Kennametal 4109641 Threading Insert NAS3R4 KCU25 Carbide

Product Description

The KENNAMETAL 4109641 is a carbide threading insert in the Top Notch series, designed for cutting Stub Acme threads at 4 threads per inch (TPI). It carries the KCU25 manufacturer grade and features a physical vapor deposition (PVD)-applied aluminum titanium nitride (AlTiN) finish for heat and wear resistance. The insert is sized at 0.1004 inches wide at the cutting tip, with a 29-degree included angle and a 0.0050-inch corner radius. At 0.1949 inches thick, this right-hand insert fits standard Top Notch toolholders and is suited for both internal and external threading operations performed by machinists and CNC lathe operators in production and job-shop environments.

This insert is intended for Stub Acme thread-form applications on both internal and external workpieces. The Stub Acme thread standard is commonly used in power transmission components, lead screws, and linear actuator assemblies where a modified Acme profile is required. The KCU25 carbide grade combined with the AlTiN PVD coating makes this insert appropriate for threading steel, alloy steel, and similar ferrous materials at moderate to high cutting speeds. It is a single-insert unit sold in multiples of five.

Key Features

• KCU25 carbide grade with AlTiN PVD coating for wear resistance in ferrous threading applications
• Stub Acme thread form at 4 TPI with a 29-degree included angle
• Right-hand cut geometry for standard lathe and CNC threading setups
• Suitable for both internal and external threading operations
• Insert size 3, compatible with Top Notch series toolholders
• 0.0050-inch corner radius for controlled thread root profile

Compatibility

Designed for use with Top Notch series threading toolholders that accept a size 3 NAS-style insert. Compatible with both internal and external threading applications.

Installation Notes

Threading inserts are installed and replaced by machinists or CNC operators. Power down and lock out the machine spindle before seating or removing any insert. Ensure the insert pocket and clamping surfaces are clean and free of chips before seating the insert. Follow the toolholder manufacturer torque and clamping guidelines for Top Notch style holders.