Sumitomo 191R845 Turning Insert TNMA433 AC420K Carbide

Product Description

The SUMITOMO 191R845 is a solid carbide turning insert designed for precision metal cutting in CNC and manual lathe applications. Manufactured to the TNMA433 ANSI style and ISO code TNMA220412, this triangular insert features a 60-degree included angle with a negative rake geometry and a clearance code of N. The AC420K grade uses a CVD-applied coating with a proprietary FF designation, delivering the wear resistance and heat control needed for consistent performance in demanding turning operations. At 0.032 pounds, the insert is a compact, single-piece cutting tool intended for use by machinists and tooling technicians.

This insert is engineered primarily for turning cast iron workpieces, corresponding to primary workpiece material code K. It is suited for applications requiring a stable, negative-rake triangular insert with clamp and pin holding methods. The TNMA style and TN series designation make it a fit for toolholders configured to accept that insert geometry. Typical use cases include finishing and semi-finishing passes on cast iron components in production and job-shop environments.

Key Features

• TNMA433 insert style with 60-degree triangular shape and negative rake for rigid, stable cutting
• AC420K grade solid carbide with CVD-applied FF proprietary coating for cast iron performance
• Corner radius of 3/64 inch (0.0469 inches) for controlled edge geometry on finishing cuts
• Inscribed circle of 1/2 inch (0.5000 inches) with insert thickness of 3/16 inch (0.1875 inches)
• Clamp and pin holding method for secure seating in compatible toolholders
• Compliant with ANSI and ISO 13399 standards for tooling interoperability

Compatibility

Designed for use in toolholders accepting TNMA-style triangular inserts with a 1/2-inch inscribed circle and clamp-and-pin holding method, per ANSI code TNMA433 and ISO code TNMA220412.

Installation Notes

Installation is performed by qualified machinists or tooling technicians. Power down and lock out the machine spindle before seating or indexing the insert. Ensure the toolholder pocket and pin hole are clean and free of chips before clamping. Follow the toolholder manufacturer's clamping torque specifications and do not overtighten the clamp screw.