Sweep seconds hand cock: Elgin 539 A-11

[arron]

Good Saturday Guys,

I finished a COA (well, the C-O part of it) on this watch.  It seemed to be running strong until I cased it up and then it soon thereafter stopped running.  The balance seems to run freely, although there's very little detectable end shake.  I thought that might be the problem until I noticed under magnification that the part of the cock/bridge that sits atop the sweep seconds spindle/pinion and holds the hole jewel did not sit perfectly flat, but it was at an angle.  I can see it from the side and also from the different light reflection from above.  When I took the cock off, the watch runs strong again.  I'm guessing this is the problem but the angle seems so perfect, like it was done intentional (and there's no other sign of damage), that I'd like to confirm my suspicion before proceeding to flatten it.

 

I would also appreciate any advice on the best way to flatten it without it snapping off. 

 

Thank you.  Arron  

[Nucejoe]

36 minutes ago, arron said:

 When I took the cock off, the watch runs strong again.  I'm guessing this is the problem but the angle seems so perfect, 

I think you have nailed the problem alright. 

Rgds

 

[LittleWatchShop]

--I reread your post and I think I get the picture now--will leave my comment below even though it probably does not apply to your situation.

Not sure I get the picture.  When you remove the upper third wheel (leaving the sweep second pinion in place), the watch runs fine?  Here is the test I would do.

Remove the sweep second pinion so that the upper third wheel (not sure what is called) is turning as the watch runs, but does not engage the SS pinion.  If it does not run, the third wheel pivot is bent or the upper third wheel is bent. 

You could disassemble the watch and put the third wheel on a poising tool to see if it runs true.

I have serviced a few of these but never had this problem.

Edited October 7, 2023 by LittleWatchShop

[Nucejoe]

6 hours ago, arron said:

When I took the cock off, the watch runs strong again.  I'm guessing this is the problem but the angle seems so perfect, like it was done intentional (and there's no other sign of damage), 

1- The small cock ( second photo ) IS  bent upward, doesn't look perfect at all   @Arron . flattening the small cock can be done in situ IN SEVERAL SMALL INCREMENTS , just push on it with flat end of your tweezers, be careful to get it done right by first attempt , as repeated ( up and down ) bending  might break it.

2- Another sign of damage is the scratch on main gear train  bridge , scratched  by the extra third wheel. ( indicating bent pivot of the extra third wheel and a pain to streigthen ) 

Either, case 1 or 2 or both together can stop the watch.

 

 

 

 

 

 

[LittleWatchShop]

9 hours ago, Nucejoe said:

bent pivot of the extra third wheel

And this is likely as a result of a previous repair where the pivot was bent while removing the wheel.  I have the correct tool to remove these, but am always a little fearful when I do it.

[arron]

I was able to bend the cock without breaking it and with everything back in place it stays running.  yay!  There are other issues with how it's running, but i'll do some research and experimentation first before posing further questions.  I also need to look into whether that third wheel pivot is bent.    Thanks for your help guys.