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Brand: | Sea-Gull, Tianjin | 
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| Family: |
Unknown
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| Height: | mm | ||
| Jewels: | 21, 23 | ||
| Reserve: | 41 hours | ||
| Frequency: | 28800 A/h | ||
| Winding: | Automatic, Bi-Directional Automatic Winding | ||
| Diameter: | mm ( ligne) | ||
| Complications: | Date, Hacking Seconds, Hand Winding, Quick Date Correction | ||
| Hands: | Central Hour Hand, Central Minute Hand, Central Seconds Hand, Date Window at 3:00 | ||
| Production: 2001 – Current | |||||||||||
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| 1910s | 1920s | 1930s | 1940s | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020s |
Cal. ST1812, produced by Tianjin Seagull Corporation, is an automatic movement with a central date wheel. The design is similar to the ETA 2892A2.
Besides finishing, there are some differences between Cal. ST1812 and ETA’s Cal. 2892A2. Cal. ST1812 uses a traditional fixed pin balance instead of the ETACHRON balance in the 2892 and has a fully slotted excentric in the regulator. The balance bridge is mounted using holes instead of pins as on the ETA. The fourth wheel on Cal. ST1812 also have six instead of eight spokes and places the winding jewel on the post bearing instead of the bridge. Some examples have an extra jewel for the barrel arbor.
Images are taken from official publications and are used here for commentary and educational purposes. Copyright is held by the original owner as noted.