Walter 7251896 CNMG431-MM5 WSM20S Turning Insert

Product Description

The WALTER 7251896 is a solid carbide turning insert in the CNMG431-MM5 WSM20S series, designed for high-performance single-point turning, facing, and boring operations. It features a multilayer PVD coating of TiCN, Al2O3, and aluminum for wear resistance and thermal protection in demanding cuts. The insert carries an 80-degree diamond shape with a neutral hand orientation, a 0.016-inch corner radius, and a 0.5-inch inscribed circle. With four usable cutting edges per insert, it delivers consistent performance in production turning environments. Typically installed by machinists and CNC operators on lathes and turning centers.

This insert is engineered primarily for stainless steel and superalloys including titanium, and serves as a secondary option for steel workpieces. The MM5 chip breaker geometry and chamfered-and-honed cutting edge style are well suited to moderate depths of cut up to 0.508 inches in interrupted and continuous cutting scenarios. It fits standard CNMG toolholders using clamp or pin holding methods and conforms to both ANSI and ISO standards. The ISO equivalent designation is CNMG120404-MM5 WSM20S, which aids cross-referencing across tooling systems.

Key Features

• PVD-coated multilayer TiCN, Al2O3, and aluminum coating for extended tool life in stainless and titanium applications
• 80-degree diamond insert shape (Shape Code C) with negative rake and 0-degree relief angle
• MM5 chip breaker geometry with chamfered and honed cutting edge for controlled chip formation
• Four cutting edges per insert for maximum tool economy
• Compatible with clamp and pin holding methods in standard CNMG toolholders
• Conforms to ANSI and ISO standards; ISO designation CNMG120404-MM5 WSM20S

Compatibility

Designed for use in standard CNMG-style toolholders accepting clamp or pin retention. Primary workpiece materials are stainless steel and superalloys including titanium (ISO material codes M and S); secondary application covers steel (ISO material code P). Material grades M20, S20, and P20 apply.

Installation Notes

Installation is performed by qualified machinists or CNC tooling technicians. Power down and lock out the turning center before indexing or replacing inserts. Use the appropriate torque wrench for clamp screws per toolholder manufacturer specifications. Inspect the insert pocket and seating surface for chips or debris before seating a new insert to ensure proper edge engagement and runout control.