Value Collection GH8860280 Solid Pilot Counterbore Hss

Product Description

The VALUE COLLECTION GH8860280 is a solid pilot counterbore designed for creating precise flat-bottomed recesses that seat fillister-head screws flush or below a workpiece surface. Built from high speed steel, it delivers the hardness and heat resistance needed for production drilling and repetitive use in metal, wood, and composite materials. The tool features a 21/32 inch counterbore diameter, a 7/16 inch pilot diameter that keeps the bore concentric with the existing hole, and a 2-flute cutting geometry that clears chips efficiently. With a 4-3/4 inch overall length and a straight cylindrical shank measuring 7/16 inch in diameter, it mounts securely in standard drill press or milling machine chucks. Machinists, toolroom technicians, and maintenance mechanics are the primary users.

This counterbore is suited for standard forward-cutting applications in job shops, maintenance facilities, and light manufacturing environments. It is sized specifically for fillister-head screw clearance work, making it a practical choice wherever that fastener type is specified in assembly or repair drawings. The standard pilot configuration is appropriate for pre-drilled holes at the corresponding pilot diameter. Typical applications include machine frames, fixture plates, and structural assemblies where recessed fastener heads are required for clearance or aesthetics.

Key Features

• 21/32 inch counterbore diameter sized for fillister-head screw seating
• 7/16 inch standard pilot diameter for concentric, accurate recessing
• 2-flute high speed steel construction for durability and chip clearance
• Straight cylindrical shank at 7/16 inch diameter for secure chuck retention
• 4-3/4 inch overall length provides reach for standard workpiece depths
• Forward cutting direction compatible with conventional drill press and milling machine setups

Compatibility

Designed as an OEM-style replacement or direct-use counterbore for applications requiring fillister-head screw recessing with a 21/32 inch counterbore diameter and 7/16 inch pilot.

Installation Notes

Installation is performed by machinists or maintenance technicians using a drill press, milling machine, or hand-held drill with adequate torque and speed control. Secure the straight shank firmly in a drill chuck or collet before operation. Always bring the spindle to the correct RPM for the material and tool diameter before contact, and use cutting fluid when working with ferrous metals to extend tool life. Ensure the workpiece is clamped or fixtured to prevent movement during the counterboring operation.