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2 minutes ago, JeremyLaurenson said:

I just got this on the time Grapher and it seems to be wavy with the frequency being every eight seconds or so. Maybe the escape wheel causes this?

 

IMG_1236.jpeg

Be good to know what the movement is to find out the lift angle then determine if this amplitude is correct.......but what happens when it approaches 360° ?

You see the break in the trace then a restart ?

Look at the discussions over the last few days and you'll find your answer.

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1 minute ago, JeremyLaurenson said:

This is a 2893-2 so the lift angle is right at 51

I didn't know there was such thing as too much amplitude... how do I correct for it? Is this the reason for a wavy graph?

Could be the reason, i brought this up earlier today, the rate can step....but a regular wavy trace can also indicate an out of axis wheel rotation.  But the amplitude is about at its limit before rebanking occurs. Excessive amplitude is certainly due to a overstrong mainspring pushing too much torque through the train. 

Pull the mainspring and verify it's dimensions against recommended 

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43 minutes ago, JeremyLaurenson said:

Thanks.. it’s a new spring but they could have sent me a shitty spring

🤔.....a shitty spring ? With those words I tend to think of a very cold and very wet spring coming out of a late winter and not wanting to leave my house.  

Oh so what about the mainspring, you dont always get the one you need. Can you throw some dimensions at us.

Its pretty much a given but before going any futher down this route, how about visually verifying the re-banking in the movement. 

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What you see on the photo of the timegrapher is not rebanking ("knocking"). But at this extreme amplitude, you SHOULD actually see it (at least every few minutes because it it doesn't usually happen constantly). 

Here are two files that were shared on the forum a few times. Sorry that I can't give credit to the member who uploaded them... shout-out to unkown! Out-of-round escape wheel or 4th wheel would be a reasonable guess. Take out balance and pallet fork and watch from the side of the movement as you spin them.

Witschi Training Course.pdfTiming-Machine-Charts.PDF

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Those movements should run like chronometer beasts; the wavy funky line isn't very chronometer-y. In some cases the machine will pick up a bad/dirty signal and double the amplitude. This is how you can end up with 350+ and it not be rebanking. I would be curious to see how it does if you clean the fork, balance, and balance jewels, oil it carefully, and recheck.

 

348 degrees shouldn't be possible, there just isn't room for the impulse jewel to swing that far without bumping the fork horns.

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2 hours ago, nickelsilver said:

In some cases the machine will pick up a bad/dirty signal and double the amplitude. This is how you can end up with 350+ and it not be rebanking.

Yes, it is a detecting issue. Cause: the machine misses the 1st (too) small impulse of the tic noise. It uses the next pulse in the noise as start. 

Because amplitude is calculated from the time interval 1st to last pulse of the noise, this is too short and so amplitude too high (as explained several times before 🙂)

Frank

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3 hours ago, nickelsilver said:

Those movements should run like chronometer beasts; the wavy funky line isn't very chronometer-y. In some cases the machine will pick up a bad/dirty signal and double the amplitude. This is how you can end up with 350+ and it not be rebanking. I would be curious to see how it does if you clean the fork, balance, and balance jewels, oil it carefully, and recheck.

 

348 degrees shouldn't be possible, there just isn't room for the impulse jewel to swing that far without bumping the fork horns.

What might be a maximum, an average over calibres with different lift angles ?

3 hours ago, nickelsilver said:

Those movements should run like chronometer beasts; the wavy funky line isn't very chronometer-y. In some cases the machine will pick up a bad/dirty signal and double the amplitude. This is how you can end up with 350+ and it not be rebanking. I would be curious to see how it does if you clean the fork, balance, and balance jewels, oil it carefully, and recheck.

 

348 degrees shouldn't be possible, there just isn't room for the impulse jewel to swing that far without bumping the fork horns.

Could a dirty fork or impulse pin dampen the strikes enough for the mic not to pick them all up.

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On 10/5/2024 at 10:21 PM, JeremyLaurenson said:

Thanks.. it’s a new spring but they could have sent me a shitty spring

What spring did you fit? Do you know the GR number or the dimensions of the spring? Did you use breaking grease on the barrel wall? Was just the mainspring replaced or a full service done on the movement?

I have found that if the amplitude is low, the timegrapher can double it up, or if it doesn't hear the first impulse and makes stuff up. If it does have a low amplitude, you should be able to see it pretty clearly, or put a mark with pen on the balance and you'll know if it really is that high an amplitude, which it isn't. No watch movement would show 348 degrees and not be knocking (rebanking). In fact, no watch movement could spin 348 degrees, as it is impossible.

I've just serviced a Rolex 1200 from 1950's and used a mainspring a strength too much, which was 0.11 mm thickness instead of 0.1 mm and it started to knock at 332 degrees. With the correct spring the movement now achieves 285 degrees. I find that if the amplitude goes beyond 330, it will knock.

