Cleveland C58516 Spiral Flute Tap 4-40 Unc 2 Flute Bottoming

Product Description

The CLEVELAND C58516 is a spiral flute tap designed for bottoming thread applications in blind holes. It cuts a 4-40 UNC right-hand thread using a 2-flute, fast-flute-style spiral geometry with a 52-degree helix angle that efficiently evacuates chips up and out of the hole. Manufactured from high speed steel with a bright, uncoated finish, this tap holds an H2 thread limit and meets 2B and 3B class-of-fit tolerances. Overall length is 1.875 inches, with a thread length of 0.31 inches. It is sized for use by machinists, maintenance technicians, and trade professionals working with small-diameter fastener threads.

The C58516 is built for blind hole threading in alloy tool steel, carbon steel, and stainless steel workpieces. The bottoming chamfer allows threads to be cut to the bottom of a blind hole, making it the right choice where thread engagement depth is limited by hole geometry. It fits Series 1093 and 1094 tooling setups and is appropriate for both production and repair threading tasks in HVAC, mechanical, and general industrial maintenance contexts.

Key Features

• Bottoming chamfer allows threading to the full depth of a blind hole
• 52-degree helix angle promotes fast chip evacuation in deep blind holes
• H2 thread limit with 2B and 3B class-of-fit compliance for precise thread quality
• High speed steel construction provides wear resistance across carbon, alloy, and stainless steel materials
• Bright, uncoated finish suitable for use with cutting fluids and standard tapping lubricants
• Right-hand flute and right-hand thread — standard rotation, no reverse-drive tooling required

Compatibility

Designed for blind hole threading applications in alloy tool steel, carbon steel, and stainless steel. Compatible with Series 1093 and 1094 tooling. Produces 4-40 UNC threads meeting 2B and 3B class-of-fit tolerances.

Installation Notes

This tap is installed and driven by a machinist or qualified maintenance technician using a tap wrench, drill press, or CNC tapping setup. Always use an appropriate cutting fluid or tapping lubricant when threading stainless or alloy steels to extend tool life and reduce the risk of tap breakage. Ensure the workpiece is firmly secured before beginning and that the pilot hole diameter matches the recommended tap drill size for 4-40 UNC threads. Avoid excessive downward pressure on bottoming taps to prevent breakage at the bottom of the hole.