Pierce 134 Help

[margolisd]

Does anyone have any experience repairing Pierce 134 movements? It has an unusual vertical clutch system. Having replaced the rubber clutch I'm almost there with it but having problems fine tuning it. Going by this I understand the clutch should float between springs J and K. But I'm not sure which spring goes underneath the clutch (ie closest to the dial) and which spring goes above the clutch. Anyone know?

[StuartBaker104]

I have answered below, but if you haven’t read it I would recommend the Esembl-o-graf manual which gives an excellent explanation of how to assemble and adjust this chrono.  There are some variations, as the manual is based on the twin pusher variant, but if you have a single pusher there are a few different parts and a few parts missing which the manual expects. I have  a note of those somewhere if you remain confused.

In summary, spring K is used to adjust the end float of the chronograph pinion, by adjusting the screw nearest the pinion. It should almost touch the pinion, but not quite.  This spring stops the pinion from riding up when the clutch is disengaged.

Spring L is the lifting spring that moves the chrono runner away from the teeth on the pinion when the chrono is stopped. This spring should run on the plain part of the chrono staff next to the rubber washer

Spring J is the tension spring that makes sure the chrono pinion doesn’t judder - like a tension spring on a centre seconds hand. This should touch the pinion ever so lightly.

No oil is required on any of these springs.

[margolisd]

Thank you for such a great description. That's much clearer.

In terms of the rubber washer I'm trying some of this nifty stuff - https://sugru.com. What would you use?

[WatchMaker]

A suitable washer stamped from one of the soft polyurethane protection 'stickers' often found on new watch crystals has been mentioned as a suitable material for this e.g.: https://forums.watchuseek.com/f11/pierce-chronograph-no-trouble-clutch-disc-1006197.html.

 

[margolisd]

Yes, I came across that too and I did experiment with it. I found the plastic to be too thin causing the springs to obstruct the clutch parts 

[StuartBaker104]

Interesting. I used a car windscreen sticker which was made of similar stuff to the watch protection film. I still have the remainder for future use and just measured it at 0.15mm. I attached it with superglue and in total it stands about 0.23mm above the smooth outer running track of the runner.

I had no problem adjusting this to work... but sadly the rest of this watch is another issue.