Amplitude fluctuates sinusoidally in a 1-minute interval

[NoMercy]

Hello fellow watchmakers,

During my work, I encountered several serviced watches with amplitude fluctuation sinusoidally in a 1-minute interval. Most are Omega 500 family & IWC 853x, 854x family.

Please look at the 2 graphs below for more details: 1 is from an Omega 504 and the other is from an IWC 8531.

Did anyone encounter the same problem before? I think it is caused by a wheel that takes 1 complete rotation in a minute, but I'm not sure.

[RichardHarris123]

I don't know but you could be correct.  Have you checked the teeth on the minute wheel? 

[Nucejoe]

You are right.

Do they actually  lose  time on bench ? 

How do you clean the parts? 

Let me clarify my quesrion. 

Does the watch actually lose time on bench?  the reason I ask is; graphes are not neccesarilty 100% reliable. 

Edited March 25, 2023 by Nucejoe

[JohnR725]

Interesting witschi software Which timing machine did it come from?

1 hour ago, NoMercy said:

During my work, I encountered several serviced watches with amplitude fluctuation sinusoidally in a 1-minute interval. Most are Omega 500 family & IWC 853x, 854x family.

So we see watches with problems do you see watches without problems? In other words could this be a normal behavior for these particular watches and if so is it representing a problem or not? Watches are interesting in that they will average out their problems sometimes.

To understand this we need something vintage like the PDF found at the link below a vintage timing machine manual.  Starting on PDF page of 15 it talks about things that repeat

http://www.historictimekeepers.com/documents/Micromat.pdf

2 hours ago, NoMercy said:

Did anyone encounter the same problem before?

More than likely other people in the group have encountered the same problem but were unaware of what the problem is. Typically on timing machines the only way that this normally manifest itself is if you're looking at the numbers like amplitude and you'll notice the numbers drifting up and down and if it's slow enough you can perhaps time it and see a pattern. But otherwise most people don't have time plot capability of the timing machine to the totally unaware of the problem.

You'll notice in the PDF manual the way they notice the problem is by looking at the variation on the paper tape. But on modern LCD screens you don't have enough screen sometimes see the problem and other times it just doesn't show up at all at least in a way that you can see. So this means a lot of people have the problem and are totally unaware of it because they don't have the right timing machine. Although there is some software programs that will show this but most people don't have that either

Typically the times when I run the time plot at work is if I'm running a timing cycle MIC fluctuations. That I run the time plot to see why have a fluctuation and then typically I never worry about it ever again. But you can have time plot issues that will affect the timekeeping and then you'll have to worry about what the problem is impossibly replacing wheel. Or in my case I once replace the entire mainspring barrel assembly to make the timing issue go away. Because for that particular incident I couldn't even run normal timing machine it wouldn't time the watch at all.

Because it looks like a sine wave things like a bent pivot or out of round wheel.

 

 

 

 

[RichardHarris123]

2 minutes ago, JohnR725 said:

Interesting witschi software Which timing machine did it come from?

So we see watches with problems do you see watches without problems? In other words could this be a normal behavior for these particular watches and if so is it representing a problem or not? Watches are interesting in that they will average out their problems sometimes.

To understand this we need something vintage like the PDF found at the link below a vintage timing machine manual.  Starting on PDF page of 15 it talks about things that repeat

http://www.historictimekeepers.com/documents/Micromat.pdf

More than likely other people in the group have encountered the same problem but were unaware of what the problem is. Typically on timing machines the only way that this normally manifest itself is if you're looking at the numbers like amplitude and you'll notice the numbers drifting up and down and if it's slow enough you can perhaps time it and see a pattern. But otherwise most people don't have time plot capability of the timing machine to the totally unaware of the problem.

You'll notice in the PDF manual the way they notice the problem is by looking at the variation on the paper tape. But on modern LCD screens you don't have enough screen sometimes see the problem and other times it just doesn't show up at all at least in a way that you can see. So this means a lot of people have the problem and are totally unaware of it because they don't have the right timing machine. Although there is some software programs that will show this but most people don't have that either

Typically the times when I run the time plot at work is if I'm running a timing cycle MIC fluctuations. That I run the time plot to see why have a fluctuation and then typically I never worry about it ever again. But you can have time plot issues that will affect the timekeeping and then you'll have to worry about what the problem is impossibly replacing wheel. Or in my case I once replace the entire mainspring barrel assembly to make the timing issue go away. Because for that particular incident I couldn't even run normal timing machine it wouldn't time the watch at all.

Because it looks like a sine wave things like a bent pivot or out of round wheel.

 

 

 

 

Out of round wheel I can understand but wouldn't a bent pivot be out all the time. 

4 minutes ago, RichardHarris123 said:

Out of round wheel I can understand but wouldn't a bent pivot be out all the time. 

Just realised that a bent pivot would vary in accuracy, sometimes binding, sometimes loose, sometimes just right.  Like goldilocks.  Hehe. 

[Nucejoe]

13 minutes ago, RichardHarris123 said:

Out of round wheel I can understand but wouldn't a bent pivot be out all the time. 

Any fault in sweep or subsecond assembly can cause this. 

Bent pivot or arbour, worn jewel hole, wobbly gear, dirty pinion leaves or even gear teeth. But OP encounters the same problem with all Omega and IWC  pieces he services. 

I am not sure if the said pieces have high precision gears, in which case poor cleaning can be problematic.

Edited March 25, 2023 by Nucejoe

[JohnR725]

Let me give you an example of something that is it or is it not a problem? The Hamilton 992B in question currently is in need of servicing. But before was in need of servicing as far as I get tell it kept really good time and worked absolutely perfectly. No idea when it was last service though I purchased it in nice running condition. So here you can see in the time plot patterns of wheels that are probably not perfect remember when the watch was made they weren't using a timing machine like this to make sure everything was perfect. On the other hand look at the timekeeping look how tight that timekeeping is despite an amplitude fluctuation.

[xyzzy]

1 hour ago, RichardHarris123 said:

Out of round wheel I can understand but wouldn't a bent pivot be out all the time.

Not a mechanical engineer, but isn't the force from the driving wheel on the pinion in a certain direction w.r.t. the plane the wheel is in?  So the bent pivot could be through as pushing the pinion into or away from the wheel driving it as the position changes.  And this would cause more or less efficient movement on a cycle the same as the wheel with the bent pivot?

[Knebo]

On 3/25/2023 at 9:43 PM, JohnR725 said:

Because it looks like a sine wave things like a bent pivot or out of round wheel

This makes the most sense, I think. If it's a pattern repeating every minute, it should have something to do with the seconds wheel (one revolution = 1 minute). The engagement (in other words: the friction) of the seconds wheel teeth with the pinions of escape wheel and the minute wheel will then vary over the course of a minute. That would explain the varying amplitude, no?

@NoMercy, have you checked the wheel yet? You may be able to see a wobble from the side while the movement is running.

 

 

PS: I might have just written what you expressed in different words.

On 3/25/2023 at 11:35 PM, xyzzy said:

Not a mechanical engineer, but isn't the force from the driving wheel on the pinion in a certain direction w.r.t. the plane the wheel is in?  So the bent pivot could be through as pushing the pinion into or away from the wheel driving it as the position changes.  And this would cause more or less efficient movement on a cycle the same as the wheel with the bent pivot?

 

[praezis]

As already indicated: a problem for the person owning a timing machine, rather no problem for the person wearing the watch.

The timing of such fluctuation can have two reasons:
a) revolution of a wheel 
b) passing of one tooth

each in 1 minute here. I see more often b).

The 1st picture shows another fluctuation (5 minutes) 

Frank