Cleveland C91701 Solid Pilot Counterbore 0.348 in 3 Flutes

Product Description

The CLEVELAND C91701 is a solid pilot counterbore designed for precision counterboring operations in metalworking applications. Built from high-speed steel with a bright, uncoated finish, this tool delivers a 0.348 inch counterbore diameter and a 0.213 inch pilot diameter, with 3 flutes for efficient chip evacuation. The straight-cylindrical shank measures 0.500 inches in diameter, and the overall length is 3.5 inches. It is compatible with socket-head cap screws in size No. 12 and features a forward cutting direction. Licensed machinists, tool-and-die makers, and maintenance mechanics install this type of counterbore in standard drill press or milling machine setups.

This counterbore is suited for use on alloy tool steel, carbon steel, and cast iron workpieces in both shop and production environments. It is intended for creating the flat-bottom recesses needed to seat socket-head cap screw heads flush with or below a workpiece surface. The standard pilot ensures accurate alignment with a pre-drilled clearance hole during the counterboring operation.

Key Features

• 0.348 inch counterbore diameter sized for No. 12 socket-head cap screws
• 0.213 inch standard pilot diameter for accurate hole alignment
• 3-flute geometry promotes chip clearance and cutting efficiency
• High-speed steel construction for durability across steel, alloy tool steel, and cast iron
• Straight-cylindrical shank at 0.500 inches diameter for secure chuck or holder retention
• Bright, uncoated finish — no coating buildup to affect dimensional accuracy

Compatibility

Designed for use with No. 12 socket-head cap screws; suitable for counterboring alloy tool steel, carbon steel, and cast iron workpieces where a standard pilot fits a pre-drilled clearance hole.

Installation Notes

Install in a drill press, milling machine, or hand-held power tool using a chuck or collet that accepts a 0.500 inch straight-cylindrical shank. Secure the workpiece firmly before beginning the cut to prevent rotation or movement. Power down the machine and lock out energy sources before changing or inspecting the tool. Operate within the speed and feed recommendations appropriate for high-speed steel tooling and the specific workpiece material.