Threaded Short Nipple English Threaded Short Nipple How to use and usage: Threaded pipe fittings are pipe fittings that use taper pipe thread connection. They are only used for inch pipes, not for metric pipes. The threaded pipe fittings produced comply with the American ANSI B16.11 and GB/T14626 standards. There are three commonly used pipe threads in engineering pipelines: 1. ISO7/1 is an international general thread sealing pipe thread, with a tooth profile angle of 55o and a taper of 1:16. There are two types of internal threads: parallel (Rp) and tapered (Rc). The external thread has only tapered R, commonly used as Rp-R, as shown in Figure a. It is used more in public works, while Rc-R is less commonly used. . 2. ISO228 is an internationally used non-thread sealed pipe thread with a tooth profile angle of 55°. The internal and external threads are parallel. 3. ANSI B1.20.1 is an American threaded sealing pipe thread with a tooth profile angle of 60° (NPT) and a taper of 1:16. Both internal and external threads are tapered, which are commonly used pipe threads in high temperature and high pressure pipelines. AMSE B16.11 threaded pipe fittings commonly use NPT threads. NPT and ISO7/1 (commonly known as BSP), although the tooth profile angle is different, the pitches of 1/2 and 3/4 are the same and can be connected to each other.