Sandvik Coromant 5781921 Threading Insert 20 Tpi Un

Product Description

The SANDVIK COROMANT 5781921 is a solid carbide laydown threading insert designed for external UN thread cutting at 20 threads per inch. Part of the CoroThread 266 series, it features a TiCrAlN/TiN coating applied via PVD process, providing wear resistance and thermal stability during high-speed threading operations. The insert has a 3/8 inch (9.53 mm) inscribed circle, a thickness of 5/32 inch (3.97 mm), and a 60-degree included angle with a single tooth per side. It is installed by machinists and CNC turning specialists on lathes and threading machines configured for right-hand external UN thread profiles.

This insert is suited for right-hand external threading operations on ferrous and non-ferrous workpieces where UN thread standards are required. It fits CoroThread 266 series toolholders and is appropriate for production turning environments where consistent thread form and tool life are priorities. The chipbreaker designation A and insert size code 16 should be matched to the corresponding toolholder geometry before installation. This insert is sold individually, with a minimum order quantity of 10 units.

Key Features

• Solid carbide substrate for rigidity and wear resistance in threading applications
• TiCrAlN/TiN PVD coating for extended tool life and thermal protection
• 60-degree included angle for standard UN external thread profile
• 20 TPI rating for consistent thread pitch accuracy
• 3/8 inch inscribed circle with 0.1732 inch hole diameter for secure toolholder seating
• Right-hand cutting geometry for standard external thread orientation

Compatibility

Designed for use with CoroThread 266 series toolholders accepting insert size code 16 with right-hand, external UN thread geometry. Verify toolholder seat and clamping compatibility using the insert size code 16 and chipbreaker designation A before installation.

Installation Notes

Installation should be performed by a qualified machinist or CNC tooling technician with the machine fully powered down and in a locked-out state. Use the appropriate torx or insert-clamping key specified for the CoroThread 266 toolholder to secure the insert without overtightening. Confirm correct seating in the pocket before resuming operation. Inspect the insert edge and coating condition at regular intervals and replace at first sign of chipping or thread form degradation.