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Cyclinder escapement / escape wheel mesh set up

roverguybm
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roverguybm Member

roverguybm

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Folks.

I removed a free moving cylinder escapement/balance cock to work on a dial for safety.

After finishing what I was doing I attempted to refit the cock - after two hours, no joy.

Is there a particular set up between the escape wheel and the balance staff void lips that has to be employed?

I started by simply ensuring the lower staff jewel was fully visible between two of the arboured teeth and reinserted the staff, hoping it would take care of its self, but the staff and teeth seem locked/meshed with no commencement of impulse no matter what I do.

Do I need to set it at tooth 'rest on outside', 'rest on inside' etc, before release? 

I know refitting any balance can be an adventure, but I just can't see what is wrong with the set up.

Can't really get a camera in to show the issue...

Any and all advice would be most welcome.

 

Edited by roverguybm
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oldhippy Distinguished Member

oldhippy

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Sorry I missed this question. I am glad you have conquered the problem.:Bravo: Cylinders can and are tricky blighters to set up. There is something already on this forum about cylinders as I can remember helping a member out. How about a write up with diagrams or photos of how you went about it, this will be valuable info you others that come across a watch or clock with a cylinder escapement.    

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roverguybm Member

roverguybm

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Hello oldhipply...happy to contribute if I can.

 

For those unfamiliar with a cylinder escapement there is no pallet fork controlling the interface between the balance and the escape wheel...the escape wheel meshes directly with (if that is the correct term) or passes through, the balance wheel staff by means of an undercut hollow slot formed in the staff itself.

This configuration is a form of 'dead beat' escapement known as a 'frictional rest'...as I understand it there is always a tooth in contact with the staff at any and all times.

The problem I had was - as there is always a tooth in contact with the staff, I had to marry up the position of the tooth with the correct position it should be at during its cycle as it passes through the lips of the hollow - if not correctly aligned then the balance wont be able to transfer an impulse to the next tooth as it isn't releasing the tooth it's currently in contact with.

An added problem is that since there isn't a pallet fork there is nothing to hold the normal turn and a half of the button to charge up the main spring to set the escapement on it's merry way - all power escapes immediately without the staff/cylinder in place.

The solution was found in Fletcher: Watch Repairing as a Hobby: p57 of the 2012 edition...and was actually pretty simple once explained (thank goodness).

I had to look for a marked slot on the rim of the balance, and then line this up with the middle dot of three set in the pillar plate.

By good fortune all marks were present, and, as I was working on a movement that I knew had a perfect balance set up before I removed the cock, as soon as I set everything up and provided a half turn of power...off went the balance...!

Learned something new...but if there is another way I'd appreciate the knowledge, as this movement is one of a job-lot of nine I've just picked up on ebay and the marks may not be present on those.

Here's an image of the movement (sorry about the quality...using an old camera in poor light).

 

 

 

 

lacoultre cylinder.jpg

Edited by roverguybm
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