Steel Pipe Fittings
National Pipe Tapered Fuel (NPTF)
National pipe 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. Measure thread diameter and subtract one quarter-inch to find the nominal pipe size.
Click here to view NPTF thread dimensions.