Value Collection GH8840423 Counterbore 21/32 in 4 Flute Hss

Product Description

The VALUE COLLECTION GH8840423 is an interchangeable pilot counterbore designed for precision hole-finishing in metal fabrication and aircraft-style applications. The tool features a 21/32-inch counterbore diameter and a 1/4-inch straight shank, making it compatible with standard drill presses, milling machines, and handheld power tools. Constructed from high speed steel (HSS), it delivers reliable cutting performance across a range of ferrous and non-ferrous materials. The bright, uncoated finish indicates an unplated HSS body suitable for general-purpose counterboring where coatings are not required. With 4 flutes and right-hand cutting direction, the tool produces clean, flat-bottomed seats for socket head fasteners and similar hardware.

This counterbore is suited for aerospace-style and general metalworking applications where interchangeable pilots allow a single body to serve multiple pilot diameter configurations. The 3-1/8-inch overall length (OAL) provides adequate reach for most standard workpiece thicknesses. Typical installation scenarios include countersinking bolt and screw seats in aluminum, steel, and alloy assemblies. The interchangeable pilot accepts a 3/16-inch pilot shank diameter, allowing the operator to swap pilots as job requirements change without replacing the entire tool body.

Key Features

• 21/32-inch counterbore diameter for precise flat-bottomed seat cutting
• 1/4-inch straight shank fits standard chucks and collets
• Interchangeable pilot design with 3/16-inch pilot shank diameter compatibility
• 4-flute geometry for smooth, accurate cutting in metal
• High speed steel construction for durability across ferrous and non-ferrous materials
• Bright uncoated finish, right-hand cutting direction, aircraft style

Compatibility

Designed as an interchangeable pilot counterbore compatible with 3/16-inch pilot shanks. Suitable for use with standard drill presses, milling machines, and power drills equipped with a chuck or collet accepting a 1/4-inch straight shank.

Installation Notes

Installation and operation should be performed by a qualified machinist or tool operator familiar with rotating cutting tools. Secure the workpiece firmly before engaging the cutter, and ensure the machine spindle is at a full stop before changing pilots or adjusting depth stops. Use appropriate cutting fluid for the material being machined to extend tool life and improve finish quality. Inspect the pilot fit before each use to confirm there is no excessive play that could cause runout or an off-center counterbore.