Kennametal 4109959 Threading Insert NTK2R KCU25 Carbide

Product Description

The KENNAMETAL 4109959 is a carbide threading insert in the Top Notch series, designed for cutting internal and external threads on CNC lathes and turning centers. Manufactured to an NTK2R insert style in grade KCU25, this insert features a PVD-applied AlTiN finish that supports elevated cutting temperatures and extends tool life in demanding thread-turning operations. It handles external pitches from 0.60 to 1.75 mm (14 to 44 TPI) and internal pitches from 1.00 to 2.00 mm (12 to 24 TPI), making it a versatile choice for partial profile 60-degree threading across a wide pitch range. Right-hand orientation is standard. The insert weighs approximately 0.004 pounds.

This insert is suited for production and job-shop environments where threading is performed on steel, stainless steel, and similar workpiece materials. It fits Top Notch series toolholders designed for NTK2R inserts and is appropriate for both internal threading on bored features and external threading on turned diameters. Machinists and CNC operators working in aerospace, energy, and general manufacturing will find the KCU25 grade and AlTiN coating well matched to interrupted cuts and moderate to high cutting speeds.

Key Features

• PVD AlTiN coating for extended tool life at elevated cutting temperatures
• KCU25 carbide grade engineered for thread-turning on steel and stainless steel
• Partial profile 60-degree thread form covers a broad pitch range without a dedicated pitch-specific insert
• External pitch range: 0.60 to 1.75 mm (14 to 44 TPI)
• Internal pitch range: 1.00 to 2.00 mm (12 to 24 TPI)
• Right-hand cut orientation; 0.08 mm (0.0031 inch) corner radius for precise thread root geometry

Compatibility

Designed for use with Top Notch series toolholders accepting NTK2R style inserts. Confirm toolholder seat size and insert size 2 compatibility before installation.

Installation Notes

Threading inserts of this type are seated and clamped by a trained CNC machinist or toolroom technician. Before changing inserts, ensure the machine is in an E-stop state, the spindle is locked, and coolant flow is off. Seat the insert fully in the pocket and torque the clamping screw to the toolholder manufacturer specification before resuming operation. Inspect the insert seating surface and pocket for chips or burrs that could cause rocking or premature edge failure.