Value Collection GH8781288 Counterbore 1-7/16 in 5 Flute 4MT Hss

Product Description

The VALUE COLLECTION GH8781288 is a 5-flute interchangeable pilot counterbore designed for precision counterboring operations in metal fabrication and machining environments. Built from high speed steel with a bright, uncoated finish, this tool accepts a 3/8 inch pilot shank and mounts via a 4MT Morse taper shank for rigid, concentric seating in compatible spindles. The 1-7/16 inch counterbore diameter and 7-7/8 inch overall length make it well suited for medium to heavy-duty counterboring of bolt seats and fastener recesses. Right-hand cutting geometry ensures consistent chip evacuation across the five flutes. Machinists and toolroom technicians are the primary installers and operators of this tool.

This counterbore is appropriate for use in vertical mills, drill presses, and machining centers equipped with a 4MT taper spindle or a compatible Morse taper adapter sleeve. It is used in job shop, production, and maintenance machining applications where a clean, flat-bottomed recess is required for socket head cap screws, hex bolts, or similar fasteners. The interchangeable pilot design allows the pilot to be swapped out to match different fastener shank diameters, increasing the tool's versatility across multiple job setups.

Key Features

• 1-7/16 inch counterbore diameter for medium to large fastener seat applications
• 5-flute geometry for smooth cutting action and improved finish quality
• 4MT Morse taper shank provides positive drive and accurate concentricity
• Interchangeable pilot accepts 3/8 inch pilot shank diameter
• High speed steel construction offers good wear resistance across a range of workpiece materials
• Bright, uncoated finish suitable for use with cutting fluids and coolants

Compatibility

Designed for use in machine spindles with a 4MT (No. 4 Morse taper) socket; accepts a 3/8 inch interchangeable pilot shank. Compatible with drill presses, vertical mills, and machining centers fitted with a 4MT taper bore or an appropriate reducing sleeve.

Installation Notes

Installation and operation should be performed by a qualified machinist familiar with Morse taper tooling. Ensure the spindle and taper shank surfaces are clean and free of chips or burrs before seating the tool. Power down the machine and engage all lockouts before changing pilots or removing the tool from the spindle. Use appropriate cutting fluid for the workpiece material to extend tool life and improve surface finish.