Q For 9F GS Quartz Owners

[RPF]

Hi guys. I was observing my GS for a long time trying to figure out the double pulse stepper design.

After a few months, I think I have finally nailed the difference to a normal stepper.

By placing the vantage point on the small overshoot second hand (the other side of the cannon pinion) the abrupt stopping of the second hand at the end of each pulse is reduced and there is less "stutter" (for want of a better word) overall. (i.e., a smoother movement in between each second)

In essence, what I think is happening is this. Instead of a velocity curve that looks like Mt. Everest (or a rollercoaster), the double pulse stepper results in a more elegant plateau shaped curve. The average velocity remains the same but the max. velocity is lower.

Am I totally off kilter here?

[Bruce Reding]

Hi guys. I was observing my GS for a long time trying to figure out the double pulse stepper design.

After a few months, I think I have finally nailed the difference to a normal stepper.

By placing the vantage point on the small overshoot second hand (the other side of the cannon pinion) the abrupt stopping of the second hand at the end of each pulse is reduced and there is less "stutter" (for want of a better word) overall. (i.e., a smoother movement in between each second)

In essence, what I think is happening is this. Instead of a velocity curve that looks like Mt. Everest (or a rollercoaster), the double pulse stepper results in a more elegant plateau shaped curve. The average velocity remains the same but the max. velocity is lower.

Am I totally off kilter here?

Interesting observation. I've never actually seen a 9F watch in the flesh. Is there a video of same somewhere on the web?

[dwjquest]

As I recall, the twin pulse movement of the 9F second hand is to lower the power required to move the hand. This is in addition to the other interesting features of the movement such as anti backlash mechanism to keep the second hand on the marks, a 50 year service life (excluding battery) and a near instantaneous date change (1/2000 of a second). It is hard to understand why the movement was not designed to allow changes to the hour hand without stopping the second hand.

Here is a thread where the two step pulse of the 9F second hand and other features are discussed:

http://www.larrybiggs.net/scwf/index.php?mod=103&action=1&id=1019873968

[RPF]

Interesting observation. I've never actually seen a 9F watch in the flesh. Is there a video of same somewhere on the web?

Yes Bruce. Search for SBGT021 on google video. Not too good I'm afraid.

[Bruce Reding]

Yes Bruce. Search for SBGT021 on google video. Not too good I'm afraid.

Thanks Bill! Shows the seconds hand motion (and date change) nicely. The former is very smooth.