Switch & Socket Retaining Screw Sizes?

[wildgoose]

Backbox Mounting Screw Replacement.

I've often come across stripped threads on metal backbox lugs which have been so badly abused, that the normal 3.5mm re-threader is useless because the hole is already too big. The only safe solution (electrically), is a replacement back box. This is time comsuming and can be cosmetically risky - especially if the backbox is set behind wall tiles!

Question:
Any of you know out there if they do bigger screws, which still fit and look ok in the moulding ? Would think 4mm or 4.5mm would do the trick but the heads must be very similar to the conventional 3.5mm screws.

 

[SirKit Breaker]

Backbox Mounting Screw Replacement.

I've often come across stripped threads on metal backbox lugs which have been so badly abused, that the normal 3.5mm re-threader is useless because the hole is already too big. The only safe solution (electrically), is a replacement back box. This is time comsuming and can be cosmetically risky - especially if the backbox is set behind wall tiles!

Question:
Any of you know out there if they do bigger screws, which still fit and look ok in the moulding ? Would think 4mm or 4.5mm would do the trick but the heads must be very similar to the conventional 3.5mm screws.

I`ve used self tappers to get over this one, dont know the screw size but they are slightly larger in diameter than the m3.5 but the heads are the same size, a trip to the local hardware shop should turn something up.

Another way is to get some extenders and some m3.5 nuts and bolt them into damaged holes, then shorten the screw and screw it in as normal.

 

[Steve1412]

You used to be able to get replacement lugs.They fit into the existing hole left in the side of the back box( a little like the ones on dry lining boxes)...mind you aint seen them in a while.

 

[Darkwood]

If the hole seems too big for a 3.5mm it is possible its an old imperial box which were just slighty larger in comparrison the steel lugs on the box are normally stronger than the 3.5mm machine screws and normally only need retapping if box is in at a slant and thus been forced into a cross thread.
You can pick up a 3.5mm and a 4mm tapping tool which is handy to keep in your tool kit.

 

[Mr Brady]

Another method similar to SirKit Breaker's 2nd is to drill and tap the back of the box, then screw extension studs in, also good if the box is seriously crooked.

 

[Spudnik]

Just buy an M4 re-threader an some M4 plate screws.

Most of the time they will fit.

EDIT: Scrap that idea. Doesnt look like you can get them anymore.

 

[bonjovi]

i always used wood screws you have heard of 1 1/2 x 8 screws i used to have a supply of 1 1/2 x 6 and 2 x 6 they come in countersunk heads that fit flush into the switch or socket and are in silver hope this helps

 

[the jock]

4mm screws don't allways fit through the socket face

 

[ajelec10]

Forget the rest if you want the best and you want a professional job then you need to invest in a heli coil thread insert kit they range from m2 to m12 so they should do a m3.5 all you do is drill and tap the hole to the required size screw the coil in snap off the tang and use a normal 3.5 plate screw.this may be expensive but a proper job?
Regards
AJ