Changing Sehwa (Korean) 31 Day Mainsprings

Discussion in 'Clock Repair' started by Richard Barkey, Aug 23, 2007.

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  1. Richard Barkey

    Richard Barkey Registered User
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    Aug 2, 2006
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    A friend at work asked me to look at his wall clock which turned out to be a Korean 31 day made by Sehwa. It has two broken mainsprings which I am going to replace with Timesavers part number 14203 (3/4” x .015” x 170”).

    Having never worked on a 31 day movement before is there anything I need to know about changing the mainsprings? I have worked on many American and European open and barrel spring movements before and am familiar with the procedures to change the springs.

    I would appreciate any advice or opinions anyone could provide.

    Richard.
     
  2. shutterbug

    shutterbug Moderator
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    The main difference is that your spring is 14 feet long and is a monster to control :) You'll need to clean and grease the new springs before use. Some of the 31 day clocks have an extra bar that the spring wraps around. Be sure you put them back in. They only look useless :) Other than that, they are not much different than the standard 8 day variety. These springs are more dangerous than the shorter 8-day springs, so gloves and goggles are a good idea.
     
  3. lpbp

    lpbp Registered User
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    These springs are very powerfull, and the plates of some of these clocks aren't very strong. I have seen some plates bent because of the strength of the springs. I know of some repairpersons who wil not work on these because of the potential danger.

    Larry Pearson, FNAWCC* #35863
     
  4. gooseup

    gooseup New Member

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    i also have two korean time pieces,they are now apart,i tryed the clamps?took off the top plate,it made a load pop then it banged all the gears out,the springs are still on the clamps,WHAT can i do NOW?i have cuts on my fingers from these springs,how can i put it back together now?
     
  5. Willie X

    Willie X Registered User

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    The springs are long but actually not any stronger than average. Only problem is that the extra bulk of the super long springs doesn't leave much room for the clamps. Good solution is to use iron 'tie' wire instead of the usual clips, hose clamps are good too.

    Many folks have trouble with open springs because they want to clamp them in the fully wound condition. This is actually opposite to what needs to be done. The spring should be clamped, or wired, in the relaxed condition, about where it would be after running 7 or 8 days. This will allow much easier dis-assembly and reassembly.

    Willie X
     
  6. harold bain

    harold bain Forums Administrator
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    There are extra steps needed to let these springs down. First, let them down far enough to remove the steel bars under the fixing nuts that force the spring out from the movement. Then wind up again, and tie them up, then let them down into your wire (or clamps). If you don't take the bars off first, you will have a problem getting the springs out, as Gooseup discovered.
    Richard, if you have a spring winder, you need to take extra care to keep the springs from going sideways as you wind them. Make sure you have one hand around the spring in the winder.
    Putting the springs back in, once you have the movement back together, wind the springs to remove the restraint, then let them down far enough to put the bar back in, then wind fully.
     
  7. Dick Feldman

    Dick Feldman Registered User

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    Richard,

    You may see secondary damage in that movement. When the springs broke, the rest of the wheels in both trains were shocked. This is not to mention the damage to the hand that was trying to wind the clock when the springs broke.

    There is a strong possibility you will find: bent arbors on the second wheels: teeth missing or bent on the first wheels: teeth missing or bent on the second wheel pinions; bent arbors on the second wheels; bent arbors on the third wheels; and teeth damaged or missing on the third wheel pinions.

    In the USA, we have all sorts of laws protecting consumers from dangerous products but those potentially hazardous clock movements have been allowed to enter the country for years. We are protected from flaws and poor manufacturing procedures with autos, baby products, appliances, etc. but not those clock movements. They should have been stopped at our borders and sent back to their country of origin.

    I am one of those who refuses to submit myself to the potential dangers of working on that type movement. The risk of injury and liability are much greater than the few dollars generated.

    Best,

    Dick Feldman
     
  8. shutterbug

    shutterbug Moderator
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    I'm a bit perplexed. If the springs were captured with clamps, there couldn't have been enough power to throw gears around the room. I'm guessing that they weren't completely let down. Perhaps the clamps were pressing against pinions and deceptively looked like they were capturing the springs power when they really weren't. Some pictures of what you have would help at this point. We can help you sort out where the gears go if needed.
     
