Alvord Polk 03086 Solid Pilot Counterbore 0.7283 in Hss

Product Description

The ALVORD POLK 03086 is a solid pilot counterbore designed for precision spot-facing and counterboring operations in metal fabrication and machining applications. Built from high speed steel with a bright uncoated finish, this tool delivers a counterbore diameter of 0.7283 inches and a standard pilot diameter of 0.4921 inches. The straight-cylindrical shank measures 0.5 inches in diameter, and the overall length is 7.125 inches. Machinists and toolroom professionals use this counterbore to create accurate recesses for socket-head cap screws, ensuring proper seating and flush or sub-flush fastener installation.

This counterbore is sized specifically for 0.4724-inch socket-head cap screws, which corresponds to a 12.00 mm fastener. It is suited for forward cutting direction and fits into standard drill press, milling machine, or CNC setups accepting a 0.5-inch straight shank. Typical applications include production machining, maintenance and repair operations, and toolroom work where a clean, dimensionally consistent counterbore seat is required for cap screw assemblies.

Key Features

• High speed steel construction for durability across a range of ferrous and non-ferrous materials
• Solid pilot design maintains concentricity between the pilot hole and counterbore seat
• Standard pilot diameter of 0.4921 inches provides accurate alignment during cutting
• Bright uncoated finish suitable for general-purpose machining use
• Straight-cylindrical 0.5-inch shank for compatibility with standard toolholders and drill chucks
• Forward cutting direction for conventional machine spindle operation

Compatibility

Designed for use with 0.4724-inch (12.00 mm) socket-head cap screws. Fits machine setups accepting a 0.5-inch straight-cylindrical shank.

Installation Notes

Installation and use should be performed by qualified machinists familiar with cutting tool safety and machine operation. Secure the shank firmly in a drill chuck or toolholder before running the spindle, and confirm the pilot fits the existing pilot hole without excessive play before beginning the cut. Use appropriate cutting fluid for the workpiece material to extend tool life and maintain bore quality. Always power down and lock out the machine before changing or inspecting tooling.