Sandvik Coromant 7860849 Turning Insert CNMG644-QM 4425

Product Description

The SANDVIK COROMANT 7860849 is a CNMG-style indexable turning insert designed for external and internal turning operations on CNC lathes and turning centers. Part of the T-Max P series, this insert carries the 4425 grade designation — a CVD multilayer coating of TiCN, Al2O3, and TiN applied over a solid carbide substrate. That coating stack delivers high wear resistance while retaining sufficient toughness for both roughing and medium machining passes. The 80-degree diamond (rhombic) insert shape and neutral hand orientation make it well suited for straight turning and facing. It features a QM chip breaker geometry engineered to handle the chip loads typical in steel and cast iron applications.

This insert is intended for use in metalworking environments where the primary workpiece material is steel (ISO P) and the secondary material is cast iron (ISO K). The QM chip breaker geometry handles roughing and medium machining operations, making it appropriate for production turning on mid-to-large diameter workpieces. It seats in toolholders that accept CNMG-style inserts using clamp or screw holding methods. The negative side clearance (N clearance code, M tolerance code) is standard for double-sided insert seating and high-load cutting. Machinists in job shops, aerospace component manufacturing, and general metalworking will find this insert applicable to a wide range of shaft, flange, and bore-facing operations.

Key Features

• CVD multilayer coating: TiCN, Al2O3, and TiN for high wear resistance in steel and cast iron turning
• 80-degree diamond (rhombic) insert shape with neutral hand for straight turning and facing operations
• QM chip breaker geometry rated for roughing and medium machining pass depths
• 4 cutting edges per insert — reduces per-edge tooling cost in high-volume production
• Negative side clearance (N) with M tolerance for secure double-sided clamping or screw retention
• ISO code CNMG 19 06 16-QM 4425 for cross-reference with standard toolholder catalogs

Compatibility

Designed for use in CNMG-style indexable turning toolholders that accept clamp or screw holding methods with a negative-clearance insert seat. Compatible with toolholders specified for the ISO size code 190616 insert format.

Installation Notes

Installation is performed by qualified machinists or toolroom technicians. Power down and lock out the machine spindle before indexing or replacing inserts. Seat the insert fully against the pocket locating surfaces before tightening the clamp or retention screw — partial seating causes premature edge failure and runout error. Inspect the insert pocket and shim seat for chips or wear before installing a fresh cutting edge.