On Sun, 19 Apr 2020 13:52:57 +0100, T i m wrote:

On Sun, 19 Apr 2020 01:08:48 -0700 (PDT), Mathew Newton
wrote:

On Saturday, 18 April 2020 09:30:45 UTC+1, PeterC wrote:

the tails have 10mm thread into the tap, with a little O-ring as a seal. If
I tighten a tail as much as I can I can still unscrew it by just twisting
the other end. The hex on the tail is no good as it's deep within the base
of the tap.

Note that the instructions for our our monoblock tap (a Franke) says to only hand-tighten the tails and explicitly says not to use any tools. It is designed so the o-rings seal against the side walls - not under compression with a mating face (it's not a washer) - and would remain doing so even if undone several turns which wouldn't happen given the compression end anchors the flexi in place. Might yours be the same?

That sounds like the most likely explanation so far. ;-)

Cheers, T i m

I agree - more in hope than confidence!
--
Peter.
The gods will stay away
whilst religions hold sway