The Robert Charles Plain Shank Counterbore is a precision cutting tool designed for clean, accurate counterboring in metalworking. Built from M35 HSS-E with 5% cobalt, it delivers outstanding heat resistance and wear life for demanding machining tasks.

• Material: M35 HSS-E with 5% cobalt for extended edge retention and high-temperature performance.
• Shank Type: Plain shank enables straightforward fitment in standard tool holders for stable, repeatable machining.
• Pilot Size: 0.140 inch pilot aids precise entry and depth control during countersinking.
• Cap Screw Compatibility: Sized for #5 cap screws, aligning with common fastener standards in assemblies.
• Counterbore Geometry: Optimized flute and cutting edge geometry deliver smooth cutting and clean bore edges.

Use this counterbore to achieve burr-free, accurately aligned holes that support secure fastener installation and reliable assembly. The cobalt-enhanced HSS resists heat and wear, reducing tool changes and enabling longer production runs in precision engineering, automotive workshops, and shop floors. Pair with appropriate feeds and speeds, use a light coolant if required, and maintain the tool to preserve edge life for consistent performance across batches.