  9. harold bain

    harold bain Forums Administrator
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    If he didn't take off the steel bars before taking the movement apart, it would fly apart when he tried to remove the plate. It would not be fully let down.
     
  10. hookster

    hookster Registered User
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    #10 hookster, Sep 24, 2012
    Last edited: Sep 24, 2012
    First of all, good to see you again on Saturday at the local Toronto NAWCC Meeting. As usual, I bought a bunch of stuff, much of which I probably didn't really need. I have saved your instructions for letting down these movements as I have never worked on one, and have always been a bit afraid of 31 day main springs. Also, if you are ever in the Schomberg area let me know, as you would be welcome to drop by and see my modest little work area, as well as to 'talk clocks'.
     
  11. Tinker Dwight

    Tinker Dwight Registered User

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    Hi Harold
    I've taken a couple of 31 day movements apart and don't recall any problems
    but obviously not the same type .
    Do you or anyone have any pictures of the mentions bars? It looks like a problem
    to look out for.
    Thanks
    Tinker Dwight
     
  12. David S

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    Hi Tinker,

    Actually I just finished working on one. I will include a picture of the front of the movement. The silver pieces on each side of the bottom plate, under the nuts, keep the springs biased outward.
    front movement.jpg
     
  13. harold bain

    harold bain Forums Administrator
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    Thanks, David, good picture.
    Hookster, you should have stuck around. There was a great presentation on how to bevel glass.
    Tinker, they are not that bad to work on, but you need a good spring winder to be able to do the springs.
     
  14. David S

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    #14 David S, Sep 24, 2012
    Last edited: Sep 24, 2012
    Tinker I have worked on lot's of these and decided to add an attachement to the Joe Collins winder to help contain these huge springs. See pic.

    large spring containment.jpg
     
  15. harold bain

    harold bain Forums Administrator
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    Great idea, David. You don't want to see what happens when those springs jump out sideways at you.
     
  16. David S

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    Harold...I DID see...hence the modification to the winder. Like the Energizer bunny when winding down these springs they keep going..and going..and going....
     
  17. hookster

    hookster Registered User
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    Indeed a great idea David. I have printed off the picture and will do the same to my Joe Collins winder. (Harold) at the next local chapter meeting I will indeed stick around as I believe the topic is french clock movements, that can prove tricky and troublesome.
     
  18. Tinker Dwight

    Tinker Dwight Registered User

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    Hi David
    I did something similar to my winder. I drilled two holes below the arbor in the base
    plate and put two rods in them. I've not had them tend to wonder out the other side
    so I just do the one side.
    Didn't think much of it at the time, just didn't like holding my hand anywhere near
    the spring in case it should let go.
    Tinker Dwight
     
  19. Tinker Dwight

    Tinker Dwight Registered User

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    Haaa, those things. Now I see, yes. These need to be removed first. Thanks for the pictures David.
    Tinker Dwight
     
  20. shutterbug

    shutterbug Moderator
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    That's one style of retainer. Another type is just two bars that slip in the plates. You have to let the springs down after getting things back together to put them in.
     
  21. lirenrui

    lirenrui Registered User

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    excuse me,what is the "steel bars" ?
    can you show me a picture ?

    many thanks !


    lirenrui
    2012.9.25
     
  22. harold bain

    harold bain Forums Administrator
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    See picture in post 12, and look at the two silver pieces attached to the movement posts at the bottom.
     
  23. lirenrui

    lirenrui Registered User

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    I see,thank you very much !


    lirenrui
     
  24. hdsoftail03

    hdsoftail03 Registered User

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    Great Idea. Contain the power. No need getting hurt. Kind of like the cage around large tires so you don't get hurt.
     
  25. sandcastcb750

    sandcastcb750 Registered User

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    This is an interseting post. I have a Statue of Liberty clock made in 1986-87 with a Korean movement. Anyway, everything was thin about this clock movement. Then one of the gears side slipped off the other gear and the strike spring literally exploded in front of me. Scared the crap out of me. My wife heard it and asked what it was. More exciting than a grandfather weight free falling 5 feet.

    I found another movement and just swapped it.
     
