Longines with 25.17 caliber

[BlueHarp]

Hi all of you,

I had an opportunity to buy a vintage watch early in the morning. It is supposed to be a Longines with a 25.17 movement. As there are some buyers who react very quickly when they see a new watch on that website, I had to make my mind at once. I made some researched immediately, and then I decided to get that watch. After that, I made some additional research, and I think it might be a real Longines.

Would you have the same opinion as you look at the pictures attached?

 

[AndyGSi]

Serial Number dates it to 1936 but according to Ranfft the 25.17 wasn't launched until 1939.

https://ranfft.org/caliber/7558-Longines-2517

[BlueHarp]

Does that mean it's a fake? I had a look on SERIAL-NUMBER-DECODER.CO.UK which confirms that the serial number 5472134 refers to 1936, but the website indicates that "I have estimated dates for years where I couldn't find any information so please consider this a guide only, it should be within a couple of years either way".

I had a try with another website which indicates 1937 and a third one which indicates 1936 (approximately). 

May I still hope that it's a real Longines? If not ... I've been to quick in my decision

[markr]

I have some water transfers I could send you one if you want.  Smallest one is 7.3 mm.

[AndyGSi]

It may just not be a 25.17 movement but I don't know enough about Longines to what came later.

Edit

Just found this which dates to 1935 so maybe the 25.17 was made before 1939 as stated on Ranfft.

https://www.joseph-watches.com/all-products/longines-cal-25-17-stainless-steel-1930s/

Re Edit

Done i little more searching and to me it looks like Ranfft is wrong
but can't find what actual date these were first produced.

Looking at other examples my thoughts would be it's a genuine movement but the dial
and case both look wrong so I suppose it all comes down to what you paid for it.

Edited April 10 by AndyGSi

[mikepilk]

Longines have a service where you can send the serial number and they will tell you the date and name of the agent the watch was sent to. 

I'm not sure about the case, but I would expect "Longines" on the dial

Edited April 10 by mikepilk

[Nucejoe]

I beleive Its a Longines, couple of variants to this calib were made,  one with flat and several  with overcoil H/S, overcoils were furthure modified, thus new designations.

 TG reveals it's  worth, when serviced. 

 

 

 

[BlueHarp]

Thank you all,

Now I just have to wait for the watch to be delivered. I will take pictures then.

[ClaudioCavalli]

7 hours ago, mikepilk said:

Longines have a service where you can send the serial number and they will tell you the date and name of the agent the watch was sent to. 

I'm not sure about the case, but I would expect "Longines" on the dial

Yep,  used it and they are pretty fast!

[BlueHarp]

On 4/10/2025 at 7:12 PM, mikepilk said:

Longines have a service where you can send the serial number and they will tell you the date and name of the agent the watch was sent to. 

I'm not sure about the case, but I would expect "Longines" on the dial

The thing is you have to provide Longines with a serial number AND a reference number when you fill the form. I have the first one on the movement, but I can't see the other one, which sould look like L.xxxxxxxxxx. I mentionned the number inside the case and I sent the mail. Wait and see...

Here are some picture I took yesterday when I received the watch.