Sandvik Coromant 5721939 Indexable Boring Bar Coroturn 107

Product Description

The SANDVIK COROMANT 5721939 is an indexable boring bar from the CoroTurn 107 series, designed for precision internal boring and turning operations on CNC lathes and machining centers. The bar features a 5/8-inch shank diameter and an 8-inch overall length, with a minimum bore diameter of 0.7717 inches (19.60 mm). Screw clamping secures a single TCMT 221 insert, providing a rigid and repeatable cutting setup. The neutral rake geometry and zero-degree lead angle make this holder well-suited for consistent, controlled material removal. Machining shops, toolrooms, and production facilities rely on this style of boring bar for tight-tolerance internal diameter work.

This boring bar is used in applications requiring reliable internal boring and turning in a compact toolholder format. The A-STFC toolholder style accommodates TCMT 221 triangular inserts with a 1/4-inch inscribed circle. With coolant-through capability, the bar supports higher cutting speeds and improved chip evacuation in demanding materials. The multi-use design supports both boring and turning operations, making it a practical choice for shops running varied part families on the same setup. The right-hand cutting orientation is standard for conventional lathe spindle rotation.

Key Features

• CoroTurn 107 series A-STFC toolholder style with screw clamping for secure insert retention
• Minimum bore diameter of 0.7717 inches (19.60 mm) for small-diameter internal work
• Coolant-through design aids chip control and extends insert life at elevated cutting speeds
• Neutral rake, zero-degree lead angle geometry for consistent, stable cutting performance
• Compatible with TCMT 221 triangular inserts (1/4-inch inscribed circle)
• Multi-use application: supports both boring and turning operations

Compatibility

Designed for use with TCMT 221 inserts (1/4-inch inscribed circle, 1/8-inch insert thickness). Part of the SANDVIK COROMANT CoroTurn 107 series. Compatible with CNC lathes and machining centers accepting a 5/8-inch round shank toolholder.

Installation Notes

Installation is performed by qualified machinists or toolroom technicians. Ensure the machine spindle and turret are fully powered down and locked out before mounting or adjusting the toolholder. Secure the shank in the turret or boring bar holder to the machine manufacturer's recommended clamping specifications. Verify insert seating and screw torque per the insert manufacturer's guidelines before initiating a cut.