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Discussion Starter · #1 ·
Hi
You may have seen my previous thread following a 7S26 rebuild where I could turn the mainspring but not get any movement from the escape wheel (with the pallet fork and balance removed). I think I have discovered the problem. The center wheel has become separated from its cog on the rotor side of the wheel so the cog and wheel are able to turn independently.
I assume this happened when I pulled off the cannon pinion from the dial side as I had to use some force to pull it off.
So I am asking how you separate the center wheel from the cannon pinion with causing damage to the center wheel? Alternatively do you not separate them, leaving them on either side of the main plate when carrying out a service?
As ever your thoughts are appreciated.
Chris
 

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I pull the canon pinion off the center wheel using tweezers and have not experienced problems refitting. Even removing a rusted on CP did not break the center wheel so I think you must have been unlucky or used enormous force (in horological context). I would also be worried about damaging the center wheel jewel if pulling hard.
 

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I use a hand remover to remove the part, no damage caused at all, as for leaving them on, i used to but now remove them, only because all my watches come from Ramon and they are full of crud so a full dismantle is aalways required.
 

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Tweezers or a cannon pinion puller. Post an image showing the damaged part...this would be very unusual...but might happen if you were lifting and twisting the cannon pinion at the same time. Regards, BG
 

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When i first started tinkering i managed to break a center wheel in exactly the same way as you have.
I very quickly learned to leave the center wheel supported by its bridge when pulling the CP off. That way theres less chance of the center wheel kicking sideways and breaking, plus it wont fall out from underneath and do a runner.
The center wheel bridge and center wheel are the last parts i remove on a full strip down.
 

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Discussion Starter · #6 ·
Thanks for all the comments and suggestions. I think I must have twisted the cannon pinion as I pulled it off and this probably also damaged the center wheel jewel as when I put in a replacement center wheel it was stiff. I ended up using a different main plate - lucky I have a number of Ramon specials.
Taking on board all the advice I modified a spare hand removal tool by taking out the central rod to provide more room to get the cannon pinion in place. This worked well and because it pulls straight up there is no chance of damaging anything.
There is a picture of the damaged center wheel below. This comes from a 7S26A movement. I notice that by the time Seiko came out with the 7S26C movement the wheel was solid and not a spoked wheel. A solid wheel should be stronger and so better able to withstand mistreatment from enthusiastic amateurs.
So I put in a replacement base plate and center wheel and so far the watch is behaving itself!!!
Thanks again for all the advice.
Chris

 

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As IB said, cp off before removing center wheel bridge. If you did so, then torque was probably the villian. Heavy tweezers...grasp...and lever straight up. If you were really desperate, the wheel might be able to be staked back on.
 

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Those Ramon specials are great for learning and practice. I have familiarized myself with some movements the same way. Just grab several different calibers and break them down and learn. Sometimes breaking something can be a great learning experience. Most of us always remember the times we screwed up and broke something and the upside is if your meant for this hobby you'll only do that once! Ramon watches are also good in another way because they teach you that not every watch you are going to work on is going to break down the way it should. That stuck or bent part will teach you how to improvise and learn new ideas. I was hooked hard on playing with watches so fast I never saw it coming.

Like a Ramon watch I bought. It was a 5606 Lordmatic one piece case. Only problem was once I removed the glass and pulled the stem out the tab that was suppose to slide out so you can depress it to remove the stem was snapped off. It took some time and finding a tool with just the right bend but I got under the set lever and was able to lift if off the stem without breaking or bending the stem.
 
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