Spotlight bar nuts

[Snakeoil]

Can anyone give me some info on the special nuts that hold the spotlight bar to the top shock studs? The part number is 3475-46a. This is for a '47 EL, but they spanned '38-'48.

What I want to know is, does the small diameter extension on the nut actually fit into the light bar mounting ear? I'm thinking that it does and this locks the bar in place on the stud and prevents it from walking up via the slot under vibration.

My bike has a period aftermarket light bar purchased back when it the bike was new. It mounts similarly to the HD light bar, but the notched slot in the ears is sized to fit the stud which is 3/8". The bike has the standard, parkerized nuts that would go on if there was no light bar.

I was going to buy a pair of the HD type nuts, but then realized that they might not work with my light bar since it will not have a mating socket for that extension to fit into.

It's not an easy thing to describe in words so I hope understand what I'm asking.

I would also like to know the size of the hex on those nuts. If HD nuts will not work with my light bar, I'm thinking of machining a pair of thin nuts to emulate the HD nuts and still work with a shakeproof washer and my light bar. Trying to scale the hex from photos knowing that ID of the thread is 5/16", I get a hex size that is either 3/4" or 13/16".

Thanks,
Rob

[46EL]

Colony sells the Nut, Washers and Lock Washers as a kit. stock number 2757-6. The Nuts measure 0.880 and that includes the plastic wrapping. The protrusion that goes into the bar to hold it in place looks like 0.500 and that also is measures still in the package with the clear plastic thickness included.

[Snakeoil]

Thanks. They won't work with my bar so I'll machine two nuts that look correct but without the reduced shoulder. I could try to open up the slot at the mounting point to accept the stock HD nut, but I'm concerned that it could peel the chrome in the process. Plus, just not right to modify original parts, even aftermarket ones. My nuts can be removed.

Regards,
Rob

[46EL]

I took an original Spotlight bar off a 47WL last year that was a one owner bike that had 16K original miles on it.
The bar did have the opened up holes and the same exact hardware as the Colony kit has.
Your bar might or might not be original but once it is mounted the way you explain nobody will ever know. 46

[Snakeoil]

It is a period correct accessory. It is in the original photos of the bike in '48. My guess is it did not come with nuts and just used the original parkerized nuts, which is what was on it. But the nuts do not achieve full thread engagement because the studs are not long enough. Hence the HD design. The thicker nuts with the stud end buried looks like a cob job. Typical of aftermarket stuff made to look the same, but not function the same.

Thanks,
Rob