Engineered for precision metalworking, the Robert Charles Plain Shank Counterbore delivers clean, accurate counterbores in demanding automotive and precision-engineering tasks. Built from M35-HSS-E with 5% cobalt, it combines exceptional heat resistance and wear life with a plain shank that fits standard tool holders for stable, reliable machining.

• Material: M35-HSS-E with 5% cobalt for superior heat resistance, extended wear life, and consistent cutting performance under high-speed counterboring.
• Shank Type: Plain shank design ensures easy fitment in standard tool holders for quick setups and stable engagement.
• Pilot Size: 0.515 inch pilot provides precise alignment with existing holes for accurate counterbores.
• Cap Screw Size: 1/2 inch cap screw size for secure mounting and compatibility with common fixtures.
• Counterbore Geometry: Optimized edge geometry delivers clean, flat-bottom counterbores with minimal burr formation.
• Applications: Ideal for precision engineering, automotive fabrication, and general workshop use where durability and repeatable results matter.
• Performance: Maintains sharpness at higher cutting speeds, reducing tool changes and downtime in production environments.

This counterbore is designed to help you achieve repeatable, high-quality counterbores with tight tolerances. The cobalt-enhanced steel resists heat and wear, so you can rely on consistent performance across long runs. The plain shank simplifies tool changes and keeps setup straightforward in everyday machining, making it a solid choice for shops that prioritize reliability, finish quality, and productivity.