Replacing a socket

No - screw will not turn properly long before it reaches the end of its route. Even without the socket, it does not turn easily. I think it is a threading or angle problem but I cannot reconcile this with the fact the screws were in previously.

Thanks. This is something I have always successfully avoided.

The thing with those screws is that they are brass and easily cross threaded, in my experience the damage is done screwing them in and you only find out when it comes to removing them after someone has raunched them in. If unscrewing them is not smooth you can guarantee the thread is knackered. As already mentioned a re-threading tool will restore the thread in the lugs at least once and is cheap enough certainly compared to getting someone out to replace the box. Even if the lug is knackered beyond re-threading there are means of fixing without removing the back box all of which I would try before going for the nuclear option.

Thanks for this helpful guidance. Could you explain it to me, please? Leaving aside the screws, if there is a problem with the thread in the box and I then create a second thread, why will I not then be left with the hole hollowed out with no usable thread remaining?

Bloody hell! its not socket science.

I feel better informed now.

Metric screws should be M3.5. Prior to that the screws were 4BA.

However as you're using the same screws as you took out, this shouldn't be a problem. Otherwise get an M3.5 tap and re-tap the lugs.

It is standard practise for the back boxes to have one fixed and one loose lug as you can align the socket to be square on the wall.

Have you tried new screws?

Sounds like the thread is damaged on the back box. You may find you can re-tap it and fit a new screw.

I tried a different screw. I didn't want to risk damaging the MK screws. I'll look out some electrical screws in the toolbox and experiment.

I tried to find out elsewhere in the thread (without success) how the screw tapper works. If there is already a thread and I bore a second one, what is to stop me being left with a hole and no usable thread?

Thanks very much. A trip to Screwfix for a re-threading tool has done the trick.

I was going to offer the same tip.

It is also possible the screws are not quite long enough / the new socket is slightly thicker. You can buy longer screws.

I made a trip to Screwfix and bought a threading tool. This worked a treat. The screws are long enought. It was just that they would not go in far enough. I did not know it was possible to create a new thread where there is an existing thread. I suppose metal is more malleable than wood in this respect.

Thanks to all who commented.

I see that you have got your problem sorted. You can get replacement screws that have an unthreaded tip which fits into the lug so that it locates properly to start threading. IIRC they were MK brand. Once the faceplate has been installed it is often possible to replace the starter screws with standard screws & keep the starter screws for future use. They won't help in all cases such as where the lug threads are damaged.

Paradoxically, these were the ones I tried in the first place. They started well (predictably) but then started seizing up. I am now assuming it was the thread.

In message snipped-for-privacy@4ax.com, Scott snipped-for-privacy@gefion.myzen.co.uk> writes

Curiously the *damaged thread syndrome* has just happened to me!

Simple job replacing the larder wall mounted light switch with one displaying a neon for on. Geriatric caterer rarely remembers to switch it off!

Electrician fitted. Fixing screws came out easily but refused to engage on re-fitting. Sorted with my trusty re-threader but why? Not misaligned or forced.

Probably the original back box had imperial threads & the new screws are metric.

I was re-using the screws fitted by the electrician. Mindful of the above thread, I was being careful with screw alignment etc.