Wanted Pattress for old MK socket

[pirate]

thank you @nicebutdim and @westward10 for you comments.
I did find, amongst my box of miscellaneous screws and bits a couple of brass-finish screws that do actually fit. No idea where they came from, but they were in a zip-lock mini bag. They appear to be 0.125" diameter or 3.02mm...my digital calipers get a bit confused...
I'll keep digging in my big box and hope to find some more.
Interested to learn that the screws on the white socket were captive. That socket has quite a small form factor, as of course has the brown one.
I haven't dismantled the white socket, but the brown one is easy to see inside as the top simply lifts off...and it looks very nice and clean in there and in good order.
I'm guessing 1950s for the brown one and 1960s for the white? Was the small white one designed to cover the small size of the old brown round pin sockets as an upgrade?

 

[pc1966]

They appear to be 0.125" diameter or 3.02mm...my digital calipers get a bit confused...
I'll keep digging in my big box and hope to find some more.

0.125" = 1/8 is a possible size for the likes of BSW/BSF, but generally smaller UK screws pre-metric would have been from the BA series.

Oddly enough they were metric, but not as we know it, and had a set of formulae to compute sizes of hex flats, etc, that did not result in "simple" sizes:

British Association screw threads - Wikipedia

en.wikipedia.org

I long suspect that the choice of M3.5 used here for electrical work, and virtually unheard of in the EU, is down to them being close to 4BA.

0BA is almost M6, but most electrical stuff I have seen used 6BA or 4BA, occasionally 8BA (small, like M2) or 2BA (almost M5).

 

[snowhead]

Screws will be BA, standard screws were 4BA, (almost same dia as 3.5mm) yours may be smaller

Conduit Box lid screws were 2BA.

 

[pc1966]

I have only once encountered an odd-numbered BA screw before (oh-er!) and that was for some 19" racks we had at my former work place. They were all from the 1940s/50s and had been adapted extensively (originally for a Muirhead-Jarvis "fax machine" used by publishers to send photographs between branches using the telephone lines) for our use as a photo-plotter

Some substantial cast aluminium things, with 1BA bolts so we still have some 1BA taps, a box of bolts, and the odd 1BA socket or nut driver around. Same really, racks went to the scrap yard ~4 years ago.

 

[westward10]

BA run from 0BA to 16BA, now 16BA must be tiny.

 

[Moley]

Smallest I've used is 14BA. Used to used a lot in model railway stuff.