Edited by Jon
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16 minutes ago, Jon said:

I've just serviced a Rolex 1200 from 1950's and used a mainspring a strength too much, which was 0.11 mm thickness instead of 0.1 mm and it started to knock at 232 degrees.

Knocking at 232° ? Was this meant to be 330?

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1 hour ago, Neverenoughwatches said:

What might be a maximum, an average over calibres with different lift angles ?

I looked at a drawing I made for an old Patek fork, and measured 325 or so rebanking. Newer stuff might hit a bit higher due to less ornate fork horns, but not a lot. Once you're over 300 for me that's a bit risky. Especially with an automatic watch.

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2 hours ago, nickelsilver said:

I looked at a drawing I made for an old Patek fork, and measured 325 or so rebanking. Newer stuff might hit a bit higher due to less ornate fork horns, but not a lot. Once you're over 300 for me that's a bit risky. Especially with an automatic watch.

Though- rarely does a watch sit perfectly horizontally for a period of time, motionless*. I've done pieces for companies that accepted 7h after full wind for no rebanking.

 

*With the exception of one placed face down at bedtime, and in the case of an auto possibly at full wind.

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On 10/5/2024 at 1:37 PM, JeremyLaurenson said:

This is a 2893-2 so the lift angle is right at 51

I didn't know there was such thing as too much amplitude...

timing specifications for watches is always interesting. Like for instance maximum amplitude for this watch fully wound up in the dial up position is maximum 315°. With the definition of fully wound up after 1 to 3 hours of winding it fully up. which is interesting because this is a much longer time that I typically see a lot of times it be 15 minutes minimum.

then the classic of after 24 hours vertical 6 o'clock up no less than 210°. I would be really curious what this watch is doing  at 24 hours.

then for the rest the timing specifications which your watch is not meeting at all like the beat you're supposed to have a maximum of 0.6 ms. Then for timekeeping often times the express it an interesting fashions such as +5 with a variation of -5+5. this would basically translate that the watch should keep time between zero and 10 seconds worst-case never be running slow like your watches.

then nice for troubleshooting as you have a microphone that rotates and thinking about that how are you holding the watch in the microphone? Some people like to hold their movement holder in the microphone and that's not a good idea. As you need a good signal and the watch itself ideally should be in the holder. Then a timing procedure like in this watch wind it up wait an hour minimum and give us a picture of dial up, dial down and crown down would be nice.

15 hours ago, Jon said:

I have found that if the amplitude is low, the timegrapher can double it up, or if it doesn't hear the first impulse and makes stuff up. If it does have a low amplitude,

20 hours ago, nickelsilver said:

In some cases the machine will pick up a bad/dirty signal and double the amplitude. This is how you can end up with 350+ and it not be rebanking. I would be curious to see how it does if you clean the fork, balance, and balance jewels, oil it carefully, and recheck.

I've never really paid attention as to whether it's actually a double amplitude. Typically what I've seen is with super low amplitudes the waveform gets stretched out and the timing machine will trigger off something in the middle confusing that with the locking signal. Then you end up with a nice happy amplitude but I don't think I've ever seen an amplitude as high as this one? this of course is why you should always visually look at your watch and see if the visual confirms what the timing machines trying to tell you.

 

17 hours ago, praezis said:

Yes, it is a detecting issue. Cause: the machine misses the 1st (too) small impulse of the tic noise. It uses the next pulse in the noise as start. 

typically I don't see this but most the timing machines that I have either have automatic gain control or limited choices. for which this timing machine does have a gain adjustment I wonder if it's set correctly? this is where we also run into the unfortunate that we don't have in our oscilloscope as you have a better idea of what's going on with the signal.

16 hours ago, Jon said:

What spring did you fit? Do you know the GR number or the dimensions of the spring? Did you use breaking grease on the barrel wall? Was just the mainspring replaced or a full service done on the movement?

then the breaking grease was something I was curious about because of that's not slipping the way it's supposed to you can definitely have too much power. but?

But still let brings up questions?

On 10/5/2024 at 12:52 PM, JeremyLaurenson said:

I just got this on the time Grapher

then I guess I get to make wild assumptions like you service this watch and this is what it's doing? There's a lot of unknown things in this discussion and things that are quite right for instance as the watch been demagnetized? Plus what was a condition like before you service  it? Or for that matter why did you service its a lot of times pre-existing conditions could be an influence.

Then?

 

 

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9 hours ago, JohnR725 said:

Then?

yes there were things that were bothering me with this discussion why? One of the things that would screw up timekeeping would be is the watch currently in a case or is just the movement in the timing machine holder?

typically I don't think about this problem because usually when servicing a watch once it's up and running it goes on the timing machine for evaluation purposes. But I've noticed that a lot of people like to entirely case up the watch hands style everything and then put it on the timing machine which is bad if you need to adjust things so is this watch cased up?

 

 

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