Repairing a damaged back box thread.

[Pete E]

It looks like the upstairs in the house has had some electrical work done in the past and I've been left with a couple of blanked off back boxes.

On one of them, the cover plate is loose and looks a little unsightly. While attempting to tighten the screws up, I found the threads on each of the bushing are buggered....

I am going to try to tidy the thread up by retapping with either a M3.5 or M4 tap.

If retapping with the M3.5 does not work, will I need to re drill/clean the holes with say a 3.5mm or 3.6mm drill before trying to run the M4 tap through it or should the M4 tap clean it up ok?

Thanks in advance,

Peter

 

[Octopus]

or replace the back box?

 

[pirate]

Replace the back box, unless it is maybe tiled-in, or other major decor damage would result?
Or try one of these,
C.K Rethreading Tool M3.5x.6 - https://www.NoLinkingToThis/p/c-k-rethreading-tool-m3-5x-6/59312?tc=JB3&ds_kid=92700022861141795&ds_rl=1249796&ds_rl=1245250&ds_rl=1249481&gclid=EAIaIQobChMI16iJkc7X2QIVS7ftCh0QTgscEAQYAyABEgJD0_D_BwE&gclsrc=aw.ds&dclid=CNy8taPO19kCFYKi7QodN_QH5A

 

[pirate]

...or this, but I can't vouch for it as I have never used one
Fix a broken screw thread in your metal back box. Raise, tilt or lower a socket faceplate - https://backboxsaver.com/
The CK tool has always been fine for me

 

[Gavin John Hyde]

Backbox saver has saved me a lot of time previously. The small cost outlay is saved in not having to replace a backbox.
With some you can insert new screw plates that hook inside the back box.
Another trick is put a blank plate on front and insert a long thin rod with a bit of paint on back and push until you reach the rear of box. Then drill this mark. Insert a plug and you can then use the long uncut machine screws to fasten socket. Switch etc

 

[camerabloke]

Squeeze the lug gently with pliers then retap 3.5 mm

 

[Pete E]

I don't really want to remove the back box as it might damage the decorating although I might remove and fill it at a later date.

I have a tool similar to the CK one for doing this sort of thing, but the shaft is double sided, one side M3.5 and one side M4...As I recall M4 threads are used on the screws and bushings on metal conduit?

Anyway, I'll give it a go running the 3.5mm through first and then if that does not work, I'll try the M4 tap....

When I managed to get the existing screws out, it looked like somebody had tried to use screws with the wrong thread...they were close but not close enough.... the screws were also a fraction too long and were bottoming out against the back of the patress...

 

[Marvo]

You could also use clinchnuts (sometimes called rivnuts) but I've only seen them in M4, not M3.5. I'd go with the squishing the existing hole and retap to 3.5 advice. You could also put a blob of 2-pack epoxy glue over and into the hole, give it time to set then carefully drill the epoxy and retap to 3.5mm

 

[westward10]

Used a Back Box Saver the other day bit fiddly but did the job.

 

[Des 56]

You can play around re tapping and good luck to you

90% of the time,if you follow the solution given by camerabloke it works just fine

 

[robd]

Agree with Des

 

[Strima]

Backbox saver has saved me a lot of time previously. The small cost outlay is saved in not having to replace a backbox.

I've just looked up the price of them and spat my coffee out all over my keyboard, they aint cheap...

 

[Pete E]

Thanks Gents..As I say I'll give the M3.5mm a go first as suggested and see where we go from there....

 

[westward10]

I've just looked up the price of them and spat my coffee out all over my keyboard, they aint cheap...

Yeah the cost is outrageous but if you have a tiled in back box they do the job.

 

[Tes369]

If your feeling really kinky you can drill and tap the back of the back box

 

[Gavin John Hyde]

I've just looked up the price of them and spat my coffee out all over my keyboard, they aint cheap...

when working in a otherwise well decorated listed building, it is not always practical to replace a backbox. Have dealt with a lot of customers in the wealthier parts of town who dont mind the price and cost of having something done, they just want it done safely and to be done well. Had a saudi customer once in one of the townhouses around corner from the royal crescent tell me my quote was far too low and upped it by £250 himself. i didnt protest! wish more customers were like that... i was only installing some lights that involved a mini tower to reach ceiling in the stairwell area that hung down at different lengths, I wish i had taken a picture as they looked impressive.

 

[telectrix]

If your feeling really kinky you can drill and tap the back of the back box

done that last week.worked a treat,but only because the masonry behind was thermalite and it didn't wreck my 3.0mm drill bit.

 

[telectrix]

if it's a council job, a couple of 4" clout nails work OK.

 

[Richard Burns]

if it's a council job, a couple of 4" clout nails work OK.

