Keo 902-000-049 Solid Pilot Counterbore 8mm 3 Flute

Product Description

The KEO 902-000-049 is a solid pilot counterbore designed to create accurate, flat-bottomed recesses for socket-head cap screws in metalworking and machining applications. Built from cobalt steel with a bright, uncoated finish, this tool delivers heat resistance and edge retention suited to ferrous and harder workpiece materials. It features a standard 3.3 mm pilot diameter, an 8 mm counterbore diameter, and three flutes that promote smooth chip evacuation and a clean seat finish. Machinists and tool-room professionals reach for this counterbore when a precise, square-bottomed socket-head cap screw recess is required on the first pass.

This counterbore fits standard M4 socket-head cap screws and is sized for use in production machining, fixture building, and general tool-room work. The 5 mm shank diameter suits common drill press chucks and milling machine holders. With an overall length of 71 mm, it provides adequate reach for typical workpiece thicknesses while maintaining rigidity. Its standard pilot configuration aligns with conventional pilot-hole drilling sequences, making it a straightforward drop-in for shops already working within M4 fastener systems.

Key Features

• Cobalt steel construction for elevated heat resistance and extended tool life in harder materials
• 8 mm counterbore diameter sized for M4 socket-head cap screws
• 3.3 mm standard pilot diameter for accurate self-centering in pre-drilled pilot holes
• 3-flute geometry promotes efficient chip clearance and a clean, flat seating surface
• Bright, uncoated finish - ready to use as delivered, no coating removal required
• 5 mm shank diameter fits standard drill press and milling machine toolholders

Compatibility

Designed for use with M4 socket-head cap screws. Compatible with standard pilot holes corresponding to the 3.3 mm pilot diameter. Suitable for use in drill press chucks and milling machine holders accepting a 5 mm shank.

Installation Notes

This tool is installed by machinists and tool-room technicians using a drill press or milling machine. Always pre-drill the pilot hole to match the 3.3 mm pilot before engaging the counterbore. Secure the workpiece firmly before operation to prevent movement during cutting. Inspect the pilot and cutting edges for wear before each use to maintain seat quality and dimensional accuracy.