Sandvik Coromant 5781918 Laydown Threading Insert 13 Tpi

Product Description

The SANDVIK COROMANT 5781918 is a solid carbide laydown threading insert engineered for right-hand external UN thread cutting at 13 threads per inch (TPI). Part of the CoroThread 266 series, it carries a dual PVD coating of TiAlN and TiCrAlN for wear resistance and thermal stability under continuous cutting loads. The insert features a 60-degree included angle, a 3/8-inch inscribed circle, and a thickness of 5/32 inch (0.1563 inch decimal). Manufacturer grade 1125 positions it for steel and alloy threading applications where edge retention and coating durability are priorities. This insert is installed by machinists and toolroom technicians on CNC lathes and threading centers.

This insert is suited for external UN threading operations in precision machining environments, including job shops, production turning cells, and maintenance repair operations. It is designed for use in CoroThread 266 series toolholders and is applicable to residential and commercial part production where standardized UN thread forms are required. The chipbreaker designation A is factory-ground into the insert geometry. Single-tooth-per-side configuration makes it appropriate for single-point threading passes on a CNC lathe or manual engine lathe equipped with a compatible insert pocket.

Key Features

• Solid carbide substrate with PVD-applied TiAlN and TiCrAlN dual coating for extended tool life
• 13 TPI, 60-degree included angle for standard UN external thread profile
• 3/8-inch inscribed circle and 0.1563-inch thickness for precise pocket fit in 266-series holders
• Right-hand cutting orientation for standard CNC lathe external threading passes
• CoroThread 266 series insert style 266RG for consistent indexing and repeatability
• 0.1732-inch hole diameter for secure clamping in compatible toolholders

Compatibility

Designed for use with CoroThread 266 series toolholders accepting a size-16 insert with a 3/8-inch inscribed circle. Manufacturer catalog number 266RG-16UN01A130M 1125 identifies the exact insert geometry and grade for toolholder matching.

Installation Notes

Insert indexing and replacement should be performed with the machine in a full stop, lockout-tagout applied, and the turret or toolpost secured. Use the manufacturer-recommended torque wrench and clamping screw for the 266-series pocket to avoid insert rocking or breakage. Inspect the insert pocket and clamping components for chips or wear before seating a new insert. Dispose of worn carbide inserts in accordance with local regulations for carbide and coated tooling waste.