Loose roller on new balance staff

[bsoderling]

Hi,

 

I need some advice on what to do with a roller that is too wide and won’t stay on the new balance staff I just got riveted in place on an old Bifora 102 movement.

 

The tolerances on the tapered part of the staff that’s supposed to hold the roller are apparently not on my side this time.

 

If there are any advice on remedies out there, I gratefully receive them.

 

I have done tightening operations on loose cannon pinions but that doesn’t feel right in this case.

 

Been thinking if it would be possible to slip a tiny sliver of al-foil in between the roller and staff to tighten the fit. Or maybe fix it with shellack. But then I don’t know what will happen with the impulse jewel that’s also fixed with shellack.

 

If worst comes to worst, a tiny droplet of cyanoacrylate would possibly do it but I know what people will say about that... :-)

 

Nothing but trouble....hoping for some good advice!

 

 

 

 

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[BUSAKAZ]

If you are doing that sort of job then you must have a staking set,use a domed punch to close the hole.


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[Nucejoe]

Some part there dosn,t belong, roller or staff .etc. Making fit by any approach  if the right impulse pin is not at proper position and not just radially, you should expect to see  error on timegràpher. 

What is wrong with the right parts?

[bsoderling]

If you are doing that sort of job then you must have a staking set,use a domed punch to close the hole.


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Yes, I do have a staking set and have replcaced a few staffs. Learning by doing (and watching Mark’s videos) .

So the domed punch should then hit over the hole on the side of the roller that grips the wide part of the tapered staff? Interesting approach but slightly scary. Should the hole in the punch then just slightly exceed the hole in the roller?



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[bsoderling]

Some part there dosn,t belong, roller or staff .etc. Making fit by any approach  if the right impulse pin is not at proper position and not just radially, you should expect to see  error on timegràpher. 
What is wrong with the right parts?

Nothing wrong with the right parts. Question is what is right in an old movement from the 30’s with unknown service history? The staff was purchased to fit a Bifora/Bidlingmeier 102. Maybe parts were swapped out for out-of-spec items at some earlier work on the watch making compatibility hard later...?


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[BUSAKAZ]

Yes, I do have a staking set and have replcaced a few staffs. Learning by doing (and watching Mark’s videos) .

So the domed punch should then hit over the hole on the side of the roller that grips the wide part of the tapered staff? Interesting approach but slightly scary. Should the hole in the punch then just slightly exceed the hole in the roller?



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Yes in your staking set you will see several polished domed punches they are for closing holes up, take your time, or if you have a jeweling set these have one in aswel but I would use the staking set as the roller table is made of steel and needs to be hit rather than pressed just take your time.


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[BUSAKAZ]

Yes in your staking set you will see several polished domed punches they are for closing holes up, take your time, or if you have a jeweling set these have one in aswel but I would use the staking set as the roller table is made of steel and needs to be hit rather than pressed just take your time.


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Sorry I missed something out, you need to hit both sides of the roller table as you are on a tapered shaft if you only hit one side the table will wobble


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[Nucejoe]

2 hours ago, bsoderling said:

 

Nothing wrong with the right parts. Question is what is right in an old movement from the 30’s with unknown service history? The staff was purchased to fit a Bifora/Bidlingmeier 102. Maybe parts were swapped out for out-of-spec items at some earlier work on the watch making compatibility hard later...?


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I am not sure but think Renata 488-599 balance complete replaces bifora102. Surely replacements were produced and are available, sorry poor memory here.

[nickelsilver]

The roller may be in plated brass or nickel, be careful punching that you don't squish it.

[bsoderling]

The roller may be in plated brass or nickel, be careful punching that you don't squish it.

I googled a bit for ”hole closing punches” and the method appears mainly used for closing worn pivot holes in brass clock plates.

Which is obviously a quite different thing than working on a tiny roller from a wristwatch movement that , as pointed out, may be made from a much harder material and may split rather than give away.

If there’s experience out there from this specific item, please chime in as I’m interested in arguments in any direction.



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[bsoderling]

I am not sure but think Renata 488-599 balance complete replaces bifora102. Surely replacements were produced and are available, sorry poor memory here.

Interesting! Is that info that can be dug out from various old catalogues (bestfit ?) ?




