Part timer wrote:
A quick issue regarding replacing an outside tap. My present one has
packed in for good (turn it to open and it doesn't actually open
anymore). I have ripped out the check valve about 3 years ago when it
last stopped working (don't need a check valve for my uses).
Bought Screwfix part 16949 "Outside Tap Without Check Valve". Claims
to be 1/2" and BS 1010. My problem is it doesn't line up (in 12
o'clock position) like the old one does when fully screwed in. Would I
be looking at fibre washers to achieve this vertical position when
it's fully tightened and are these a common, standard size? Out of
interest, where is the 1/2" measurement measured?

Thanks

J.
Use PTFE tape and or washers. Should be able to get them from plumbers
merchants.
There is no dimension of a 1/2" bsp thread that measures 1/2"
It is based on the bore of thick wall iron pipe around the time the
thread was defined.
Pipe is thinner wall now.
Thread is 14 tpi so you can work out what thickness of washer you need
for a given number of degrees of rotation.
It works out to be 0.005mm per degree with less than 1% error
hth

Bob