Screw taps for NPT pipe thread ANSI B 1.20.1

NPT thread – American tapered pipe thread

In Germany, plumbing and heating technology primarily uses the Whitworth pipe thread identified by the letter G. However, this is not the only thread used in this field. The National Pipe Thread standards from the USA represent another pipe thread system that is frequently applied. The NPT thread is the most prominent representative and is used for a wide range of pipe connections. In the BAER online shop, you will find numerous products for producing, reworking and inspecting NPT pipe threads. Browse our categories and find exactly the tool you need for your threading application.

Everything you need to know about the NPT (National Pipe Taper) thread according to ANSI B 1.20.1

The NPT thread is a pipe thread used for a wide variety of screw connections on pipes, fittings and valves without special requirements. It is primarily used in North America, but also in parts of South America such as Brazil.

The NPT pipe thread is a tapered thread with a taper of 1:16 and is standardized according to ANSI B 1.20.1. The abbreviation NPT stands for National Pipe Taper, with the term taper referring to the conical shape. It is an inch-based thread, meaning all dimensions such as the outside diameter are specified in inches. The pitch is given in threads per inch.

As with all pipe thread types, tightness is a central issue. A combination of NPT external and internal threads is not mechanically sealing, so an additional sealing compound must be used.

The NPT thread has a flank angle of 60°, which is a significant difference compared to the Whitworth pipe thread commonly used in Europe with a 55° flank angle. The two thread types are not compatible and must never be combined, as this would not result in a tight connection. However, adapters are available that allow a secure connection.

The NPT thread table contains information on thread size and pitch. For pipe threads, the nominal size specified in the thread designation can be confusing because it does not correspond to the outside diameter. This is due to modern materials allowing pipes with thinner walls, which mainly affects the inside diameter. The thread designations were never adapted to this development. A thread designated 1" – 11 1/2 NPT therefore actually has an outside diameter of 1.308 inches. Common sizes include NPT 1/8 - 18, NPT 1/4 - 18, NPT 3/8 - 18 and NPT 1/2 - 14.

The NPT is just one of several pipe threads from the USA. The extensive list of versions includes threads for general applications as well as those with very specific purposes. One example is the NPTF thread. The abbreviation stands for National Pipe Taper Fuel and Oil and refers to a thread type that can be used generally, but is specifically designed for fuel lines. The NPTF is a dry-sealing fine thread.

NPT thread – Our range

In the BAER online shop, you will find a wide selection of threading tools for NPT threads. Purchase taps and dies individually as needed, or make things especially easy by choosing our threading sets.

Threading sets for NPT threads

Would you like to cover your entire need for tools for machining NPT threads in one go? Then we recommend our NPT threading sets. These are available in two sizes: NPT 1/8 - 1" and NPT 1/8 - 2". The sets include not only taps and dies in the specified thread sizes, but also die stocks and tap wrenches required for use. All tools are neatly arranged in an attractive wooden case, which is ideal for transport and storage.

Taps for NPT threads

With an NPT tap from BAER, you can produce threads in no time at all – whether blind holes or through holes. Left-hand threads are also no problem. With an NPT single-cut tap, you remain flexible and can decide whether to work by hand or by machine. For frequent use and demanding applications, we recommend our NPT machine taps, which cut through steel with ease.

Dies for NPT threads

You can cut external threads quickly and easily with an NPT die. Round dies are available in many sizes in our shop. And if it comes to re-threading or working in confined spaces, take a look at our hexagonal die nuts. These can be operated with a standard open-ended wrench, making them particularly flexible to use.

Thread gauges for NPT threads

After cutting an NPT pipe thread, you may want to check whether it falls within the tolerances specified by the standard. This is particularly easy with NPT thread gauges. Our plug gauges and ring gauges for NPT pipe threads are extremely reliable and provide precise results.

Discover tools and accessories for NPT threads in the BAER online shop now!

Browse the BAER online shop and discover our high-quality products for thread machining. Do you have questions about one of our items or need comprehensive purchasing advice? Then do not hesitate to contact our customer service. We will be happy to help you with all your concerns.