On Wed, 29 Apr 2009 14:19:37 +0100, Grimly Curmudgeon
wrote:

Varies from maker to maker.

I'm surprised by this, since the pipes they fit are standard sizes, I
assumed the fittings would be standard sizes too.

If someone made a fitting bigger than necessary/other makes, it would
cost them more, so I can't see any manufacturer doing that. If a
fitting required a different spanner to most other fittings, surely
people would not buy the unusual sized fitting because of that
inconvenience?

That said, the nuts on my Horstmann 2-port valves seem to be one
millimetre bigger than those on any other 22mm fitting in my house.
The truly awful Monument spanner[*] that is supposed to fit 15mm and
22mm fittings at either end, will not fit the nuts on the valve.

BTW, what's all this about Stilsons being used on pipes. How do you/
why would you grip a pipe? Surely you want to grip the fitting?

Thanks,
Stephen.
[*] Screwfix code 82712, I find it too thin