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[nickelsilver]

Fitting a loose roller is almost always a pain. The taper on the staff is maybe a few microns larger than the hole in the roller, much more and the roller can split or squish when fitting. If the dimension is small by a few microns then a convex punch on the roller usually works. If the size difference is great, like a couple hundredths of a mm, it can be near impossible to close the hole enough.

Here's where the techniques that'll get you a failing grade in school come in. Grinding paste in the hole, shellac or glue, or my favorite an eyelash.

[rodabod]

I had this same issue last week when replacing an Omega staff with a Ronda replacement. The roller just didn’t grip. So, as Busakaz suggests, tap it with a domed punch. I tapped the narrower side and this gave a firm grip. Just do it gradually, and give the punch a twist to make sure it is centred over the hole ok. Regarding the punch, what matters is the radius of the dome. It’s likely that one which is a little larger than the hole should be ok. 

[BUSAKAZ]

Fitting a loose roller is almost always a pain. The taper on the staff is maybe a few microns larger than the hole in the roller, much more and the roller can split or squish when fitting. If the dimension is small by a few microns then a convex punch on the roller usually works. If the size difference is great, like a couple hundredths of a mm, it can be near impossible to close the hole enough.

Here's where the techniques that'll get you a failing grade in school come in. Grinding paste in the hole, shellac or glue, or my favorite an eyelash.

An eyelash, that is rough, that is nearly as bad as using a hair to tighten the cannon pinion, there is a thing called tools and skill but it seems to be fading fast.


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[Nucejoe]

Eyelash  .     

   I guess beauty salon is where to source it,  plucked out ones, valentine special,  £1.99 a bag.

I get the punch and hammer.

[bsoderling]

Thanks for all the info and contributions. This is what makes this forum such a great place!

I checked around a bit and indeed, the there seems to be a Renata complete balance available for the movement. Cousins can also sell me a complete balance at 50 £, which is roughly 10 x what I paid for the watch in the first place... :-)

Closing the hole with a punch seems to be a viable and used method here, even though not easy. Will gather some courage to take that on.

Regarding the ”alternative” methods I am not one to shy away for the odd eyelash now and then. If I can save a close to historic watch from the scrap heap and doing it as part of my hobby and learning curve, I’m fine. I can always return to the thing later and do better if I learned how to. So from that point of view a non-destructive shortcut can be a better alternative than hammering away with something I’m not comfortable with. (Been there, done that ...)

[BUSAKAZ]

Have a go at the repair that’s why you are on this forum, anybody can buy a part but not anybody can repair a watch, and if you mess it up then buy the part.


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[praezis]

If you need another opinion: hole  closng with a domed punch (no hole)  works. Just apply a light tap.

Another method: a light tap in the middle exactly like tightening loose cannon pinions .

 Both only if its really tolerances, not a wrong, wobbling roller.

Frank

NB. I would not apply above methods on a hard steel roller.

Edited January 5, 2019 by praezis

[bsoderling]

Another piece of info - I turned the roller upside down on the staff and seated that way it doesn’t go all the way down.

To me this would indicate that the roller isn’t far away from what it should be. It’s more like it may have become somewhat widened from being pushed onto a staff a few times.






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[nickelsilver]

Another piece of info - I turned the roller upside down on the staff and seated that way it doesn’t go all the way down.

To me this would indicate that the roller isn’t far away from what it should be. It’s more like it may have become somewhat widened from being pushed onto a staff a few times.






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That's a good sign, you'll probably succeed in getting it tight with a punch.

[bsoderling]

Yeah, now I just have to give it a try.... :-)


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[BUSAKAZ]

Don’t forget the staff is tapered you need to keep it the original way.


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[bsoderling]

Gave it a try tonight. No success I’m afraid.

The roller tube was really soft and got compressed and tilted even with the lightest tap on the punch.

It sort of stayed on the staff anyhow but then I managed to break off the inner timing pin when turning it back to the right position. One off those without a slot for a screwdriver that you have to grip around to turn. And I got careless...

When it rains it pours....

Donor movement anyone ? :-)




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[BUSAKAZ]

What’s the roller tube ?


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[bsoderling]

Sorry if the wording isn’t correct. I was referring to the cylindrical part between the roller table and the opposite part with the notch for the protection pin on the pallet.


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