Kennametal 4121718 VNMG431MS KCU25 Carbide Turning Insert

Product Description

The KENNAMETAL 4121718 is a solid carbide turning insert in the VNMG431MS geometry, grade KCU25, with a Physical Vapor Deposition (PVD) AlTiN coating. It carries a 35-degree diamond (rhombic) insert shape, a 0.5-inch inscribed circle, and a 0.0156-inch corner radius. The MS chip breaker geometry is rated for roughing and medium machining operations. With four cutting edges, a negative rake angle of 13 degrees, and a honed cutting edge style, this insert delivers moderate wear resistance and toughness across a range of workpiece materials. It is installed and indexed by licensed machinists and CNC turning technicians.

This insert is suited for turning, facing, boring, back turning, and back boring operations on steel, stainless steel, cast iron, aluminum and non-ferrous materials, and superalloys including titanium. The KCU25 grade targets ISO material groups P, M, K, N, and S, making it a multi-application insert for production turning and job-shop environments. The KENLOC series design is compatible with clamp and pin insert-holding methods. Maximum depth of cut reaches 0.5806 inches, supporting moderate to aggressive material removal strategies in both roughing and semi-finishing passes.

Key Features

• VNMG431MS geometry with 35-degree diamond shape and negative side clearance for stable interrupted and continuous cuts
• KCU25 grade with PVD AlTiN coating for moderate wear resistance and toughness on steel, stainless, cast iron, and superalloys
• MS chip breaker supports roughing and medium machining operations
• Four cutting edges per insert reduce per-edge tooling cost
• Honed cutting edge style suited for controlled engagement on difficult materials including titanium and superalloys
• Compatible with clamp and pin holding methods for secure seating in VNMG-style toolholders

Compatibility

Designed for use in VNMG-style toolholders that accept the ANSI insert code VNMG431 and ISO insert code VNMG220404. Compatible with KENLOC series insert-holding systems using clamp or pin clamping methods. Conforms to ANSI and ISO standards for interchangeability with toolholders designed for the VNMG insert family.

Installation Notes

Installation and indexing should be performed by a qualified machinist or CNC turning technician with the machine in a full stop and lockout-tagout procedures followed per OSHA and shop safety requirements. Seat the insert fully in the pocket before tightening the clamp or pin to the toolholder manufacturer's specified method. Inspect the insert pocket and seating surface for chips or debris before each index to maintain accurate tool geometry. Do not operate beyond the maximum depth of cut or feed parameters established in the job setup documentation.