Reply With QuoteThere might be slightly more wear, but if you like to see it running leave it running.
Originally Posted by paskinner
Exactly my point, same idea as watch winders.....Why???
There might be slightly more wear, but if you like to see it running leave it running.
I agree with the unnecessary running of a chronograph, only use it when you need to, but the car analogy is terrible.
The only mechanism left running when not in use would be a watch. When not worn it still shows the time.
And a reduced power reserve
Why do you think the power reserve would be affected by running the chrono? Can't see any logical reason why it should be affected , it's not as if the mainspring will run down faster.
The point at which the mainspring can't provide sufficient torque to overcome resistance in the movement will be reached a tiny bit earlier, but if that makes 30 minutes difference to the power reserve I'd be surprised. The last few hours of power reserve are no use to anyone because the amplitude will be so low that the timekeeping will be way out anyway.
Paul
Last edited by walkerwek1958; 4th May 2017 at 15:41.
Maybe that too.
With regards the Seiko 6138/9's with the vertical clutch I always advise customers to use the chronograph as they see fit, but when putting the watch away (if part of a watch rotation) leave the chronograph engaged. This means there'll be less stress on the clutch spring (which can't be serviced) when the watch is hibernating back in the watch box.
This is my point of interest, how to leave the stored chronograph. I know nothing about watch movements, but don't like the idea of leaving a stressed spring if it can be avoided.
Judging by a peek through the glass caseback of my Orient Star chronograph, different advice may be applicable (or not) to Seiko 6S Series calibres.
Mine has a Seiko 6S28 inside which I read features an oscillating pinion as opposed to the vertical clutch arrangement inside a 6138/9.
From my observation, in the chrono running state, where an arm appears to withdraw from the castellated wheel, the two legs of an adjacent and substantial U shaped spring are compressed closer together.
When switched to chrono stopped state, the arm appears to engage between the castellations of the wheel and the two legs of the spring move further apart, suggesting a relaxed state.
I have deliberately avoided guessing at horological terms for these components because choosing the wrong ones might further confuse my explanation!
On the advice of the 6138/9 video to which I posted a link and as verified by Thewatchbloke above, my 6S chrono has been getting stored in the chrono on state because without foundation I assumed technical similarities between the two calibres.
Do my eyes deceive me? I really would appreciate some insight please.
So where does the power come from?
More complications active the more power needed surely?
The Daytona used to be quoted 72 pr and 44 pr with chrono running full time, telling me Rolex are wrong?
Your query is the same as I saw on the dive watch forum at WUS recently where a person complained about numbers on a dive watch bezel making things look cluttered. A chrono with the seconds measurement on a sub-dial can work but its not an optimal design for the purpose.
This is an issue of being frustrated because you bought a specialist tool for a purpose you don't really need and are probably more interested in it's aesthetics than anything else.
Last edited by bedlam; 5th May 2017 at 01:31.
Think about it like the geartrain in a car. There's no way the mainspring can unwind faster due to the chrono being engaged.
Paul
Ok, but in a car the more you use say radio, headlights, AC, the more fuel you use. So I just don't see how running a chrono all the time use no power, it must do
Reasons to leave the chrono running:
The 'main' second hand will operate - fewer people will tell you your watch has stopped!
It may prevent springs losing effectiveness in certain chrono models
Reasons to leave the chrono stopped:
Less wear to the chrono parts - maybe a cheaper service.
Slightly longer power reserve?
My conclusion:
When the watch is run down, start the chrono - otherwise leave it stopped.
Last edited by Caruso; 6th May 2017 at 22:38.
Yes, at idle, turn on all light etc and engine revs faster.
Hei, please check your msg quota, I cannot PM you.
A watch isn't a car engine, they are different surely? The gearing in a watch is constant and regulated very precisely (isn't that the point?). So as Paul said earlier I think, using the chrono isn't going to unwind the mainspring faster ('rev faster'). But as it gets close to being unwound, the torque it needs to deliver decent amplitude will be more if the chrono is running, so accuracy may drop off a little faster and the watch may stop a little sooner that it would have done. I guess that in effect means the power reserve is a shorter, but it's not because the 'engine' has run out of 'fuel' quicker. Hope I've understood that correctly.
