BSPT - British Standard Pipe Taper
BSPT: British Standard Pipe Taper -also known as "R" or "Rc" threads
- BSPP: British Standard Pipe Parallel -also known as "G" or "Rp" threads
Both BSPT and BSPP have the same thread angle, shape, and pitch (threads per inch). However,
- BSPT threads are tapered and BSPP threads are straight (parallel).
- BSP threads have a 55° included angle and have rounded peaks and valleys (this is a Whitworth thread form).
Here are the actual thread dimension data for BSP threads. The major diameter is a bit smaller than the actual OD of the pipe, and the minor diameter should be very close to what you would measure inside the female threaded end of a fitting. Note that the Gage Length dimension pertains only to the BSPT (tapered) thread.