| Manufacturer | Seiko |
| Caliber Number | 6138A, 6138 |
| Movement Type | Automatic, self-winding mechanical, chronograph |
| Diameter | 27mm |
| Height | 7.9mm |
| Jewel Count | 21 |
| Beat Rate / Frequency | 21,600 bph / 3 Hz |
| Lift Angle | Unconfirmed |
| Power Reserve | Unconfirmed |
| Hand-Windable? | Yes |
| Anti-Shock Device | Diashock |
| Hand Count | 5 |
| Functions | Central hours; central minutes; central chronograph seconds; 12 hours chronograph counter at 12:00; 60 minutes chronograph counter at 6:00; day and date at 3:00 |
| Hacking Seconds? | Unconfirmed |
| Country of Manufacture | Made in Japan |
| Known Models | Seiko Sports Speed-Timer (Add your watch to the comments below…) |
The Seiko caliber 6138A is a vintage automatic column wheel chronograph movement. This chrono has a vertical bi-compax 12-6 layout, with a day/date at 3:00
Official Seiko documentation listed the 6138a as having the following features:
- An advanced automatic winding chronograph
- Easy-to-use, regular chronograph mechanism
- Seiko’s special clutch mechanism without starting/stopping errors
- Day and date instant setting device operated simply by revolving the crown
- Bilingual change-over mechanism for day indication selectable by preference
- Auxiliary hand winding device instantly usable for measuring time
- External devices with many functions
Additional Resources:
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