Little French traveler clock

[rodabod]

.... and does it look any better when held upside-down?

[Endeavor]

6 hours ago, rodabod said:

.... and does it look any better when held upside-down?

Just out of bed, tried the up-side-down and the clock stops. Also the speed-up / slow-down frequency suggest the escape-wheel rpm. Will dig into later today ...... first

Edited March 25, 2021 by Endeavor

[Endeavor]

Hmm ........ interesting !

Removed the balance assembly and (hand driving the train) adjusted the platform until the escape-wheel ran smooth. Checked all the escape-wheel wedges; there is some wear, but they all seem equally "worn".

Checked the end shake and the side-shake of escape wheel and balance assembly, both do have some but what I would consider within reason. Checked the pivots, they all seem straight, correct length and smooth.

Now with the platform adjusted, the clock runs in any position, including upside down.

Made a mark on the escape-wheel to see if the dot during speed-up (causing a lower amplitude) matches each time up with the slower period (bigger amplitude); it doesn't ! That's to say that with the dot on the escape wheel at one point when the balance amplitude decreases and the speed-up occurs, at the next speed-up the dot has advanced about a 1/4 of a turn. I would guesstimate that the speed-up occurs every 1-1/4 turn of the escape wheel; each revolution the dot advances about a 1/4 of a turn before the next speed-up . This means to me that it is not a particular set of escape wheel teeth that are causing the problem. I can not see the hairspring or its coils touching anywhere. It also seems that the speed-up period is much shorter than the slow-down period; again a guesstimate, 5 teeth speed-up followed by the rest slowing down and increasing amplitude.

Any ideas where to look next are very welcome

[transporter]

I know 99%of problems are with the escapement on time pieces, but I always re check all wheel assemblies, I start by placing either the intermediate wheel or centre wheel ( depends on if you have an intermediate wheel ok ) between the plates to check freedom of movement and endshake etc, I then remove it and place the 3rd wheel between the plates and do the same checks, and the the escape wheel. The I place the first two wheel that mesh in together and do the same, then remove one ie the centre wheel and leave the 3rd wheel but also install the escape wheel, do this until you are sure all are fine. Then you know the problem is going to be with the escapement and you can concentrate on that alone.

[oldhippy]

When it came to oiling the platform what actually did you oil? What oil did you use?

[Endeavor]

I oiled a few of the escape wheel teeth with Dr.Tillwich 1-3, probably equivalent with the thin Moebius 9010.

Sorry, misunderstood; all the balance & escape jewels were oiled with Dr.Tillwich 3-5, which is a slightly thicker oil than the Moebius 9010

Edited March 25, 2021 by Endeavor

[oldhippy]

I know it's difficult in helping when you only have photos to go by. It looks like wear on the cylinder and the tip of the pivot staff looks worn at the tip. With a cylinder escapement if the balance speeds up or slows down it is normally the cylinder or the escape wheel teeth or both. How are the jewels? Do they look good clean and no marks.   

[Endeavor]

I'll study the escapement and its behavior today.

My suspicion is that something is happening in the escapement. The frequency at which the irregularity occurs doesn't really match up with the speed of any of the other wheels in the train.

It is as if when the amplitude increases and the clock starts to run at quiet more regular pace, something causes a short burst of rapid "escapes", causing the amplitude to decrease to a quick succession of balance wheel movements. Perhaps once the balance wheel is "calmed down", it starts up again to "normal" until the amplitude reaches and certain amount of degrees. We "know" that it is not caused by a particular set of escape-teeth but it seems more caused by, or due to the increase of the amplitude.

I also can't remember that the clock ran this irregular before the service. What for sure has since altered is the shape of the hairspring and the slightly higher (≈0.8mm) hairspring collet

To rule out a sudden re-occurring vibration in the bearings, I can oil the jewels with heavy clock oil.

I added some additional cylinder shots, just in case something "off" is spotted. If other shots are preferred / required, please let me know .....

Edited March 25, 2021 by Endeavor

[oldhippy]

Have you checked to see if it's the same teeth when the clock speeds up. Also the cylinder has wear on this edge. 

[Endeavor]

As I mentioned, the speed-up & slow down doesn't seems to happen at the same escape-wheel spot. The dot I made on the escape-wheel shifts by about 1/4 turn before the next irregularity. Therefor I concluded that it is certainly not the same set of teeth causing the problem, as it seems to happen with any set of teeth.

I also oiled the escape and balance jewels with thick clock-oil, but that did not made any difference.

If in the end it turns out to be general wear, I guess I'm done and the clock will be "as is"

However, I will observe and have to think a little what could cause this phenomena. As said, I can't recall that the clock ran like this before, so something has changed and perhaps the cause sits in what was changed(?).

I have to give it some time and thoughts .....

Thank you for all the help so far

[rodabod]

Does it still run the same when upside-down?

[Endeavor]

yes, it runs the same in any position ......

[rodabod]

How many leaves does the escape wheel pinion have?

[Endeavor]

That was very good thinking & question and it could have been ...... the pinion has 8 leaves, much less than the number of escape-teeth. If the pinion would have had more leaves than the number of escape teeth, it could have well been the answer !? Than again, one revolution of the escape is one revolution of the pinion

I double cleaned the pinion leaves, but sadly no difference .....

I'm sure it's one of those "time will tell" problems

Edited March 26, 2021 by Endeavor

[oldhippy]

I'm sure it is wear on that cylinder. 

For teeth and pinion and how many look here.

http://www.clock-works.clara.net/cata/wnpc2.html

[rodabod]

Another thing I will mention which is sometimes overlooked by “watchies” like me and less so by the “clockies”:

When you check the free-running of the train with the balance removed, it really needs to be under load so that the side-thrust of the wheels changes the depthing. People sometimes inspect individual pairs of wheels by letting one slip through their finger (to create resistance) while turning the other. It should feel smooth and not lumpy. Trying this with all wheels fitted sometimes masks the issue due to the fact that the entire weight of the train has momentum (a bit like a flywheel). 
 

So, in short, always check the free-running of the train, but try to also do it under load where possible. 

[Endeavor]

Good point ! ...... will try to simulate a load, but for now the clock has to wait a few days. A few other outstanding projects are back on my desk.

Rest assured, I'll be back, like clockwork

Thanks for you help !

[Wardybits]

Hey I’ve got the exact same clock purchased from ebay, needs a new mainspring barrel as some teeth are missing and also some adjustment to the escapement. Any advice on where I might be able to find another barrel (other than ebay) would be helpful. Thanks in advance.