Walter 6388430 Turning Insert CNMA643-RK5 WKK20S Carbide

Product Description

The WALTER 6388430 is a solid carbide turning insert in the CNMA643-RK5 WKK20S configuration, engineered for high-performance machining of cast iron and steel. It carries a CVD-applied multilayer coating of TiCN, Al2O3, and TiCN, designated under WALTERs proprietary grade WKK20S and aligned with the Tiger-tec Silver series. The insert features an 80-degree diamond shape with a negative rake angle and a chamfered and honed cutting edge, delivering controlled chip formation and edge stability under demanding cutting conditions. With four available cutting edges and compatibility with both clamp and pin holding methods, it provides extended tool life and consistent performance in turning, facing, and boring operations.

This insert is suited for roughing and semi-finishing applications on cast iron (ISO material code K) and steel (ISO material code P) workpieces. It fits standard CNMA toolholders used in CNC turning centers and manual lathes across production machining environments. The RK5 chip breaker geometry is designed to manage chip evacuation at moderate-to-heavy depths of cut up to 0.315 inches (8.00 mm). Licensed machinists and CNC operators in job shop and production settings will find this insert appropriate for general turning, facing, and boring tasks requiring stable edge geometry and predictable wear behavior.

Key Features

• CVD multilayer coating: TiCN, Al2O3, TiCN under proprietary grade WKK20S for wear resistance on cast iron and steel
• 80-degree diamond insert shape with negative rake and chamfered and honed cutting edge for stable cuts
• Four cutting edges per insert maximize utilization and reduce per-edge tooling cost
• RK5 chip breaker geometry supports turning, facing, and boring with maximum depth of cut of 0.315 inches
• Compatible with clamp and pin holding methods for secure seating in standard CNMA toolholders
• Meets ANSI and ISO standards; ISO code CNMA190612-RK5 WKK20S

Compatibility

Designed for use in standard CNMA-style toolholders that accept a 3/4-inch inscribed circle insert. Suitable for turning, facing, and boring operations on cast iron (ISO K) and steel (ISO P) workpieces. ISO equivalent designation is CNMA190612-RK5 WKK20S.

Installation Notes

Installation should be performed by a qualified machinist following the toolholder manufacturers seating and clamping procedure. Ensure the machine spindle is fully stopped and all motion is locked out before indexing or replacing inserts. Confirm the insert pocket is clean and free of chips before seating to prevent uneven clamping and premature edge failure. Verify clamping torque and pin engagement per the toolholder manufacturers specification.