Ornatus-Mundi
[Zenith]
7136
It stands for 40-T, one of Zenith's Observatory Chronometer movements...
It could find out the following:
The Cal. 40-T is a 12" hand wound movement (thanks blomman for the pointer!) beating with 18.000 bph, produced between 1947 and 1963 in a quantity of 162.000 pieces. There were standard and chronometer-certified movements. It is Zenith's second-famous chronometer movement (after the slightly larger Cal. 135).
Here are a few images from a fellow Purist (of a non-chronometer 40T):
The particular watch in question is identical to one owned by famous watch journalist and historian Christian Pfeiffer-Belli. Assuming that all is still original and no parts (movement or dial) have been exchanged, chances are high that you own a true chronometer piece.
Hope this helps!
Best,
Magnus
Old Zenith chronomete
what is this printing in dial between centre and small cecond?...
It stands for 40-T, one of Zenith's Observatory Chronometer movements...
It could find out the following: The Cal. 40-T is a 12" hand wound movement (thanks blomman for the pointer!) beating with 18.000 bph, produced between 1947 and 1963 in a quantity of 162.000 pieces. There were standard and chronometer-certified movements....
A comparative pic between a chronometer-certified and a standard T-40...
which I found on the web: (left, non-chronometer; right, chronometer version) Note the difference in finishing as well as in the balance wheel and the hairspring stud. Furthermore, the chronometer version is individually numbered also on the barrel bridge...