Sandvik Coromant 7861078 Turning Insert Tcmt Triangle

Product Description

The SANDVIK COROMANT 7861078 is a TCMT-style solid carbide turning insert from the CoroTurn 107 series. It features a triangular shape with a 60-degree included angle, a 1/4 inch (0.2500 inch) inscribed circle, and a 1.19 mm (0.0469 inch) corner radius. The insert carries a CVD-applied multilayer coating of Al2O3, TiN, and TiCN over a 4425 carbide grade substrate, making it well suited for steel and cast iron turning operations. With 3 cutting edges, a neutral hand orientation, and compatibility with both clamp and screw holding methods, this insert is designed for reliable, repeatable performance on CNC lathes and turning centers operated by machinists and tooling professionals.

The 7861078 is intended for external and internal turning applications where a TCMT-style insert is specified. Its primary workpiece material designation is steel (ISO P), with cast iron (ISO K) as a secondary application. The PR chip breaker geometry handles general-purpose steel turning at moderate cutting parameters. This insert fits toolholders designed for TCMT 11 03 12 inserts (ISO code TCMT 11 03 12-PR 4425, industry standard TCMT110312PR4425). It is sold individually with a minimum order quantity of 10 inserts per order.

Key Features

• CVD multilayer coating: Al2O3, TiN, and TiCN for wear resistance and thermal protection
• 4425 carbide grade optimized for steel and cast iron turning
• Triangular insert shape with 60-degree included angle and 7-degree relief angle
• 1/4 inch inscribed circle with 1.19 mm corner radius for consistent edge geometry
• 3 usable cutting edges per insert for extended tooling economy
• PR chip breaker geometry suited to general-purpose steel turning
• Compatible with both clamp and screw insert holding methods

Compatibility

Designed for toolholders accepting TCMT 11 03 12 inserts per ISO and industry standard TCMT110312PR4425. Verify toolholder pocket geometry, clearance code C, and tolerance code M before installation.

Installation Notes

Installation is performed by qualified machinists or tooling technicians. Power down and de-energize the machine spindle before seating or removing inserts. Use the correct torque wrench and insert screw driver per the toolholder manufacturer specifications when using screw-lock holders. Inspect the insert pocket for chips or debris before seating a new insert to ensure proper contact and edge alignment.