VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 thread type

Hi all, Happy New Year,
Can anyone confirm the type of thread used on the T piece that fits into the oil distribution fitting. The T piece screws into the top of the oil distribution fitting then one line goes to the oil pressure gauge and the other to the oil filter.
1/8 NPT seems to fit as does BSPT. Which thread is original.
Also The Brass compression fitting as supplied by the filling station RW717 1/8 pipe to 5/16 tube are the threads NPT or BSPT.

The reason for the question I'm looking at fitting a modern type oil filter and seem to have a couple of thread types on various fittings. I want to standardise so all the fittings are the same.

regards Peter.

Peter,

The NPT threads are almost certainly original. British threads were very rarely seen in the USA in the 1920s.

The 1/8 NPT and 1/8 BSP threads can easily be distinguished from each other.

1/8 NPT 27 threads per inch, major diameter 0.405 inches
1/8 BSP 28 threads per inch, major diameter 0.383 inches

The American thread angle is 60 degrees, the British system uses 55 degrees.

Regards,

Frank.

Thanks for the reply Frank I,ve used the NPT.