Trouble fixing metal back box

[OM2]

I need to fix a metal back box
Both the threads have gone on the screws
When I screw a new screw in, that screw loses its thread

I got some metal bits to fix the problem
But I can't figure out how to use! I think I got them from Screwfix - can't remember

See below

As it is, I can't push into the metal back box
I have to bend loooads and even then, it's really fiddly

Does anyone know the correct way to use?

I thought I'd ask before buying other fixing bits that look a lot easier to use

ELSE: what would be the best way of solving the screws losing their thread?

Thanks.

I asked for help on this forum a looong time ago - I hadn't got round to fixing. Can't find the original post

 

[Wayners]

You can buy a bigger thread tool and bigger screw.
Standard m3 size but you can make it a m4 with m4 screws

C.K Re-Threading Tool

Designed for clearing dirt and debris from pattress screw tabs. Precision ground thread for accurate threading and a 50mm long tap length for improved access. Tough impact resistant handle. High speed steel tap for a clean cut and long lifeSize: M3.5 and 0.6 mm thread pitchSpecifically designed...

www.toolstation.com

Or just replace back box. Easy job tbh. Wedge in position.

I just set new box in toupret filler. Dries in 12 hours

 

[OM2]

@Wayners thanks. I think it might be easier to get one of the little bits to fix the backbox
Being lazy and tight - looking for the easiest and cheapest way

That thread tool cost £9 - I'll never use again!

 

[Wayners]

Cheap tools available. I picked the Pro branded one.

 

[Wayners]

BGS 1900-M4X0.7-B | Tap Set | Starter & Plug Tap | M4 x 0.7 mm | 2 pcs. https://amzn.eu/d/34EScpk
£3.31
Just need 2 screw.


Probably best find hardware store.
Normally get tool for £2.99 then pack off screws off the packet rack. Job done.

There is another way.
Maybe this will fit?
Should have a cef place local. That's only one though.

for Metal Knockout Boxes (Sold in 1's)

Saves the installer the time and trouble of replacing the back box

www.cef.co.uk

There are similar products on market.

Like

Fix a broken screw thread in your metal back box. Raise, tilt or lower a socket faceplate

Back Box Saver saves time and money in providing a new secure fixing if your electrical back box has a broken screw thread. Two Back Box Savers can also be used to raise, tilt or lower a mis-aligned socket faceplate.

backboxsaver.com

Not sure what you have will work?

 

[RandomGrinch]

Does anyone know the correct way to use?

 

[Wayners]

Just looked those up and they are used for surface mounted plastic boxes.
Can be used on other plastic boxes. I guess those teeth dig in the plastic.

Guess you will have to be shook by the ankles. Ha