Cleveland C91737 Solid Pilot Counterbore 1-3/16 in Hss

Product Description

The CLEVELAND C91737 is a solid pilot counterbore designed for precision counterboring of socket-head cap screw seats in metalworking applications. Built from high-speed steel with a bright, uncoated finish, it features a 1-3/16 inch cutting diameter, a 13/16 inch standard pilot diameter, and a 1 inch straight-cylindrical shank. The 3-flute geometry provides a balance of cutting efficiency and surface finish quality. At 8-13/16 inches overall length, it offers adequate reach for a wide range of workpiece thicknesses. Machinists and tool-room professionals working in job shops, production facilities, or MRO environments are the primary installers of this tool.

This counterbore is suited for creating recessed seats for 3/4 inch socket-head cap screws. Compatible material applications include alloy tool steel, carbon steel, and cast iron. It is appropriate for use on manual milling machines, drill presses, and CNC machining centers where a straight-cylindrical shank is accepted by the spindle or toolholder. The standard pilot ensures the counterbore tracks concentrically with the existing clearance hole, producing clean, flat-bottomed recesses.

Key Features

• 1-3/16 inch counterbore diameter sized for 3/4 inch socket-head cap screw seats
• 13/16 inch standard pilot diameter for concentric alignment with the clearance hole
• High-speed steel construction suitable for alloy tool steel, carbon steel, and cast iron
• 3-flute design for efficient chip evacuation and smooth seat finish
• 1 inch straight-cylindrical shank fits standard toolholders and drill-press chucks
• Bright, uncoated finish — no special coolant compatibility restrictions

Compatibility

Designed as an OEM-style replacement and standard counterbore for 3/4 inch socket-head cap screw applications in alloy tool steel, carbon steel, and cast iron workpieces. Accepts a 1 inch straight-cylindrical shank interface.

Installation Notes

This tool is installed by machinists and tool-room technicians in accordance with standard machine shop practice. Always secure the shank firmly in the toolholder or chuck before operation and verify spindle speed is appropriate for the workpiece material and tool diameter before cutting. Ensure the pilot is fully seated in the pilot hole before engaging the cutting edges to maintain concentricity. Power down and de-energize the machine before changing or inspecting the tool.