Keo 902-000-059 Solid Pilot Counterbore 15mm 3 Flute

Product Description

The KEO 902-000-059 is a solid pilot counterbore designed for machining precise recessed seats for socket-head cap screws. Built from cobalt steel with a bright, uncoated finish, this tool delivers the hardness and wear resistance needed for production and maintenance machining in metal fabrication, toolrooms, and machine shops. It runs a 15 mm counterbore diameter with an 8.4 mm standard pilot and a 12.5 mm shank diameter, offering a stable, concentric bore with minimal runout. Three flutes provide a balance of chip clearance and cutting edge support. Overall length is 100 mm, keeping the tool rigid across typical drilling and milling setups.

This counterbore is suited for creating flat-bottomed recesses that allow socket-head cap screw heads to sit flush or below the workpiece surface. It is used in ferrous and non-ferrous metal applications where fastener compatibility with 8 mm socket-head cap screws is required. Typical applications include fixture building, die and mold work, structural fabrication, and general machine shop operations where clean, concentric counterbores are critical to final assembly.

Key Features

• Cobalt steel construction for increased hardness and heat resistance compared to standard HSS
• 15 mm counterbore diameter sized for 8 mm socket-head cap screws
• 8.4 mm standard pilot maintains concentricity with the pilot hole
• 3-flute geometry balances chip evacuation with cutting stability
• Bright, uncoated finish suitable for general-purpose machining applications
• 12.5 mm shank diameter fits standard drill chuck and collet setups

Compatibility

Designed for use with 8 mm socket-head cap screws. Counterbore diameter is 15 mm with an 8.4 mm standard pilot, compatible with pre-drilled pilot holes sized to accept 8 mm fasteners.

Installation Notes

This tool is installed and operated by machinists using a drill press, milling machine, or CNC machining center with a compatible chuck or collet holding a 12.5 mm shank. Secure the workpiece firmly before operation to prevent movement during cutting. Use appropriate cutting fluid for the workpiece material to extend tool life and improve surface finish. Inspect the pilot hole size before use to confirm proper pilot engagement and concentricity.