Cleveland C91735 Solid Pilot Counterbore 1-5/32 in Hss

Product Description

The CLEVELAND C91735 is a solid pilot counterbore designed for precision spot-facing and counterboring operations in ferrous and tool steel workpieces. Built from high-speed steel with a bright, uncoated finish, it delivers consistent cutting performance on alloy tool steel, carbon steel, and cast iron. The tool features a 1-5/32 inch counterbore diameter, a 25/32 inch standard pilot diameter, and a 1 inch straight-cylindrical shank. With 3 flutes and forward cutting direction, it produces clean, flat-bottomed seats for socket-head cap screws in production and maintenance machining environments. Machinists and toolroom technicians are the primary installers of this tool.

The C91735 is sized specifically for 3/4 inch socket-head cap screw clearance applications. Its 8-13/16 inch overall length provides reach for deep counterboring setups. The straight-cylindrical shank seats directly into standard drill press, milling machine, or lathe chuck holders. Typical use cases include creating accurate recessed screw seats in structural and mechanical assemblies where a flush or sub-flush fastener head is required. The bright finish is suited for general-purpose cutting without the added cost of a coated variant.

Key Features

• 1-5/32 inch counterbore diameter sized for 3/4 inch socket-head cap screw compatibility
• High-speed steel construction for cutting alloy tool steel, carbon steel, and cast iron
• 3-flute geometry with forward cutting direction for smooth, flat-bottomed counterbore seats
• Standard 25/32 inch solid pilot for accurate hole alignment without a separate pilot insert
• 1 inch straight-cylindrical shank fits standard chuck holders on drill presses and mills
• Bright, uncoated finish suitable for general-purpose machining applications

Compatibility

Designed for counterboring 3/4 inch socket-head cap screw seats in alloy tool steel, carbon steel, and cast iron workpieces using standard drill press, milling machine, or lathe setups.

Installation Notes

Secure the 1 inch straight shank firmly in a properly sized chuck or collet before operation to prevent runout. Ensure the workpiece is clamped securely and the pilot hole is pre-drilled to the correct clearance diameter before engaging the counterbore. Use appropriate cutting fluid for the material being machined to extend tool life and improve surface finish. Inspect the pilot and cutting edges for wear before each use.