Hertel 331-204100 Carbide Countersink 5/16 in 120 Degree

Product Description

The HERTEL 331-204100 is a single-flute carbide countersink designed for producing clean, accurate countersunk holes in a wide range of materials. With a 5/16 inch head diameter and a 120-degree included angle, this tool is well suited for standard fastener seat preparation where precise angle geometry is required. The straight-cylindrical shank measures 5/16 inch, making it compatible with standard drill chucks and collet holders. Carbide construction provides the hardness and wear resistance needed for consistent performance in both production and maintenance environments. Licensed machinists, tool-and-die professionals, and metalworking tradespeople are the primary users of this type of countersink.

This countersink is applicable in machining operations where fastener heads must sit flush or below the workpiece surface. The 120-degree included angle is commonly specified for certain aerospace and industrial fastener standards, and is a less common angle than the more standard 82-degree or 90-degree countersinks — making it a targeted selection for specific fastener or drawing callouts. Typical installation scenarios include bench work, drill press operations, and CNC or manual lathe setups where controlled countersinking is required. It is sold individually as a single-piece unit.

Key Features

• 5/16 inch head diameter for compact countersinking in tight or small-diameter applications
• 120-degree included angle for specialized fastener seat geometry
• Single-flute design reduces chatter and promotes cleaner entry in certain materials
• Carbide construction for extended tool life and wear resistance
• Straight-cylindrical shank for secure seating in standard chucks and collet holders

Compatibility

Designed as an OEM-style replacement or direct-use countersink for machining setups requiring a 5/16 inch head diameter, 120-degree included angle, single-flute carbide countersink with a straight-cylindrical shank. No specific machine model compatibility was provided in the product data.

Installation Notes

This tool is intended for use by qualified machinists or metalworking professionals. Secure the straight shank firmly in a drill chuck, collet, or tool holder rated for the intended spindle speed before operation. Always reduce spindle speed and apply appropriate cutting fluid when countersinking harder materials to prevent premature tool wear or chipping of the carbide edge. Inspect the cutting edge for chipping or wear before each use.