Fusee pocket watches routine cleaning question

[Ned L]

I recently purchased two fusee pocket watches. Mechanically they both seem sound and should just need a routine servicing.
I understand the idea of a Fusee movement, but have not delved into them in actuality yet.
I am wondering what sort of increase in difficulty or complexity is considered to be involved with them?


one is by a James Ferro in Lowell Massachusetts and the other is by a John Graham (England),
Thank you,

 

[roughbarked]

First step. Don't break anything as it is all pretty much irreplaceable.

 

[Chris Radek]

They are harder to work on than American watches. The fusee is fiddly, the clicks inside are often worn, the chain is fragile and tedious. The mainsprings are hard to find, and they can have weird ends/pinnings. When the mainspring or chain breaks, often other parts are broken too and need to be remade, especially pallet arbors. There are no parts, you have to make what you need. Of course staffs, verges, etc all need to be made custom if they are broken.

You know how even with American watches, interchangeability of parts is often overstated and you have to make or at least adjust many things? It's much more of the same in English work.

That being said, they're really neat!

 

[Ned L]

Thank you both! This pretty much confirms my suspicions and is why I have done nothing yet to them, and will tred very carefully if I do decide to make a go of it.
I do believe they are both in mechanically good condition. I have been looking at them and studying them under the microscope and want to know I have them understood before doing anything.

 

[roughbarked]

If you do pull one down. Realise that it needs to be upside down or you may break the pallet staff.

 

[karlmansson]

Pre-tensioning the chain is another tedious task that sometimes requires a special tensioning block and key. It needs to be the right amount and engage with the stop lever at the correct height.

 

[gmorse]

Hi Ned,

It needs to be the right amount and engage with the stop lever at the correct height.

When the chain is fully wound onto the fusee and the stop is engaged, there must be some chain still on the barrel, at least 1/4 turn and preferably a little more. If the chain is too short it won't lift the stop before it's pulled taut on the barrel and that's when chains break. Half a turn on the barrel arbor to give it some initial tension is a good place to start; this is to ensure that the chain never goes completely slack and falls off the barrel, even when run right down. You can always adjust the setup either way when you see how the watch runs. (It should also only allow the spring to work in its middle zone, where the torque curve is flatter).

Regards,

Graham

 

[karlmansson]

Hi Ned,


When the chain is fully wound onto the fusee and the stop is engaged, there must be some chain still on the barrel, at least 1/4 turn and preferably a little more. If the chain is too short it won't lift the stop before it's pulled taut on the barrel and that's when chains break. Half a turn on the barrel arbor to give it some initial tension is a good place to start; this is to ensure that the chain never goes completely slack and falls off the barrel, even when run right down. You can always adjust the setup either way when you see how the watch runs. (It should also only allow the spring to work in its middle zone, where the torque curve is flatter).

Regards,

Graham

What he said. More descriptive than my attempt. Thanks Graham!

 

[SKennedy]

Before splitting the plates make sure there is no power anywhere. This means letting down the 'set up' ratchet which is on the barrel arbor under the dial and also ensuring the 'maintaining power' pawl is disengaged from the ratchet teeth on the outside of the fusee since there can be enough power in this mechanism to make parts fly across the bench. I'm fairly sure both of your watches do have maintaining power.

 

[gmorse]

Hi Ned,

It's also most important that you observe roughbarked's advice in his post #5. The lever protrudes into the gap under the balance potence and can get caught under there if you dismantle the movement dial down, breaking a lever pivot in the process. This is perfectly repairable, but better not to break it in the first place!

Regards,

Graham

 

[Ned L]

Before splitting the plates make sure there is no power anywhere. This means letting down the 'set up' ratchet which is on the barrel arbor under the dial and also ensuring the 'maintaining power' pawl is disengaged from the ratchet teeth on the outside of the fusee since there can be enough power in this mechanism to make parts fly across the bench. I'm fairly sure both of your watches do have maintaining power.

Yes, both watches are fully wound and would of course require complete letting down.