Kennametal 4050399 CNMG4305MS Turning Insert KCU25 Carbide

Product Description

The KENNAMETAL 4050399 is a CNMG-style indexable turning insert in grade KCU25, designed for general turning, facing, and boring operations on CNC and manual lathes. The insert features an 80-degree diamond shape with a negative rake geometry and a honed cutting edge for consistent edge stability. It is coated with AlTiN via a PVD process, providing heat and wear resistance when cutting steel, stainless steel, superalloys, and titanium. The 0.5-inch inscribed circle and 0.1875-inch thickness conform to ANSI and ISO CNMG standards. With four usable cutting edges per insert, this carbide grade delivers reliable tool life across a range of interrupted and continuous cuts.

This insert is suited for medium-duty turning applications in job shop and production environments. The KCU25 grade and MS chip breaker geometry are optimized for primary workpiece materials including carbon steel, stainless steel, superalloys, and titanium. Typical applications include OD turning, facing passes, and light boring where controlled chip formation and edge toughness are both required. It is held using a clamp and pin insert holding method, compatible with KENLOC-series toolholders.

Key Features

• 80-degree diamond insert shape (Shape Code: C) with negative rake for strong cutting edge geometry
• AlTiN PVD coating for heat resistance and extended tool life in steel and high-temperature alloys
• MS chip breaker design for controlled chip formation across turning, facing, and boring operations
• Four cutting edges per insert for cost-effective indexing
• Honed cutting edge style reduces microchipping on entry and exit
• Conforms to ANSI and ISO standards; ISO code CNMG120402MS

Compatibility

Designed for use with KENLOC-series toolholders that accept CNMG-style inserts with a clamp and pin holding method. Suitable for multi-use application in turning, facing, and boring operations. Compatible primary workpiece materials are steel (P), stainless steel (M), superalloys, and titanium (S) per ISO material codes.

Installation Notes

Installation is performed by a machinist or tooling technician on a powered-off or e-stopped machine with all spindle motion confirmed stopped. Seat the insert fully into the pocket and engage the clamp and pin mechanism to the toolholder manufacturer torque specification before resuming cuts. Inspect the insert pocket for debris or wear before indexing to a fresh cutting edge. Dispose of worn inserts per applicable shop safety and sharps-handling procedures.