Waitham model 1883 (No. 15 PS Bartlett

[Candix]

Hi,
I am a clockmaker of 20 years plus, have done pocket watches in the distant past, but gave it away because of problems other than the fault because of ham fisted past repairers.
I have been given a pocket watch from a close friend which suddenly stopped and asked to fix it.
It is a Waltham model 1883 (15 PS Bartlett) and in nice condition. It has been operating well and keeping good time but told it suddenly stopped.
I have had a look at it and it would appear that the fork has been dislodged from the roller pin.
The balance wheel turns freely one way but not the other.
Somewhere I seem to remember that this watch has a 'side lever' escapement?
It is difficult to see this with the back open and the balance wheel is very close to the plate. I think that the watch has been dropped or shocked in some way to dislodge the fork.

Am I on the right track, how is the easiest way to correct this without getting too involved.
Have included a picture of the movement for clarity.
Many thanks for any help - Regards candix

 

[Skutt50]

The balance wheel turns freely one way but not the other.

This indicates that your analysis is correct. Overbanked is what we call it......

Remove the balance and put it back. This should get the watch moving again.... but for how long?
Now the real question is why did it overbank? There is a small pin on the lever called the guard pin. Its job is to prevent overbanking. It may have been slightly bent for some reason and is not doing its job properly. There may be other explinations such as a bent balance pivot that shift the balance enough to allow overbanking in certain situations. Hard to say without proper examination.

When you have the balance removed you might want to carefully inspect the pivots for damage.

(To remove the lever you need to disassemble the movement. A bit fiddly to assemble afterwards so not something you want to do if you are avoiding getting too involved.......)

 

[Rob P.]

As Skutt said, it's likely overbanked.

Pull the balance and inspect for damage such as broken or bent pivots or a broken roller jewel,. I'd also check that the pallet fork pivots are unbroken and in their jewels as well as checking the safety dart isn't broken or bent. If it looks good, look down into the balance wheel hole and see which way the fork is pointing. Rotate the balance bridge 90* further in that direction and drop the balance in, rotating the bridge back to its proper orientation once the balance is in place. This maneuver rotates the roller jewel into the fork.

See if it runs. It yes, tell your friend to take it to a qualified watch repairer for servicing. If no, tell your friend to take it to a qualified watch repairer for servicing.

If you choose to tackle it yourself - disassembly for full plate 18 size American pocket watches should be done "upside down". Normally one would just undo the screws and remove the top plate. HOWEVER, on some 18 size watches disassembly done in this manner can break the pivots of the pallet fork. The proper method is to remove the screws and flip the movement over to lift the main plate off of the top plate. Assemble by installing the gears into the top plate and placing the main plate in position before wiggling the pivots into place.

 

[Candix]

Hi again,
After removing the balance cock I find the lever fork quite different to what I expected. I think this model is fitted with a Breguet Balance -
Have included more pictures showing the underside of the balance when and a shot of the fork (without the traditional Guard Finger)

Is this type prone to 'over banking' - as mentioned I am a clock maker and have done some pretty standard pocket watches in past years - but not seen this one before
So what do I do? - Just put is back in the right position and hope for the best?
Thanks to Skutt50 and Rob P. for their input!

Regards candix

 

[gmorse]

Hi Candix,

This is a single table roller and there's nothing apparently missing. Unlike a double roller, this type doesn't have a dart but the safety function is achieved by the vertical pin in the lever only allowing the fork to engage with the impulse pin when it aligns with the passing crescent in the roller. If this isn't happening correctly, it may be that the pin in the lever is slightly bent, but there are also signs that the roller has been messed with; do you know if this is a replacement? This type of roller shouldn't be any more prone to failure of the safety system than a double roller if properly made and adjusted, and the Breguet overcoil has nothing to do with it.

If this thread is a continuation of another thread on the same watch/problem, it would be better if they were merged, which a moderator can do for you if you request it.

[Edit] I've asked a moderator to merge this with your other thread on this problem.

Regards,

Graham

 

[Skutt50]

So what do I do? - Just put is back in the right position and hope for the best?

That is where I would start! You will find out if everything else is working.
If it seems to work well I would then try to provoke the overbanking.

One test is to let the mainspring down all the way, so there is no force on the escape wheel, and swing the balance.

If you need to dig deaper into the repair (which you indiated you did not want) you need to adjust the vertical pin Graham described above, slightly towards the balance. I am not sure if this can be done safely with the lever in place or if you need to take the movement apart. Hopefully someone else can advice.

 

[gmorse]

Hi Candix,

...you need to adjust the vertical pin Graham described above, slightly towards the balance. I am not sure if this can be done safely with the lever in place or if you need to take the movement apart...

The pin is normally brass, so should in theory be quite easy to bend, but if you try to adjust this without dismantling, there is a risk that you may break a lever pivot. However, I wouldn't advise you to bend or alter anything until you have a better understanding of how the safety failure is happening. An alternative explanation is that the pin may be perfectly upright as it should be, and the problem may instead lie in excessive side shake in the balance or lever pivots, due to damaged jewels or just wear. Unfortunately it's very hard to see what's going on with the escapement in a full-plate movement like this.

Regards,

Graham

 

[Rob P.]

The tip of the lower pivot is smooth and rounded in your pic so it looks like Lady Luck is on your side that it's unbroken and doesn't appear bent. The jewel looks good too. I think the scratches are from someone scraping off shellac after installing the roller jewel. I hope so anyway because I can't see any other reason to be scraping or filing on the roller table. The fork and guard pin appear to be fine.

Carefully stick it into some Rodico a couple of times to be sure there isn't any crud on it. Double check that the upper pivot is good by letting it hang from the bridge and looking at it under magnification. You won't be able to use Rodico on it unless you take it off the bridge and based on your experience and questions, I'd say not to do that at this stage. If the upper pivot isn't bent or broken, I'd re-install the balance and see if it's working correctly.

The procedure to do that is: With tweezers, hold the balance bridge above where it normally mounts and let the balance hang above the hole. Based on where the fork is in the picture. and with the movement in the same orientation as it was in the picture you posted, rotate the bridge until it's at 3 o'clock and lower the balance into the hole. Once the balance is all the way down in the hole, spin the bridge until it is over its normal location and set it down on the plate. Nudge gently if necessary until it settles into position and the pivot goes into the bridge jewel. It will click when this happens.

If it's correct, and there's power to the train, the balance should immediately start to swing. Check under magnification that the pivot is actually in the hole in the bridge jewel then install the bridge screw and observe as you tighten it. The balance shouldn't stop or slow.. Amplitude should be around 270* and vigorous.

Tell your friend to have it serviced by a watch repairer even if you're successful at getting it to run again.