Omega quartz second hand explained

[mjb]

After reading a recent thread regarding Omega quartz second hand not hitting markers, I contacted my semi-official source (you can email me if you are curious.). The following are based on his explainations & my understanding:
(1) The second hand of Omega quartz doesn't hit markers, is it normal?
Yes, it is perfectly normal, and it's due to the movement design, not due to quality control. It doesn't have any influence on accuracy.

This phenomenon is caused by the play in the gears, and the inertia of the second hand jumping motion (related to the second hand's size & weight). The smaller the watch (thus smaller & lighter second hand), the smaller the inertia, the smaller the play, the more accurate it will hit the markers.

This explains why the complaints are often SeMPs (not Constellations and Devilles), becaue of SeMP's long & heavier second hand.

This also explains a phenomenon I noticed in at least 2 of Omega quartzes I've owned: After about 2 years, the second hand started to hit markers more accurately. The lower the battery, the lower the voltage, the less the force driving the second hand, the less the inertia, the less the play, then more accurately hitting markers.

Then, why the play (looseness)? High end quartz movement are jeweled to reduce wear, may not be as tight fit as non-jeweled movements. The looseness also helps to negate the inertia feedback to the movement to prevent wear.

This explains why a $20 watch can accurately hitting markers, while some Omega quartzes often don't, because the $20 watch is not designed to last very long.

(2) Is Omega aware of this? What they do about it?
Yes. Omega recently modified all newer calibers of this type with an iron disc on the second wheel and an tiny magnet attached to the geartrain bridge which makes the second hand jump more accurate and smooth. (like a magnetic brake to negate inertia). Whenever a watch with these calibers is sent in for service the whole movement will be replaced by the new version which is cal. 1538B.

I've owned quite a few quartz Omegas, some exhibit second hand problem, some don't. To me, his explanations totally make sense, and I finally don't have to wonder why.

For us who own current version quartzes, I think there is a "solution": use a half drained battery.:-d

Thanks for reading,
mjb

[Mick no:8]

Thanks for such an indeep explaination. I to have a quartz SMP and just thought that is was just the angle I was looking from. I was so wondering about the 1538-B, since I have the older movement will Omega automaticly change over the movement for me durling the next battry change or do I have to/and only when I ask them to.

[mjb]

Thanks for such an indeep explaination. I to have a quartz SMP and just thought that is was just the angle I was looking from. I was so wondering about the 1538-B, since I have the older movement will Omega automaticly change over the movement for me durling the next battry change or do I have to/and only when I ask them to.

You are welcome. I think "service" means overhaul/repair service, battery change doesn't seem count.

[Terry M.]

Very interesting info. Thanks for sharing!

[g-banger]

thank you... very infomative indeed. ive learnt something new again :)

[fmalloy]

This is one of those weird cases where I can see both sides:

- You're buying quartz - it's already ultra accurate. If the dial isn't printed exactly right or the hand isn't exactly aligned, what do you expect? Shut up and enjoy your precision timepiece!

- You spent HOW MUCH on a watch, and the stupid second hand doesn't line up like a $30 Casio? What is UP with Omega anyway?

I just checked my $30 Timex and you know what? It pretty much hits the mark. Every time I replace the leather band, I'm pretty much re-paying the price of the watch :think:

It just makes me feel good about my Speedy Pro and AT mechanicals. They just sweep so smoothly across the dial you don't even think about it. :-d

[M4tt]

I'm not sure this sounds right. The second hand on a 1970's 36000 manual is moving by around ten discrete ticks a second, more than the sort of error mentioned here. I cannot for the life of me see how a modern cnc cut drive chain has more slack than that.

Second, it seems very odd to claim that the tolerances on a jewelled surface are looser than on a plain surface. Even if they were I cannot see how this is the surface that matters - surely it is the tolerances between the teeth that matter?

