Value Collection GH8862104 Solid Pilot Counterbore Hss

Product Description

The VALUE COLLECTION GH8862104 is a solid pilot counterbore designed for creating flat-bottomed recesses that seat socket head cap screws and similar fasteners flush or below a workpiece surface. Built from high speed steel, this tool delivers consistent cutting performance across steel, aluminum, and other common shop materials. It features a 21/64-inch counterbore diameter, a 13/64-inch pilot diameter for precise centering in pre-drilled holes, and a straight cylindrical 5/16-inch shank for secure chuck holding. The 3-flute geometry balances chip evacuation with surface finish quality. Machinists and tool-and-die professionals use this counterbore for production and maintenance work on manual and CNC machines.

This counterbore is sized for No. 10 fastener compatibility, making it a standard choice for machine screw counterboring operations in fabrication shops, maintenance facilities, and production environments. The standard pilot fits snugly into a pre-drilled clearance hole to keep the tool concentric during cutting, reducing chatter and improving recess geometry. Forward cutting direction suits conventional milling and drill press operations. It is suited for use in both light production runs and one-off maintenance applications where a clean, accurate counterbore seat is required.

Key Features

• 21/64-inch counterbore diameter sized for No. 10 fastener head clearance
• 13/64-inch standard pilot for self-centering in pre-drilled holes
• 3-flute design balances chip removal and surface finish
• High speed steel construction for durability across common workpiece materials
• Straight cylindrical 5/16-inch shank for use in standard drill chucks and collets
• Forward cutting direction compatible with conventional drill press and milling setups

Compatibility

Designed as a standard pilot counterbore for No. 10 fastener sizes. Fits standard drill press chucks, milling machine collets, and CNC tool holders accepting a 5/16-inch straight shank.

Installation Notes

A licensed machinist or experienced tooling technician should verify spindle speed and feed rate against the workpiece material before use. Ensure the machine spindle is fully stopped and locked out before installing or removing the tool from the chuck or collet. The pilot diameter must match the pre-drilled pilot hole closely to maintain concentricity and prevent tool deflection. Use appropriate cutting fluid for the workpiece material to extend tool life and improve finish quality.