Value Collection GH8817009 Counterbore 2in 5 Flute Cobalt

Product Description

The VALUE COLLECTION GH8817009 is a cobalt steel interchangeable pilot counterbore designed for precision counterboring operations in ferrous and hard materials. With a 2-inch counterbore diameter and a 1-1/2-inch straight shank, this tool seats securely in compatible toolholders on manual mills and CNC machining centers alike. The 5-flute geometry distributes cutting load evenly, reducing chatter and improving surface finish at the counterbore seat. An 8-3/8-inch overall length provides clearance for deeper workpiece access, while the 5-7/8-inch shank length maximizes grip in the spindle. The bright, uncoated finish is standard for cobalt tooling used across general-purpose and aerospace-adjacent machining applications.

This counterbore is suited for machinists and toolroom operators working in job shops, maintenance and repair operations, and light production environments. It is used to create flat-bottomed recesses that accept socket head cap screws, dowel-pin shoulders, and similar fastener geometries. The interchangeable pilot design allows the operator to swap pilots to match different clearance hole sizes without replacing the body, making it a cost-effective option for shops cutting a range of bolt patterns. A licensed machinist or experienced toolroom technician typically selects and installs this tool.

Key Features

• 2-inch counterbore diameter for large-diameter recess cutting
• Cobalt steel construction provides heat and wear resistance in tough materials
• 5-flute design reduces cutting forces and improves seat finish
• 1-1/2-inch straight shank for secure, concentric spindle holding
• Interchangeable pilot accepts 1/2-inch pilot shank diameter
• Bright uncoated finish — compatible with most cutting fluids without coating interference
• Right-hand cutting direction, standard for conventional and climb milling setups

Compatibility

Designed for use with interchangeable pilots having a 1/2-inch pilot shank diameter. The 1-1/2-inch straight shank is compatible with standard straight-shank toolholders, shell mill adapters, and set-screw holders of the appropriate bore size.

Installation Notes

Installation should be performed by a qualified machinist or toolroom technician. Power down and lock out the spindle before inserting or removing the tool from the holder. Ensure the straight shank is fully seated and the set screw is properly tightened before initiating a cut. Verify pilot fit and concentricity before running at full feed to avoid pilot damage or counterbore runout.