Sumitomo 191R282 Carbide Turning Insert CNMG643 AC420K

Product Description

The SUMITOMO 191R282 is a CNMG-style carbide turning insert designed for precision metal cutting on CNC lathes and turning centers. Manufactured to ANSI and ISO 13399 standards, it carries the AC420K grade designation with a CVD-applied proprietary FF coating. The insert features an 80-degree diamond (rhombic) shape, a 3/4 inch inscribed circle, and a 3/64 inch corner radius. A neutral hand orientation and negative side clearance geometry make it suitable for both light and medium machining passes. Machinists and CNC operators working with cast iron and hardened materials will find the AC420K grade balances moderate wear resistance with adequate toughness across a range of cutting conditions.

This insert is intended for use in ferrous machining applications, primarily targeting cast iron (ISO material group K) and hardened materials (ISO material group H). The ENZ chip breaker geometry supports chip control across light to medium material removal rates, making it a practical choice for finishing and semi-finishing operations in production turning environments. Typical installations include CNC horizontal and vertical turning centers in job shops, production facilities, and maintenance machining operations.

Key Features

• AC420K grade with CVD-applied FF coating for wear resistance in cast iron and hardened material applications
• ENZ chip breaker geometry supports light and medium machining operations
• 80-degree diamond insert shape (CNMG style) with negative side clearance for rigid, stable cutting
• Positive rake angle of 4 degrees reduces cutting forces
• Compatible with clamp and pin insert holding methods
• Conforms to ANSI and ISO 13399 standards for insert geometry and tolerancing

Compatibility

The 191R282 uses ANSI insert code CNMG643 and ISO insert code CNMG190612N-UZ, fitting toolholders designed for CNMG-style inserts with a 0.3126 inch hole diameter, clamp or pin retention, and M-tolerance seating. Verify toolholder pocket specifications before installation.

Installation Notes

This insert is installed by qualified machinists or CNC tooling technicians following standard turning insert change procedures. Power down and lock out the machine spindle before accessing the turret or toolholder. Use the appropriate torque wrench and manufacturer-specified clamping hardware for the toolholder; do not substitute fasteners. Inspect the insert pocket and seating surface for chips or debris before seating the new insert to ensure proper contact and prevent premature edge failure.