Tales from the bench - A beginners guide to dissembly

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Thread: Tales from the bench - A beginners guide to dissembly

  1. #11
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    Quote Originally Posted by agent orange View Post
    I know what you mean Andy taking stuff apart is a lot easier than putting it back together. The first watch movement I stripped I remember thinking, 'well this is pretty easy, what's all the fuss about?'. Then I spent the next two days trying to re-assemble it .

    A handy hint is to take photo's of every stage, especially when you're starting out, that way if you forget how something fits you've got a quick reminder. I still do this when working on a movement I haven't dissembled before although I try and work it out before resorting to looking at the camera. I find I remember more if I work it out for myself, it's etched more into my (pathetic) memory for some reason.

    The beauty of practically all good movements is the parts will only fit in one place on the main plate. They're like a 3D puzzle really, a bit of time and logic can usually solve it.

    I still struggle a bit with the lingo tbh, especially as there seems to be about three different names for each watch component, depending on region and whether you use the older traditional names. Again like the camera/memory thing, writing it down commits it more to memory. It's also good to speak the names aloud when working with them, you feel a plonker but it does work.

    Cheers,
    Gary
    Some great tips - I'm sure that, as in all things, as you get more familiar and competant you'll probably be able to do a pocketwatch with your eyes closed - a fascinating journey.

    I'd personnaly love to have someone strip a few of mine and explain the ins and outs better - I've got a basic grasp and know a column wheel from a bridge, but you can't beat hands on.

    I'm amazed at your camera taking such good macro shots - that's astounding, I'll log that one for reference for next christmas...

    Andy

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    Here's a youtube vid of how a watch works and what the parts do Andy. It's a bit slow but it is a very good and easy to understand demonstration. Skip to around 4 minutes to get to the watch bit.

    http://www.youtube.com/watch?v=508-rmdY4jQ

    Cheers,
    Gary

    P.S. Anyone got any idea why I can't embed a video in the normal way?

  3. #13
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    The sky had a rare bright yellow orb in it this morning so I thought I’d continue with the dissembly of the Molnija movement.

    Not much left to do now just take apart the keyless works, so called as before crowns and stems, a key was used to wind and adjust the time in pocket watches.

    So here’s where we were, the top plate with the keyless works.



    Here’s the individual components of the keyless works.



    From left to right and top to bottom they are:
    Crown and stem
    Winding pinion
    Clutch wheel
    Bolt
    Setting wheel
    Intermediate wheel
    Minute wheel
    Cover plate and bolt spring
    Return spring
    Return bar

    I’ve posted this up first as it hopefully makes the following a little easier to follow.

    So back to the parts back in situ.



    The large part directly on top is called the cover plate or set bridge. The thin arm of which is called a bolt spring. The cover plate name is pretty self explanatory as it covers and holds in place a minute wheel (the large brass wheel just off the centre) and the setting and intermediate wheel.

    The bolt spring section of the cover plate interacts with the bolt which controls whether the stem is used for winding or setting the watch.

    First job is to remove the cover plate revealing the setting wheel, intermediate wheel and winding wheel.



    Whilst we’re here I’ll try and explain how the stem works in conjunction with the clutch to either wind or set the watch. The following pic shows the keyless works in a set position.



    The large lever held in position with the brass post is called the return bar. You’ll notice how it’s sat in a groove in the clutch. Pulling the stem out has moved the bolt which in turn has pushed the return bar forwards so the clutch is pushed towards the set wheel.

    So now the clutch is connecting the stem to the set wheel, intermediate wheel and minute wheel, ready to set the time.

    With the cover plate back in position this is how it looks.



    At the end of the bolt spring there’s two notches that connect with a pin on the bolt. The two notches dictate whether the bolt is in a wind or set position. Remember the bolt pushes the return bar, which in turn moves the clutch wheel.

    It sounds complicated and it’s difficult and long winded to explain in words but hopefully the pics make it pretty self explanatory.

    Time for the keyless works in the wind position.



    Pushing the stem back in has moved the bolt, this has moved the return bar to the left which in turn has made the clutch engage with the winding pinion. The top section of this connects to the crown wheel, which in turn winds the ratchet wheel and barrel.

    The cover plate back on to show the bolt spring in the winding position.



    Whilst we’re here I’ll show a common issue with keyless works and why they sometimes won’t wind or set. The pics below shows that the return bar has slipped out of the groove in the centre of the clutch wheel. The result is it can’t move the clutch wheel to either the wind or set positions.



    This happens quite a lot on ETA 2836 and 2824 movements but to rectify it you have to remove the hands, dial, day/ date wheels and cover plate. So whilst it’s an easy fix the dissembly and re-assembly takes a bit of time.


    Here’s a pic of the stem, winding pinion and clutch wheel to illustrate how the teeth work. Clutch wheels used to be called castle wheels and you can why with the shape.



    Hopefully that makes some sort of sense. It also hopefully demonstrates how clever even a relatively simple movement is, with many parts having multiple functions. Movement designers are nothing short of geniuses imho.

    Thanks for reading.

    Cheers,
    Gary
    Last edited by agent orange; 15-01-2013 at 17:42.

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