WS 19: Servicing a SEIKO Chronograph 6138

These few parts below comprise one of the most sophisticated, simplest yet most efficient automatic winding systems. The rotor on top, the plate with the bearing just below it, the ratchet wheel on its left. A flat plate to guide the jeweled magic lever at the bottom center of the picture. Plus three screws. That is most likely one of the most ingenious engineering master pieces of SEIKO. The magic lever with its special shaped hooks in collaboration with the ratchet wheel makes sure that the ratchet wheel turns always into the same direction regardless of the rotor direction. A true and very simple bi-directional winding system. John Davis explains with graphics the functioning of the magic lever included in his now famous "Seiko Diver Cal. 7S26" review. Go to and click on "Reviews" and you will find additional information on how the magic lever works there.

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