The Robert Charles Plain Shank Counterbore is a precision cutting tool designed for accurate, clean counterboring in engineering, automotive, and general workshop applications. Crafted from M35 HSS-E with 5% cobalt, it delivers reliable heat resistance and long-lasting cutting performance in demanding tasks.

• Material: M35 HSS-E with 5% cobalt for enhanced heat resistance and wear life during high-speed cutting.
• Shank Type: Plain shank for straightforward fitment in standard tool holders, enabling stable and consistent machining.
• Pilot Size: 0.39" pilot to guide the bore with precision and repeatability.
• Cap Screw Size: Compatible with 3/8" cap screws to secure the counterboring setup.
• Design & Geometry: Optimized counterbore geometry for clean, flat-bottomed holes and reliable depth control.
• Applications: Ideal for precision engineering, automotive work, and general workshops where durable, repeatable counterboring is essential.

Designed to deliver consistent, repeatable results, this counterbore minimizes rework and ensures solid fastener seating. The cobalt-enhanced alloy maintains sharpness longer under heat, reducing tool changes and downtime. With its plain shank and compatible cap screw sizing, setup is straightforward, making it a dependable choice for both routine production and precision prototyping. Whether you’re working with metal sheets, plates, or assemblies, this tool helps you achieve precise depths and clean faces for a professional finish.