Walter 6917251 CCMT120408-FM4 WSM20S Turning Insert

Product Description

The WALTER 6917251 is a solid carbide turning insert with ISO designation CCMT120408-FM4 WSM20S, engineered for precision metal removal in demanding machining environments. This insert features a diamond 80-degree shape with a 7-degree relief angle and a positive rake geometry that reduces cutting forces and minimizes heat buildup at the cutting edge. The PVD-applied TiCN/Al2O3/Al coating stack in proprietary grade WSM20S delivers wear resistance suited to difficult-to-machine materials. The FM4 chip breaker geometry controls chip flow across a range of feed rates and depths. Licensed machinists and CNC operators working in production turning, facing, and boring operations will find this insert a direct fit for standard CCMT toolholders.

This insert is primarily intended for machining stainless steel and superalloys and titanium, with secondary application in general steel turning. Its 0.5-inch inscribed circle and 1/32-inch corner radius make it appropriate for medium-stock-removal passes where chip control and edge stability are priorities. The FM4 chip breaker geometry supports turning, facing, and boring operations within the rated maximum depth of cut. It is sized and toleranced per ANSI and ISO standards, with an industry-standard cross-reference of CCMT432-FM4 WSM20S for shops using inch-based catalogs.

Key Features

• PVD-coated TiCN/Al2O3/Al multilayer coating for wear and heat resistance on stainless steel and superalloys
• FM4 chip breaker for controlled chip formation in turning, facing, and boring
• Diamond 80-degree insert shape with positive rake and honed cutting edge for reduced cutting forces
• 1/32-inch corner radius balances edge strength with surface finish capability
• Screw-held mounting via center hole; neutral hand suits left- or right-hand toolholders
• Two usable cutting edges per insert

Compatibility

Designed for use in CCMT-style toolholders conforming to ANSI and ISO standards for screw-clamped turning inserts. Compatible with toolholders accepting a 0.5-inch inscribed circle CCMT insert. Industry-standard cross-reference number is CCMT432-FM4 WSM20S.

Installation Notes

Installation is performed by machinists or CNC setup technicians. Power down and lock out the machine spindle before seating or indexing the insert. Use the appropriate torx or hex key to tighten the clamping screw to the toolholder manufacturer's specified torque. Inspect the insert pocket and clamping screw for debris or wear before each index to ensure proper seating and runout control.