Timegrapher Interpretation

[chadders1966]

Hi

I'm currently re-assembling a Felsa 1560 I recently aquired, and get the attached reading on the Timegrapher. Can someone advise me on what the pattern means? I can see that it is showing a large beat error, but the wave pattern has me puzzled. Thanks.

Stephen

 

[jaycey]

My immediate concern would be the amplitude. Get that above 250 on a full wind and then have a look at the readings.

[chadders1966]

That's obviously an issue, it's not on a full wind at the moment. I think I may have put too much braking grease in the barrel and the spring may be slipping too easily.

I am wondering what the shape of the top line may signify. Problem with one of the pallet jewels perhaps?

Stephen

[jdm]

47 minutes ago, chadders1966 said:

That's obviously an issue, it's not on a full wind at the moment. I think I may have put too much braking grease in the barrel and the spring may be slipping too easily.

I don't think that the MS is slipping. Do not assume always that poor amplitude is due to the MS, in my experience, in most cases, it is not. Reference article  http://watchguy.co.uk/service-allaine-felsa-1560/

[rodabod]

The cycle of sooner and later for one of the pallets looks around 15 beats long.... Is the escape wheel looking ok? I'd maybe have a look under close magnification. 

[jdm]

19 minutes ago, rodabod said:

The cycle of sooner and later for one of the pallets looks around 15 beats long.... Is the escape wheel looking ok? I'd maybe have a look under close magnification. 

As mentioned before, with 100 deigree less than the normal amplitude, pattern has no significance.

[chadders1966]

No cracked jewels, damaged pivots, pinions or wheels that I can see under magnification. I think the mainspring may not be connecting properly. It is one of this with a seperate bridle, and I'm wondering if the hook is not catching and the spring not getting full tension.

Stephen

[MrBeat]

From the pattern id say its either one of the following or a combination >

Pallet stone loose/damaged

Escape wheel pivot bent / Damaged Escape wheel tooth

Usually when an escape wheel pivot is bent both lines will form a wave pattern in a regular fashion, this has only a single line and whilst it could still be an escape wheel issue id start by looking that the pallet stones are fixed correctly.

There are a few other things which can cause the pattern but i think the above is most likely

[jdm]

36 minutes ago, MrBeat said:

From the pattern id say its either one of the following or a combination >

Pallet stone loose/damaged

Escape wheel pivot bent / Damaged Escape wheel tooth

Usually when an escape wheel pivot is bent both lines will form a wave pattern in a regular fashion, this has only a single line and whilst it could still be an escape wheel issue id start by looking that the pallet stones are fixed correctly.

There are a few other things which can cause the pattern but i think the above is most likely

As mentioned before, with 100 degree less than the normal amplitude, pattern has no significance.

Amplitude is the first and foremost paramenter to be looked on the timegrapher. No correct timekeeping can be had below 200 deg.

 

 

 

 

 

 

Edited October 24, 2016 by jdm

[MrBeat]

Quite right, i didn't even look at the amplitude . Teach me for jumping in head first

[chadders1966]

Well I re-inserted  the maispring and the amplitude is now 250-270 dial up/down, 220 pendant up/down. I do believe the wave cycle on the timegrapher did have a cause, and it was the escape wheel. The wheel itself is fine, but I realised I'd put the escape cap jewel on upside down - whoops!

The beat error is still a problem, but not as much. It's 0.8 DU/DD, 1.4 PD and 0.4 PU. I did observe the balance jewel and it appeared to be pretty well centred in line, where to look now? Thanks

Stephen

[StuartBaker104]

Since you don't have a beat adjuster on the regulator, you will have to revove the balance and twist the collet round slightly.

However with an error this small it will be hard to work out which way to adjust by observation, you will just have to try it. Alternatively you could leave well alone at this stage. I would normally consider anything less than 1ms to be a good result.

 

[chadders1966]

Stuart 

Thanks for the response. I pretty much agree and I was going to leave it, but I was wondering about the variation in BE as I mentioned from 0.4 PU to 1.4 PD.

Stephen

[jdm]

 
I pretty much agree and I was going to leave it, but I was wondering about the variation in BE as I mentioned from 0.4 PU to 1.4 PD.

Now look at the rate in different positions. If no more than about 20 secs a day and you can regulate to average for the most used positions like crown down, 12 down and dial up, you have achieved a great result already.

[matabog]

Regarding your graph, I cite Donald De Carle in "Practical Watch Adjusting" page 131:

one pallet stone is not being held by the escape wheel when in position of rest - there is a lack of "Draw"

 

Good luck setting that stone correctly!

 

[chadders1966]

Thanks everybody. I'm happy enough with it now, and I've figured out what probably caused the pattern so alls well.

Stephen

[rodabod]

I'm guessing the inverted stone caused the escape wheel to sit at an angle, or at least not straight. Well spotted anyway!