IWC cal 49 or cal 52 ??

I would like to ask, what is the main difference between cal 49 and cal 52?

Cal. 52 curved balance cock, winding wheels fastened with only one central screw with a notch for screw driver.

Cal. 49 straight balance cock, winding wheels fastened in a different way.

Hope this helps!

Th. Koenig

Thanks for the infromation, what do you think about this movement? For me it is different from cal 52

It is difficult to differ from opinion with Th. Koenig as it turns out that he is right almost all the time. I am not sure what he means by a curved or straight balance cock. In my opinion the balance cock in cal 49 and cal 52 is the same : curved.
However, the knowledge I provide here is coming from another expert: Ralph Ehrismann. He extensively studied cal. 52 and its forerunners.
The main difference between cal 52 and cal. 49 ( which is a forerunner of cal 52) is the shape of the threequarter plate. There is a semi-circular cut away of this plate nearby the balance wheel in cal. 49. The plate of the cal. 52 has a smooth "S"-shape. So, the watch you show is definitely a cal. 52 and not cal 49 nor another forerunner. But a further more precise determination is difficult because too few details are visible on the picture.
It could be cal. 52 model 1893 or model 1894. In cal. 52 model 1904 and later the winding wheels are no longer fixed by one screw but by 3 screws for each wheel. There are also differences in the pallet cock or pallet bridge but also this cannot be seen on your picture.
Kind regards,
Adrian
(alwaysiwc)

Hello,

I see that you have lots of knowledge on old IWC Calibers, and I need some help.

My IWC Cal 52 watch needs a new mainspring and I haven't been able to find one.

Any idea of where could I get one or a similar one that might work?

Maybe the size of it so I can get a similar one that my watch maker can set in the movement.

Any feedback will be highly appreciated !!

Thanks for your time.

Rodolfo

Hi Chamuko,
I guess it will be difficult to find a balance spring for a cal. 52 in Mexico, although 300.000 of these watches have been made. The solution via IWC Schaffhausen will cost effort, time and a considerable amount of money. If I was living in Mexico, I would search ebay for a non-running IWC cal. 52 or part of it. It may well be that the balance spring from another brand can be used but I do not know from which brand.
Kind regards,
Adrian,
(alwaysiwc).