BTW I have a vintage chrono where the centre seconds hand runs continuously but can be paused or reset to 0 with 2 different buttons, one in the crown and one at about 8.
That's exactly correct. The mainspring barrel turns at the same rate regardless of the load on the wheel train. It just stops sooner due to extra torque requirements when the chrono is engaged; disengage it and the watch will start running again as normal for a few more hours.
Mate, you just don`t understand cars or watches. Suggest you spend a bit of time reading up on how a clockwork clock or watch really works, then it'll all become clear.
Paul
Full marks, 10 out of 10 , you've been paying attention
I`ve never let a chronograph run down fully with the chrono running then tried switching the chrono off to see how long it'll run.....life's too short!
Paul
Really depends on the chronograph guys. The car analogy is tempting but is not correct. Using the chronograph is not the same as "tuning on the engine", its already on. For a vertical clutch, running the chronograph pretty much doesnt make any difference.
^
Well, at least until the minute counter needs to advance, that is. ;)
Cheers Paul. I was worried I'd taken another wrong fork ;)Full marks, 10 out of 10 , you've been paying attention
What happens to all that potential energy in the mainspring if it isn't all used to run the movement I wonder? Some turns into the ticking sound obviously. Does a watch tick more quietly if the chrono is running? Does it warm up infinitesimally somehow if the chrono is stopped?
The energy from the mainspring is dissipated in driving the movement and imparting impulse to the balance. Most of it is taken up overcoming friction, including driving the hands around etc. The additional energy needed to run the chrono work is very small compared to that required to run the watch. Watches run with lower amplitude when the friction in the pivots, wheels and pallets increases; more torque is needed to run the watch. If a stronger spring is installed a watch gives higher amplitude. Sometimes this factor can be used to good effect with an old watch that's worn.
Friction produces heat, so theoretically a watch will produce heat if left in an isothermal environment.
Clearly we're both definitely overthinking this.........and the only fork I`ll be taking within the next 2 hrs is the one to eat my dinner with
Frankly, I`m sick of chronographs at the moment. Just finished work on a 60s Bulova automatic chrono with micro rotor, that's been an absolute pig of a job. Now I`m fitting a movement to a cheap Fossil quartz chronograph for a friend of a friend.....turns out the watch has had water in and the hands are corroded, I thought the hands were black but it turns out it's tarnish/ corrosion. Wish I`d told him the bloody watch was scrap now!
Anyhow, that's another puzzle to consider.....do quartz chronos run the battery down faster if the chrono's running?
Paul
Cheers Paul. If I wasn't spending time overthinking this I'd have to do some work.
Re quartz chronos, without using Google I'd say yes, they will run down a bit quicker if the chrono is running. Essentially it's just a few more motors running isn't it? So drawing a bit more current.
Also I'm sure I read in the instructions for an old quartz Tissot that the chrono ran down the battery faster. Mind you that was 20 years ago.
While I haven't bothered to do this intentionally, the out-of-chrono-reserve thing has happened to me a few times.Full marks, 10 out of 10 , you've been paying attention
I`ve never let a chronograph run down fully with the chrono running then tried switching the chrono off to see how long it'll run.....life's too short!
Paul
Example scenario: I pick up my Daytona after a few days off the wrist and it's still running; cool, no need to wind and set. I begin making my morning coffee and start timing the extraction — that's typically 90 seconds if I'm using the Aeropress. I've seen the seconds counter moving at the start, but when it seems like it's about the time to press down on the plunger, the hand is stopped at the 60s mark, as there isn't quite enough force left inside the barrel to overcome the resistance of the minute counter's click spring. As soon as the chronograph is disengaged, the watch starts running again. (And then I have to reset it if I'm picky about the time.)
The 4130's power reserve is said to be 66 hours with the chronograph running (vs. 72 hours when disengaged), and I have no reason to doubt this. So while it's apparently true that the additional friction from the chrono geartrain isn't very significant, there's about a six-hour window where the mainspring doesn't have enough torque left to advance the minute counter.
You're absolutely correct, to be able to advance the minute counter wheel has to be driven to overcome the pressure from the jumper/detent spring that acts on its teeth. The spring exerts hardly any pressure, just enough to hold the wheel in position so the registers hand stays on its marker, but as you've observed once the power get very low it's enough to stop the movement dead. Again, as you've observed, disengage the chrono function and the watch will carry on ticking until the power is fully exhausted.
