adampecush;1114883 said:NPT/NPS, M10x1, BSP/BSPT, and SAE (ex. 3/4 x 16) are all different thread forms, and generally incompatible with one another.
the block female threads were harsh on the adapter because the threads did not match. Properly matched threads should never be harsh to engage or tighten (with the exception of tapered threaded connections)
NPT and BSPT are both tapered threads, but the tapers are slightly different. As Ian said, they both seal on the threads.
TheNewRed;1115337 said:Thank you sir, i new i wasnt off! Now try telling Figge that :biglaugh:
The mistake a BSPT is a metric thread is common...the major/minor diameters are often expressed in metric, as is the drill size. Read this:
http://www.britishfasteners.com/threads/bstp.html