Randomly stops Fusee time piece

[transporter]

Ok some of you have seen the previous work carried out on the movement, ie fusee pivots and motion works.M

Mods feel free to link all these together if needed.

Well, it runs it  stops, it ran for 2 whole weeks ( 2 full winds ), left for a few days unwound, wound back up ran for about an hour, looked for faults saw none started the pendulum again and away it went for the night then stopped. 
There is no pattern to when it stops, I’ve marked the wheels ans pinions each time and the marks never line back up.

Ive bushed all pivot holes and depthing is correct, side shake good, there is a reasonable amount of end play on each arbor and all spin freely.

With a low power test the train runs free, when fully wound with no pallet in place it picks up speed instantly and runs without  any change in speed.

When it does stop I have narrowed it down to a lose of power at the fusee to the centre wheel.  The escape wheel and third wheel have play in them between teeth and leaves and the third wheel to the centre wheel again there is play between teeth and leaves.

Having filed and burnished the fusee pivots and re-bushed the plates I’m wondering what the cause of this lack of power could be when power is on the train? Everything is free when no power is on the train, none of the arbors are bent, I’ve chucked them up on the lathe and all run true. 
The customer did comment when I called her as I’d reached my 8 week time estimate to finish the clock and she said that even after the last service it randomly stopped!!! Didn’t tell me this when I collected it. 

So I know a diagnosis is really hard over the net but has anyone any ideas? Anything will do, I’ve had this clock apart more times than I care to count now trying to figure this out inbetwen other customers work.

Instagram, white_time_horology 

[rodabod]

Can you mount only the Fusee and centre wheel and check how well they mesh when under load? Just grip the centre arbor tightly with your fingers and then turn the fusee. See if it feels lumpy or not. 

[transporter]

Thanks for the suggestion, I’ll try anything, the whole train feels smooth and runs fine on a low power test, ie 1-2 clicks on the mainspring, it seems like it’s binding under power. 
i changed the mainspring for a new one and have also gone back to the old and still the same problem. 
But I’ll try your suggestion, cheers 

[HectorLooi]

I have a similar problem with a Smiths 8 day Westminster chime clock. It runs fine when mounted on a test stand. Going train runs freely with just 1 or 2 clicks. But when it's cased up and ready for the owner to pickup, it'll stop. When it's removed from the case, it'll start running again.

Last night I managed to get it out of the case when it was siezed up and studied it for awhile. There was a complete loss of power to the escape wheel and 4th wheel. Even trying to move the 3rd wheel manually with a wood stick couldn't free it. All the bushings look fine. It only broke free when I released the mainspring power and removed the pallets.

I'm beginning to suspect the motion works or the chime and strike somehow fouling up the gear train.

[transporter]

As for your Westminster I feel for you, I just done a Westminster that kept stopping coming up towards the warm on the hour. I diagnosed that as the L shaped  lever that  has a spring running across its top was getting Getting caught up on the canon pinion due to the spring not being completely flat.
anybway my fusee hasn’t any of the motion works attached at the moment, it’s just a bare bones train that keeps stopping so atleast it’s easier for me to strip down and inspect  

[oldhippy]

What fusee movement are you having problems with. Can I see a photo? What work have you done to it a list would do. 

[transporter]

On 10/7/2022 at 3:55 PM, oldhippy said:

What fusee movement are you having problems with. Can I see a photo? What work have you done to it a list would do. 

Hi OH, 

apologies for late replty to this subject, right the fusee mvt, no photos at the moment but I will post a few shortly. I do believ that between myself and my mentor we have resolved the problem, basically I had to adjust the depthing on the fusee to centre whell as it was out, having adjusted the clock ran once more but again stopped, the teeth on the fusee are quite warn where the depthing has been too shallow. 

Having changed out the mainspring for a new one and then again for a lower one as we thought that maybe the other one was rubbing on the barrel cap and causing enough  friction to stop- the movement we still had the same problem of stopping.

So a last ditch attempt at solving it and my mentor decided to look at the depthing again and found that although I had changed the depthing I had also gone too shallow by a nats cock so the teeth and leaves were almost at the point of not meshing correctly ( too shallow ) but werent quite deep enough and were catching causing the train to lock.

This was exagerated by the fact that the teeth on the fusee were so warn in shape from the previously bad job on hole closing by punching and adjusting the depthing by one of the previous reapairers. 

So far we have had it on test for 2 weeks and its run with all motionworks fitted aswell, i will fit it back into the case this week and test it for another few weeks before giving it back to the customer.

[oldhippy]

Now you know why depth of teeth are so important and also the shape of teeth. It sounds as if you have fixed it.   

[watchweasol]

Hi According to the book the degree if intersection of a pair of gears.  The depth is said to be correct when the pitch circles meet

[transporter]

All very well, but these are the teeth on the fusee

3 hours ago, watchweasol said:

Hi According to the book the degree if intersection of a pair of gears.  The depth is said to be correct when the pitch circles meet

 

[oldhippy]

Nasty teeth no wonder you had problems. A clock depthing tool wouldn't help because the runners cannot take a fusee wheel unless you make a runner that could hold it, then you have the means to work out what the correct depth should be. 

[watchweasol]

Agree with Old Hippy  getting a good depth with  the teeth like that would be difficult to say the least.  The profile of the teeth is bad so to get the the maximum power delivery with out bottoming the teeth and if too high cause slippage and further damage. A hard act as you are dealing with a clock with a very powerful spring.

[transporter]

Just thought I'd better give an update to this saga, I got a new cap wheel cut and fitted and the clock runs like a train now, and is now back with its owner.

[oldhippy]

I thought it would be those teeth. Who cut the wheel for you? Have you let the owner have the old part back you should always hand back replaced parts and record all work carried out.