Seiko Caliber 4r35b Drawing

Seiko Caliber 4R35

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Seiko Caliber 4r35b Drawing

Manufacturer Seiko
Caliber Number 4R35, 4R35A, 4R35B
Movement Type Automatic
Diameter
27.4mm (casing 27mm)
Thickness
5.32mm
Jewels 24
Vibrations Per Hour
21,600 bph
Lift Angle
53 degrees
Power Reserve
~40 hours
Hand Windable? Yes
Winding Direction
Clockwise
Hacking? Yes
Anti-Shock System
Seiko Diashock
Regulator System
ETACHRON
Functions Hours, minutes, central seconds, date calendar at 3:00
Country of Manufacture Japan
Known Models
(Add yours in the comments below…)

The Seiko caliber 4R35 is an automatic used by Seiko Watch Corp. in their own branded watches. This movement was released circa 2011. This caliber was considered to be an upgrade from the popular 7S26 movement as it offers the user the desirable hacking and hand-winding functionality.

Caliber 4R35 VS SII NH35:

The caliber 4R35 is basically a Seiko-only version of the NH35A. Seiko Instruments (aka SII) sells the NH35 to other manufacturers for use in non-Seiko watches.

Caliber 4R35 VS 4R36:

There is also a similar caliber 4R36. The difference between the two is that the 4R35 has a date calendar complication at 3:00, and the caliber 4R36 has a day/date at 3:00. Everything else is the same, including dimensions, jewels, accuracy, etc.

Differences Between 4R35A and 4R35B?

The “A” in 4R35A indicates that it is the first generation of this caliber. The 4R35B was an upgrade from the original caliber where Seiko increased the jewel count from 23 to 24 jewels. This happens to be the same jewel count at the 4R36 mentioned above, so it could be for ease of production and documentation. If anyone in the community has more insight on this evolution, please talk about it in the comments below…

Accuracy Rating:

Seiko claims that the accuracy of caliber 4R35 is between +45 / -35 seconds per day. This rating is based on normal daily wear on the wrist in temperatures between 5 ºC and 35 ºC. When testing your watch for timekeeping, make sure it is fully wound.

Crown Position Functions:

0 (against the case): Clockwise = Manual Winding / Counterclockwise = Nothing
1 (pulled out one click): Clockwise = Nothing / Counterclockwise = Date setting
2 (pulled out two clicks): Time setting clockwise and counterclockwise

Stem Removal:

To remove the stem, make sure the crown is in position 0 or normal position (not date or time setting position). There is a lever with a small indentation for your tool. Gently press down while pulling the stem out. See official instructions below for more guidance:

Seiko Caliber 4r36 Stem Removal

Examples of Watches With This Movement:

Additional Resources:
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