Cleveland C44578 Tool Bit Blank M42 Cobalt Square

Product Description

The CLEVELAND C44578 is a square-ground tool bit blank machined from M42 cobalt high-speed steel. It measures 3/8 inches wide by 3/8 inches high with a 3-inch overall length. Tool bit blanks are unfinished cutting tool stock that machinists grind to a custom profile for use in lathe toolposts, boring bars, and similar metal-cutting applications. The M42 cobalt grade provides elevated hot hardness compared to standard M2 HSS, making it well suited for interrupted cuts, harder ferrous alloys, and high-feed operations where heat buildup at the cutting edge is a concern. The square cross-section and ground finish ensure consistent seating in standard toolholders.

This blank is intended for use in machine shops, tool-and-die operations, and maintenance environments where custom tooling geometry is required. Machinists grind the blank to a specific relief angle, rake angle, and nose radius based on the material being cut and the operation being performed. The 3-inch OAL is a common size suited for bench grinder shaping and fits standard tool bit holders used on engine lathes and manual milling setups.

Key Features

• M42 cobalt HSS construction for improved hot hardness and wear resistance over standard HSS
• Square cross-section at 3/8 inches by 3/8 inches for consistent toolholder seating
• 3-inch overall length provides ample stock for grinding multiple cutting edges over the tool life
• Ground finish on all faces ensures dimensional accuracy before custom profiling
• Square end shape allows grinding to virtually any single-point cutting geometry

Compatibility

Designed as a standard-size tool bit blank for use in 3/8-inch tool bit holders and toolposts on engine lathes, turret lathes, and manual milling machines requiring custom single-point HSS tooling.

Installation Notes

Grinding tool bit blanks is performed by a machinist using a bench or pedestal grinder fitted with an appropriate wheel for HSS material. Eye protection and a grinding rest set to the correct angle are required for safe, accurate profiling. Allow the blank to cool frequently during grinding to prevent overheating the cutting edge, which can reduce hardness in the cobalt steel. Secure the finished tool bit firmly in the toolholder before initiating any cutting operation.