Sandvik Coromant 5721288 Indexable Boring Bar Coroturn 107

Product Description

The SANDVIK COROMANT 5721288 is a steel indexable boring bar from the CoroTurn 107 series, designed for internal boring and turning operations on CNC lathes and machining centers. The toolholder features a 0.25 inch shank diameter and an overall length of 3.25 inches, with a minimum bore diameter of 0.3425 inch (8.70 mm). Insert clamping is achieved via a screw-lock method, which provides rigid, repeatable insert seating. The neutral rake angle and zero-degree lead angle make this holder suitable for a wide range of workpiece materials. It accepts TCMT 1.21.20 inserts with a 0.1563 inch inscribed circle and supports coolant-through delivery for chip evacuation in deep-bore applications. Machinists and CNC operators install this bar in both production and job-shop environments.

This boring bar is suited for small-diameter internal boring and turning on lathes and turning centers where tight bore tolerances are required. The right-hand cutting orientation and A-STFC toolholder style position it for standard front-facing internal cuts. The multi-use designation allows application in both boring and turning setups with a single holder. Its compact shank diameter and short overall length make it practical for small-bore work on both manual and CNC turning equipment. One insert is used per toolholder, keeping setup straightforward for production runs and prototype work alike.

Key Features

• Minimum bore diameter of 0.3425 inch (8.70 mm) for small-bore internal machining
• Screw clamping insert retention for rigid, repeatable seating
• Coolant-through capability supports chip evacuation in deep or tight bores
• Accepts TCMT 1.21.20 inserts with 0.1563 inch inscribed circle
• Neutral rake (0 degrees) and zero-degree lead angle for broad material compatibility
• Multi-use design supports both boring and turning applications

Compatibility

Compatible with TCMT 1.21.20 series inserts. Part of the SANDVIK COROMANT CoroTurn 107 toolholder series. Designed for use in CNC lathes and turning centers that accept a 0.25 inch round shank toolholder.

Installation Notes

Installation is performed by qualified machinists or CNC setup technicians. Ensure the machine spindle is fully stopped and all power is locked out before changing inserts or mounting the toolholder. Secure the shank in the tool turret or boring bar holder to the appropriate clamping torque per the machine manufacturer specification. Verify coolant-through port alignment if using internal coolant delivery to avoid restricted flow during operation.