PVC Threaded Reducer Bushing

BSP fittings (parallel threads) commonly seal via a 30° chamfer on the male thread to a 30° recessed cone inside the female thread (swivel only). If it is a port application, an O-ring and washer or a bonded washer are needed to achieve a proper seal for parallel threads. For tapered BSP threads, a seal is acquired via thread wedging with additional support from thread dope or Teflon tape. As previously mentioned, a male BSPT (tapered) can thread into a female BSPP (parallel), so long as the female thread is fixed and not swivel (this is because of the recessed cone seat).