Cannot tighten 2 gang switch to wall

[EnfantTerrible]

Hi all, just signed up.

I've just bought my first house by myself and I'm completely new to DIY and anything involving any kind of tools! I work in IT and have always relied on friends/relatives to help me out but now I have my own place, I want to learn.

ANYWAY, I rewired a new 2 gang switch because the old one that did the lounge and hallway lights was grotty but when screwing it back to the wall, it got to a point and then the screws just start spinning freely.

I'm guessing this is because the holes in the pattress box (is that what it's called?) have smoothed so the screws aren't actually in a thread (I noticed I can just pull them out now) so what are my options?

I'd rather just find a way to use the current box if possible but if I need to replace it, how is this done?

If you need any more information to be able to help, I'll reply asap!

Thanks in advance!

 

[Jackrae]

Boxes are usually steel and screws are brass (nickel plated) so suggest failure may well be the screw threads since that's the weaker material. You can get replacement screws at your local B&Q amongst others. Just make sure the ones you get are neither too long nor too short.

 

[b13kal]

Hi

It sounds like the box is 15mm and the screws you are using are too long. Take the switch off and try the screws in the box with out the switch . If the fit then screw them in till it touches the back of the box. If the screws are sticking out then they need cutting.

 

[EnfantTerrible]

Thanks for quick reply guys. It's definitely not screws as I thought that to begin with and bought a pack of new ones but same problem. The screws basically just slide in and out of holes now (while catching on what little thread is left). They're short enough to not touch back and they are the same size as the old screws which were fine until I changed the switch. I think the holes in the box are just old and smooth.

 

[xr4x4]

Sounds like new back box time.

 

[EnfantTerrible]

Are there any guides to doing this? I'm such a newbie it's unreal.

 

[rjm2k]

Bend the lugs in a bit and you might find they catch more.

 

[b13kal]

Can you put up a pick?

It's not hard to do. It's just you might need filler after you have taken and put the new box in.

Basically the box is secured with a screw or nail. Remove what is securing it and cut around the box. Label the wiring and remove from switch . Pull the box out.
Now the new box might be deeper ie 25mm then you have to chisel out the wall behind the box. Fit in and bobs ur uncle.

Alternatively you can just fit normal self tappers? Depends on your prefer ?

 

[securespark]

You could try a rethreading tool.

Along with fresh screws of the correct length, that may do the job.

http://www.screwfix.com/p/ck-rethre...atafeed-_-Tools-_-CK Rethreading Tool M3.5x.6

IF you're going to do a lot of this, it might be worth the investment.

 

[EnfantTerrible]

You could try a rethreading tool.

Along with fresh screws of the correct length, that may do the job.

http://www.screwfix.com/p/ck-rethre...atafeed-_-Tools-_-CK Rethreading Tool M3.5x.6

IF you're going to do a lot of this, it might be worth the investment.

Thanks for the suggestion, I will try this. I'm guessing I just run it through once slowly and then back out and the lugs should take a screw? Will it still take m3.5 electrical screws? I'm using 25mm ones from Screwfix.

I'd much rather do something to fix the existing box then fit a new one (bit advanced for me at the moment!). I did try bending in the lugs and they took a screw at first but as soon as it started getting tight, the thread just went again and they started spinning so I've got it screwed against wall now, it's just not tight enough to be flush. Will do until I can get hold of the rethreading tool though.

Thanks for all the replies everyone, I'm sensing this forum will be the most valuble tool of them all!

 

[phatboy]

I would try re-threading soon. Depending on the wall type, and the way the box is fixed to it you could end up with a big mess! In my house, the builders have cemented / hardwalled the boxes in, so its a nightmare to chisel them out!

 

[Iggifer]

I would also vote for a go at rethreading. Just take it slow & steady. Insert keep turning until you feel it starting to bite, turn it a few more turns, then gently unscrew it again.

If it doesn't ever start to bite, get a pair of grips and give the lug a gentle squeeze (this will make the hole oval shaped) you should then feel it bite when you try again

I've got one of those CK ones listed and it's pretty good (a rethreader is a rethreader though at the end of the day).

 

[Jackrae]

An alternative you could try if the box is deep enough is to use a couple of short stand-off pillars. These are fixed into the defective holes using nuts and the faceplate screws then screw into the pillar holes. The likes of Maplins should stock them as they are commonly used on electronic gizzmos.

 

[EnfantTerrible]

I'll try rethreading tomorrow and see how it goes! I don't think the box is deep enough for the standoff pillars but I'll look into it if rethreading fails. Thanks for advice all, really helpful.

 

[DetlefSchmitz]

OK - this depends on how handy you are. Drill out the holes to 4mm. Now araldite 3.5mm nuts to the back of the tabs, very carefully without getting the resin near the threads.

Best way to do that is to screw some short 3.5mm screws right in to position the nuts before applying a smidge of araldite to the edge of the nut using a matchstick.