Vintage Omega does not look right.

sfa26 · Mar 24, 2026

Please be gentle as I’m new here.
I recently fell in love with what I thought was a vintage 1940’s watch but something is not quite right. I cannot identify the movement and I’m beginning to think it was put together using different donors.
Please help put my mind at easy one way or another.
Many thanks.

Dan S · Mar 24, 2026

Center second version of the cal 17.8 maybe? I don't see anything wrong yet, but so far there are no photos of the dial.

sfa26 · Mar 24, 2026

Dan S
Center second version of the cal 17.8 maybe? I don't see anything wrong yet, but so far there are no photos of the dial.

Thank you, Dan.
Here it is.

sfa26 · Mar 24, 2026

sfa26
Thank you, Dan.
Here it is.

Yes, I never heard of 17.8 calibre and its variants. Any idea of variant and also is there anyway I can tell precisely year it was made?
Many thanks.

DON · Mar 24, 2026

Small second and sweep. Later changed to 301 or 302 small seconds. Can’t find a sweep caliber with new change.

Serial number on movement. Maybe 39-49

sfa26 · Mar 24, 2026

DON
Small second and sweep. Later changed to 301 or 302 small seconds. Can’t find a sweep caliber with new change.

Serial number on movement. Maybe 39-49

Yes, thank you for the help.
I’ve done some more digging with the calibre and maybe it’s a R17.8SC for the sweeping seconds. As you said 39/49 in line with the 1947 described by the seller. At least now I know it’s legit and original.
I’ll probably have it serviced but will definitely keep the “scars” of that patina.
Glad I found this place for Omega lovers and alike.
Many thanks.

Dan S · Mar 24, 2026

sfa26
Yes, thank you for the help.
I’ve done some more digging with the calibre and maybe it’s a R17.8SC for the sweeping seconds. As you said 39/49 in line with the 1947 described by the seller. At least now I know it’s legit and original.
I’ll probably have it serviced but will definitely keep the “scars” of that patina.
Glad I found this place for Omega lovers and alike.
Many thanks.

My estimate would be early 1940s, 1942-ish.

OneTwo · Mar 24, 2026

I have an omega from mid to late 40s with the same caliber that I inherited when my uncle passed. It’s actually on of the omegas he had which led me here to OF originally. I haven’t looked at in some time as I have it stored but IIRC, the dial design and serial number are similar. Albeit your watch looks to be bigger. I believe mine had a 32-33mm diameter case.

I’ll round up photos later on and share them here.

sfa26 · Mar 24, 2026

OneTwo
I have an omega from mid to late 40s with the same caliber that I inherited when my uncle passed. It’s actually on of the omegas he had which led me here to OF originally. I haven’t looked at in some time as I have it stored but IIRC, the dial design and serial number are similar. Albeit your watch looks to be bigger. I believe mine had a 32-33mm diameter case.

I’ll round up photos later on and share them here.

Mine is a 33/34mm including crown. It’s a lovely watch and as @Dan S says probably early 40’s.

OneTwo · Mar 24, 2026

sfa26
Mine is a 33/34mm including crown. It’s a lovely watch and as @Dan S says probably early 40’s.

Yes, I’d agree with Dan as well. It looks like yours with a 9.7M serial is estimated to be 1943 with many of the decoders like this.

The date range I shared in my post, was just saying for my similar caliber R17.8 with a 10.4M serial which I’m relearning is from a year later than yours. Here are photos of mine if you’re curious to see other examples with the same caliber. Not the best photos I’ll admit as I gifted it to my brother before ever taking good photos.

Watch is on the small one of the bottom left.

Vintage Omega does not look right.

sfa26

Dan S

sfa26

sfa26

DON

sfa26

Dan S

OneTwo

sfa26

OneTwo

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