Help Identifying Vintage Omega 26.5 SOB T1 — Looking for Original Strap Info

Hi everyone,

I'm a 22-year-old hobbyist watchmaker from France, and I've been servicing watches for about 8 months now. The watch I’m sharing today is particularly special to me — it belonged to my grandfather, and restoring it has been my goal since I first picked up this hobby.

A month ago, I finally felt confident enough to take it on, and I’m proud to say that it’s ticking again!

Here’s what I did during the restoration:

The crystal was heavily scratched, so I sanded and polished it to preserve the original.

The hairspring was destroyed, and sourcing a replacement for this Omega 26.5 SOB T1 caliber was a challenge. I managed to find one in better shape, but still had to adjust and reshape it.

The balance staff was broken and replaced.

The dial was quite dirty, so I gave it a gentle clean.

The movement was fully serviced and regulated. Adjusting the beat error was the toughest part, but I got it down to around +/–5s/day, 270° amplitude, and 0.8ms beat error — which I’m happy with.


I’m now trying to find more information about this specific model. I haven’t seen another example with this exact dial layout, and case online, so if anyone has seen one like it or has catalog references, I’d love to learn more.

I’m also curious about what the original strap might have looked like. The one it came with is a black leather strap (you’ll see it in the "before" pics), and while it’s fine, I’d love to return the watch as close to its original look as possible. Any info or suggestions would be really appreciated.

I've attached before/after pictures for reference — would love to hear your thoughts!

Thanks in advance for your help!

Ps: the pictures

Sorry to tell you, but you wouldn’t find more information about this specific model.
You have 26.5 movement in wrong case. This case belonging to a hammer movement caliber 30.10 - if I'm not mistaken.

Hey !
I may be mistaken, but I think the movement is the correct one for this case, a 30.10 wouldn't fit in this case at all, as the inner diameter for the case is almost exactly 26.5mm (26.3~mm). That's because the yellow part in the inner case is not detachable/ a movement ring, but it's part of the case itself, so the movement fits really tight in the case. Also a 30.10 would be way too thick to fit in this watch, as it is relatively thin and is a small diameter. Are you sure the movement is not the correct one ?

I meant to say caliber 28.10 instead of 30.10.

The case ref is 2446 fit caliber 28.10, 344,351.

I think you may be right, but that's so weird because of the golden part in the inner diameter of my case :/
My case reference number is not exactly the same, mine is 2398-2 H

I didn't assume anything I just found it weird that mine had a perfectly shaped case for the 26.5 movement 😅
But yes you guys are right, it seems that the right movement for this case is the 30.10.
Do you guys have any suggestions on to how this movement could have ended up in this case with this "modified" case ?

"As long as it fits, prepare to make people bid on ebay" That's what watch modifiers in my country would say.