Why does the rate start to rush when I work out?

[VWatchie]

One of my favourite vintage watches from the 70s houses an automatic ETA 2772. I have serviced it and everyday use is unproblematic. At full wind its amplitude is about 280 degrees dial up and dial down, and about 250 degrees in all other positions. The beat error varies between 0.0 ms and 0.3 ms depending on position and the rate is normally +/-5 seconds per day.

However, when I take the watch for a brisk walk and some jogging while also moving my arms quite vigorously for about 40 minutes, the rate speeds up to about 400 seconds per day. As soon as I stop working out the rate returns to its normal +/-5 seconds per day.

So, I have two questions:
a) Why does my watch start to rush when I work out, swinging my arms, and
b) Is there anything that can be done to fix it?
 

Edited July 1, 2020 by VWatchie

[JohnR725]

You probably should time the watch in six positions and write all the numbers down. So style up dial down and four separate  Crown positions  or the dial on the watch like 6 o'clock high 6 o'clock low something so you know what all the four positions are. Then typically on any watch you wind it up let it run about 1530 minutes before timing but wind it up all the way until you feel the mainspring slipping is this an automatic  or  wind it up until its tights even though it is an automatic then time it.. If your mainspring is not slipping it's going to get that little bit of extra energy  and it's going to screw up timekeeping possibly. You might even put it on the timing machine and when it's stable slowly wind it up and see if you can wind it up to the point where it speeds up.. Then you're also doing six position timekeeping to make sure there isn't some position where they hairspring is touching something it's not supposed to.

[saswatch88]

8 hours ago, VWatchie said:

So, I have two questions:
a) Why does my watch start to rush when I work out, swinging my arms, and
b) Is there anything that can be done to fix it?
 

A: because laws of physics do exist inside of a watch escapement. Vigorous movement will add force to the balance wheel, causing it to store more energy and run faster. The amount of energy stored will depend on the duration of the activity...and that will determine how long it takes for the additional force to be expensed and return back to normal rate.

B: nothing you can do its the laws of physics at work.

[Nucejoe]

In dynamic state and with associated random high amplitude, hairspring may stick.

A video of HS  as you manually complement barrel power, would reveal such sticking. Should you set up for vid, I try to capture the guard pin as well.

 

[rodabod]

I have to agree with JohnR in principal here. It's not typical for a movement (especially a quality movement like that) to encounter a terrible error like that. Escapements like these are designed to be isochronous to the extent that they should not vary considerably in rate with the amount of energy that is transferred into them, unless they are driven into banking. I exercise most days and I've never encountered any of my watches doing anything like that. Maybe I've been lucky.

 

[saswatch88]

17 minutes ago, rodabod said:

I have to agree with JohnR in principal here. It's not typical for a movement (especially a quality movement like that) to encounter a terrible error like that. Escapements like these are designed to be isochronous to the extent that they should not vary considerably in rate with the amount of energy that is transferred into them, unless they are driven into banking. I exercise most days and I've never encountered any of my watches doing anything like that. Maybe I've been lucky.

 

The movement is a much older eta, so it could very well need a cleaning, the hairspring could be sticking like NUCE said causing the dramatic increase in rate.

[Nucejoe]

Wear and damage brings imperfections, Is this balance complete the Genuine? or rebuilt and properly? Is it as perfect as it left the company? Same questions apply to the rest of escapement.  Oscillations can get out of control in dynamic state if a faulty guard pin isn't guarding right.

I think VWatchie posted a walkthrough of this, helps to browse over it.

Regards 

 

[eric9000k]

Time should be passing more slowly if you accelerate, maybe it's just general relativity.

[Nucejoe]

19 minutes ago, eric9000k said:

Time should be passing more slowly if you accelerate, maybe it's just general relativity.

Not if HS sticks.

[rodabod]

42 minutes ago, eric9000k said:

Time should be passing more slowly if you accelerate, maybe it's just general relativity.

[VWatchie]

10 hours ago, Nucejoe said:

I think VWatchie posted a walkthrough of this, helps to browse over it.

Yes, you're right about that joe. Here it is!

[Nucejoe]

Ya, I remember the clean and picture quality stuck that walkthrough in mind. 

I wonder if you had discussed or paid special attention to the guard pin back then. One picture shows the fork short of guard pin.

