Hi Everybody, firstly I hope you are all well and not suffering too much in this strange time we're all going through. Secondly, can you believe it's now over a year since that fantastic event Capriciation? Doesn't time fly?
Now onto the reason for this post. I have a set of genuine driving lights that I'm attempting to install on my 1970 V6, however the type of thread on the mounting bolt that protrudes from the light that has the wire coming through the centre of it has me stumped.(trust Lucas to make it hard) I'm not great at identifying different threads and being locked down in a small country town doesn't allow me to get out and about to different tool/machine shops in the general area. I have a feeling it might be whitworth, although someone suggested BSF, although it looks quite a coarse thread. It's definitely not UNC or UNF. Question is does anybody here know for sure? Secondly does anyone have a couple of these nuts in the parts bin that they would be willing to part with? As I said before my options here in Renmark are limited. I know I should go out and buy a thread gauge, maybe that's the next step but I thought I'd pick the brains of the experts on this forum first. All the best, Tim

I’ll have a look to see if I have spares

Thanks
 

Hi Timmo,
FYI, UNC and Whithworth (BSW) are similar (except for 1/2") and for this reason in most applications you can interchange. BSF and UNF (which is most MK1 ) are not interchangeable.
I have stripped my Capri down and (painfully) back together and I remember some weird ones (the only thing I think I'm sure of is they are not metric). I will also have a look. I can definitely recommend buying a set of thread gauges for common threads. Not expensive, but man can they save you some wasted time pissing around for the proverbial needle in a haystack. As you you said being Lucas?????
Let you know what I come up with
Mark

Thanks

Well the pics tell most of the story. I do not know if the lights are the genuine items or indeed if the brackets are? They were in the usual box of bits sitting in the boot when you purchase an old 'stored in a barn' car  for 20+ years. The last pic shows the Made in England so I assume they are genuine, though Lucas brand name is not visible.
Either way the mounting bolt is just a loose bolt and nut arrangement so not fixed liked yours Timmo.

 
Timmo just read your original post again. Sorry I got the wrong bolt. Though would be good if someone could authenticate the lights/brackets for me.
I will check out the one with the wire coming out and get back to you.
Mark

Hi Mark, yes you've definitely got the genuine article, very rare I might add, especially the brackets. Yes it's the thread of the nut and bolt with the wire going through. Thanks Tim
 
 
 

Hi Tim, Well no dice sorry. Not Whithworth, UNC, UN/UNF, SAE. I have a funny feeling it may be a pipe thread like NPT or BSP which kind of makes sense given the application. Comparing pitch and threads per inch BSP looks very similar. I have 3/4" bsp and up.
If you have a refrigeration guy/plumber around they may have fittings or taps to do the job. Otherwise depending on your workshop skills, take them to an engineering shop and get a couple machined up.
If your not overly fussed with originality then get a suitable diameter bolt, drill a hole down through the centre and acorn nut (with hole drilled) to lock the bracket on.
The reflectors in mine are pretty stuffed (by the looks of the one I pulled apart anyway) but lenses etc look fab so worst case I'm sure I could part with them.

Hi Mark,
Thanks for all the trouble you went to, I appreciate it. Looks like another 5 minute job turning into a bit of a saga. I've got a huge collection of nuts and bolts collected over the years and could not find one that fitted and so your guess re: a pipe thread or similar is probably on the money. Make sure you hang onto those lights and brackets, as I said before very rare now, you could possibly have the reflectors redone? Would be worth finding out. All the best Tim
 
 
Hi Tim, Well no dice sorry. Not Whithworth, UNC, UN/UNF, SAE. I have a funny feeling it may be a pipe thread like NPT or BSP which kind of makes sense given the application. Comparing pitch and threads per inch BSP looks very similar. I have 3/4" bsp and up.
If you have a refrigeration guy/plumber around they may have fittings or taps to do the job. Otherwise depending on your workshop skills, take them to an engineering shop and get a couple machined up.
If your not overly fussed with originality then get a suitable diameter bolt, drill a hole down through the centre and acorn nut (with hole drilled) to lock the bracket on.
The reflectors in mine are pretty stuffed (by the looks of the one I pulled apart anyway) but lenses etc look fab so worst case I'm sure I could part with them.