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February 2, 2018 at 12:57 pm #50027smokercraftParticipant
Double roller table is loose on newly replaced balance staff …any suggestions on how to secure it
Thanks!February 6, 2018 at 11:25 am #64753Bob TascioneModerator
There are a few techniques that are used to tighten the fit between an undersized staff roller seat and roller.
The first I’ll mention is, in my opinion the ‘correct way‘ and that is to order or make a new balance staff that fits the roller.
I’ll mentioned some methods that have been used in ‘watch repair’, some more common than others, not so much for readers of this post to choose to use but to identify when running across them.
The main thing to remember is never permanently alter the watch; only the part. Meaning in this case, don’t modify the roller, only the staff or how the extra space between the roller and roller seat is dealt with.
A couple of the following alternate methods although considered unacceptable to use in a customer repair “may” be fine if used for ones own watch.
One way this is done is by melting a small amount of shellac between the fit. If the roller hole isn’t too large this works well and can always be reversed. Problem is if/when the timepiece ever moves on to a new owner and is in need of a new staff the shellac will need to be removed. Also if ever in need of a roller jewel adjustment or replacement the entire roller will most likely fall off of the staff when the roller is heated for the jewel adjustment/insertion.
This can also be done with many of the modern adhesives on the market like crazy glue or LocTite but once again can become an issue for a future repair.
The old hair fix. This is the same technique used to tighten a loose cannon pinion fit by inserting a scalp or eye brow hair between the roller and staff before pressing it on. The hair is elastic enough to compress but still offer enough resistance to hold the part in place. You’ll see this used more often than one might think! There are three cons to this though.
First; is if the roller fit is too sloppy then the hair may throw off concentricity enough to effect escapement function.
Second; next watchmaker to service has to deal with the problem.
Third: In addition to using watch cleaning solution a good shampoo may be needed. Ok. only two cons then!
Using oilstone dust or similar mixed with a little oil. A tiny amount of this paste is then placed in the roller hole and pressed onto the staff. This is the same process that I use in re-pivoting a clock arbor in the lathe course video. Although this will work the rule of never altering the watch and only the replacement part is slightly breached as the inside surface of the roller hole is scratched and possibly permanently embedded with oilstone dust.
Closing the holes at both ends of the roller with a rounded punch on a staking set. This one is seen quite often and breaks the ‘don’t mess with the watch’ rule.
Put a knurl on the staff roller seat. In my opinion this is the most acceptable method second to aquiring or making a new staff. The ‘part’ (staff) is being altered slightly and doesn’t cause a future watchmaker any significant problem if a new staff is required. At least I think this would be the case.
So my recommendation would be to go with a new staff for sure if this is for a customer. If it’s your own personal watch that you would like to get up and running fast I would also recommend a new staff to avoid any future issues but that is entirely your choice.
Hope this helps,
BobFebruary 6, 2018 at 9:27 pm #64754smokercraftParticipant
I will try a new staff..
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