NPT thread

What is an NPT Thread?

The NPT thread (National Pipe Thread) is a pipe threading system standardized in the United States, widely used in pipe connections, particularly in hydraulic and pneumatic systems. It is based on the ANSI/ASME B1.20.1 standard and is a tapered thread that ensures a tight seal without a separate gasket when tightened properly.

Features of NPT Threads

NPT threads are designed so that both the external and internal threads are tapered, which creates a tight connection when they are screwed together. Thread pitch and angles are precisely defined and differ from, for example, BSP threads used in Europe. Typically, NPT threads are set at a 60-degree angle, whereas BSPT threads are at a 55-degree angle.

Use of NPT Threads in Machine Shops and Workshops

In machine shops and workshops, NPT threads are used especially in compressed air, hydraulic, and liquefied gas systems, where tight connections are essential. As it’s a tapered thread, creating these connections requires precise machining and may involve the use of sealing materials such as Teflon tape or thread sealant to ensure a secure joint.

Differences Between NPT and BSP Threads

Although NPT and BSP threads may look similar, they are not compatible without special adapters. BSP threads can be either parallel or tapered, while NPT threads are always tapered. This distinction is important, especially in international projects where parts from different standards might need to be connected.

Summary

NPT threads are commonly used in the United States and in many industrial applications where a tight seal is critical. Their tapered design enables tight joints without separate gaskets, but requires accurate machining and the right type of sealant. In machine shops and workshops, NPT threads are mainly used in compressed air and hydraulic systems.