Is the 'Swiss Made' signature below the sub-dial a red flag for this model? Given the production year is circa 1948, could this be a transitional period from 'Swiss' to 'Swiss Made'?
Happy to contribute to this archive with my Zenith Chronograph ref. GZ 1.76 powered by the 146D caliber. I have owned this piece for several years and it remains a cornerstone of my collection. Finding an example in this condition was a long search but the effort was certainly rewarded.
I shared a quick shot in the daily thread yesterday yet I felt this timepiece deserved to be documented here for its technical character. Opening the case back is always a reminder of why I enjoy this hobby so much.
Zenith Sporto from early 1960s. This is an interesting watch with Zenith cal 2511 ticking inside (aka Martel 1111 that was renamed to Zenith cal. 2511 after Zenith acquired Martel around this period). This is also the period when Zenith went from stepped to stacked logo. Dial has the new stacked logo, whereas the caseback has somewhat unusual engraved caseback with older stepped logo. When I found this Sporto I assumed that the caseback was just swapped in from an older watch at some point. However recent conversations have convinced me that this being a transitional period in Zeniths history, it is not unreasonable to think that this Sporto would have come out in this configuration. Also, only at recent service the watchmaker pointed out to me that this is among the models where the case number is found between the lugs.