On Wed, 15 Mar 2017 15:46:09 -0000, Andrew Mawson wrote:

"James Wilkinson Sword" wrote in message news

On Wed, 15 Mar 2017 11:55:07 -0000, Andrew Mawson
wrote:

"James Wilkinson Sword" wrote in message
news
I just bought a self bleeding valve to fit into a half inch thread.
What
arrived was 3/4". It's sold as 1/2" BSP, and according to this page,
1/2"
BSP is meant to be 3/4". WTF?

https://en.wikipedia.org/wiki/Britis...e_thread_sizes

It never ceases to amaze me that tit bits of knowledge that I've swept up
and stored over my considerable years from childhood have never come to
the
attention of the younger generation. We as kids were playing with BSP
threads, Whitworth and BSF nuts and bolts, and even UNC / UNF and
occasionally BSCy and NPT . But in those days we did real things, schools
had workshops with real machines, and we made real objects. Nowadays its
virtual models and people know virtually nothing apart from how to push
buttons !!!

Nowadays we normally use more sensible measurements. Metric that you can
easily divide by ten to get the next size. A 15mm pipe that actually
measures 15mm.



Ah - is that the measurement system based on an incorrect calculation for
the circumference of the Earth, imposed on (initially) France by a one armed
Corsican in a silly hat

-- yes I use that system almost exclusively in my workshop, but am also able
to work in other measurement systems with equal facility !

Easier in multiples of 10.

--
Confucius say: "Foolish man give wife grand piano. Wise man give wife upright organ."