Another problem

[Keith Dunbar]

See my previous posts

Having bought a 12mm socket allen key I have successfully removed the tails (is that what they are called?) from the radiators. The next problem to arise is that the old fittings have a shorter thread than the new ones and were only inserted into the tail for about 4 mm. The existing thread in the radiator is of course totally gunged up, so I need to clear it. I presume the best way would be to get a tap to clear/recut the thread. The now understand that the fitting is BSP - I think someone said 1/2 inch. So presumably I need a 1/2 BSP "tap?" I am very uncertain of terminology here - and understand there are different kinds of tap. So could someone please tell me exactly what I need to ask for?

Thanks again,

Keith

[Peter Ashby]

It depends, are the threads simply gunged or is the metal actually damaged? If the threads are ok then all you need is a brass brush to clean the threads out. The ones sold in Halfords etc for cleaning spark plugs should suffice.

Peter

[RobertL]

countrywww.the-brights.net

Have you considered replacing the radiators with new ones? If they are quite old maybe they are approaching the end of their useful lives.

Robert

[Cicero]

=================================== You can make a tool to do this job. Bend a long panel pin at 90 degrees about 1/4" from the sharp end. Hold this in a Mole wrench and carefully scrape the threads clear and finish off with the brass wire brush suggested by another poster.

If you've got an old set of darts (the kind you throw at a round board) you can use one to do the same job as above but no bending needed if you're careful.

p.s. A 1/2" BSP tap would probably cost about 10 GBP so not really economic and not the best tool for this job.

Cic.

[chrisj.doran]

Since you're only cutting soft gunge rather than hard metal, you don't need an expensive proper hardened steel tap. Fabricate one by filing tap-like lengthwise =A6/ slots on a bolt (if you can find one) or sacrifice one of the new tails. As with a real tap, oil it and work it backwards and forwards, or take it all the way out occasionally, to keep removing the gunge from the slots.

Chris

[Dave Plowman (News)]

If you go to a PM and get a steel fitting with a suitable length of thread on it, cut some slots along the threads with a hacksaw and use that to clean the threads, lubricating with WD40 or similar. A proper tap is likely to be pricey.

[Keith Dunbar]

I have, but ......

they don't seem to be standard sizes - e.g. the first one I took off is 95 cm wide - which would give me a whole new set of problems!

How does one tell if they are approaching the end of their useful life? If they go thin, is it usually in any particular place. They actually seem quite solid and substantial to me. Would they have been made to a better standard 20 + years ago?

Keith

[Lobster]

They might do what one of mine did a few years ago, which was suddenly to develop a hole right in the middle of a panel without warning (ie corrosion from the inside) and the disgorge the hot steaming contents of the CH system into the house...

David

[RobertL]

Exactly the same problem that I had. Corrosion from the inside suddenly causing a weeping hole with no warning.

As the yare 20 years old, if it were me, I'd take the opportunity to replace them, probably with something more powerful. But, as you say, there will be some plumbing to make the pipes match.

Robert

[Lobster]

Not quite 'exactly' the same - I'd describe my problem more as 'hosing' than 'weeping'... :-)

David

[Ed Sirett]

The tails have either a taper or they seal on an O-ring at the end of the threads. I doubt you need to do very much other than apply your favourite jointing tape/gunge/string to the new threads and tighten up.

To allow for differently sized radiators you can get adjustable tails (screwfix do them).