Hello, I just got this 1942 Bulova with a 10AX movement. I am puzzled by the "extra" wheel. What does it do? The normal power train is visible and it doesn't appear to be part of the power train.

Whatever could it be?

Thanks, Jim

Dial side

Jim,
The sweep center second hand is the clue for the "extra" wheel. Normally, the second hand is a long pivot extension on the 4th wheel, which rotates once a minute. On your watch, the 3rd wheel has a gear on top of the plates with the same number of teech as the normal one, located down between the plates. This "extra" wheel drives a pinion gear that extends down through the hollow center wheel and cannon pinion. This pinion will now also rotate once a minute (just like the 4th wheel) and the sweep second hand is attached to the long shaft that is part of the center pinion.

Thanks Ed, With your great explaination it makes sense.

Regards, Jim

Jim,

Ed is of course correct, but I wanted to add that this arrangement is often referred to as an "indirect center (or sweep) seconds" movement.

Regards,

Cary

Thanks Cary, I'm sure glad I have such a rich resource as the people on these boards. I have so much to learn

Regards, Jim

P.S. Lyndell would be quick to remind me that there is no such thing as a dumb question, except the one that you don't ask.