Hi Adriano,

This is a great bit of technical information to add to the knowledge base of the Seiko community and I appreciate you researching it and sharing it with us all. Thanks of course also for your kind words about my writing.

Typically pivots designed for capped jewel bearings are conical as opposed to straight. That is, they have the curved shape found on balance pivots as opposed to the square shoulder found in normal (uncapped) power train pivots. Whether or not the overall arbor is longer or shorter depends on the specific movement design in question.

If these two extra jewels found in the 7S36 are truly functional (and I'd have to assume they are), the pivots in question should be conical. This should reduce the friction in the power train a little bit in the dial down position as well as hold the oil in place around those pivots a little better/longer. These are real world advantages for the performance and longevity of the mechanism, but certainly arguably very subtle ones.

Is it a purely marketing based decision to add these two jewels or is it an attempt to upgrade the movement in earnest? Who knows. I wouldn't be surprised if there are watchmakers and/or engineers within Seiko itself that would argue that.

_john

Responses