pieces