On Fri, 17 May 2019 09:07:52 +0100, Roger Hayter wrote:

Had this with a pair of Bristan 1901 bib taps and upstands.
One was perfect; the other was 150 deg. out. I had nothing that would
correct the bad one, so I swapped them over and found that nylon washers
just did the job and made them both the same. Needed a bit more tape in on
of them but it's not a noticeable difference.
I was lucky to have the washers - in an Aldidl kit, IIRC.

Given the total price of the fittings, they should be correct to start with.

It is technically impractical with ordinary manufacturing to make the
two brass parts and a (variable) standard washer do up to a precise
predicted angle. And it is not what is expected by plumbers. Not
least because the supply pipe can come from any quadrant (or any
intervening angle if one is untidy enough).

Agreed, in most cases, but _upstands_ tend to be from below. Making the taps
to fit upstands would at least get rid of one aspect and be no worse for the
others.
The worst case would be if the threads were intended to match but the tap
wouldn't quite tighten to upright - need some ingenuity to solve that one!
--
Peter.
The gods will stay away
whilst religions hold sway