The Robert Charles Plain Shank Counterbore is designed for engineers and machinists who demand clean, precise counterboring with reliable durability. Crafted from M35 HSS-E with 5% cobalt, it delivers exceptional heat resistance and wear life for consistent performance in challenging materials.

• Material: M35 HSS-E with 5% cobalt for enhanced heat resistance, wear life, and cutting performance.
• Shank Type: Plain shank for easy fitment in standard tool holders, enabling quick changes and stable machining.
• Size & Pilot: 1/4 cap screw size with a 0.281" pilot for accurate hole depth and alignment.
• Counterbore Geometry: Optimized geometry and cutting edges to produce clean, flat-bottom counterbores with minimal chatter.
• Tolerance & Finish: Precision-ground to deliver consistent hole dimensions across multiple operations.
• Applications: Ideal for precision engineering, automotive manufacturing, and general workshop fabrication where durability matters.

This counterbore provides dependable performance in daily machining tasks, reducing rework and downtime. The cobalt-infused HSS optimizes heat management during deep countersinking, helping maintain edge life and cut quality even in tougher metals. The straightforward plain shank simplifies setup in common tool holders, supporting steady feeds and true hole depth for accurate fastener seating and fixture alignment.