Third, the idea of adding a magnet which will put a lot of strain on the drive chain and force the stepper motor to overcome the magnetic force every tick seems, to say the least, odd.

These are all intuitions - as it stands I don't know. But I'm going to find out!

[mjb]

I'm not sure this sounds right. The second hand on a 1970's 36000 manual is moving by around ten discrete ticks a second, more than the sort of error mentioned here. I cannot for the life of me see how a modern cnc cut drive chain has more slack than that.

Second, it seems very odd to claim that the tolerances on a jewelled surface are looser than on a plain surface. Even if they were I cannot see how this is the surface that matters - surely it is the tolerances between the teeth that matter?

Third, the idea of adding a magnet which will put a lot of strain on the drive chain and force the stepper motor to overcome the magnetic force every tick seems, to say the least, odd.

These are all intuitions - as it stands I don't know. But I'm going to find out!
Hi Matt,
Well, if you haven't observed an Omega quartz ticking, this whole thing is really odd: Most WalMart $20 watches are ticking dead on markers, while an $1K+ Omega quartz couldn't.

The explanations are mostly in my words based on my understanding, especially the why the slackness part. They should not be considered claims. But I think I passed on the key reasons rather very accurately.

For you point (1), mechanical watches are totally different animals, the second hand is virtually continuously moving, non-stop. But quartz second hand needs to stop every second, if with very little friction, it can stop at un-wanted places (not hitting the markers).

For you point (2), mounting a gear train to the jewels involving more parts. At the very least, you need to drill big holes to mount the jewels, then mount the gears into the holes of the jewels. If drilling a hole has the tolerance of x, then jeweled geartrain will be 2x of the tolerance of non-jeweled geartrains where gear trains are directly mounted to the holes on a metal plate.

Also, due to less friction between jewels and metal, the gears are moving more freely. If there is any feedback force, it's more easily to move the second hand out of its supposed position.

Slacks between the teeth could be another factor too. But those are all by design, not manufacturing error.

For your point (3), that is not an "idea", it's an already implemented modification by Omega. I consider my source semi-offical because of his profession, his qualification, and where he is working. Part 2 of my post are close to his exact words.

It doesn't sound odd to me. Let's look what makes a quartz ticking: The electrical circuit alternate the magnetic poles of the stator every second, then the rotor (a permanent megnat) rotates and causes the second hand ticking. Basically, it's not the battery who provided the force for second hand ticking, rather it's the magnetic attracting force. Adding a magnetic brake doesn't hurt anything, rather it's a smart way to increase friction without inducing wear I don't see why it would add strains to the geartrain. Due to the inertia force of the second hand, if the geartrain has very little friction, the second hand can easily bounce out of position after each tick. I think low end non-jeweled quartz watches doesn't have the second hand accuracy problem because there is enough friction (more wear) to restrain the inertia force.

Thanks for reading,
mjb

[M4tt]

Hi,

Before I start I just want to make it clear that I really have no intention to insult. Initially this sounded wrong. now I am sure that it is. I guess I am a just a bit pedantic.

Well, if you haven't observed an Omega quartz ticking, this whole thing is really oddFunnily enough I have. I own a ten year old SeMP, a two year old Perpetual Double Eagle Constellation (the one with the precision thermocompensated movement) and a humble Deville, All of them hit the second markers perfectly - as do all of my mechanical Omegas - every eighth tick.

Most WalMart $20 watches are ticking dead on markers, while an $1K+ Omega quartz couldn't. Sorry, in my experience, neither of these claims are true.

For you point (1), mechanical watches are totally different animals, the second hand is virtually continuously moving, non-stop.This was my point, they certainly are not continuously moving. A modern mechanical Omega's second hand will utterly stop eight times a second - and start again - if this is hard to believe, examine one under a loupe.

