Sumitomo 16GC254 Pcbn Turning Insert Diamond BN350

Product Description

The SUMITOMO 16GC254 is a PCBN (Polycrystalline Cubic Boron Nitride) turning insert in the CNMA series, designed for precision single-point turning operations on demanding workpiece materials. Manufactured to ANSI code NUCNMA432 and ISO code NU-CNMA120408, it features an 80-degree diamond insert shape with a negative rake angle and a 0-degree relief angle. The inscribed circle measures 0.5 inches, the corner radius is 0.03125 inches (1/32 inch), and the insert thickness is 0.1875 inches (3/16 inch). The BN350 grade is uncoated and offers a single cutting edge. Licensed machinists and CNC turning specialists handling high-hardness or high-temperature alloy components are the primary installers of this insert.

This insert is engineered for turning cast iron, hard materials, and superalloys. Its PCBN construction makes it well suited for high-speed finishing and semi-finishing passes where conventional carbide or coated inserts experience accelerated wear. The CNMA-style seat profile with clamp-and-pin holding keeps the insert secure under the interrupted or continuous cuts typical in production turning of hardened steel and similar H, K, and S material group workpieces. The neutral insert hand provides flexibility across a range of tool holder orientations.

Key Features

• PCBN insert material rated for cast iron, hard materials, and superalloy turning (Material Groups H, K, S)
• BN350 uncoated grade delivers consistent edge geometry without coating delamination risk
• 80-degree diamond insert shape (Shape Code C) for strong nose angle and controlled cutting geometry
• Negative rake, 0-degree relief angle (Clearance Code N, Tolerance Code M) for stable edge support
• Clamp and pin holding method compatible with standard CNMA-style tool holders
• Compliant with ANSI and ISO 13399 standards for reliable tool management system integration

Compatibility

Designed as an OEM-style replacement and production insert for CNMA-series tool holders accepting a 0.5-inch inscribed circle, 80-degree diamond insert with clamp and pin retention, per ANSI code NUCNMA432 and ISO code NU-CNMA120408.

Installation Notes

Installation should be performed by a qualified machinist or CNC tooling technician with the machine fully powered down and the spindle locked before changing inserts. Use the appropriate torque wrench and clamp hardware specified by the tool holder manufacturer to secure the insert without overtightening. Inspect the insert pocket and seating surfaces for chips or debris before seating the insert, as contamination will affect runout and edge life. Always verify insert orientation and rake direction relative to the tool holder before resuming cutting operations.