Cleveland C91724 Solid Pilot Counterbore 13/16 in Hss

Product Description

The CLEVELAND C91724 is a solid pilot counterbore designed for precision counterboring operations in ferrous and tool steel materials. Built from high-speed steel (HSS) with a bright, uncoated finish, this tool delivers clean, concentric seats for socket-head cap screws in demanding machine shop and fabrication environments. It features a 13/16 inch counterbore diameter, a 9/16 inch standard pilot diameter, and three flutes for efficient chip evacuation during forward cutting. The 3/4 inch straight-cylindrical shank ensures secure, concentric clamping in standard drill press and milling machine holders. Machinists and tool-and-die technicians are the primary users of this tool.

This counterbore is suited for creating accurate seating surfaces for 9/16 inch socket-head cap screws in alloy tool steel, carbon steel, and cast iron workpieces. Typical applications include production machining, jig and fixture construction, and maintenance repair operations where socket-head fastener seating must be flush or recessed. The 7-1/2 inch overall length provides reach for deeper counterboring setups and extended-reach applications on heavier workpieces or fixtures.

Key Features

• 13/16 inch counterbore diameter sized for 9/16 inch socket-head cap screw compatibility
• Standard 9/16 inch solid pilot for precise, concentric bore alignment
• High-speed steel construction supports cutting in alloy tool steel, carbon steel, and cast iron
• 3 flutes provide efficient chip clearing during forward cutting
• 3/4 inch straight-cylindrical shank fits standard drill press and milling machine collets and chucks
• Bright, uncoated finish — inspect and resharpen easily without coating interference

Compatibility

Designed for counterboring 9/16 inch socket-head cap screw seats. Compatible with alloy tool steel, carbon steel, and cast iron workpiece materials as specified by the manufacturer.

Installation Notes

Installation and use of this counterbore should be performed by qualified machinists familiar with drill press or milling machine operation. Secure the workpiece firmly before engaging the cutter, and ensure spindle speed is appropriate for the workpiece material and tool diameter. Keep cutting speeds conservative when working in alloy tool steel to preserve cutting-edge life. Inspect the solid pilot for wear before each use, as pilot damage will cause counterbore runout.