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Serviced ETA 2763 having erratic rate and amplitude


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10 hours ago, VWatchie said:

No, the Peseux 7040 is doing very well as far as the rate (and amplitude) is concerned. The maximum delta measured was 20 seconds between fully wound, crown down (+8 s/d) and fully wound minus 24 hours, crown up (-12 s/d). Compare that to the ETA 2763 having a delta of over 80 seconds.

What I was trying to convey was that I observed that the much higher amplitude of the Peseux movement during a 12-minute measuring period could momentarily fluctuate by 30° just like the much lower amplitude on the ETA 2763. I haven't studied the History graph on @praezis PCTM software for any other than these two movements but I wouldn't be surprised to learn that these fluctuations in amplitude during a 12-minute measuring period are the rule rather than the exception for all typical non-high-end-chronometer movements.

PCTMETA2804-2.thumb.jpg.f39d39793a8f10838e264de4cb401060.jpg

This graph is from my most reliable movement, an ETA calibre 2804-2. It too is a manual wound movement. Over a 12-minute measuring period, it is clear that the amplitude is constantly fluctuating. The average amplitude, as can be seen, is 292° but the delta is 26° So, I would think that rapid fluctuations in amplitude are perfectly normal. The reason I bring this up is that it is sort of new to me and not visible in the same way on a Weishi TM. On the Weishi there's only a number for the amplitude to look at it doesn't seem to change very often.

So does the weishi average the rates out ? But over how long ? 

10 hours ago, VWatchie said:

So, I would think that rapid fluctuations in amplitude are perfectly normal. 

They maybe rapid short fluctuations, but they are going from low to high extremes over the course of 1 or 2 minutes thats not exactly radid. A Weishi takes readings quicker than this, 🤔 how come it doesn't pick up this fluctuation of 26° ?

5 hours ago, nevenbekriev said:

In this situation (where amlitude increase leads to rare increase). 

When a spring is unwinding naturally over time an amplitude drop of say 50° does not effect the rate. So in this case are the amplitude fluctuations so quick that the rate doesn't have time to settle to be isochronical again before the next fluctuation occurs ?

Edited by Neverenoughwatches
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8 hours ago, Neverenoughwatches said:

When a spring is unwinding naturally over time an amplitude drop of say 50° does not effect the rate. So in this case are the amplitude fluctuations so quick that the rate doesn't have time to settle to be isochronical again before the next fluctuation occurs ?

This needs another lecture, but I have faulty X-ray machine 130 km away so have to prepare and go. I will try to answer when have the time.

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On 3/15/2024 at 10:30 AM, nickelsilver said:

Adjustment is done with the balance out, hairspring on, in ideally a set of hairspring truing calipers. These permit a better view of the spring, and better access, than regular calipers, though those work as well.

When you manipulate the hairspring do you leave it in the hairspring truing calipers? I'm trying to picture myself giving this a try and I find it difficult to imagine how I would hold the calipers with my non-dominant hand while trying to manipulate the spring with my other hand. Perhaps the hairspring truing calipers are being held/pressed against the table (as seen in your picture) to keep it steady?

On 3/15/2024 at 10:30 AM, nickelsilver said:

The caliper is adjusted so the balance can spin with no play.

Not sure about this either. Are the staff pivots held in jewel holes?

On 3/15/2024 at 10:30 AM, nickelsilver said:

Adjustment in the flat is done 180 degrees from maximum error

This is something I've been thinking about quite a bit. When truing the hairspring in the round (90° from the maximum error) the spring is only bent either inward or outward. The need for truing in the flat I guess could be because the spring has been either twisted or bent (like breaking off a branch). The point of manipulation would of course be the same (180° from the maximum error) but the method of manipulation would be quite different, wouldn't it? It would be very interesting if you could talk a bit about this.

On 3/15/2024 at 10:30 AM, nickelsilver said:

Another reason not to chase dynamic poise if everything isn't as perfect as possible.

Well, let us say it's beginning to sink in 😱

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Yes you do the truing in the caliper, with it resting on the bench or at least the hand holding it resting on something ( I do them under the microscope). The pivots are in holes similar to a regular truing caliper, supported on their cones.

