The Robert Charles Plain Shank Counterbore is a high-performance cutting tool designed for precise, repeatable counterboring in metalwork. Built for machinists, engineers, and workshop technicians who demand clean recesses and durable reliability, it delivers consistent results across demanding applications.

• Material: M35 HSS-E with 5% cobalt for enhanced heat resistance, wear life, and cutting performance.
• Shank: Plain shank for easy fitment in standard tool holders, promoting stable and reliable machining.
• Sizes: 5/16 cap screw size with a 0.328" pilot to guide alignment and depth control.
• Applications: Ideal for precision engineering, automotive assemblies, and general workshop use where durable, repeatable counterboring is essential.

Thanks to the cobalt-enhanced alloy, the counterbore maintains sharpness and depth consistency under higher cutting temperatures, reducing wear and delivering clean, flat-bottom recesses. The plain shank simplifies setup in common tool holders, helping you minimize runout and downtime. The 0.328" pilot size ensures accurate alignment with the through-hole, enabling repeatable results when fastening with a 5/16 cap screw. This tool is designed for serious, everyday machining in metalworking shops and automotive fabrication environments, providing dependable performance when precision matters most.