We have had this discussion before. But is one these the type dip switch for a 16H/Big4. they are Lucas LU31482 & LU31482A. Both available repro for 7/8" bars.
My bars are 1" if anyone can help with info. Ron
email (option): ronpier@talk21.com
I have a feeling that neither of them are completely correct. Pre-war Nortons utilised combination control lever clamps and were fitted with a dip switch that screwed directly to the handlbars. As far as I can tell from the best image I have, it seems to have had more of a plain toggle than the 'bishop's mitre' shape of lever. However, it may be that both shapes were available.
There is photographic evidence of early war bikes using the clamp-on type switch but they seem to be a more oval form of switch and to have a small thumb lever with a ridged edge (this type of lever is commonly seen on the chromed combination dip/horn pattern switches).
The 'mitre' shaped switches turn up occasionally as NOS as well as pattern but with 1970s looking vinyl coated wiring. The reason for this is that they were used for operating the two-tone horns and blue lamps on Norton Commando Interpols. The Lucas part number given was 31482.
Ron, if you look at page 38 of Gavin Birch's book with a magnifying glass, you can see the switch that looks more like a post-war dip/horn...
Bakelite switches are something which probably lasted about a week on a WD bike and I doubt if there are many 1930s bikes where it is known for certain that all switchgear is original. I think that you'll be pretty unlucky to be picked up by a hostile rivet-counter.
(Lex and I are friendly so that's two that you don't have to worry about).
Not so sure Rik. Lex always tells me when I'm wrong 
Anyhow I need a 1" dip switch.Ron
email (option): ronpier@talk21.com
Mine came from him too, on an eBay 'second chance' - a bit less than £60 at the time though.
The angular one looks earlier to me - the rounded one has a 1960s look but that doesn't mean that it is. Knowing Lucas, it's quite possible that they superseded and then later went back to the original moulding.
Is this for the RAF Big 4, Ron? 
Anyhow I need a 1" dip switch.RonOnly trying to be honest!!!
Anyway, I only say that when I'm 100% sure.
Cheers,
Lex
email (option): welbike@welbike.net
Thanks Roger, will check it out. Here's a nice picture from Lex. Ron
email (option): ronpier@talk21.com
Lex, I do feel that the shape of the toggle on the pre-war switches (even if the clamp is different) could contribute to the whole story. To be honest, I don't know what Ron's up to at the moment. It wouldn't surprise me if he had JMK 783 on the workbench !
Do you reckon the knob on the photo that Ron's posted is the squared-off 'Bishop's Mitre' type ? The more I stare, the less I can see.
I'd like that type to be correct for 1940/41 'cause it's what I've got but I wouldn't be offended if you told me it was wrong !
Yes Sir. Take a look at the orange rubber between the switch panel and the headlamp shell also.
Henk
email (option): ahum@quicknet.nl
That's bang-on Henk ! Paper parts-ordering label on the reflector too. I'm convinced.
What's the date on the ammeter ?
I can't remember the date on the ammeter, we need Clive for that.
Why did I ever sell that headlamp?????
Henk
email (option): ahum@quicknet.nl
Why did I ever sell that headlamp?????
Henk
Gierige Hollander ?
That Lucas part number might be in the VAOS of a WD/C or 3SW which might help pin down the date.
The colour doesn't look like KG No.3.I'm more inclined to think that it's the 1939 dull (bronze) green
Hi Ron...You should get a replica from Britbits no problem and they do look OK...Both types are replicated....(though I know you'll probably hang it out for a NOS example... ). I got mine from the Czech boys for the B30, though I chose the rounded one because I liked it more.....Ian
email (option): ian@wright52.plus.com
Here's another 1941 shot of a dipswitch, this seems to be the most used after the chrome top one (that screws directly to the handlebars, and is for the combination levers only)
But dont worry Ron, I also have one picture with a bakelite Miller dipswitch fitted, the big round one, with half round metal rear clip, with the lighthouse logo on it!
I'm trying to find the AJS Matchless conversations that said the round knob was prewar, and the Bishops thingy postwar, but no luck yet.
Cheers,
Lex
email (option): welbike@welbike.net
OK, found it! seems that all types could have been used from 1938 onwards, maybe earlier, but have no proof of that.
Here a page from an 1938 Halfords catalog:
So, Ron, just pop down to your local Halfords, and buy one!! (while you're at it, clear them out, I can use one too!)
Cheers,
Lex
PS, they even had that horrible "Foreign" stuff back then!!
email (option): welbike@welbike.net
Fascinating stuff.
Its interesting that the bottom right one in Lexs ad says its "Foreign", I wonder if they were still being imported after the start of the war?
Here is a similar one with a combined horn button, 3 of which I obtained with some other military bits, I had been assuming it was late or just postwar perhaps from the period when blackouts were removed?
The clamp on the back is just wide enough for 1" bars but with it fully tightened it would grip 7/8" bars.
Rob
email (option): robmiller11@yahoo.co.uk
email (option): ahum@quicknet.nl