Electrical socket imperial screws

I'm getting some old artex skimmed out in the hall and some of the electrical socket backboxes are of the old imperial type. I would prefer to avoid having to change the back box if I need longer screws, but I can't find anywhere that sells the old BA screws. Is there an easy solution? - I thought about trying to tap the threads, but not sure if this is likely to work.

Reply to
John Miller
Loading thread data ...

You may be able to find a metric or Whitworth screw that is close enough. What is the approximate diameter and threads per inch?

Type Size Dia Inch TPI Dia mm Pitch mm BA 3 0.1614 34.84 4.10 0.73 M 4.5 0.177 33.87 4.5 0.75 BA 2 0.185 31.35 4.70 0.81 BSF 3/16 0.1875 32 4.76 0.79 BSW 3/16 0.1875 24 4.76 1.06 MF 5 0.197 50.80 5 0.5 M 5 0.197 31.75 5 0.8 BA 1 0.2067 28.25 5.25 0.90 BSW 7/32 0.21875 24 5.56 1.06 BSF 7/32 0.2188 28 5.56 0.91 BA 0 0.2362 25.38 6.00 1.00 MF 6 0.236 33.87 6 0.75 M 6 0.236 25.40 6 1

Reply to
Matty F

Namrick sell some B.A. items.

formatting link

Reply to
Edgar Iredale

tapping the threads is easy and works ok.

NT

Reply to
NT

Accessory screws are M3.5, I'm surprised that the OP can't find BA screws. Plenty of seller hits when googling...

OK you won't find them in the DIY sheds but I'd have thought a decent electrical wholesaler might, more likely to find a little hand held M3.5 tap though. 6BA is 0.11 inch (2.794mm) so the hole can simply be tapped out.

Reply to
Dave Liquorice

I think I've seen a sparks using a simple hand tool to do this.

Reply to
stuart noble

like this

formatting link

Reply to
Bob Minchin

Although quite expensive. Mine is just a 3.5mm tap, a cheap file handle and some epoxy.

Reply to
Andy Dingley

Thats what I've got. No predrilling needed, just use the tap once and its done.

NT

Reply to
NT

Yup, most electrical wholesalers will sell you something like:

formatting link

Reply to
John Rumm

I thought that this was the case, but forebore giving what might be bad advice.

many electricians carry just such a tap: I assumed it was to sort out stripped or tight threads, but maybe it is quire often necessary when working on older installations.

Reply to
The Natural Philosopher

Mine is a tap and a large chocky block section. It was given to me mumble, mumble years ago.

Dave

Reply to
dave

formatting link

Reply to
Ian French

formatting link
> Ian. Thanks to all who replied. I was looking for the specific domed head screws, but hadn't considered that plain BA screws would do just as well. Senior moment! May try the tap solution though as this seems to be the favoured way to go.

John Miller

Reply to
John Miller

Think the actual name is 'raised head' IIRC and yes, they are near impossible to find - especially in the original finish which might be chrome or bronze, etc. However a countersunk head BA one will work just fine.

The other alternative to re-tapping the threads on a steel back box is to enlarge the hole to clearance for a metric screw and superglue a nut to the back of the lug. But you won't find nuts in the average DIY place.

Reply to
Dave Plowman (News)

And connect a link between the earth terminals on the back box and the socket since the superglue means that you won't be able to rely on earth continuity through the fixing screws.

Reply to
Mike Clarke

You never rely on that connection anyway. Screws can come loose. Corrosion can occur. Etc.

Reply to
Dave Plowman (News)

The regs haven't allowed that for a while. Link required from backbox to accessory.

Reply to
Dave Liquorice

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.