I was going through some old stuff and came across a BoR bracelet with 5 rows of "rice". The clasp says "No. 12" and "1036". As I looked more closely, I found that the two end-links were numbered differently, "11" and "511", respectively, despite the fact that they look absolutely identical to me. Can anyone clear this up for me? Is one of them aftermarket? I'd also be interested in knowing what reference the end-links are suited for. Sorry, I searched but didn't find a reference thread.

 

511 are just slightly later aren't they.

Just like 6 evolved into 516. I've got a few pairs of each though and I seem to remember that the 511's are slightly different from the 11's.

 

Paging @Lucasssssss

Yes, 511 is the later number for the earlier 11, and is near identical to the 12/512. These were for multiple references like pre-62 Seamsters and for the 166.010.168.024.

If you don't intend to use it and want to unload it, PM me

 

Good to hear that they are at least authentic. If there is a difference, it must be very subtle. I looked closely, and even installed it on a watch, and really couldn't see anything.

 

Perhaps the 511’s themselves evolved over the years?

I don’t have my parts etc with me at the minute but i think on mine the 511 has a curved lip on the underside that the 11 doesn’t have (or vice versa).

 

I'd be interested to see yours if you have a chance to look. Both my 11 and 511 have the curved lip underneath. Sorry about the photo, I didn't realize it was out of focus until I uploaded it.

 

There has been some quite extensive discussion on this. It is clear that the 11's were earlier than the 511s, I would speculate that the 511s came in during the late 60s (the latest I can find was from an original owner in 67), but this is only from observation. I have never seen a bracelet which I could confirm was original and had miss-matched end links, however clearly the dealers changed over at some point. As these endlinks/bracelet combinations were added at the point of purchase I suppose it is possible that they grabbed one 11 and one 511 without noticing. It is also possible one damaged endlink was swapped by Omega/Watchmaker/Owner.

As for the difference between the 11s and 511s, there has been some discussion on it previously (here: https://omegaforums.net/threads/bor-for-50s-seamaster.74084/). As @Edward53 observes in this thread, the 11s have a 'raw leading edge' as oppose to the 511s 'folded leading edge', a distinction which I have incorporated into a table I have been drawing up.

My table also indicates that the 1036 came on both 11s and 511s

 

Interesting, many thanks for these details. I believe that both the 11 and 511 have a folded edge in my particular case, as can be seen in the photos above (but not very well). I will take better end-on photos and post them tonight.

 

IMHO n° 6 evolved in n° 506...

 

This is correct: 6@19mm, 506@19mm, 516@20mm

That is interesting, some good photos would be very helpful

 

Yes that's what I meant.
No.16 into 516.

 

I love watching @Lucasssssss nerd out on this stuff!
Learn something new every time

 

More photos, hopefully these are clear. Both have folded edges and they really look identical to me. Of course, looking at what is inside the end-links at high magnification makes me gag just a bit.