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Posted

My current project is the restoration of a pocket watch. I already wrote in another thread about the broken dial of the watch.

Now I'm trying to disassemble the movement. I am stuck at the point where I try to remove the cannon pinion from the central wheel. I have a Bergeon cannon pinion removal tool, and it is impossible to remove what I identified as the cannon pinion. Before I damage something I wanted to ask whether it should actually be possible to detach it from the dial side.

I have attached two images. The first one is from the dial side where I marked the cannon pinion with a red circle.

pocketwatchcannonpinion.thumb.jpg.f693f7da608ed9de730785be714d539b.jpg

The second image shows the central wheel from the other side of the movement.

PXL_20250204_185315664.thumb.jpg.ab12491602b05757e473bf14291881d3.jpg

Should it be possible to pull off the piece that I identified as the cannon pinion from the dial side? What can I do if it is stuck so hard to the axis of the central wheel? Try to loosen it with WD40 for example?

Thanks

Stephan

Posted (edited)

This looks to be a pressed on cannon pinion, and does not fit on with the snap detent you have probably encountered before. This type is common on pocket watches before the 1920s and has a firm friction fit between the center wheel arbor and the cannon pinion. It can't be levered off (at least not safely).

If you have a jeweling press, position it under the center wheel arbor with the lower train bridge installed and push on the tip of the pin from the dial side where it protrudes through the cannon pinion. It should only take a small motion to loosen it so it can be pulled out the back side.

Or a staking set with a flat punch to gently tap it loose from the dial side.

If you don't have a jeweling tool or a staking set, install the bridge behind the wheel, and you can take the back end of your tweezers to lightly tap on the pin where it protrudes, with the aim of dislodging it just enough that it can be pulled out the back of the movement. If it won't move, a little penetrating oil might help.

Whatever method you choose, the important thing is that the pin goes down - the cannon pinion does not go up.

Here's Kalle at Chronoglide doing it with a Horia press 

 

Edited by mbwatch
  • Like 1
Posted
19 minutes ago, mbwatch said:

If you have a jeweling press, position it under the center wheel arbor with the lower train bridge installed and push on the tip of the pin from the dial side where it protrudes through the cannon pinion. It should only take a small motion to loosen it so it can be pulled out the back side.

Or a staking set with a flat punch to gently tap it loose from the dial side.

If you don't have a jeweling tool or a staking set, install the bridge behind the wheel, and you can take the back end of your tweezers to lightly tap on the pin where it protrudes, with the aim of dislodging it just enough that it can be pulled out the back of the movement. If it won't move, a little penetrating oil might help.

I don't have these tools. It seems to be too dangerous for me with my available tools and my current skills to try to remove the cannon pinion without risking catastrophic damage. So probably I just should leave the center wheel as-is with the cannon pin when I put the base plate into the ultrasonic cleaner. I think I will still be able to get some oil into the center hole after cleaning.

Thanks for the video, it shows very clearly that removing the axis is a fairly difficult operation...

Posted
On 2/4/2025 at 12:26 PM, stm said:

it shows very clearly that removing the axis is a fairly difficult operation.

Maybe sometimes it's better not to watch the videos as this really isn't that difficult operation at all. So before the video with both plates together and the screws in place. In other words you do not want the center wheel flopping around as if it's jeweled you could crack the jewel that it's in. So holding the watch in one hand and a small hammer In your other hand just The center pin gently. You really don't need a lot.

Then the problems would be some of these watches do not have a pin sticking out and then you really should have a staking set. Which is also very useful for putting this back together again. But you do have to be careful staking set of how you support the backside not to break anything. Often times their stuff sticking out on the back side like if it is a key setting that would be sticking out on the backside that has to clear the staking set.

This is an example of key setting on the backside. Where fear using a staking set versus holding it you have to be careful that the stuff here is over a hole as all of it will come out with the pin.

image.png.2c0d3723e4225d98c1c5263fe7a8d8e9.png

Here's what the parts look like out of the watch at least for one like this

image.png.6b357887a6407c458fa70c356d22821c.png

Then some additional information just in case you need it

image.png.4330e001cf5eed64a215d53af4fc3775.png

image.png.39e2db8691d03125e2358d105f5580c9.png

 

 

 

 

 

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