Zenith launched their first automatic movement in 1951. Calibre 133 utilised a pendulum weight that would swing back and forth half oscillating to wind the movement. By 1951 this design was already starting to look obsolete compared to the competition, but the design was compact and well made, it also featured a directly driven sweep seconds wheel and had several upgrades during production.
Calibre 133: 18000 B/H
Calibre 133.8 21600 B/H
Calibre 71 21600 B/H with date.
Zenith calibre: 133-71
- Made from approx 1951-1958
- Made in Switzerland
- Power reserve around: 35h
- 20 Jewels
- 18000-21600 B/A
- Lift angle 52
- DM 30mm
- H 4.9mm-6.1mm
Gear train bridges have a nice finish with nice beveled edges and Côtes de Genève decoration.
Top surface finish on bridges: 8 Points
Surface finish on screws: 10 Points
Surface finish on ratchet and crown wheel: 7 Points
Movement Jeweling: 7 Points
Movement design for 1951: 7-8 (point for 133.8 higher beat rate)
The Zenith base plate is not as nice as the top plate with fair finish and non polished screw heads and a standard winding and setting mecansim.
Base plate finish: 6 Points
Setting and winding mechanism: 7 Points
Gear-train finish: 10 Points
Movement durability: 7 Points
Date wheel is designed to be forwarded several dates by setting the time back after midnight and forwards again until desired date is found.
Date mechanism snappiness: 5
Nice sweep second wheel jeweling inside the canon for the canon pinion.
Cool two spoke regulator tip. Shock protection was standard on all 133.
The 133 had a relatively smooth autowinder device for being a bumper, but is under a fair amount of stress that can cause wear.
6 points
The Zenith 133 tends to have very good timekeeping.
Accuracy: 9 points
+ 1 point for the chronometer
Not the longest of power reserves at 35 hours
Power reserve: 7 point
Zenith 133-71 points summary:
Surface finish on bridges and top side of base plate: 8
Surface finish screws: 10
Surface finish on ratchet and ratchet wheel: 7
Movement Jeweling: 7
Movement innovative design for ca 1951: 7-8*
Base plate finish: 6
Setting and winding mechanism: 7
Gear-train finish: 10
Movement durability: 7
Date train: 5
Autowinder mecanism 6
Total bonus points: 0.
Accuracy: 9-10*
Power reserve: 7
Grand total: 91-98
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