Sandvik Coromant 7859256 Turning Insert CNMG643-PR 4415

Product Description

The SANDVIK COROMANT 7859256 is a CNMG-style indexable turning insert designed for metal cutting on CNC and manual lathes. It carries the ISO designation CNMG 19 06 12-PR 4415 and belongs to the T-Max P series. The insert features an 80-degree diamond (rhombic) shape with a neutral hand orientation and a negative side clearance. The carbide substrate is CVD-coated with a TiCN, Al2O3, and TiN multilayer stack, providing high wear resistance suited to roughing and medium machining operations. Four usable cutting edges extend tool life between insert changes.

This insert is engineered for turning steel (ISO P) as its primary workpiece material and cast iron (ISO K) as its secondary workpiece material. The PR chip breaker geometry is optimized for roughing to medium machining passes. It is typically used in external turning applications on production lathes in both job-shop and high-volume manufacturing environments. The T-Max P series is a widely used platform among machinists running moderate-to-aggressive metal removal rates on ferrous materials.

Key Features

• CVD multilayer coating: TiCN, Al2O3, and TiN for high wear resistance and thermal stability
• 80-degree diamond insert shape (ISO Shape C) provides a strong cutting edge geometry
• PR chip breaker designed for roughing and medium machining on steel
• Four cutting edges per insert reduce per-edge tooling cost
• Negative side clearance (Clearance Code N) compatible with rigid, top-clamp or screw-lock toolholders
• Inscribed circle of 0.75 inches (19.05 mm) and corner radius of 0.0469 inches (1.19 mm)

Compatibility

Designed as an OEM-style replacement or direct-use insert for CNMG 643 toolholder pockets in the T-Max P series. Compatible with toolholders accepting CNMG inserts with a 0.312-inch (7.93 mm) hole diameter, clamp or screw holding method, and Tolerance Code M with Clearance Code N. ISO size code 190612.

Installation Notes

Installation is performed by qualified machinists or toolroom technicians. Power down and lock out the machine spindle before seating or indexing the insert. Use the correct torque driver for the clamping screw to ensure positive seating without cracking the carbide substrate. Inspect the insert pocket and seating surface for chips or debris before each edge change.