Kennametal 4109939 Threading Insert NT2LK KCU25 Carbide

Product Description

The KENNAMETAL 4109939 is a carbide threading insert in the Top Notch series, designed for cutting both internal and external threads on a lathe or CNC turning center. Manufactured in a left-hand configuration with a 60-degree partial profile included angle, this insert handles external pitches from 0.70 to 3.00 mm (8 to 36 TPI) and internal pitches from 1.25 to 3.50 mm (7 to 20 TPI). The AlTiN finish is applied via PVD coating, providing heat and oxidation resistance during high-speed threading operations. Insert size is 2, with a corner radius of 0.1 mm (0.0039 inches) and a tip-to-top-of-insert measurement of 0.0752 inches. Machinists and tooling technicians working in production or job-shop environments will find this insert suited to threading a wide range of ferrous and non-ferrous workpieces.

This insert is intended for use in Top Notch series threading toolholders that accept the NT style, left-hand insert geometry. It supports both internal and external threading applications on manual lathes, CNC turning centers, and multi-axis machining equipment. The K-style chipbreaker promotes controlled chip evacuation during threading passes. Typical applications include producing unified, metric, and 60-degree thread forms across a broad pitch range in production or repair machining environments.

Key Features

• Carbide substrate with PVD-applied AlTiN finish for elevated heat resistance
• Left-hand insert orientation for reverse-rotation or back-turning thread applications
• 60-degree partial profile supports both internal and external thread cutting in a single insert
• External pitch range: 0.70 to 3.00 mm (8 to 36 TPI)
• Internal pitch range: 1.25 to 3.50 mm (7 to 20 TPI)
• K-style chipbreaker for chip control during threading passes
• Top Notch series platform for positive indexing and repeatable tool-edge positioning

Compatibility

Designed for use in Top Notch series threading toolholders accepting NT2 left-hand insert style. Verify toolholder compatibility with the NT insert style and insert size 2 before ordering.

Installation Notes

Installation should be performed by a qualified machinist or tooling technician. Power down and lock out the machine spindle before seating or indexing the insert. Use the appropriate torx or clamp screw driver as specified by the toolholder manufacturer to secure the insert - do not overtighten. Inspect the seating pocket for chips or debris before installing a new cutting edge to ensure proper insert contact and repeatable tool-tip positioning.