But quartz second hand needs to stop every second, if with very little friction, it can stop at un-wanted places (not hitting the markers).
While this is ambiguous, both possible meanings are false. The stepper motor of a modern watch moves the drive train by a precise amount. This movement is passed along the drive chain - with a minuscule amount of play. If friction stopped the second hand early then the watch simply would not keep time.

If however you mean that there is less friction in the drive chain then the watch would move the second hand with more precision - as it in fact does.

More to the point, this is an utterly different explanation to your first one - which was:

This phenomenon is caused by the play in the gears, and the inertia of the second hand jumping motion (related to the second hand's size & weight). The smaller the watch (thus smaller & lighter second hand), the smaller the inertia, the smaller the play, the more accurate it will hit the markers.So, is it friction or inertia?

For you point (2), mounting a gear train to the jewels involving more parts. At the very least, you need to drill big holes to mount the jewels, then mount the gears into the holes of the jewels. If drilling a hole has the tolerance of x, then jeweled geartrain will be 2x of the tolerance of non-jeweled geartrains where gear trains are directly mounted to the holes on a metal plate.Your assumptions are: first, that we cannot machine both metal and jewels to tolerances that are orders of magnitude higher than our eyes can perceive. Second tolerances multiply like this in this application. Both assumptions are false.

Also, due to less friction between jewels and metal, the gears are moving more freely. If there is any feedback force, it's more easily to move the second hand out of its supposed position.I'm not sure I understand what you mean by 'feedback force' I will assume you mean inertia. In which case, are you trying to say that the inertia of the second hand moves the second hand beyond the point the designers intended?

If so then you really need to do some research on both the accuracy of a stepper motor and the precision of the drive train - A modern drive train's backlash would not be perceivable, even through a loupe, unless the watch was dreadfully worn - by which time the watch's accuracy would have gone to pot anyway.

Slacks between the teeth could be another factor too. But those are all by design, not manufacturing error.No, see above


It doesn't sound odd to me. Let's look what makes a quartz ticking: The electrical circuit alternate the magnetic poles of the stator every second, then the rotor (a permanent megnat) rotates and causes the second hand ticking. Ok, I'll call that close enough - but it is just a teeny weeny bit more complex than that... (see: http://en.wikipedia.org/wiki/Stepper_motor )

Basically, it's not the battery who provided the force for second hand ticking, rather it's the magnetic attracting force. Yes it is; the battery both powers the control circuitry and provides the power for the electromagnets that move the stepper motor by a very very accurate series of steps. This power comes indirectly from the battery and explains why a watch stops when the battery goes flat.

Adding a magnetic brake doesn't hurt anything, rather it's a smart way to increase friction without inducing wear I don't see why it would add strains to the geartrain. First, a magnet will not increase friction at all. friction occurs when two objects rub together - I'll assume that was just a mistake.

Second. The reasons it is a bad idea are many. The first is simply that the electromagnet in the stepper motor would need to be more powerful to overcome the effect of the magnet. This would drain the battery faster and stress the stepper motor further. Second the part of the drivetrain between the motor and the magnet would certainly be under more stress as it would have to transmit the force needed to overcome the magnet - and stress means wear.

Due to the inertia force of the second hand, if the geartrain has very little friction, the second hand can easily bounce out of position after each tick. As above. No it cannot as it is held very precisely in place by the drivetrain.
There simply isn't the sort of play in the drivetrain that you imagine there is.

I think low end non-jeweled quartz watches doesn't have the second hand accuracy problem because there is enough friction (more wear) to restrain the inertia force. If your logic was correct - which I am now quite certain it isn't - then the cheap watch would have the opposite problem - there would not be enough momentum in the second hand to overcome the friction and the hand would undershoot.

Sorry to be so dismissive.

[mjb]

There are a lot of flaws in your reply, here are a few:
is it friction or inertia?
Low friction or big inertia have the same effect on the second hand play. Are they related or
utterly different?

it is just a teeny weeny bit more complex than that...
No, it's much simpler than the "stepping motor" you pointed to. Care to figure out how a quartz watch is designed?

