Automatic winding

[ratty]

Hello

Happy New Year.

Can anyone give me some idea about how many revolutions the weight in an automatic watch has to make to keep a watch wound up? If a watch is fully wound, roughly how many revs are required in, say, 24 hours to keep it fully wound?

Thanks.

[Tools]

It takes around 650 turns of the rotor each 24 hours just to keep the watch at a static state of wind.

From a dead stop, it would take around 1,300 turns of the rotor to wind the typical 31xx movement completely.

It is much easier to just give the watch ~40 turns of the crown.

[ratty]

That was quick!!

Thanks for this.

Recently I've been thinking about how much movement the rotors in my watches actually get in day to day life. I doubt that walking about makes much difference as the rotor will not move much in relation to the case / movement when walking. Is there much difference in the revolutions required to keep a simple 3 hand watch like a Sub. wound in comparison to a Daytona?

Thanks again

[nevergiveup]

Walking certainly does wind your watch, unless you walk without moving your arms.

[ratty]

Originally Posted by nevergiveup

Walking certainly does wind your watch, unless you walk without moving your arms.

It's not the arm's movement which winds the watch, it's the movement of the rotor weight in relation to the watch's movement which winds it.

I suspect walking is not an efficient way for the self winding system to work. As the arm swings, the rotor is unlikely to remain pointing directly downwards, gravity is acting on it but so is centrifugal force, albeit lightly. The arm would have to swing thousands of times in order to make the rotor turn full circle hundreds of times. I suspect that someone would have to walk miles to keep a watch fully wound.

[Tools]

Originally Posted by ratty

. . . Is there much difference in the revolutions required to keep a simple 3 hand watch like a Sub. wound in comparison to a Daytona?

Thanks again

Efficiency of the rotor is a function of gearing. A Daytona, without the chronograph running, is a "simple 3 hand watch".

If the chrono is running, a Daytona will need more power, since the laws of physics apply. You cannot do more work at the same power level.

Since the Daytona has a larger mainspring (power reserve), it would take more "winds" to fully wind it from a dead stop, both at the rotor, or at the crown.

[ratty]

Thanks again.

[Yess]

If it's not walking, then is it those times you lift your hand, or scratch your nose, or....?
Genuinely interested in what actions are most beneficial.

[Andad]

Originally Posted by Yess

If it's not walking, then is it those times you lift your hand, or scratch your nose, or....?
Genuinely interested in what actions are most beneficial.

Ummmmm.........??

[Yess]

Originally Posted by directioneng

Ummmmm.........??

It seems that it doesn't take much movement to get a revolution. But I do get the walking, arm down, and gravity issue as possibly not the most efficient way to wind. I can imagine lifting your wrist vertically to your face/sky, which we do more often than we realise, is likely the best way (particularly at speed, which is what we do when we have an itchy nose). But I am interested in the 'mechanics' behind it.