Value Collection GH8790214 Counterbore 21/64in 3 Flute Hss

Product Description

The VALUE COLLECTION GH8790214 is a 3-flute interchangeable pilot counterbore designed for precision spot-facing and counterboring operations in metal fabrication and machining environments. The body measures 21/64 inches in counterbore diameter with a 5/16-inch straight shank, and the tool runs in a right-hand cutting direction. Constructed from high speed steel with a bright, uncoated polished finish, it is suited for general-purpose counterboring where moderate heat and wear resistance are required. Licensed machinists, toolroom technicians, and maintenance mechanics are the primary users of this style of counterbore.

This counterbore is intended for use in drill press, milling machine, or CNC machining center setups where a clean, flat-bottomed recess is needed for socket-head cap screws or similar fastener heads. The interchangeable pilot design accepts a 3/32-inch pilot shank, allowing the pilot to be swapped when the application changes. It is appropriate for use in both production and maintenance-repair-operations (MRO) environments working with steel, aluminum, and similar machinable materials.

Key Features

• 21/64-inch counterbore diameter for precise flat-bottomed recesses
• 3-flute geometry for smooth chip evacuation and clean finish
• 5/16-inch straight shank for broad collet and chuck compatibility
• Interchangeable pilot accepts 3/32-inch pilot shank diameter
• High speed steel construction provides durable cutting performance
• Bright, uncoated polished finish suitable for general-purpose applications

Compatibility

Designed as an OEM-style interchangeable pilot counterbore for use with standard straight-shank drill press chucks and collet holders accepting a 5/16-inch shank; pilot compatibility is 3/32-inch shank diameter.

Installation Notes

This tool is installed by machinists or toolroom technicians into an appropriate chuck or collet holder on a drill press or milling machine. Power down and lock out the machine before securing or changing the tool or pilot. Ensure the pilot is fully seated and the shank is clamped with adequate gripping length before operation. Use appropriate cutting fluid for the workpiece material to extend tool life and achieve the desired surface finish.