A modern mechanical Omega's second hand will utterly stop eight times a second - and start again - if this is hard to believe, examine one under a loupe....
That is true. but your what you imply is false. For example, when you ask to run at certain speed vs. to jump at the same speed, the body impact is quite different.

move the stepper motor by a very very accurate series of steps.
False. Quartz watch is one step per second, each step is 180 degree rotation of the rotor.

a magnet will not increase friction at all. friction occurs when two objects rub together -
I should say "equivalent friction". Due to the magnet, the second wheel won't be moving as freely as when without. I guess that's equivalent to friction, a restraining force, unless you have a better word for it.

"...a bad idea"
Again, this is not just an idea, it's an already implemented modification by Omega. The information was from a person who actually do your services at Secaucus, NJ. I have no reason to doubt him.

I never noticed the second hand error in Omega constellation and Devilles (I've owned a few of those too), but I noticed the error in Omega Seamaster SeMP quartz (cal.1538), Omega SeMP ladies (cal.1424), Omega Aqua Terra 35mm quartz (cal.1538), Omega Aqua Terra 38mm quartz (cal.1538), Omega Aqua Terra 38mm 18K/SS (cal.1538). Every single one of them, except the SeMP bond, which magically became almost dead on after about 2 years.

Probably, you can do some research, make some contacts, and provide us your explanations regarding the quartz second hand issue.

Let me know what you find out.
Thanks,

[M4tt]

Enough said.

I think our replies speak for themselves.

For any who are interested I vaguely remember that there was a thread on this over at the HEQ forum.

[Sushirob]

One item that has been missed in this whole discussion, and that is, the center of the dial, and the center of the movement are NOT properly aligned in some of these watches. This will cause the second hand to be on the markers on part of the dial, but not on others. My Citizen watches are inexpensive watches, and that company took the time to make sure the centers of the dial and movement are lined up on the same center line. Other than that, one only needs to place the second hand to be in line with one of the markers and you're off to the races.:-)

[mjb]

One item that has been missed in this whole discussion, and that is, the center of the dial, and the center of the movement are NOT properly aligned in some of these watches. This will cause the second hand to be on the markers on part of the dial, but not on others. My Citizen watches are inexpensive watches, and that company took the time to make sure the centers of the dial and movement are lined up on the same center line. Other than that, one only needs to place the second hand to be in line with one of the markers and you're off to the races.:-)

That is indeed a possibility. I strongly believe that Omega's quality control is at least as good as Citizen.

The dial is fitted to the movement by 2 dial feet. Before the dial feet are soldered to the back of the dail, there are already marks on the back. Unless the feet are both out of position by the the same amount, they cannot be installed properly. If that's the case, it will cause slightly misalignment. But for every tick, the second hand will miss the marks by same amount. In my experience with Omega 1538, that is not the case. Every tick is not even. I don't think dial installation error or mis-printed marks are to blame.

[mjb]

Enough said.

I think our replies speak for themselves.

For any who are interested I vaguely remember that there was a thread on this over at the HEQ forum.
Cool. That is the purpose of a forum. Debating discussing, sharing info, and having fun.
I feel that we have a lot in common. I won't easily believe what I've been told, unless I can make logical sense of it. Whoever that person is. I like your post.

This issue has been poping up in watch forums since long time ago. There have been several versions of explanations by various people. I'm not saying the everything in my previous post is accurate or valid (mostly based on my knowledge of quartz watches), but I can say that the key points are accurately presented, as what I've told by a watchmaker who works in Swatch Group Service/Omega department.

Cheers,
mjb

[M4tt]

That's cool,

You were right about the complexity of the stepper motor by the way. I understand the point about inertia and play in the system I'm just not sure there is enough to notice. We will just have to agree to disagree. I think we have both made our points.

Sushirob's explanation is certainly the one generally agreed, after a fair bit of discussion, by the HEQ forum.

