Stuck Cannon Pinion on ETA 2873

[Hoe]

Dear Watchmakers

I am writing my first post, because I need some advice and can’t find a solution myself.

I am working on an old ETA 2873. I completely disassembled it, cleaned and checked all the parts and finally reassembled everything together.

Problem: I can’t set the time manually by turning the crown. The crown in the time setting position is stuck. Everything else works fine.

My findings: The cannon pinion on this type of movement is held in place between two spokes (see attached photos). I guess there needs to be the right amount of friction between the two parts. Enough friction to hold the cannon pinion in place to rotate the hands by the movement itself, but not too much friction in order to be able to turn the crown and set the time manually. Right?

I think there is too much friction now. The two parts after decades somehow stick together. I tried to rotate them against each other, but I see damage coming, when I try to overdo it…

What can I do to get this running as it should?

Best wishes

[Nucejoe]

Oil the groove of canon pinion that sits between the two spokes.

Make sure the minute train bridge is not pushing on the train.

Good luck.

[watchweasol]

As Nucejoe said oil the groove,   put a pin vise over the cannon and try manipulating the wheel SLOWLY to free it off some what.  I take it that you have the tech sheet as you have the part number.

[watchweasol]

Hi  the recomended lubricant was Jismaa grease (expensive) but others including Roland Ranfft recomend just oil.    A list of alternative greases.       Mobeuis SYNT-HP1300,  Novostar winding grease or KT-22 Microlubrication

[HectorLooi]

Did you by any chance use an ultrasonic cleaner to clean this?

Parts in close contact should not be placed in an ultrasound, such as scissors, pliers, ball bearings, etc. Especially items under spring tension. The parts vibrating against one another will cause indentations in the metal surface. This type of damage is called Brinelling ( named after the Brinell hardness test guy ).

[Hoe]

SOLVED:

I put a lot of Moebius HP1300 between the two parts and let it rest for 1-2 hours. Afterwards I removed the superfluous lubricants and installed everything back together. Turning the crown initially needed some torque but then the cannon pinion became loose and turntable. Setting the time is possible again.

Thanks for the encouragement and the other tipps!

[MaverickWaz]

Did you by any chance use an ultrasonic cleaner to clean this?
Parts in close contact should not be placed in an ultrasound, such as scissors, pliers, ball bearings, etc. Especially items under spring tension. The parts vibrating against one another will cause indentations in the metal surface. This type of damage is called Brinelling ( named after the Brinell hardness test guy ).

Cheers for that information Hector. First time I’ve heard of that so will avoid in the future!