Andrew Mawson wrote:
"James Wilkinson Sword" wrote in message
news

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.


James, you will be absolutely delighted to know that the "ISO" metric
pipe threads (GXX ) are entirely based on British Standard Pipe
threads so you had better get used to it

Andrew

Please don't feed the troll.