 

31 minutes ago, VWatchie said:

This is something I've been thinking about quite a bit. When truing the hairspring in the round (90° from the maximum error) the spring is only bent either inward or outward. The need for truing in the flat I guess could be because the spring has been either twisted or bent (like breaking off a branch). The point of manipulation would of course be the same (180° from the maximum error) but the method of manipulation would be quite different, wouldn't it? It would be very interesting if you could talk a bit about this.

 

Yes any hairspring truing is due to something happening to the spring. Errors in the flat are indeed due to a twisting of the spring. Most truing one might do is near the stud, as this is the easiest place for an error to be introduced. Problems at the collet generally come when the hairspring is removed. Truing in the flat at the collet is actually usually a matter of pushing down at the maximum high point or lifting up at the low point, though there are times when you do have to get in there with very fine tweezers and tweek/twist it. The tweezers would be held so they are offset from vertical in relation to the spring, then closed to induce the twisting motion. Same as you would do if truing the flat at the stud. But  - this really would only ever be done in the first few degrees coming out of the pinning point, best is to do the correction simply lifting or pushing on the first coil.

 

It gets to be a real pain with collets where the spring is very close to the balance arms, as there isn't necessarily enough room to effect the plastic deformation necessary (going far enough so that the metal doesn't spring back to the original faulty position). Then it has to come off, and go on a broach, and leveled in relation to the collet- which is often just fine then- but hopefully close enough that any further correction can be done on the balance now.

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20 hours ago, Neverenoughwatches said:

A Weishi takes readings quicker than this, 🤔 how come it doesn't pick up this fluctuation of 26° ?

if you look at your timing machine you'll notice that it is running an average over a certain quantity of seconds. Otherwise the instantaneous variations would drive you totally insane. Remember this is a mechanical watch. You're looking more at a trend over at times span averaged then you are looking at individual ticking sounds. but if you're paying attention you will see the fluctuations. It's why run the time plot at work when I'm looking at a watch and I see the numbers going up and down slowly around the time plot the see why it's doing that and whether it's going to be a problem or not.

4 hours ago, VWatchie said:

hairspring truing calipers

here's an example from a Rolex service manual of the tool used for centering and flattening the hairspring at the collet. Because the only way he can see either is in some method where you can see in all directions and spin the balance wheel. Then you shouldn't have to be doing major reconstruction or manipulation your usually just tweaking a problem.

image.png.799d35b06dbda1921815c9cdd5ade8dc.png

here's an example of the balance wheel in the truing caliper. The only problem with the example is in the lot of the examples are there from people learning how to vibrated hairspring. In other words they started with a raw hairspring and there's no stud things only way more dramatic you're only supposed to be checking to see if there even is a problem

https://youtu.be/RrFpjqzEBv4?si=nB0JDqSunygnsRhm

 

 

 

 

 

 

 

c01-precision-timing_brochure_en wostep.pdf

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1 hour ago, JohnR725 said:

here's an example of the balance wheel in the truing caliper. The only problem with the example is in the lot of the examples are there from people learning how to vibrated hairspring. In other words they started with a raw hairspring and there's no stud things only way more dramatic you're only supposed to be checking to see if there even is a problem

https://youtu.be/RrFpjqzEBv4?si=nB0JDqSunygnsRhm

The video clearly shows the problem when the spring is out of round at the collet. It's something I've never taken much notice of before - apart from a visual check the first coil looks OK.

When tweaking the hairspring on the balance, I've always sat it in a hole in a bench block, held with some Rodico, so I can tilt it. Never thought of using calipers 🥴.  I will from now on though.

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The caliper John shows is the same as from a previous post of mine. Just to be more precise to VWatchie's question on how the pivots are held:

In these calipers the pivots are in V cones, held at the tip. They are really nice and I've never broken or damaged a pivot in one. But man, like all their other tools* the Levin are the absolute bomb. And the pivots are held on the cones.

 

*For lathe work, serious lathe work, a slide rest is essential. The Levin slide rests are miles away from all the others. Many people have used my lathe over the years and they always ooh and ahh how awesome it is (it's a Leinen and pretty awesome), but what really sets it apart is the Levin slide rest. Those boys made amazing tools, all of them, snap them up on Ebay, all of them!

 

-and, having viewed John's link, you can't see f all in that vid. Sorry John your links are usually great.

Edited by nickelsilver
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