Hertel H59875567 Boring Insert TPCG321 HC620B Solid Carbide

Product Description

The HERTEL H59875567 is a solid carbide boring insert designed for precision metal-cutting operations on CNC and manual boring bars. Manufactured to TPCG321 geometry in grade HC620B, this insert features a 60-degree triangular shape with an 11-degree relief angle and a 1/64-inch (0.0150-inch) corner radius. The multi-layer CVD coating stack - TiN, TiC, TiCN, TiN - delivers wear resistance and thermal stability suited to C7 material-grade applications including cast iron and nonferrous alloys. The screw-holding method and left-hand designation make it a direct-fit choice for compatible TPCG-style left-hand boring bar holders. Installation and replacement are performed by machinists and toolroom technicians in production and job-shop environments.

This insert is applied in internal boring operations on lathes, machining centers, and boring mills where tight tolerances and consistent surface finishes are required. The 3/8-inch inscribed circle and 0.127-inch thickness conform to standard ANSI TPCG321 sizing, allowing use in any tool holder dimensioned for that insert class. Typical applications include finish and semi-finish boring of ferrous castings, aluminum components, and nonferrous workpieces where the C7 grade and CVD coating provide the right balance of hardness and edge retention. The catalog number for this insert is TPCG321L.

Key Features

• Solid carbide substrate in manufacturer grade HC620B, material grade C7
• Multi-layer CVD coating: TiN outer, TiC, TiCN, TiN sequence for extended tool life
• 60-degree triangular TPCG geometry with 11-degree relief angle
• 1/64-inch (0.0150-inch) corner radius for controlled surface finish
• 3/8-inch inscribed circle, 1/8-inch (0.127-inch) thickness - ANSI TPCG321 standard sizing
• Left-hand designation with screw-holding method for secure, repeatable seating

Compatibility

Designed as an OEM-style replacement insert for TPCG321L-style left-hand boring bar holders and tool blocks dimensioned for a 3/8-inch inscribed circle triangular insert with screw clamping.

Installation Notes

Insert replacement should be performed by a qualified machinist with the machine powered down, spindle locked, and all motion axes secured. Use the appropriate Torx or hex key to remove and reinstall the clamping screw to the tool holder manufacturer's specified seating procedure - do not overtighten, as carbide inserts are brittle and can fracture under excessive clamp load. Verify insert seating is flush and square in the pocket before resuming cuts. Inspect the insert pocket and screw threads for wear or damage each time the insert is indexed or replaced.