Engineered for precise counterboring, the Robert Charles Plain Shank Counterbore delivers durable, consistent performance for metalworking projects. It’s designed for professionals in precision engineering, automotive work, and general workshops who demand reliable, clean counterbores.

• Material: M35 HSS-E with 5% cobalt for exceptional heat resistance, wear life, and cutting performance.
• Shank Design: Plain shank for easy fitment in standard tool holders and stable, repeatable machining.
• Cap Screw Size: Compatibility with 3/8" cap screws to ensure proper counterbore sizing for common fasteners.
• Pilot Size: 0.375" (3/8") pilot to establish correct depth and alignment for accurate seating.

This counterbore enables precise, flush seating of fasteners with a clean, square bottom. The cobalt-enhanced HSS-E construction resists heat and wear during high-speed machining, extending tool life and maintaining edge fidelity. The plain shank design minimizes runout in standard holders, delivering stable cuts and consistent hole depths across a range of materials. Ideal for projects where accuracy and repeatability matter—from fine automotive machining to general workshop counterboring tasks.