Sandvik Coromant 5757960 Threading Insert 12 Tpi Un

Product Description

The SANDVIK COROMANT 5757960 is a laydown threading insert designed for cutting internal UN threads in machined components. Built from solid carbide with a PVD-applied TiCrAlN/TiAlN dual coating, this insert delivers wear resistance and thermal stability during threading operations. It runs at 12 threads per inch (TPI) with a 60-degree included angle and a right-hand cutting orientation. The insert carries a 3/8-inch (9.53 mm) inscribed circle and measures 5/32 inch (3.97 mm) thick. It belongs to the CoroThread 266 series and is intended for use by machinists and toolroom professionals on CNC lathes and turning centers.

This insert is applied in internal threading operations on workpieces requiring UN-standard thread forms. The right-hand orientation suits standard spindle-direction threading passes on conventional and CNC turning equipment. With two teeth per side and the A chipbreaker geometry, it is suited to moderate-depth threading in steel and similar machinable alloys. Typical install scenarios include production threading of hydraulic fittings, fastener blanks, and other components requiring precise UN thread profiles. The insert slots into CoroThread 266 series toolholders using the standard 0.1732-inch (4.40 mm) mounting hole.

Key Features

• Solid carbide substrate with PVD TiCrAlN/TiAlN coating for extended tool life
• Right-hand internal UN thread form at 12 TPI with 60-degree included angle
• A chipbreaker geometry with 2 teeth per side for controlled chip evacuation
• 3/8-inch inscribed circle for use in CoroThread 266 series toolholders
• Manufacturer grade 1125 for compatibility with the CoroThread 266 insert system

Compatibility

Designed for use with CoroThread 266 series threading toolholders. The manufacturers catalog number for cross-reference is 266RL-16UN02A120M 1125. Verify toolholder bore and insert seat dimensions before installation.

Installation Notes

Installation is performed by qualified machinists or toolroom technicians. Ensure the machine spindle is fully stopped and the toolholder is secured before seating or removing the insert. Use the correct torx or hex key as specified by the toolholder manufacturer to achieve proper clamping force — do not overtighten, as carbide inserts are brittle and can crack under uneven clamping load. Confirm thread form, hand, and TPI match the workpiece drawing before commencing the threading cycle.