BSP size confusion

Sep 03, 2019 Last reply: 6 years ago 4 Replies

I ordered an airbrush hose with connections specified as '1/8" BSP Female and 1/4" BSP Female'. I don't yet have any other fittings to test it with but I do have a ruler.



Obviously I can't measure them very accurately with a ruler but the internal diameters are approximately 3/8" and 1/2". Is that what I should expect or did they send the wrong part?



Thanks


sounds right, IIRC external thread sizes are 1/4" larger than nominal internal size of the corresponding pipe, so your internal threads will match.

BSP thread sizes

formatting link

Yup the thread sizes can be confusing... the diameter refers to the nominal *internal* diameter of the pipe. When you thread the end of a pipe, the threads end up being on a much larger diameter due to the double thickness of pipe wall you need to add to the internal diameter.

So a 1/4" BSP pipe thread will actually be about 1/2", and 1/2" BSP thread will be closer to 3/4" etc.

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required