[VWatchie]

13 hours ago, Nucejoe said:

One picture shows the fork short of guard pin.

This is the final picture of the pallets during the assembly of the actual watch that is rushing when moving my arms around while working out. I browsed through all of the pictures where the pallets are visible but in none of them the guard pin is missing. Perhaps that's not what you're saying? Can you copy and paste the picture in which "One picture shows the fork short of guard pin"? Hopefully that will make it clear!

EDIT: No I haven't tested the clearance of the guard pin but I'll consider it.

Edited July 3, 2020 by VWatchie

[rodabod]

In my opinion, mislocking would be less likely to cause a rate increase like that. I think it's more likely that the balance is naturally oscillating at a higher frequency.

Edited July 3, 2020 by rodabod

[Nucejoe]

If the guard pin gets pushed in towards fork pivot (say during the clean) the created  excess clearance from the roller table lets untimely exist of guard pin out of the roller hollow, in the event of vigorous wrist motion. 

Just by look, guard pin seems Ok in the pic you show above, motion picture should show if such excess clearnace exists.

 

[Nucejoe]

On 7/2/2020 at 3:10 PM, eric9000k said:

Time should be passing more slowly if you accelerate, maybe it's just general relativity.

No need to accelerate,  time passes slower by just motion.

Time is the amount of motion. The faster you spend of the amount, the sooner you run out.

[rodabod]

I'd be interested to know if you have ever encountered a mislocking (due to lack of safety roller function) lever which has caused a watch to gain considerably like this. I certainly haven't. Mislocking of that nature can lead to the balance being "over-banked" which stops it entirely which is certainly something I have experienced before.

[Nucejoe]

Clicked on where you said " here it is" , doesn't show all the pictures, only this,

[Nucejoe]

1 hour ago, rodabod said:

I'd be interested to know if you have ever encountered a mislocking (due to lack of safety roller function) lever which has caused a watch to gain considerably like this. I certainly haven't. Mislocking of that nature can lead to the balance being "over-banked" which stops it entirely which is certainly something I have experienced before.

1-Imperfect hairspring coil can foul itself when amplitude gets too high so the rate goes fast , until such time that  HS coil jumps back to normal. 

2- Loose and pushed back guard pin, fails to guard the roller table- impulse jewel properly, in which case if the balance wheel gets in a hurry on wrist it is susceptible to the condition in section 1. 

Faulty guarding by the pin, can let the condition for sticking to come about.

 

 

 

 

 

[VWatchie]

So, I have some interesting and encouraging news. Instead of analyzing what could possibly be wrong with my automatic ETA 2772 watch, I studied how exactly I move my arms when working out. It turns out that after each interval training session I would jerk my elbow quite violently while walking and recovering my breath. I'm pretty sure this induces a very unnatural stress on the balance wheel, and my elbow, so decided to go slightly easier without really sacrificing any natural motion of the arms.

The result? My watch won't rush and works perfectly normal. I believe I read in an automatic watch manual some years ago that the watch should not be subjected to sudden impacts like when playing golf or tennis. The manual didn't state what "damage" it would do, but I think I know now. So, I believe @saswatch88 was right on the money in this post.

[anilv]

4 hours ago, VWatchie said:

I believe I read in an automatic watch manual some years ago that the watch should not be subjected to sudden impacts like when playing golf or tennis.

I think the danger mentioned in the manual is related to dislodging the regulator / hairspring and thereby messing your timing up.

Anilv

[CaptCalvin]

Got a test I think would be interesting to try. Fully wind it and put it on the time grapher. Then with a piece of peg wood or something soft grip the teeth on the barrel and push it in the direction in which it unwinds with gradually increasing force. How would the rate change/line look as you're doing this?

[VWatchie]

3 hours ago, CaptCalvin said:

Got a test I think would be interesting to try.

I agree, that would be interesting! If/when I get around to it I'll report back.

[VWatchie]

When I worked out today I tossed around my arms a little more vigorously than the previous time, but not excessively, and again the escapement/rate started to rush. Not quite as much this time but still definitely unacceptably to about 133 seconds per day. So, there's definitely something that's not quite right. I'll try to find the time to test @CaptCalvin's idea.

[rodabod]

Do you not have another mechanical watch that you can compare to?