Walter 7251975 Turning Insert VNMG331-MM5 WSM20S Carbide

Product Description

The WALTER 7251975 is a solid carbide turning insert in the VNMG-MM5 series, designed for precision metal removal on CNC lathes and turning centers. It carries the industry-standard designation VNMG331-MM5 WSM20S and features a multilayer PVD coating of TiCN, Al2O3, and aluminum for extended tool life in demanding cuts. The 35-degree diamond shape (Insert Shape Code V) provides a sharp, acute cutting geometry suited to finishing and light roughing passes. With a 3/8-inch inscribed circle and a 0.016-inch corner radius, this insert delivers consistent edge performance across a range of depths of cut up to 0.654 inches.

This insert is engineered primarily for stainless steel and superalloys and titanium (ISO material codes M and S), with steel (ISO code P) as a secondary workpiece material. The MM5 chip breaker geometry is optimized for turning, facing, boring, and back turning operations in both light finishing and medium stock-removal applications. The neutral hand orientation makes it adaptable to standard right-hand and left-hand toolholders with VNMG-style pockets. It is typically specified by CNC machinists and toolroom operators working in aerospace, medical, and general precision machining environments.

Key Features

• PVD-applied TiCN and Al2O3 multilayer coating for heat and wear resistance on stainless steel and superalloys
• MM5 chip breaker geometry supports turning, facing, boring, and back turning
• 35-degree diamond shape with 4 usable cutting edges for extended insert life
• 0.016-inch corner radius with chamfered and honed cutting edge for controlled surface finish
• Negative rake, zero-degree relief angle (Clearance Code N) for rigid clamping stability
• Clamp and pin holding method compatible with standard VNMG toolholders
• Meets ANSI and ISO standards; ISO equivalent designation VNMG160404-MM5 WSM20S

Compatibility

Designed for use in VNMG-style insert pockets that accept clamp and pin holding; compatible with toolholders specifying a VNMG 3/8-inch inscribed circle, 3/16-inch insert thickness, and 0.150-inch hole diameter. Suitable for material grades M20, S20, and P20 per ISO classification.

Installation Notes

Installation is performed by CNC machinists or toolroom personnel. Power down and lock out the machine spindle before seating or removing inserts. Use the correct torx or clamp screw torque driver as specified by the toolholder manufacturer - do not overtighten the clamp screw. Inspect the insert pocket and seating surfaces for chips or debris before installing a fresh insert to ensure proper seating and edge repeatability.