However, I just want to make it clear that Citizen make a wide range of watches - from the dirt cheap into the Omega price range. At the moment the two most accurate watches on the planet are both Citizens: the Chronomaster with the A660 movement (less than +/- 5 seconds a year) and the Exceed; either A690 or E501 (+/- 10 seconds). The closest Omega to this are the Perpetual Constellations at +/- 20 seconds.

The experience of the HEQ mob is that the Citizens usually better this minimum out of the box while Swiss brands need fettling before they start to give this degree of accuracy. Maybe the Citizen quality control is not so bad on the higher end watches.

My personal experience is that my Perpetual and my Exceed have remained exactly in sync and bang on time for the last two months.

[mjb]

We will just have to agree to disagree. I think we have both made our points.
Sure. Some details of my analysis may be subjected to debate. But the reason and solution (cal.1538B) was provided by semi-official source in a private communication, not my opinion. I added my own analysis to help people to understand. If I simply played a messenger, it's gonna be a simple post: "normal. due to play in the gears, and weight-length of 2nd hand. ...1538-b....".


However, I just want to make it clear that Citizen make a wide range of watches - from the dirt cheap into the Omega price range. At the moment the two most accurate watches on the planet are both Citizens: the Chronomaster with the A660 movement (less than +/- 5 seconds a year) and the Exceed; either A690 or E501 (+/- 10 seconds). The closest Omega to this are the Perpetual Constellations at +/- 20 seconds.


I believe Citizen makes good watches in their top range. But all those thermal compensation and accuracy talks are pretty much marketing hype, and if you're not planning to go to a desert or explore the north pole, it offers very little practical advange. Thermal compensation only improves consistancy w.r.t. temperature, it's the accuracy of the quartz crystal that ultimately determines the accuracy. If the quartz crystal is slightly off, thermal compensation could make the watch accuracy worse. Also, thermal compensation is simple, only worth a class project of an EE major freshman, by no means high-tech, certainly not worth all those hoopla. From what I've read, Citizen recommends wearing the watch for 12hrs/day to guarantee accuracy, what? Isn't it thermal compensated?

Many non-thermal compensated watches are already super accurate, for example, my SeMP bond was about 1 second fast in 1.5 years, my Constellation was about 10 seconds fast in 1 year.

The beauty of normal quartz is its simplicity, both in design and implementation. As for thermal compensated watches, the IC circuit is slightly more complex. ETA thermal-line (SuperQuartz) seems to store the thermal curve in the memory as lookup table, then use the value indexed by thermal sensor to adjust frequency in order to compensate temperature change. It may require more battery drain.


The experience of the HEQ mob is that the Citizens usually better this minimum out of the box while Swiss brands need fettling before they start to give this degree of accuracy. Maybe the Citizen quality control is not so bad on the higher end watches.

My personal experience is that my Perpetual and my Exceed have remained exactly in sync and bang on time for the last two months.
I've never seen a highend Citizen in person. They seem very nice and accurate. I like quartz watches too, just that I never consider accuracy a factor in my buying decisions, I put more weight on workmanship and design.

[M4tt]

Like I have said already we will just have to agree to disagree on that one - I get paid to argue and there's only so much I want to do in my free time.

I'm sorry you feel that way about high end quartz. Given the quite unique accuracy of your particular SeMP I can see why you consider that thermocompensation is a waste of time. However, most people do not have such a wide range of watches performing quite so well as yours.

As for whether it is 'just hype' I guess we come back to the old ' a five dollar Timex is more accurate than any mechanical so why pay more?' argument. Like you, I like excellent design and execution and I am prepared to pay for it. You may "never consider accuracy a factor in my buying decisions" but I do, I consider this to be part of excellent design and I am prepared to pay for it.

If, as you seem to imply, you do not think Citizens are well designed or made then I encourage you to try a higher end one. You would be surprised.