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Pivoting a Pocket Watch Balance Staff

jdrichard

By jdrichard
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jdrichard Distinguished Member

jdrichard

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I am working on a pocket watch and was thinking of re-pivoting the upper balance staff vs making a new balance staff. Questions:

1. Should I repivot the upper balance staff or make a new staff? Pros and Cons.

2. If I repivot the staff, should I taper the pivot or would a straight pivot work.

3. Should I do this on a lathe and if so do I need to remove the roller table?

A different repair for me for sure.

JD

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nickelsilver Distinguished Member

nickelsilver

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46 minutes ago, jdrichard said:

I am working on a pocket watch and was thinking of re-pivoting the upper balance staff vs making a new balance staff. Questions:

1. Should I repivot the upper balance staff or make a new staff? Pros and Cons.

2. If I repivot the staff, should I taper the pivot or would a straight pivot work.

3. Should I do this on a lathe and if so do I need to remove the roller table?

A different repair for me for sure.

JD

1- I personally prefer always to make a new staff, the exception being something like a marine chronometer where the staff is very large (and usually very beautiful). Pros of making new: very easy to make sure it's all concentric, takes about the same time as repivoting. Cons- none. Pros of repivoting: can retain some originality for historically important pieces, on complex staffs could save time. Cons: real risk of problems drilling, like drill wandering excentric, drill breaking, drill drilling oversize. Difficult to blend the conical portion and making an invisible job. As always, a risk of splitting the original part when fitting the plug. Time consuming to do a proper job.

2- If you repivot you should make every effort to make the job invisible and original. This is basic good workmanship and applies equally to professionals and hobbiests.

3- This is absolutely a job for the lathe or turns (also a lathe), and yes you should remove the roller table.

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jdrichard Distinguished Member

jdrichard

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39 minutes ago, nickelsilver said:

1- I personally prefer always to make a new staff, the exception being something like a marine chronometer where the staff is very large (and usually very beautiful). Pros of making new: very easy to make sure it's all concentric, takes about the same time as repivoting. Cons- none. Pros of repivoting: can retain some originality for historically important pieces, on complex staffs could save time. Cons: real risk of problems drilling, like drill wandering excentric, drill breaking, drill drilling oversize. Difficult to blend the conical portion and making an invisible job. As always, a risk of splitting the original part when fitting the plug. Time consuming to do a proper job.

2- If you repivot you should make every effort to make the job invisible and original. This is basic good workmanship and applies equally to professionals and hobbiests.

3- This is absolutely a job for the lathe or turns (also a lathe), and yes you should remove the roller table.

Really appreciate the comment and advice. I am on the fence but would love to try and do a repivot job for a change. I did buy some wire that I think will work well, but we shall see.

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nickelsilver Distinguished Member

nickelsilver

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33 minutes ago, jdm said:

For clocks only indeed, the same concept of "capping pivot" cannot be applied to watches for reasons of size and construction.

Yes, and it also completely flies in the face of:

2 hours ago, nickelsilver said:

 

2- If you repivot you should make every effort to make the job invisible and original. This is basic good workmanship and applies equally to professionals and hobbiests.

 

Also, while it looks like a good idea for simplifying the process, the reality is to install those caps you will need to:

-not only remove all traces of the original pivots, but also some of the length of the arbor, equal to the wall thickness behind the pivot on the cap. This will require measuring that thickness, and some precision lathe work on the end of a likely long and spindly shaft. Not simple.

-turning a precision diameter, concentrically, to accept the pivot cap. Ideally for a friction fit. Again on the end of a long, thin, possibly quite hard shaft. Not simple.

 

In my opinion it would be simpler and better workmanship all around to drill and fit a new pivot than use those caps. The technique could be useful in the event the arbor splits when fitting a new pivot (it does happen) or some other situation where planting a pivot is simply not possible. Otherwise they just look like the panacea to folks who aren't yet comfortable drilling and fitting pivots.

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