Sumitomo U100100 Pcbn Turning Insert BN250 Triangle

Product Description

The SUMITOMO U100100 is a single-tipped Polycrystalline Cubic Boron Nitride (PCBN) turning insert in the NUTNMA432 style, grade BN250, left uncoated for direct application. The triangular insert carries a 60-degree included angle, a 0.5-inch inscribed circle, and a 0.03125-inch (1/32 inch) corner radius. It runs a negative rake geometry with a neutral hand orientation and a clearance code of N, tolerance code M. This insert is installed by machinists and toolroom technicians on CNC or manual turning centers where conventional carbide grades lose performance against hard or abrasive workpiece materials.

This insert is engineered for turning operations on cast iron, hard materials, and superalloys, corresponding to ISO workpiece material groups K, H, and S. The NUTNMA432 geometry with the A chip breaker is suited to finishing and light semi-finishing passes where consistent edge geometry and tight tolerances are required. Its single cutting edge design focuses performance on one precisely ground tip, making it appropriate for applications where edge repeatability is critical. The ISO equivalent designation is NU-TNMA220408 and it conforms to both ANSI and ISO 13399 standards.

Key Features

• Polycrystalline Cubic Boron Nitride (PCBN) insert material for hard and abrasive workpiece cutting
• Uncoated BN250 grade — no coating process applied, preserving as-sintered edge sharpness
• 60-degree triangular shape (insert shape code T) with negative rake for strong edge support
• Single tipped construction for focused, repeatable cutting edge performance
• Compatible holding method: clamp and pin, NUTNMA432 style toolholder
• Conforms to ANSI and ISO 13399 standards for interchangeability and documentation

Compatibility

Designed for use in NUTNMA432-style toolholders that accept a triangular PCBN insert with a 0.2031-inch hole diameter and clamp-plus-pin holding. Suitable for turning centers running cast iron, hard materials (50+ HRC), and superalloy workpieces in ISO material groups K, H, and S.

Installation Notes

Insert seating and clamping should be performed with the machine fully powered down and the spindle locked. Verify that the toolholder pocket and locating pin are clean and free of chips before seating the insert. PCBN inserts are brittle — avoid impacts against the cutting edge during handling or installation. Follow the toolholder manufacturer torque specifications for the clamping screw; do not exceed the recommended clamping force.