Robert Charles Plain Shank Counterbore – Standard Metric (M3.5) is a precise countersinking tool built for machinists who require reliable, metric-sized hole preparation. Designed for compatibility with standard tool holders, it delivers stable cutting performance and clean, repeatable results across metalworking projects.

• Size & Standard: Metric M3.5 counterbore designed to match standard metric hole requirements for predictable drilling and finishing outcomes.
• Shank Type: Plain shank for straightforward mounting in common tool holders and collets, enabling quick setup and solid retention during cutting.
• Cutting Geometry: Precision-ground edges ensure clean, flat-bottom counterbores with minimal burr and consistent depth control.
• Compatibility: Suited for metric hole standards and versatile across milling machines, drill presses, and CNC setups in general engineering, automotive, and workshop environments.
• Durability & Finish: Robust construction with a smooth finish designed for repeatable performance in demanding shop conditions.

This counterbore helps you achieve accurate seating surfaces for metric fasteners and prepares holes with reliable depth and edge quality. The plain shank stabilizes the cut, reduces runout, and supports clean chip evacuation, contributing to faster setups, fewer reworks, and consistent results across projects. Ideal for engineers, technicians, and hobbyists who value precision, repeatability, and straightforward tool compatibility.