Yep, that's my take on it, the battery should run down faster provided it's a movement with a single battery and stepper motor. Some have more than one.
Having thought about mechanical chronos, when the mainspring runs down they should always stop just as the minute counter is incrementing (or trying to). Even though there's very little tension on the jumper spring it's enough to cause the watch to stop if the mainspring's totally unwound (almost).
Paul
Last edited by walkerwek1958; 11th May 2017 at 17:02.
This was just posted on another forum by watchmaker Al Archer. It touches on this topic towards the end, but I've included the whole thing as it's very interesting.
By request here is some information on vertical clutch chronograph watches. But before we talk about vertical clutch mechanisms, we should cover the basics of the more common horizontally coupled chronograph.
The first thing we should look at it the design of the teeth on the wheels (gears). Now here is what typical wheels look like in the wheel train of a watch. So here you see the teeth on these are multi-radius teeth, with rounded tips, and they are designed with efficiency, low running friction, and minimal wear in mind:
Here is a photo of an Omega Cal. 861:
Now I just want to point out that the part with the “A” on it will swing in and out in the direction of the red arrow to engage and disengage the chronograph. This part is the coupling yoke.
Now here is a closer shot of the teeth:
Now the shape of the teeth here are quite different than those I showed above, and they are very sharp and pointed. The reason for this is that the wheel on the left in that photo is always turning, and when the chronograph is switched, that wheel moves in towards the wheel on the right with much smaller teeth. If the teeth were not pointed, there is a much greater chance that the teeth will not mesh correctly, and the very tips of the teeth will hit each other, causing the chronograph to not engage or the hand to jump forwards or backwards. Even with these sharp teeth the hand can jump forward when you press the start button sometimes.
In addition, these teeth are not as efficient as those designed for pure power transmission as show above, and these teeth can wear more both from just running and also from the teeth hitting each other when they are trying to couple and start the chronograph.
Another horizontally coupled chronograph is the very common ETA 7750. However is is a bit different design than the Cal. 861 is. In this style there is a very small gear called the oscillating pinion that is used to turn the chronograph on and off. Here is a video that shows the oscillating pinion being engaged and disengaged:
So how is a vertical clutch different? Well as the name suggests the action to engage and disengage the chronograph is vertical, so along the axis of the shaft of the chronograph runner. Here is a photo of an Omega Cal. 3300 series movement that is based on a F. Piguet movement during a service I performed some time ago:
You can see the column wheel there at about the 1:30 position, and it has a small cap on top of it. The column wheel is just a type of switch, and both this and cam operated chronographs perform the same function, and are not related to the vertical clutch at all. So to see more I need to show the large main bridge removed. This is a different watch, but still the same movement family. With that bridge and some other parts removed, you can see that the column wheel has a spring that holds it in place when it’s being indexed, and there are a series of levers that are actuated by it:
In this photo those levers are in towards the center of the movement, so they are lifting the disk on the chronograph wheel that engages the vertical clutch – the chronograph is not running in this position. When the column wheel is switched, the levers move away from that disk and let it drop, and the chronograph runs:
So this is more difficult to see the details of than in a horizontally coupled chronograph. To help explain, this is what the central chronograph wheel looks like from this movement:
This is the part that carries central seconds hand for the chronograph function – a long post goes through the middle of this assembly. In a horizontally coupled chronograph, this wheel is separate from the timekeeping train of the watch, and is only activated when the chronograph is switched on. In a vertical clutch system, this wheel serves 2 purposes. It is both a train wheel and a chronograph wheel, so in fact a portion of this wheel assembly runs all the time when the watch is running. Essentially the brass coloured parts are running all the time, where the steel parts only turn when the chronograph is running. The disk that you see on top of the largest diameter wheel is the spring loaded part that is either lifted or lowered by those levers in order to make the chronograph stop or run.
