Sandvik Coromant 7861257 Turning Insert TNMM333-QR 4425

Product Description

The SANDVIK COROMANT 7861257 is a TNMM333-QR 4425 grade solid carbide turning insert from the T-Max P series, designed for external and internal turning operations on CNC lathes and turning centers. The insert carries a CVD-applied multilayer coating of Al2O3, TiCN, and TiN, which provides thermal resistance and wear protection across a range of cutting conditions. The inscribed circle measures 3/8 inches and the corner radius is 0.0469 inches. The trigon shape with a 60-degree included angle and neutral hand orientation makes it suitable for general-purpose turning where versatile approach angles are required. Installation is by clamp or screw holding methods.

This insert is intended for turning applications on workpiece materials classified under ISO material groups P (steel) and K (cast iron). It fits standard TNMM-style toolholders and is well-suited for medium to rough turning passes where edge security and coating durability matter. The QR chip breaker geometry supports chip control across a range of depths of cut and feed rates. It is used by machinists and CNC operators in production and job-shop environments handling ferrous components.

Key Features

• CVD multilayer coating: Al2O3, TiCN, and TiN for thermal and abrasion resistance
• Trigon insert shape with 60-degree included angle and 0-degree relief angle (clearance code N)
• 3/8-inch inscribed circle with 0.0469-inch corner radius
• Neutral hand orientation for flexible toolholder compatibility
• QR chip breaker geometry for medium-duty chip control
• Compatible with clamp and screw holding methods

Compatibility

Designed for use in TNMM-style toolholders compatible with the T-Max P series. Suitable for ISO P and K workpiece material groups. ISO designation TNMM 16 04 12-QR 4425.

Installation Notes

Installation is performed by qualified machinists or CNC setup technicians. Always power down and lock out the machine before indexing or replacing inserts. Confirm toolholder seating and clamp or screw torque per the toolholder manufacturer specification before resuming cutting. Inspect the insert pocket and seating surfaces for chips or debris prior to installation to ensure proper insert support.