center wheel separated

[brtvandenbroeck]

Hi all,

I am in the process of (trying) to fix an old Longines 847 which I bought second hand. Thanks for the plenty post on this forum, a beginner like me got quite far already. However, now I bumped into a rather strange issue.

After testing for obvious all things first I found out that the center wheel is broken in a unexpected manner. In the picture added gear 1 rotates freely from gear 2 and is thus unable to pass energy down the train.

Does anybody have any advise how I could fix his? I am guessing that both parts were manufactured separately and combined afterwards in the factory as well (welded?). Or is this just broken and I should start searching for a replacement?

kind regards,

Bert

[watchweasol]

In the first instance wheel 2 is friction fitted to gear 1  ( rivited)   therefore with a hollow punch it is possible to tighten 2 onto pinion shaft 1 thereby restoring the drive.    

[Poljot]

1 hour ago, brtvandenbroeck said:

Does anybody have any advise how I could fix his? I am guessing that both parts were manufactured separately and combined afterwards in the factory as well (welded?). Or is this just broken and I should start searching for a replacement?

kind regards,

Bert

 

You can fix it as described above if you have a staking tool at your disposal. Something similar to K&D #18 Inverto.

[brtvandenbroeck]

Hi,

Thanks for the fast reply! I believe I get it, only have to look after a suitable tool.

For future reference (any one stumbling on here with the same question): https://youtu.be/J_bQu8D3Tdg

Kind regards, bert

[JohnR725]

Just because I'm curious can we have a picture of the other side of the wheel?

On some American pocket watches the center wheel pinion can unscrew.. This is because  when the mainspring breaks it can release a lot of bad energy back into the watch and that was their safety feature.  Otherwise normally the two parts should be really tightly riveted together..

 

[Poljot]

1 hour ago, JohnR725 said:

Just because I'm curious can we have a picture of the other side of the wheel?

On some American pocket watches the center wheel pinion can unscrew.. This is because  when the mainspring breaks it can release a lot of bad energy back into the watch and that was their safety feature.  Otherwise normally the two parts should be really tightly riveted together..

 

I believe you are referring to Safety Pinion design.

It is not crystal clear what is rotating in this case, but if it looks like this, then you are right on target:

http://4.bp.blogspot.com/-VL0Oeyv4-_E/VogGjjYgUYI/AAAAAAAAA1M/_JdSZ2vivzA/s1600/SP1.jpg