So the two portions of this part have some friction between them when the watch is running, but the chronograph is turned off - the central shaft is stationary while the rest of the wheel is turning. When the chronograph is switched on, the whole unit turns, so although there is added load from moving other parts in the chronograph, the friction between the two parts of this runner (wheel and chronograph parts) is less than when the chronograph is turned off. So which state causes more load on the system? The only way to measure this is through the balance amplitudes. Here is a freshly serviced movement on the timing machine, with the chronograph turned off, so in this case there is some friction between the two parts of that chronograph wheel assembly:
Now let’s see what happens when I turn the chronograph on:
You can see that the balance amplitude dropped 5 degrees from 299 to 294. So is this significant? Well in comparison, on a horizontally coupled chronograph, say the Cal. 1861 based Speemdasters, Omega allows the amplitude on those to drop as much as 40 degrees when the chronograph is switched on, and the watch is still in spec. Personally that seems like a lot to me, and I like to see more like 20 degrees drop, but in comparison, 5 degrees is mostly insignificant. Note that I had not yet adjusted the timekeeping in these photos.
The advantages to the vertical clutch, at least in theory, are many. For one it does not cause a "jump" of the chronograph seconds hand when the chronograph is started due to teeth meshing. Second, because there are no sharp teeth to engage/disengage the chronograph, this one can run all the time with no harm done or excess wear. Lastly, this design actually causes less drag and amplitude drop when the chronograph is running than a horizontally coupled design does.
The biggest draw back is the chronograph wheel assembly – these often can't really be "serviced" at all, and they should not even be put through the cleaning machine according to most brands as this will wash away the factory applied lubrication. The lubrication between the gear that turns all the time and the chronograph runner post is critical, and in some cases it can’t really be renewed in the field, so if this part is seized, it has to be replaced. That is the case for the Omega 3300 series watches certainly, so I end up replacing the chronograph wheels sometimes. When these two parts seize together, the watch will run with the chronograph on, as the whole unit turns, but when the chronograph is switched off, the watch will stop as the large gear will no longer turn. Here is an example of that – freshly serviced movement using the chronograph wheel that came with it:
So the video starts with the chronograph on, and the watch runs fine. As soon as I turn it off, the watch stops. It then restarts when I turn it on again. Replacing this wheel resolved the problem. On vintage watches like the Seiko 6139, new old stock chronograph wheels are sometimes quite hard to find. One thing you should always check if you are considering a purchase is if the watch runs with the chronograph switched off on a 6139. If it runs with the chronograph on, but stops when it's turned off, the wheel has seized and it will be difficult if not impossible to get it running again without a new one. Once they have failed I’ve never been able to get one working properly again.
Now about leaving your chronograph running all the time...personally for most watches where parts are available, I really would not have any problems letting the chronograph run. So on an Omega 861/1861, or a 7750 based watch, the parts that would need replacing from excess wear are readily available and not all that expensive. So if you want to let it run all the time, then in my personal view, go ahead. For a watch where parts are less easy to find, such as a Cal. 321, I would not recommend it. Again you want to preserve the parts in that movement as much as possible.
Now many people have asked on various forums “Does leaving my chronograph running all the time change the power reserve?” The answer to that is no it doesn’t Power reserve is a calculated value based on the number of turns the barrel makes and the gearing in the watch, and since none of those change when the chronograph is switched on, the reserve is not changed. Any watch stops running when the torque delivered by the mainspring drops below the loads in the movement. So anything that adds load to the movement (dirt, debris, or added complications like dates, chronographs, etc.) can cause the watch to stop sooner than without those things - the watch will stop sooner with the chronograph on, simply because the torque supplied by the mainspring can’t overcome this additional load.
You can prove this by fully winding your chronograph watch, setting it aside, and seeing how long it runs before it stops with the chronograph turned off. Then fully wind it, start the chronograph, and then set it aside until it stops. Keep track of how long it ran, and after it stops turn the chronograph off – the watch will likely start up again and run for a few hours depending on the design. if you were to add the total running time of the second test, it will likely equal that of the first test.
Nice one Sean 🖒
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Brilliant photos, excellent explanation of how chronos work. Thanks for posting, one of the best posts qe've had for a while.
My vote goes emphatically for the robust simplicity of the horizontally coupled chrono, others will disagree, but that's my opinion.
Paul
Wow, thanks for the amazing post. Incredible detail
I like to run the chronograph on my Sinn 356 - a 7750 movement (well, SW 500) for aesthetic reasons. It's a good looking watch, may as well get the best enjoyment of watching it moving. This is even more important for those watches with red chronograph second hands.
I think excessive wear would take years before it's an issue, and service periods should handle it, surely?
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