Erratic anchor motion?

Discussion in '400-Day & Atmos' started by Elliott Wolin, Dec 24, 2019.

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  1. Elliott Wolin

    Elliott Wolin Registered User
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    Nov 18, 2019
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    How erratic is the anchor motion normally?

    I cleaned and oiled a Nisshin (Master, plate 1461e) and it runs with a fairly short rotation, but watching the anchor pin makes me think something is wrong. As the pendulum turns the anchor pin moves smoothly from one extreme over to the other until the drop, whereupon it jumps forward and then back, then smoothly goes forward again during the lock to the other extreme.

    There is a 1/4 twist in the spring starting about half-way down to the lower block below the fork. I'm getting a new spring, but it doesn't seem likely the spring causes this problem (if it is a problem). Tiny rotations of the upper block cause big changes, including flutter, but there's none now. It just seems erratic to me.

    Or is what I'm seeing normal?

    The motion isn't completely symmetric, but I'm waiting for the new spring to work on that. I had no success stroking the spring against a flat surface with a wood dowel to remove the 1/4 turn...what technique should I use?
     
  2. Elliott Wolin

    Elliott Wolin Registered User
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    Found some internet videos, not as worried as I once was, but according to one I'm experiencing too much "bounce." I believe I see that it is normal for the anchor to "twitch" at some points, e.g. the moment the escape wheel tooth moves from the locking face to the impulse face of the pallet. But mine does this too much.

    My fork may be open too wide. I believe I once opened them up as they were rubbing the anchor pin, perhaps I opened them too much. I understand a piece of normal paper should just fit between the fork and pin.

    And in one video he raised the fork a smidgen. I once thought the lock was way too deep and considered lowering the fork, now I'm not so sure.

    Amazing how sensitive these clocks are to minute modifications...perhaps that's part of the challenge...
     
  3. KurtinSA

    KurtinSA Registered User
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    I wouldn't worry about the quarter twist if it is below the fork. As for the bounce, I think what you indicate is why it does bounce...moving from the lock face to the impulse face. Definitely check the fork tines...I've seen that before when the fork width is not adjusted right.

    Kurt
     
  4. Elliott Wolin

    Elliott Wolin Registered User
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    Nov 18, 2019
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    Current problem, although it runs, when I put the cannons and hands on it stops. By tightening the minute hand nut as little as possible I can keep it running, but the hands and cannons may be too loose.

    Might there be something wrong, or is this par for the course?

    I just cleaned and oiled it, and it runs without the cannons and hands (I still have to work on the fork and excessive bounce). The minute cannon has a loose fit over the center wheel arbor and relies on a washer behind it and pressure from the nut. Unless I'm putting it together wrong...when I got it it wasn't running at all, and it's not clear I put things back together in the correct order. So I may have introduced extra friction somewhere.
     
  5. Wayne A

    Wayne A Registered User
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    Sep 24, 2019
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    Suggest eliminating known problems such as fork clearance and beat setting. All these torsion clocks have some bounce but excessive fork clearance just means it has further to swing freely. Have a couple of pictures of my master when I took it down in case they might help.

    20191020_182023.jpg 20191020_185728.jpg
     

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