Value Collection GH8790644 Counterbore 1 in 3 Flute Hss

Product Description

The VALUE COLLECTION GH8790644 is a 3-flute interchangeable pilot counterbore designed for precision enlarging and finishing of bolt-seat recesses in metal workpieces. Built from high speed steel with a bright, uncoated finish, this tool delivers clean cutting action in ferrous and non-ferrous materials. The 1-inch counterbore diameter pairs with a 3/4-inch straight shank for secure tool-holder engagement. The pilot shank compatibility is 5/16 inch, allowing interchangeable pilots to be swapped for different clearance hole sizes. Right-hand cutting direction is standard. Machinists and tool-and-die professionals use this counterbore in manual mills, drill presses, and CNC setups requiring controlled seat depth and finish.

This counterbore is suited to general industrial and maintenance machining applications where a flat-bottom recess is needed to seat socket-head cap screws, bolts, or similar fasteners flush or below the workpiece surface. The straight shank and standard pilot interchange system make it compatible with common collet chucks and drill-press keyless chucks. It is appropriate for job-shop, MRO, and production environments working in mild steel, aluminum, brass, and similar machinable materials.

Key Features

• 1-inch counterbore diameter for flat-bottom bolt-seat recesses
• 3 flutes for smooth chip evacuation and consistent finish
• High speed steel construction for durability across ferrous and non-ferrous materials
• 3/4-inch straight shank fits standard collet chucks and drill-press chucks
• Interchangeable pilot system accepts 5/16-inch pilot shank diameter
• Bright, uncoated finish — no coating buildup to affect dimensional tolerance
• Right-hand cutting direction, standard for conventional machine setups

Compatibility

Designed as an OEM-style interchangeable pilot counterbore for use in manual milling machines, drill presses, and CNC machining centers equipped with a 3/4-inch straight-shank tool holder; accepts standard 5/16-inch interchangeable pilot shanks.

Installation Notes

Installation is performed by machinists and tool-and-die technicians. Secure the 3/4-inch straight shank in a properly sized collet or chuck and verify runout before cutting. Insert the correct interchangeable pilot into the counterbore body and confirm it is firmly seated before operation. Always power down and lock out the machine spindle before changing pilots or removing the tool from the holder.