Manufacturer | Seiko Time Corp. |
Caliber Number | 4006, 4006A |
In-House? | Yes |
Movement Type | Automatic, self-winding mechanical |
Diameter | 31.2mm |
Height | 7.15mm |
Jewel Count | 17 / 21 / 27 |
Beat Rate | 19,800 bph |
Lift Angle | 52 or 58 degrees (unconfirmed) |
Rotor Winding Direction | Bi-directional (Magic Lever) |
Manual-Winding? | No |
Mainspring Count | 2 |
Anti-Shock Device | Diashock |
Hand Count | 3 |
Functions | Central hours; central minutes; central sweeping seconds; day and date at 3:00; alarm |
Hacking Seconds? | No |
Country of Manufacture | Made in Japan |
Known Models | Seiko Bell-Matic, Seiko Business Bell (Add your watch to the comments below…) |
The Seiko caliber 4006A is a vintage automatic movement watch a built-in mechanical 10 second alarm mechanism. This calibre is found in Seiko Bell-Matic watches which were produced in the 1960s into 1970s.
Seiko cal. 4006A can be found with 17, 21, or 27 jewels depending on what market the watch was intended for.
How to set the alarm:
The Bell-Matic has an internal rotating bezel with a red arrow pointing to the time you set the alarm for.
There is a button at 2:00 that has 3 positions. When pressed in, the button serves to quickset the date (off topic, but the day of the week is not quickset).
The alarm functions via a spring that gets wound up when you have the button in neutral position and wind the crown. Winding the crown does not wind the movement.
The button also pulls out one click to engage alarm mode. When the alarm is activated or buzzing, press the button back to neutral position to turn it off.
Similar Calibers:
There is a Seiko caliber 4005A which is the date-only version of the 4006A.
Video – Seiko Bell-Matic 4006-6010 Alarm Sound:
Video – Bellmatic Disassembly and Assembly:
Additional Resources:
Recent Comments
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