Anyone who nails a back box in place should be shot while being tortured!

 

[telectrix]

was talking about nailing the socket faceplate on.

 

[snowhead]

if it's a council job, a couple of 4" clout nails work OK.

Not forgetting the pencil lines on the nails to make them look like screws..

 

[Wilko]

As per @camerabloke post #6, I usually squeeze and ream (oh dear, what've I admitted to?)

 

[Pete E]

As per @camerabloke post #6, I usually squeeze and ream (oh dear, what've I admitted to?)

Yes, sorted it this way tonight...thanks everyone for their suggestions!

 

[Risteard]

Anyone who nails a back box in place should be shot while being tortured!

But not shot through the heart or head so that they can be subsequently decapitated whilst still conscious.

 

[Tes369]

Not forgetting the pencil lines on the nails to make them look like screws..

* please make sure the pencil lines are parallel with the floor you wouldn't want the QC council inspector complaining.

Cheers

 

[Squid]

Drill a hole at the back of the back box tap it to 3.5mm then either use a long screw or an extender.

 

[Squid]

Or if you want to bodge it some insulating tape around the current screw........

 

[telectrix]

push screw through faceplate. dab gorilla glue on the end.and round the eges of the socket, screw in and support faceplate with a few copies of your old regs books overnight.

 

[camerabloke]

push screw through faceplate. dab gorilla glue on the end.and round the eges of the socket, screw in and support faceplate with a few copies of your old regs books overnight.

What happens when your horse kicks the regs books over?

 

[telectrix]

What happens when your horse kicks the regs books over?

in the civilised North, we keep horses in a stable, not in the house with the chickens and pigs.

 

[Tes369]

There's a cow in my living room in this part of the north, I'm going to let my girlfriend's mother know what she is soon enough.

 

[CACJL]

It looks like the upstairs in the house has had some electrical work done in the past and I've been left with a couple of blanked off back boxes.

On one of them, the cover plate is loose and looks a little unsightly. While attempting to tighten the screws up, I found the threads on each of the bushing are buggered....

I am going to try to tidy the thread up by retapping with either a M3.5 or M4 tap.

If retapping with the M3.5 does not work, will I need to re drill/clean the holes with say a 3.5mm or 3.6mm drill before trying to run the M4 tap through it or should the M4 tap clean it up ok?

Thanks in advance,

Peter

I have happen on many of the black boxes in my 1960 house, just went straight in with a M4 tap, no drilling, success every time.

 

[CACJL]

It looks like the upstairs in the house has had some electrical work done in the past and I've been left with a couple of blanked off back boxes.

On one of them, the cover plate is loose and looks a little unsightly. While attempting to tighten the screws up, I found the threads on each of the bushing are buggered....

I am going to try to tidy the thread up by retapping with either a M3.5 or M4 tap.

If retapping with the M3.5 does not work, will I need to re drill/clean the holes with say a 3.5mm or 3.6mm drill before trying to run the M4 tap through it or should the M4 tap clean it up ok?

Thanks in advance,

Peter

I have happen on many of the black boxes in my 1960 house, just went straight in with a M4 tap, no drilling, success every time.

 

[Squid]

I have happen on many of the black boxes in my 1960 house, just went straight in with a M4 tap, no drilling, success every time.

Any white ones?

 

[Michael Bloomfield]

Another way of fixing, is to drill out the back of the back box inline with the lug , use a threading tool to put in a thread and then use a long 3.5mm thread front screw can save all re-decorating, was told by an old electrician friend, and Iam getting on now but it works!

 

[telectrix]

Another way of fixing, is to drill out the back of the back box inline with the lug , use a threading tool to put in a thread and then use a long 3.5mm thread front screw can save all re-decorating, was told by an old electrician friend, and Iam getting on now but it works!

i do the same, but it's a pig if you have hard brick tight up behind the box.

 

[Michael Bloomfield]

Also if lug is in place you can drill out then pinch another lug from another back box and put behind first knackered lug and screw faceplate on that way, it will pull tight.

 

[willy fixit]

If your feeling really kinky you can drill and tap the back of the back box

And use a couple of these!

 

[willy fixit]

Or if you want to bodge it some insulating tape around the current screw........

NOOOOOooooooo!!!!

 

[Steve Bramah]

If your feeling really kinky you can drill and tap the back of the back box

Another quick fix is to get a piece if 1 mm earth,about 30mm long, out of a T&E, then put it in the lug that is stripped and bend it over to keep it in place. Then use a steel 3.5mm socket screw, and screw the socket/switch home. The steel screw will tap itself into the copper cable. Don't overtighten. It's worked for me on several occasions.