Zenith started making calibre: 1953 to about 1960. The indirectly driven minute allows a big balance and low profile. hacking by stopping the 4th wheel. The 120 has fixed stud on the balance cock and the 120T is adjustable. Around 100.000 where made.
Zenith Calibre: 120-120T
- Made approximately: 1953-1960
- Made in Switzerland
- Power reserve 47h
- 15/16 Jewels
- 18000 B/A
- Lift angle 52°
- DM 26.75mm
- H 4.6mm
Surface finish on the T120T is of high quality. All screws are highly polished and of excellent finish. The bridges are nicely finished with rhodium plating and gilt in the lettering. chamfered bridge edges. Ratchet wheel and crown wheel has a good finished. Standard jewel count.
Surface finish on the T120 is a little more rudementery than the T120T
Surface finish on top side of the plate and bridges: 8 Points (120T) 7 Points (120)
Surface finish on screws: 9 Points
Surface finish on crown and ratchet wheel: 8 Points
Movement Jeweling: 7 points
The movement is pretty innovative for 1953.
Movement design innovation (for 1953): 8 points
The Zenith base plate has a fine finish, but no detail. Winding mechanism is well made, no rough finishes. Gear train has a very nice finish on wheels and pivots.
Base plate finish: 6 Points
Setting and winding mechanism: 8 Points
Gear-train finish: 8 Points
Movement durability: 7 Points
All models have shock protection, but only the 120T has a balance cock regulated beat error regulator (movable stud) Note the cool V shaped regulator.
120T* bonus point for boot regulator: 3
Hacking lever: 4 Points
The Zenith 120 in good condition gives excellent accuracy.
Accuracy: 9 points
Power reserve is good: 8 points
Zenith calibre 120 summary:
Surface finish on bridges and top side of base plate: 7/8*
Surface finish screws: 9
Surface finish on ratchet and ratchet wheel: 8
Movement Jeweling: 7
Movement innovative design for ca 1953: 8
Base plate finish: 6
Setting and winding mechanism: 8
Gear-train finish: 8
Movement durability: 7
Total bonus points: 4-6*
Accuracy: 9
Power reserve: 8
Grand total: 88-93*
*If it is the 120T