The national pipe tapered (NPT) and the National Pipe Straight (NPS) are actually different forms of pipe threading. This classification emanates from the American National Pipe Standard. Considering its accuracy and comprehensiveness, it has gained traction globally and become the most recognized naming approach. The BSP, the British pipe standard is a close second.
Having said that, this article will explain the differences between those threads So you can optimize your choice moving forward.
Understanding the differences
When you view the thread of the NPT sideways, you’ll notice that it is tapered and reduces in size as it approaches the end. The NPS, on the other hand, appears straight all through its length. The only edge the national pipe tapered version has over the straight is in the ease of securing it. In essence, you’ll find it relatively easier to secure a tapered thread without using any form of tightening tool. Essentially, all you'd typically need is a plumbing tape and your hand strength.
This hand tightening difference can be necessary for some forms of the fitting. For instance, if you use wrenches or pliers in some fittings, you may scratch them and take a toll on their appearance. But by hand fitting, you can tighten everything easily without any tool. This ensures that your process is not only scratch-free but also features relatively quicker disassembly and assembly processes.
Another thing to note is that both threads feature similar shapes, thread angles, and pitch. However, you’ll typically find the tapered threads at couplings, tees, nipples, and pipe ends. Remember that these threads with sharp angles are necessary to create joints devoid of leaks. Again, to finalize the seal, you'd typically need a thread sealant.
For straight pipe threads, creating a seal request an O-ring or a basket.
While both threads may sometimes engage, you will never find them sealing properly. They may as well engage for roughly two turns before the NPT fittings start interfering. If you find yourself in a situation whereby female/Male threads interact but with limited movement or turning, chances are your fitting has two different thread styles.
To measure NPT fitting
Just like several other fittings in the piping world, you can evaluate this as well by measuring the tubes inside diameter. This gives a clearer and more concise overview that what measuring the outer diameter would give.
Best way to get the National tapered thread
A tapering machine is your best bet when it comes to getting an NPT thread. This machine can help you increase or reduce pipe diameter without hassle. Its application spans everything from motorcycle, naval, plumbing, and the list goes on and on.
With our tube tapering product at Mingyi Pipe Machine, you can be sure you’re getting a machine that is straightforward to operate without taking anything from its affordability.
Call us now or fill out the contact form to get your quote, machine parameters, and video guides, and see how we can work together to maximize your profitability and productivity.
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