Carmex 20403678 Threading Insert 28 Tpi Un Carbide

Product Description

The CARMEX 20403678 is a laydown carbide threading insert designed for external UN thread forms at 28 threads per inch. It carries the BLU manufacturer grade with a PVD coating applied for extended tool life in demanding cutting conditions. The insert follows the 16ER series style with a 60-degree included angle and right-hand cutting orientation. Licensed machinists and CNC lathe operators install this insert into compatible 16ER toolholders for precision thread-turning operations. The inscribed circle measures 3/8 inches and the cutting edge to theoretical edge length is 0.0200 inches, confirming its suitability for fine-pitch external threading applications.

This insert is suited for threading operations on stainless steel, cast iron, non-ferrous metals, superalloys, and titanium workpieces. It performs in both production and job-shop environments where consistent 28 TPI UN external threads are required. The ISO designation is 16 ER 28 UN. Typical applications include CNC lathes and manual threading operations where controlled chip formation and thread accuracy are critical. The single cutting tooth per side geometry supports clean thread profiles on a range of workpiece materials.

Key Features

• 16ER series laydown insert style for external threading
• 28 threads per inch UN thread standard with 60-degree included angle
• Carbide substrate with PVD coating for extended wear resistance
• BLU manufacturer grade optimized for stainless steel, superalloys, and titanium
• Right-hand cutting orientation, single tooth per side geometry
• Inscribed circle of 3/8 inches; face of insert to tip centerline 0.0300 inches

Compatibility

Designed as an OEM-style replacement threading insert for 16ER-style toolholders used in CNC and manual lathe threading of external UN thread forms.

Installation Notes

Installation is performed by qualified machinists or CNC setup technicians. Ensure the lathe is fully stopped and locked out before changing inserts. Seat the insert firmly and squarely in the toolholder pocket and tighten the clamping screw to the toolholder manufacturer's specified torque. Verify thread pitch and profile with a thread gauge before returning the machine to full production.