Prevent radiator valve turning when tightening?

There is. Called Mole Grips :-)

Or drop a box spanner over the top.

In article , Sgt. Pinback writes

The mole grips are fine if you wrap something soft, such as a rag, round the valve first to stop it marking the surface. On some fittings there will be enough of a flat for a simple adjustable spanner to stop it rotating.

Thanks for the replies. I just discovered that a piece of 22mm copper pipe with the end cut flat (i.e. not squashed by those rotating cutters) fits my valves exactly.

I use an 'F' wrench.

(That's F as in the shape, not an initial letter of anything ;-))

s all the time. But whenever I am putting back a radiator valve with the co pper pipe still inserted (usually after replacing a radiator), every time I tighten the nut that pulls the valve onto the radiator, it grips the valve , and wants to turn it. Obviously, I don't want this to happen, because it will bend the pipe. I usually end up holding it with Mole grips, but I'm no t completely happy with this, as they seem much too rough to me. So, what d oes everyone else do? Is there a tool to hold them still?

Yes its called a Radwrench, designed to do what you are asking perfectly, and nothing else.

So he has been sitting there with a radiator valve since 2012 then. Brian

Yes it's a bit of a late reply, but useful to know and it doesn't seem that babbit61 is trying to *sell* the radwrench.

Andy Burns wrote in news: snipped-for-privacy@brightview.co.uk:

In 2012 I would suggest lubricating the nut.