Pipe Thread (NPTF)
National Pipe Tapered Fuel (NPTF)
Steel Pipe Fittings
National Pipe Taper is still widely used in hydraulic applications, even though it is not recommended by the National Fluid Power Association (NFPA). The thread is tapered and the seal takes place by deformation of the threads.
On the initial installtion, thread sealant or tape is not required as the threads are mechnically deformed. On subsuquent installations, it is recommened that you use thread sealant or tape, according to your manufacturer's specifications.These fittings are designed to interchange with Parker, Weatherhead, Gates, Aeroquip and other major suppliers part #s and products.
Measure thread diameter and subtract one quarter-inch to find the nominal pipe size.
See the table below for thread sizes and dimensions.