How do you put together pendulum cogs from an automatic?

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  • #48450
    rozeerox
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    Right basically its an automatic wristwatch, i bought it for myself about 4 years ago. 2 yrs in, it stopped winding itself and has since sat in a drawer until i studied bobs videos :D
    It wouldnt let you wind it using the crown either, so i got it out took out the pendulum, and also underneath 1 bridge. This was a little stuck and it popped out on me and the springs skidded a few millimetres out of where they aught to be. now there is nothing to hold these cogs in place once you have them where you want them, so you literally have to screw on the bridge and see if it will let you wind it.
    now it lets me wind it, and it works! however, the cogs that sprang out are responsible for automatically winding the movement since they interact with the pendulum. and now iv been trying half the night and i cant get the springs in the right order or the right way so that it will wind itself. somebody please help!!!!!!

    #52612
    rozeerox
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    heres a picture of what the automatic ratchet (at least i think thats what its called…) looks like.
    Now can someone please tell me how to get the cogs iv pointed to in red in the right setting so that it will work? any help would be much appriciated :)

    #52613
    david pierce
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    Rozeerox,
    The two middle wheels that engage the mainspring barrel are called compound gears. Their function is to increase the torque provided by the pinion on the counterweight. The two gears that you refer to as cogs are set so one engages in a clockwise direction and the other in a counter clockwise direction. From your picture it appears that the mainspring barrel needs to move in a clockwise direction to wind the spring. If you ignore or remove the bottom cog from the winding train, there should be five axels from the counterweight pinion to the mainspring barrel. This means that in order for the system to wind properly, the counterweight must move in a clockwise direction in order to move the mainspring barrel in a clockwise direction. This also means that the cog must engage the train in a counterwise direction and spin freely or slip in a clockwise direction. Once this is established, the idler cog can be added in. Because the cogs ratchet in opposite directions, it effectivally adds a sixth gear into the train when the counterweight spins in a counterclockwise direction.
    david

    #52614
    rozeerox
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    thanks for your response, I tried this method and its great except that now it wont allow the crown to be wound.
    I believe the wheel that you said aught to spin freely in a clockwise direction is to blame as sometimes it would spin freely and others it would seem to jam up the mechanism so that the crown could not be turned. what could be the problem there? why would this only happen sometimes?

    #52615
    rozeerox
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    oh god, now it makes a grinding feeling when the crown is turned… 😮
    what the hell could that be?!

    #52616
    david pierce
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    Rozeerox,
    The grinding you are experiencing is called learning how to repair watches and everybody goes through this. The best way to mitigate the pain is to practice on old junk watches. At this stage of the learning experience it does not matter if the practice watches work or even if they are complete. The only improtant thing is that you practice taking them apart, examine them for problems and reassemble them. I have launched numerous springs, screws and anything else that can come out of a watch into low earth orbits; we all have. I have broken more pivots than I can count and turned many hairsprings into Brillo pads. Through practice and only through practice will you learn the repair techniques that work for YOU. Books, videos and courses can teach principals and give you a good theoretical understanding of these mechanisms but practice, making mistakes and breaking things is the only way I know to apply the knowledge to the real world.
    david

    #52617
    rozeerox
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    thanks, I thought I was just being stupid 😳
    I didnt realise everyone went through this. I dont feel so bad now :D

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rozeeroxHow do you put together pendulum cogs from an automatic?