Sandvik Coromant 5857578 Threading Insert 16 Tpi Un

Product Description

The SANDVIK COROMANT 5857578 is a laydown threading insert designed for external UN thread cutting on CNC lathes and turning centers. Part of the CoroThread 266 series, this solid carbide insert carries a PVD-applied TiCrAlN/TiN finish that resists heat and wear during continuous threading passes. It cuts right-hand external threads at 16 threads per inch with a 60-degree included angle and a single tooth per side. The inscribed circle measures 3/8 inches and the insert thickness is 5/32 inches (0.1563 inches decimal). Manufacturer grade 1135 and chipbreaker style F make it suited to a range of steel and alloy workpiece materials in precision threading applications.

This insert is used in external threading operations on lathes and turning centers in production machining environments, including job shops, aerospace component manufacturing, and general precision metalworking. The UN thread standard applies to unified inch-series fastener and fitting threads common in North American manufacturing. Machinists and CNC operators working to close thread tolerances on shaft diameters will find the 16 TPI specification and right-hand orientation appropriate for standard bolt and fitting profiles. The F chipbreaker geometry helps control chip evacuation during threading passes on ductile materials.

Key Features

• Solid carbide substrate with PVD TiCrAlN/TiN coating for extended tool life in threading operations
• 16 threads per inch, right-hand external UN thread form with 60-degree included angle
• CoroThread 266 series insert style with chipbreaker designation F
• Inscribed circle of 3/8 inches (9.53 mm) and thickness of 5/32 inches (3.97 mm)
• Single tooth per side geometry for controlled thread profile accuracy
• Hole diameter of 0.1732 inches (4.40 mm) for standard CoroThread toolholder mounting

Compatibility

Designed for use in CoroThread 266 series toolholders that accept the 266 insert style with a 16-size insert code. Consult the SANDVIK COROMANT CoroThread 266 toolholder selection guide to confirm shank size and insert pocket compatibility for your specific application.

Installation Notes

Installation should be performed by a qualified machinist or CNC setup technician with the machine powered down and the spindle locked before indexing or replacing inserts. Use the appropriate Torx wrench to seat and torque the clamping screw to the toolholder manufacturer specification. Inspect the insert pocket and seating surface for chips or debris before seating the new insert. Follow all shop safety procedures for handling carbide inserts, as edges are extremely sharp.