Kern Miniature 57

Discussion in '400-Day & Atmos' started by Bod, Sep 9, 2019.

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  1. Bod

    Bod Registered User

    Mar 10, 2019
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    Just acquired this..
    IMG_1713.JPG IMG_1708.JPG IMG_1709.JPG
    It has a few problems, bent hour hand, spiral suspension spring, and excess lubrication!
    Been well sprayed with WD40, the locking cup beneath the pendulum, seems to have been filled with axle grease.
    It appears to want to run, just the twisted wire stopping it. I've removed the Suspension Guard, to get a clearer view of the back, it appears to be a plate 1406A (page 130) there is no serial number.
    Whilst removing the guard, I noticed that the clamping screw for the top block was loose, and the top block was not clamped tight, would this be enough to cause problems?
    Which would not have been cured either by "winding the clock up via the pendulum" or a "good oiling".
    IF I can remove most of the twisting from the suspension, how long would be considered a good test run, 1hour, 24 hours, a week, I know that regulation would be pointless until a new wire is fitted. I don't want to spend money on a clock that is worthless, if it won't run.

    Bod

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  2. tracerjack

    tracerjack Registered User
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    Jun 6, 2016
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    From my experience, unless something is actually broken, it will run. They can be fussy to get going, but they aren't very complicated, so there isn't much that can go wrong. But, I'm doubtful you can get it to run with a suspension spring as twisted as that one. You don't mention if you are planning to completely disassemble the movement and clean it. That is the first thing I do with these clocks, since a dirty mainspring will stop these clocks every time.
     
  3. Harry Hopkins

    Harry Hopkins Registered User
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    Nov 16, 2011
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    Your clock can probably be made to run without spending much money. As Tracer said it would be best if it was disassembled and cleaned but you might be able to make it go as is. I have seen one clock with a spiraled suspension spring like yours able to run. If you can use some tweezers and flatten and untwist the area of the spring between the fork and the top block it may go at least for a test... getting it in beat will be troublesome with any bend at all above the fork. If you can get it to run for a few hours with good overswing (at least a half inch in both directions) I would consider that a successful test run. The loose top block would also cause enough of a problem to keep it from running. Good luck and let us know if it will go.
     
  4. MartinM

    MartinM Registered User

    Jun 24, 2011
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    Before doing anything else with the spring, try simply reversing the twist, going progressively further in multiple attempts till it's straight, again. It's weird, but it often works.
    The top block is supposed to be slightly loose in its saddle.
     
  5. Bod

    Bod Registered User

    Mar 10, 2019
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    Well, it's now been stripped and cleaned.
    Lesson 1. Don't over oil.
    Lesson 2. Don't keep clocks near budgerigar cages. Millet seeds soak up oil, and stick to gears.

    It's now "running" for a short while (50 minutes) but with a suspension spring twice as thick as it should be. This has I think, caused a lack of overswing, which stops the clock, there is not enough power to run the hands, which are at present removed.
    The old twisted wire is beyond hope, flexible as a length of string!
    Correct suspension is now on order, so in a week or two, tick tock!
    As a sign of how cheaply this clock was made, only the 3 sides of the main plates, that are seen, are polished, the 4th still has the guillotine cutting marks.

    Bod
     
  6. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    I still wonder about the notion that a thicker suspension spring will stop a clock. I'm not sure that's a fact, but stand to be told differently.

    I just discovered something about a Kern regular size clock that I'm working on. I'm beginning to understand the escapement more as I work on them and realize that I have to change the locks/drops in some cases. In my current case, I felt good that the drops were correct so no adjustment was needed there. I noticed that the locks were "a lot" but figured I'd just give the clock a try as-is. I didn't seem much evidence of a past repair, so figured maybe it was OK. Well, the clock would run but after 2-3 hours it would stop...and the amount of over swing was really small. Figured I'd need to attack those locks. I did a lot of fiddling, moving the pallets up into the anchor. I had the range of results. I moved them too far and the EW was landing on the impulse face and the clock fluttered. I had the anchor out 2-3 times, making changes and then reassembling to see how I did.

    Finally, I got a set up where I liked the locks...the EW just landed on the lock face and then slide up the face as part of over swing. Right away I noticed that my over swing was respectable. That really has to do with having the proper locks. If the locks are too much, then a lot of power is needed to slide the EW across the pallet and the anchor has to move so far away from vertical in order to clear the lock face which also requires a lot of power. On this clock the total rotation is not wonderful, but it's all about the over swing. I've got a healthy 45 degrees of over swing and I think the clock will continue to run once I put the motion works on.

    So, I don't think the suspension wire necessarily controls the escapement. But getting those locks/drops right certainly does!

    Kurt
     
  7. Bod

    Bod Registered User

    Mar 10, 2019
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    Kurt.
    My thoughts on the much thicker spring, are that it will not twist as easily as the correct thin one, hence restricting the movement.
    This clock is showing no signs of being "worked" on before, other than the excess oiling. The pallets do seem to be rather long, but at present I'm not skilled enough to move them! same with the EW adjustment.
    Once I get the correct wire, that will show the rotation, and may be I'll have to follow your lead.
    Please let us know how yours goes when finished.

    Bod
     
  8. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    Bod -

    Certainly twisting is required. But don't get hung up on the total rotation. You need a good amount of over swing after each tick and tock. People give inches for over swing, but I can see degrees of over swing better than estimating inches. If the escapement was correct in your case, then likely the total rotation would be reduced but you might still have some over swing.

    Granted, if the suspension spring was 1/4" thick (I'm exaggerating) there wouldn't be any rotation at all. How thick is "too" thick I don't know. I guess you'll know when you get the right spring. Note that you can actually go through a process to thin a suspension spring. It takes some sandpaper and some time. But trying to go from say 0.0045 to 0.0023" is going to be a real pain and probably not recommended. But still, a spring can be made thinner.

    Kurt
     
  9. Bod

    Bod Registered User

    Mar 10, 2019
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    The current overswing is barely nothing, I think it is a combination of lack of power at the top, and lack of mass at the pendulum, and stiffness of the wire all combine.
    A less thick wire, 1/8-1/2 as thick again, probably would work, with other adjustments, on a well ordered clock.
    Just waiting for the postman now.

    Bod
     
  10. Bod

    Bod Registered User

    Mar 10, 2019
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    The Postman knocked.
    How big is the parcel containing 3, 0.002 suspension springs?
    Well it wouldn't go through the letterbox.
    New spring fitted, runs well, with plenty of over-swing, but very fast. 8 minutes per hour gain.
    When I get time away from making Christmas presents, I'll thin down the spring as per John Hubby's method.
    Been running for nearly a week....now it's stopped...can't be anything to major.

    Bod
     
  11. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    Ha! I've got two clocks that will run for a week, in one case it runs for a month and then stops. I've had them apart several times and can't find anything wrong. It's getting frustrating!

    They both tend to stop with minute hand rising in the 0:45 region. They don't have enough power to raise the hand, yet it does it for a week or three. It's looking more and more like main springs...they run OK with the clock wound near full, but as soon as the power comes off a bit, they stop.

    Hope you're more successful!

    Kurt
     
  12. Bod

    Bod Registered User

    Mar 10, 2019
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    Lowered the fork a little, 24hrs and still running, albeit very fast still.

    Bod
     

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