Date change mechanics

[aaronch]

Hi all, I know there have been a couple of similar threads in the past but I haven't been able to find a definitive explanation of why the date change on Rolex watches aren't exactly on midnight?

Is there a difference between when the date changes if you manually move the hands past midnight vs letting the movement tick over?

The reason I ask is that I have a Cartier Tank Solo XL, which date changes exactly on midnight when I manually move the hands past midnight - if Cartier can do it, why can't Rolex?

Appreciate your thoughts

Cheers!


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[Brew]

Hi: https://www.rolexforums.com/showthread.php?t=738359

[aaronch]

Originally Posted by Brew

Hi: https://www.rolexforums.com/showthread.php?t=738359

Thanks, Brew! Maybe I'm misunderstanding but I'm still unclear as to why the two methods (manual vs movement) would have different results? I thought that manually moving the hands will move the gears/movement in the same way as it would move naturally so why would the result be different? Someone mentioned lubrication, oils etc as a factor but wouldn't those factors also be a factor if you manually move the hands as well?

Thanks again


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[Jostack]

The Rolex specification does not call for it to change exactly at midnight.

[aaronch]

Originally Posted by Jostack

The Rolex specification does not call for it to change exactly at midnight.

Yes but why?


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[Jostack]

Probably the same reason they don’t spec timekeeping accuracy at +/-0

[Quailhunter]

Rolex probably thought no one would care if the date flipped exactly at midnight or a few minutes past.

[Bigblu10]

Originally Posted by aaronch

Hi all, I know there have been a couple of similar threads in the past but I haven't been able to find a definitive explanation of why the date change on Rolex watches aren't exactly on midnight?

Is there a difference between when the date changes if you manually move the hands past midnight vs letting the movement tick over?

The reason I ask is that I have a Cartier Tank Solo XL, which date changes exactly on midnight when I manually move the hands past midnight - if Cartier can do it, why can't Rolex?

Appreciate your thoughts

Cheers!


Sent from my iPhone using Tapatalk

It can be corrected by removing the hands and repositioning them when the date wheel snaps to the next date. But I believe Rolex allows for some deviation either way. Remember it is a mechanical movement. Enjoy it the way it is. You could send it into RSC for adjustment, and have a scratched watch returned to you.

[aaronch]

So is it due to technical difficulties in getting it to tick over exactly at midnight or just that they didn't bother to do it?

If technical difficulties, would someone be kind enough to explain why the date will tick over exactly at midnight if the hands are manually moved but not if it's left to tick over by itself?

Please forgive my lack of knowledge of watchmaking.. Just trying to learn!

Thanks


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[AJV_36]

Originally Posted by aaronch

So is it due to technical difficulties in getting it to tick over exactly at midnight or just that they didn't bother to do it?

If technical difficulties, would someone be kind enough to explain why the date will tick over exactly at midnight if the hands are manually moved but not if it's left to tick over by itself?

Please forgive my lack of knowledge of watchmaking.. Just trying to learn!

Thanks


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Now this doesn’t bother me, but to be honest the first time I saw it yes sometimes I work nights and do see it I was like what the heck but reading here learned it’s normal for my sub to change at 12:02 but I do get your point you pay for a highly accurate time keeping piece and man are they ever highly accurate it does seem strange it does click over exactly when ones watch hands hit midnight. Though 90%of the time we never see it anyways haha!


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[DCheeta]

Buy a smartwatch.

[pickettt]

Originally Posted by aaronch

So is it due to technical difficulties in getting it to tick over exactly at midnight or just that they didn't bother to do it?

If technical difficulties, would someone be kind enough to explain why the date will tick over exactly at midnight if the hands are manually moved but not if it's left to tick over by itself?

Please forgive my lack of knowledge of watchmaking.. Just trying to learn!

Thanks


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Maybe it'd be a better question in the Rolex Watchtech subforum. If you're lucky you can get an answer from someone who knows why it doesn't, instead of apologist reasoning as to why it doesn't need to.

[aaronch]

Originally Posted by pickettt

Maybe it'd be a better question in the Rolex Watchtech subforum. If you're lucky you can get an answer from someone who knows why it doesn't, instead of apologist reasoning as to why it doesn't need to.

Thanks Pickett, will do. Don't know why people get so defensive over this... I'd imagine anyone working night shifts would find inaccurate dates pretty annoying.


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[One&done]

Originally Posted by aaronch

Thanks, Brew! Maybe I'm misunderstanding but I'm still unclear as to why the two methods (manual vs movement) would have different results? I thought that manually moving the hands will move the gears/movement in the same way as it would move naturally so why would the result be different? Someone mentioned lubrication, oils etc as a factor but wouldn't those factors also be a factor if you manually move the hands as well?

Thanks again


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Tools’ post in the linked thread explains clearly and succinctly. It is obvious that when you take up slack in the gear train in one direction, you create a difference in the relative position of the hands vs some gears as compared to when they sit closer to the middle of the range of play. You should be able to feel (and see) the slack taken up if you are gentle. Just play with it.

[THC]

I am never up that late, anyway... I have had a DD since last December and have yet to see when it changes over. Lol

[padi56]

Originally Posted by aaronch

Thanks Pickett, will do. Don't know why people get so defensive over this... I'd imagine anyone working night shifts would find inaccurate dates pretty annoying.


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Cannot understand why as long as the date changes as it can only change when the hour hand has made two complete 12 hour turns around the dial.Then the date will change instant but depending on how the hands are placed on the hand stack. Some change a little before midnight some a little after and its nothing to do with accuracy.And can assure your the only thing a night worker would be interested is the time on the dial.And not the date that might change a few minutes either side of midnight.