Help Amplitude and self-starting

Discussion in 'Clock Repair' started by Snapper, Feb 16, 2020.

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  1. Snapper

    Snapper Registered User

    Nov 30, 2014
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    I am currently working on a good quality fusee ship's clock of unknowm make. It has a bit of history behind it in that it was present at the D-Day landings. Sadly over the years it has been treated badly having a cracked balance staff end stone and apparently being dunked in a bucket of oil! There was a pool of oil inside the brass case when Iremoved the movement.

    The clock is fitted with an English lever escapement which despite a thorough strip and clean I cannot persude to self-start nor obtain an amplitiude of more than190 to 200 degrees. A fob watch with an English lever movement which I possessed some years ago would not self-start either so is this usual with such an escapement and also is the ampltude sufficient?

    I should add that the movement without the escapement spins freely on less than a quarter turn of the key.

    If this thread is more appropriate to the watch repair section, please feel free to move it.
     
  2. gmorse

    gmorse Registered User
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    Hi Snapper,

    How far have you dismantled and cleaned the platform?

    Regards,

    Graham
     
  3. Snapper

    Snapper Registered User

    Nov 30, 2014
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    Thanks for the reply. I have completely stripped and cleaned it with the exception of removing the balance spring from the stud. The stud is permanently affixed to the cock and the balance spring is pinned to it. I haven't the tools (or courage!) to remove it. However as the platform is oversized I could get sufficient access to thoroughly clean the jewel holes. The end stone is easily removed with the regulator arm.
     
  4. gmorse

    gmorse Registered User
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    Hi Snapper,

    In that case, how closely have you been able to examine both staff pivots and both jewel holes and endstones? Is this platform mounted horizontally or vertically? Can you post pictures?

    A lever escapement should be self-starting if it's close enough to being in beat.

    Regards,

    Graham
     
  5. Snapper

    Snapper Registered User

    Nov 30, 2014
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    The platform is mounted vertically. that is with the balance staff parallel to the movement arbours. As far as inspection is concerned, I use a stereo microscope to examine jewel holes and pivots and they appear to be clean and in good shape. There is a little surface rusting to the balance spring which I know of no method of safe removal.

    I will post pictures shortly.
     
  6. Snapper

    Snapper Registered User

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    Here are photographs as requested.

    1.jpg 2.jpg
     
  7. gmorse

    gmorse Registered User
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    Hi Snapper,

    Thanks for the pictures, I see what you mean about the oil!

    I suspect that the platform may be Swiss, from the style of the balance spring stud, which looks like the usual Swiss product, a press fit in the balance cock, and the partially cut balance rim is also something often seen in their escapements.

    You mentioned a cracked staff endstone; have you replaced that, and does the pivot that end show the slightest sign of mushrooming? How much endshake does the balance have? if you take the lever out and give the balance a puff with the blower, how long does it go on oscillating?

    I can't see how the balance spring is sitting between the regulator pins, is there the proper clearance there?

    Regards,

    Graham
     
  8. Snapper

    Snapper Registered User

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    Hi Graham. Thanks for the suggestions. I should have clarified that I have replaced the broken endstone. The endshake is fine and I checked for mushrooming when I found the broken end stone. I will try the blower test too.I think this afternoon, given the weather, is an ideal time to strip the escapement again and double check that I have not missed anything. I have worked on platform escapements before but I can't say I particularly enjoy doing them. I will post further pictures as work progresses.
    Thanks again.
    Robert
     
  9. Snapper

    Snapper Registered User

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    I have stripped the platform again and this time took a deep breath, a staking punch and a heavy dose of courage and successfully removed the stud from the cock giving me easy and clear access to the jewel in the cock. Problem 1 is clear to see in the pear shaped hole. Problem 2 was much more of a surprise in that the jewel in the base plate is also cracked. I'm not sure how I missed that first time around.

    Anyway graham's comments spurred me on to retrace my steps and for that I'm grateful. hopefully after replacing the offending jewels I might see and improvement in amplitude. I will report back.
    Balance staff jewel - cock.jpg Balance staff jewel - Base plate.jpg
     
  10. bangster

    bangster Moderator
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    To self-start, it has to be slightly out of beat, so there is pressure on the lever.
     
  11. gmorse

    gmorse Registered User
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    Hi Robert,

    That's good that you've found some solid faults, it's when you can't find anything and the thing still misbehaves that it's so frustrating.

    Regards,

    Graham
     
  12. kinsler33

    kinsler33 Registered User

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    Wow. I wish I could do delicate work like that. While you're about it, check the condition of the jewels in fork and escape wheel. Lost motion here will really reduce the balance-wheel motion.

    That's a lovely clock. It was likely placed in the oil to preserve it from rust and other damage. It might have been unpleasant to clean, but someone had foresight, for a ship is always damp and full of unexpected shocks and blows.
     
  13. Snapper

    Snapper Registered User

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    Thanks for the tips all. It really is appreciated.

    The oil bath sadly was not intended to preserve the clock but to try to get it to run! The result is that the plates will forever bear the scars. But hey, it is all part of ite long history.
     

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