Restaking a wheel and arbor

[Garfield]

I have a watch on the bench and it is defying any attempt to fix.

A wheel in the self wind mechanism of a Fossil watch has come apart, the wheel has left the arbor. I've restaked this - well I've tried - but once you go under test it just separates again. The wheel sits on the arbor / pivot at the position arrowed in the image below

It is absolute hell to see what you're doing and this thing is murder to see - balance shafts are a doddle by comparison since I cannot locate the arbor and wheel appropriately in any anvil I have available and stake, seems to be begging for more force than I'm happy applying to the face of a gear (I think these were pressed together not staked at the factory), the movement is a hybrid mechanical (main hands only) and quartz day / date / hours / seconds Chinese in origin with no significant identifying marks anywhere.

Fossil are not exactly forthcoming, I've been told by others that they will not sell spare parts and that anyone you can reach will be clueless, in fact this is a none issue since they won't even respond - the owner has sentimental attachment to this thing, don't ask me why.

Anyone here ever successfully fixed something like this without replacing ? - if yes how did you achieve it ?

Watch is an ME-1123 if anyone happens to have a complete self wind assembly available - I'd consider a complete watch runner or otherwise.

 

[Karl Burghart]

I would try slightly closing the hole in the wheel prior to staking it back on.

 

[Garfield]

I'll give it a shot but I'm running low on options, the faces on the arbor where it goes inside the wheel are tapered away from the gear so it naturally wants to move away from it. with the staking tools I have it is hard to keep the wheel against the gear, I pressed it on then staked - I'll try to stake the wheel instead of the arbor because that clearly ain't working.

 

[Skutt50]

I actually discussed the same type of problem today with a fellow watchmaker who struggled with a loose center wheel........

Some small things that might help besides closing the hole in the brass wheel slightly:

- Turn the wheel upside down.

- Use a small drop of locktight.

 

[Garfield]

Going to give that a shot - both closing up and using one of those once its together forget it grades of loctite - just need to buy some now - I hadn't considered that until now.

 

[karlmansson]

I’ve seen a similar repair where, if end shake allows it, you can turn a minute amount of the pinion back a little oversize and that will create teeth that will bite into the wheel and secure it in rotation.

 

[Garfield]

Well I'm admitting defeat on this one for a number of reasons

a) it is just too darn small for my fat fingers - getting the parts together is a challenge but is achievable
b) with any kind of fluid on there the parts just stick to the tools - using an oiler and the wheel comes away on the oiler or the tweezers or the stake or the press tool ... the fluid can't penetrate the joint when assembled and just sits there ...
c) I simply have no way to adequately secure the arbor in a way that will let me stake the wheel instead of the arbor

So this part is parked until I figure out something to hold the sucker properly - but it is so damned small - I've burned way too many hours on this thing, far more than this piece is worth.

 

[praezis]

I don't know how this wheel was assembled, but usually a wheel is rivetted on the pinion similar to a balance staff.

When I have to do this kind of work, I hold the pinion in a lathe collet and run a burnisher over the bent rivetted tooth tips to straighten them.
Then the wheel is put on the pinion and rivetted with rounded, then flat hole punch.

You may get better result if you turn the wheel by 1/2 pitch to avoid the old rivett marks.

Frank

 

[Garfield]

I've been planning a lathe for two years - everytime I think it is time something else steals the budget but I need to do it this year I think - it is holding me back in some areas. Time to start getting serious about it I guess, I was close last year but then I saw the price for collets etc that weren't included and near choked. Something on the bench I can't fix is causing mega OCD ... I keep going back to it but making less progress each time - at least it feels that way and the frustration is off the scale right now.