Hertel H59874735 Boring Insert TPCH221 Solid Carbide Tin

Product Description

The HERTEL H59874735 is a solid carbide boring insert designed for precision internal turning and boring operations on CNC and manual lathes. It carries the TPCH221 insert style designation and is manufactured to the HP520B grade, a PVD-applied titanium nitride (TiN) coated carbide classified at material grade C5. The triangular 60-degree included-angle geometry provides three usable cutting edges. With a 1/4-inch inscribed circle, a thickness of 0.0960 inches, and a 1/64-inch corner radius, this insert is sized for fine-bore and finish-bore work. A licensed machinist or toolroom technician is the typical end user.

This insert suits finish boring and light roughing in steel, cast iron, and similar materials where a C5-grade TiN-coated carbide performs reliably. The TPCH style uses a screw-clamping holding method, making it compatible with TPCH-designated boring bar pockets and modular boring head systems. It is appropriate for small-diameter bore applications in job-shop, production, and maintenance machining environments. The 11-degree relief angle reduces rubbing and supports consistent surface finish in close-tolerance bores.

Key Features

• Solid carbide construction at material grade C5 for wear resistance in steel and cast iron
• PVD-applied TiN coating extends tool life and reduces built-up edge
• 60-degree triangle shape with 11-degree relief angle for reduced cutting forces in boring operations
• 1/64-inch corner radius suited to fine-finish boring with minimal nose chatter
• Screw-clamp insert holding method for secure, repeatable seating in TPCH boring bars
• Compact geometry with 1/4-inch inscribed circle for small-diameter internal work

Compatibility

Designed for use in TPCH-style boring bars and boring heads that accept a 221 insert size with screw-clamp retention. Verify pocket geometry, insert size code, and relief angle match before installation.

Installation Notes

Insert installation and indexing should be performed by a qualified machinist or toolroom technician. Power down and lock out the machine spindle before seating or indexing the insert. Use the manufacturer-recommended torx or hex key to tighten the clamp screw; do not overtighten, as solid carbide inserts are brittle and can crack under excessive clamping force. Inspect the insert pocket and clamp for chips or debris before seating a fresh edge.