Sandvik Coromant 5757998 Threading Insert 18 Tpi Unj

Product Description

The SANDVIK COROMANT 5757998 is a solid carbide laydown threading insert designed for external UNJ thread cutting at 18 threads per inch. Part of the CoroThread 266 series, it features a TiCrAlN/TiAlN PVD coating that extends tool life in demanding threading operations. The insert carries a 3/8 inch inscribed circle, a thickness of 0.1563 inches, and a 60-degree included angle with a single tooth per side. It is sized with insert size code 16 and is designated for right-hand cutting. This insert is installed by machinists and toolroom technicians working on CNC lathes and turning centers where precise UNJ thread forms are required.

This insert is suited for external threading applications where UNJ thread standards are specified, commonly encountered in aerospace and defense component manufacturing. The CoroThread 266 insert style provides consistent thread form geometry in production environments. At 18 TPI, it covers a common thread pitch range for medium-diameter fastener and fitting threads. The chipbreaker designation A and the PVD-applied TiCrAlN/TiAlN dual-layer coating make it appropriate for a range of workpiece materials where controlled chip formation and wear resistance are priorities. This product is sold individually with a minimum order quantity of 10 units.

Key Features

• Solid carbide substrate with TiCrAlN/TiAlN PVD dual-layer coating for extended wear resistance
• CoroThread 266 series insert style, size code 16, right-hand cutting orientation
• External UNJ thread form, 18 TPI, 60-degree included angle
• 3/8 inch (9.53 mm) inscribed circle with 0.1563 inch (3.97 mm) thickness
• Chipbreaker style A for controlled chip formation during threading passes
• Single tooth per side design for consistent thread profile on each pass

Compatibility

Designed as an OEM-style replacement threading insert for CoroThread 266 series toolholders accepting size code 16 laydown inserts with a 0.1732 inch (4.40 mm) hole diameter. Refer to your toolholder documentation to confirm insert size and geometry compatibility before installation.

Installation Notes

Installation is performed by qualified machinists or toolroom technicians. Power down and lock out the machine spindle before seating or removing inserts. Use the appropriate torx or hex key specified by the toolholder manufacturer to achieve proper clamping torque without over-tightening the insert screw. Inspect the insert pocket for wear or debris before seating a new insert to ensure correct thread form geometry is maintained.