Roller Table Loose On New Balance Shaft

[PostwarO27]

 

Hi All,
I just completed my first balance staff repair on a vintage Tissot caliber 27-2t.  I was able to get a NOS staff (actually two of them) on Ebay still in their packages.  I fitted the staff into the balance wheel and its all trued up.  However when I went to install the roller table onto the staff, it just slipped on right down to the flange on the staff and spins around the staff when touched.

I checked to make sure that the part # was correct (it was) and measured the old and new staff diameters with a micrometer and they're both within .0002in of each other.  This leads me to believe I expanded the hole in the roller table when removing the damaged balance staff.

Is there a way to tighten the fit...perhaps close the hole or should I search out another roller table?

Thanks in advance

[rodabod]

Hi, if it’s a close fit then I will use a minuscule amount of Loctite applied with a fine oiler. I think this is acceptable as it’s entirely reversible. If it’s very loose to the point where the roller will possibly not sit in correct alignment with the staff then you can very carefully close it with a punch and a staking set. I can’t stress enough how delicate these things are - it’s easy to deform them and break the impulse jewel off. 

[PostwarO27]

11 hours ago, rodabod said:

Hi, if it’s a close fit then I will use a minuscule amount of Loctite applied with a fine oiler. I think this is acceptable as it’s entirely reversible. If it’s very loose to the point where the roller will possibly not sit in correct alignment with the staff then you can very carefully close it with a punch and a staking set. I can’t stress enough how delicate these things are - it’s easy to deform them and break the impulse jewel off. 

rodabod,

I've read some pretty interesting methods and the Loctite seemed to be the most popular and widely acceptable between both watchmakers and tinkerers.  Over on the NAWCC boards someone suggested to use a strand of hair between the shaft and ID of the roller table.

While a novel concept, being a toolmaker by trade I know that putting an object in between two fit parts that is literally 1/3 the diameter of the shaft, will throw it out of balance when spun and if the roller table is as delicate as you suggest, I would bet that the roller table becomes distorted wedging that hair between the to parts.  So not only is the roller table sitting off center of shaft because the hair interference, its also no longer the proper shape.

Another option was to use shellac to fix the roller table in place.  I see how that would work but with limited experience as a tinkerer, I would not want to risk knocking the roller jewel out of place while heating the shellac for the table.

 

 In the end I decided to go with using the removable type of Loctite I use for stem threads.