Sweeping seconds hands - nerdy question

[Fullook]

I've recently bought a spring drive grand seiko, which is currently boxed up in storage awaiting my birthday before I can give it a lovely cuddle.

I really wanted a spring drive model, being somewhat in thrall to the cleverness of the movement, the history / difficulty of its development and the way its unique combination of mechanics, electrical charge and magnetism is manifested in that incredible smooth sweep of its seconds hand.

I have however since noticed the occasional wall mounted quartz (I presume) clocks that appear also to have totally smoothly sweeping seconds hands.

I was in Lisbon at the weekend and the platform clocks at Sintra railway station had this appearance.

Can anybody shed any light on what's going on here - is there a type of quartz mechanism that produces a totally smooth sweep? If so, is it only ever used for clocks rather than watches... and if so, why? I saw a thread on here recently that mentioned a 'tuning fork' mechanism developed some decades ago that produces a smooth sweep, but that eats batteries for breakfast - is that what's likely to be in use in these clocks & maybe they are mains powered rather than battery?

Anybody know?

Thanks!

[Lorne]

they've all got electric motors driving the hands through a thousand fold reduction gearing so have smooth hand motion.

Have you noticed how the seconds hand on any mechanical watch appears to be more 'jumpy' in its sweep at the bottom of the dial than at the top? This is due to a brain image processing something or other.

[LordGrover]

I have a Bulova accutron which has a smooth(ish) second hand sweep. It's not perfectly smooth but makes my posh(ish) mechanicals look somewhat juddery in comparison.

[lostkiwi]

There are also the Bulova Precisionist (aka 262kHz) movements that are eerily smooth.
Several other quartz movements have since appeared with smooth sweep second hands.

[Fullook]

Lorne said:

they've all got electric motors driving the hands through a thousand fold reduction gearing so have smooth hand motion.

Thanks all for the answers so far...

Forgive my continuing ignorance - some further questions:

1) Are these clocks' electric motors 'quartz regulated' in the same way as a regular quartz watch movement?

2) Does the 'thousand fold' reduction gearing mean the hand is actually moving in tiny steps (1000 / sec ??) but appears smooth to the naked eye?

3) Are the mechanics of these movements the same as the smooth-seeming quartz watch movements mentioned by LordGrover & lostkiwi - i.e. is the difference between them and 'regular' quartz watches just in the gearing?

4) If, as a huge generalisation, automatic watches with their characteristic stuttery-sweep seconds hands command a premium over one-second tick quartz watches - and that consumers very often value the appearance of a thing over the underlying substance - why aren't many more quartz watches manufactured using gearing that mimics the appearance of automatic watches?

[lostkiwi]

It's far more energy efficient to move the second hand once per second than many times per second. In a wall clock battery life is rarely a consideration but in a watch it becomes very much more important.

[Lorne]

Fullook said:

Lorne said:

they've all got electric motors driving the hands through a thousand fold reduction gearing so have smooth hand motion.

Thanks all for the answers so far...

Forgive my continuing ignorance - some further questions:

1) Are these clocks' electric motors 'quartz regulated' in the same way as a regular quartz watch movement?

2) Does the 'thousand fold' reduction gearing mean the hand is actually moving in tiny steps (1000 / sec ??) but appears smooth to the naked eye?

3) Are the mechanics of these movements the same as the smooth-seeming quartz watch movements mentioned by LordGrover & lostkiwi - i.e. is the difference between them and 'regular' quartz watches just in the gearing?

4) If, as a huge generalisation, automatic watches with their characteristic stuttery-sweep seconds hands command a premium over one-second tick quartz watches - and that consumers very often value the appearance of a thing over the underlying substance - why aren't many more quartz watches manufactured using gearing that mimics the appearance of automatic watches?

1) I think most big electric clocks at train stations etc aren't actually quartz driven but are simply electric powered.
2) for an electric clock it'll be a perfectly smooth motion as the driving thing is a rotating electric motor
3) no idea
4) as 3

[seefarr]

Here you go - probably true for other places' railway clocks:

https://en.wikipedia.org/wiki/Swiss_railway_clock

wiki said:

The station clocks in Switzerland are synchronized by receiving an electrical impulse from a central master clock at each full minute, advancing the minute hand by one minute. The second hand is driven by an electrical motor independent of the master clock. It requires only about 58.5 seconds to circle the face, then the hand pauses briefly at the top of the clock. It starts a new rotation as soon as it receives the next minute impulse from the master clock.[4] This movement is emulated in some of the licensed timepieces made by Mondaine.

[Fullook]

seefarr said:

Here you go - probably true for other places' railway clocks:

https://en.wikipedia.org/wiki/Swiss_railway_clock

wiki said:

The station clocks in Switzerland are synchronized by receiving an electrical impulse from a central master clock at each full minute, advancing the minute hand by one minute. The second hand is driven by an electrical motor independent of the master clock. It requires only about 58.5 seconds to circle the face, then the hand pauses briefly at the top of the clock. It starts a new rotation as soon as it receives the next minute impulse from the master clock.[4] This movement is emulated in some of the licensed timepieces made by Mondaine.

Cool - thanks!

[NDA]

Which model Spring Drive have you bought?

One of the GMT models is on my shopping list - I am also an admirer of the technology and that it's married to exceptional levels of finishing detail too.

[Fullook]

It's the steel diver sbga229.

I ummed and ahhed between it, the snowflake and the spring drive gmts, but ultimately the snowflake felt a bit too grown up, the gmt with the sapphire bezel had a too much going on visually for me and I wasn't crazy about the power reserve treatment on the other gmts.

Good luck with your choice - GS are quite special!

[NDA]

Fullook said:

It's the steel diver sbga229.

Yes, I know it... lovely. Really lovely.

Post some pics when you unwrap it!

[ZesPak]

I found myself wondering the same thing, bought my parents a modern looking wall clock (Karlsonn I think) a couple of years ago. It wasn't really expensive, and as far as I know, hasn't need new batteries yet.

But it runs perfectly smooth, both seconds and minutes...

[Fullook]

I decided to actually do a little research and found this:

https://www.quora.com/Why-are-battery-powered-Quar...

As per the responses above, it seems it's about gearing and the power consumption price you pay for incrementally smaller (higher?) gearing to get a smooth looking sweep.

Now I know the answer to my question and the world seems a slightly emptier place...