The Carmex Carbide Threading Insert – NPT, TiAlN Coated, model 21-14NPT is a versatile cutting solution built for machinists who routinely produce pipe-thread profiles. With robust carbide and a TiAlN coating, it delivers reliable performance across common NPT and related thread jobs.

• Thread profiles covered: A single insert family designed to address all common threading profiles you encounter in pipe fittings and hydraulic components.
• Five length options: Available in five lengths spanning 12 mm to 40 mm to fit a variety of recess depths and tooling setups.
• Pitch range: Depending on length, capable of handling pitches from 0.5 mm (32 TPI) up to 6.0 mm (4 TPI).
• Double-edged design (where applicable): Most profiles use two cutting edges for extended life; note that BSPT, NPT, NPTF, American Buttress, and API RD variants are exceptions to the double-edged rule.
• Internal/external threading compatibility: For many thread profiles, the same insert can machine both internal and external threads, reducing tool changes (with some profile exceptions such as ISO / UN / NPSM / UNJ / Acme).
• TiAlN coating: Titanium aluminum nitride coating provides enhanced hardness and heat resistance for longer tool life and consistent thread quality.
• Carbide construction: Premium carbide body delivers precise, stable cuts and long-term durability in demanding threading operations.

This insert is ideal for machine shops and production environments where a single tool family must cover a wide range of NPT and related thread applications—from hydraulic fittings to pneumatic connectors. The TiAlN coating helps maintain sharpness under heat, while the various lengths and pitch options let you tailor each cut to the specific job. Use with compatible holders and appropriate coolant strategies to maximize life and achieve smooth, accurate thread finishes on both internal and external threads where supported.