Vargus 51509 3ER18UN Vkx Solid Carbide Threading Insert 18 Tpi

Product Description

The VARGUS 51509 is a laydown-style solid carbide threading insert designed for external UN thread cutting on CNC lathes and turning centers. Manufactured to the VKX grade with a PVD-applied TiN coating, this insert produces right-hand UN threads at 18 threads per inch (TPI) with a 60-degree included angle. The 3ER insert style carries a 3/8-inch (0.3750 inch) inscribed circle for secure seating in compatible toolholders. It is intended for use by machinists and CNC programmers working in production or job-shop environments where consistent, repeatable thread form is required across a wide range of workpiece materials.

This insert is suited for external threading operations on materials spanning multiple ISO workpiece categories, including carbon steels, stainless steels, cast irons, non-ferrous alloys, and heat-resistant superalloys. The universal material compatibility makes it a practical choice for shops running mixed-material schedules. Typical applications include threading shafts, fasteners, fittings, and hydraulic components where ANSI B1.1 UN thread standards must be met. The solid carbide substrate combined with PVD TiN coating provides wear resistance and edge retention across these material groups.

Key Features

• Solid carbide substrate with PVD TiN coating for extended tool life
• 18 TPI right-hand external UN thread form, 60-degree included angle
• 3ER insert style with 3/8-inch inscribed circle for rigid toolholder engagement
• Universal workpiece material compatibility across ISO material codes H, K, M, N, P, and S
• Meets ANSI B1.1:74 and ISO 9001:2008 standards

Compatibility

Designed as an OEM-style replacement threading insert for 3ER-style external threading toolholders requiring an 18 TPI UN thread profile with a 3/8-inch inscribed circle.

Installation Notes

Threading inserts of this type are installed and replaced by qualified machinists or CNC tooling technicians. The machine spindle must be fully stopped and the tool turret indexed to a safe position before insert removal or installation. Use the correct torque wrench and insert screw specified by the toolholder manufacturer to avoid seat damage or insert fracture. Inspect the insert pocket and clamping screw for wear or contamination before seating a new insert.