  26. hdsoftail03

    hdsoftail03 Registered User

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    Sand I have one of those statue of liberty clocks ticking away like a time bomb on the wall right now. I just pulled out the movement and did just a basic inspection of it oiled and ajusted. The springs were coated with a thick black grease like moly-coat. The clock keeps great time but I have heard the springs slip after running for awhile. Just waiting for the explosion. American statue of libery commemortive clock made in Korea Huh
     
  27. harold bain

    harold bain Forums Administrator
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    Well, the original Statue of Liberty wasn't made in America either:whistle:. Sounds like it's time to bite the bullet and clean that puppy's springs before it bites you.
     
  28. hdsoftail03

    hdsoftail03 Registered User

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    Harold it's Not going to bite me as the clock is not worth much anyway. Let it explode the trash can is ready.:cool:
     
  29. harold bain

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    Yeah, but it's likely to let go while you are winding it. Keep the gloves on, and you'll be OK.
     
  30. sandcastcb750

    sandcastcb750 Registered User

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    Harold, you are correct about that winding those Liberty clocks. It has a real funky uneven feeling about it when winding. Maybe someday the key will become a spinning helicopter in the air.
     
  31. harold bain

    harold bain Forums Administrator
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    I repaired one recently where the pinion on the second wheel had worn enough that it allowed the spring wheel to escape, a bit at a time. I noticed the problem before it became a UFO. Replaced both wheels.
     
  32. dAz57

    dAz57 Registered User

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    this one did
     

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  33. Tinker Dwight

    Tinker Dwight Registered User

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    It is pictures like this that tell me to let down
    slowly on the keys. Every time one hammers them
    by dropping the key, on the click, is one time it is closer to fail
    and a black thumb.
    Tinker Dwight
     
  34. shutterbug

    shutterbug Moderator
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    Wow. I've never see a click break like that!
     
  35. harold bain

    harold bain Forums Administrator
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    I've seen a few broken like that on Asian movements. Never had one break while I was winding one though.
     
  36. shutterbug

    shutterbug Moderator
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    Judging from the condition of the teeth, I wonder if it blew by a few teeth and anchored itself solidly into a 'good' one after it picked up considerable speed?
     
  37. harold bain

    harold bain Forums Administrator
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    I suppose it could have been caused by having the key slip while winding, allowing a quick release of teeth, then have the click catch one, fracturing the click with the force of the runaway click wheel.
     
  38. sandcastcb750

    sandcastcb750 Registered User

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    A friend of mine spent a year in Korea while stationed there in the Army. He came back with the saying "almost good".

    That click could have been bad metallurgy and was destined to fail.
     
  39. Kevin W.

    Kevin W. Registered User

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    Just glad my thumb and fingers was not on the key when that happened, it hurts just thinking about it.
     
  40. dAz57

    dAz57 Registered User

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    don't know, the ratchet teeth were pretty good, the click was thin, only half the thickness of the ratchet wheel teeth, I replaced it with a click twice as thick.

    here is another shot of the click off the wheel, it looks it was torn, it is still hanging together by a thread
     

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  41. Willie X

    Willie X Registered User

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    They don't just break. It's usually a mishap as mentioned by Bugs and Harold. Or, just bad winding habits.

    When a ratchet hangs, tip to tip, there are at least 5 things that can happen. The click can snap directly into the present gullet of the click wheel, the click can snap out of the wheel and into the next gullet, or the click can snap out for a short length of time and catch soundly two or three gullets down, it can snap out for a longer length of time and skate over several click wheel teeth before landing solidly somewhere, or the outward snap can bend or break the click spring and allow a full let down.

    Each of these 5 steps spells the dissipation of more and more energy. The first one would probably go unnoticed. The second probably would not do much damage. Three and four will cause damage but the damage might be overlooked until further damage is caused by continued use. The fifth one can wreck your clock movement and your poor fingers.

    My 2, Willie X
     
  42. capone47

    capone47 New Member

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    does anyone have a internal type picture of above clock--found extra piece on bottom?? Do not know if it is a replaced item or goes somewhere else. looks like possible flat spring
     
  43. David S

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    I think it would be most helpful if you can post a picture of what you found, then we could be more helpful.

    David
     
  44. harold bain

    harold bain Forums Administrator
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    If you show us a picture of what you have, good chance we can tell you if it could be from your clock movement.
     
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