The American National Standard Pipe Thread is often abbreviated as National Pipe Thread. From here comes the name of the NPTF compound - National Pipe Thread, Female. Connection with a conical external inch tight carving according to the American standard. The NPTF fitting has a tapered thread and a 60 ° inner cone. Seal fittings RVD NPTF is due to collapse of threads. These connections are not recommended for hydraulics by the National Fluid Power Association (NFPA), although they are widely used in hydraulic systems.
NPTF fitting compatible with NPTF, NPSF or NPSM female thread. The NPTF and BSPT compounds are similar, but not interchangeable. The thread pitch is different for most sizes. In addition, the thread angle is 60 ° instead of 55 ° on BSPT threads.
NPSF - (national pipe cylindrical fuel thread) - the seal is hemispherical. Sometimes used as female threaded ports for NPTF fittings. However, instead of NPSF, SAE recommends using NPTF.
NPSM - (national pipe cylindrical engineering thread) sealing is carried out by a cone of 60g.
