Value Collection GH8790354 Counterbore 35/64 in Hss

Product Description

The VALUE COLLECTION GH8790354 is a 3-flute interchangeable pilot counterbore designed for precision countersinking and seat preparation in metal fabrication and machining applications. Built from high speed steel with a bright, uncoated polished finish, this tool delivers consistent cutting performance in ferrous and non-ferrous materials. The straight shank measures 1/2 inch in diameter and 3-1/16 inches in length, with an overall length of 4-5/16 inches. The counterbore diameter is 35/64 inch, and the tool accepts a 3/16 inch pilot shank. Right-hand cutting direction is standard. Machinists and toolroom technicians are the primary users of this type of tooling.

This counterbore is suited for manual and CNC drill press work where a flat-bottomed recess is required around a through-hole, typically for socket head cap screws or similar fasteners. The interchangeable pilot design allows the tool body to be reused with different pilot sizes, making it a practical choice for shops that work across multiple hole and fastener sizes. It is commonly used in general manufacturing, aerospace prep work, and maintenance machining environments.

Key Features

• 35/64 inch counterbore diameter for precise flat-bottomed recess cutting
• 3-flute geometry provides smooth chip evacuation and clean seat finish
• Interchangeable pilot accepts 3/16 inch pilot shank for flexible use
• High speed steel construction maintains edge integrity across a wide range of workpiece materials
• Bright, polished, uncoated finish reduces friction and facilitates easy chip removal
• Straight 1/2 inch shank compatible with standard drill chucks and collet holders

Compatibility

Designed as an OEM-style replacement and standard fitment interchangeable pilot counterbore for use with 3/16 inch pilot shanks in 1/2 inch straight shank drill chucks and collet systems.

Installation Notes

This tool is installed and operated by machinists using drill presses, milling machines, or CNC equipment with compatible 1/2 inch straight shank chucks or collets. Secure the shank firmly before operation and confirm the pilot is fully seated before engaging the workpiece. Always power down and lock out the machine spindle before changing pilots or removing the tool. Cutting speeds and feeds should be selected based on workpiece material per standard machining reference tables.