First Barrel hook replacement.....

Discussion in 'Clock Repair' started by ChrisBeattie, Feb 19, 2007.

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  1. ChrisBeattie

    ChrisBeattie Registered User
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    Dec 9, 2004
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    I have replaced my first mainspring barrel hook! I have been putting off trying to replace teeth on a barrel spring, but I am going to try this next!!!!! I just love it when I try new things and it works out well.

    I do have one question though.... when I was peening the nail that I installed for the barrel hook, the nail pulled closer to the inner wall losing the edge I was hoping for. I had to wiggle it slightly back into the barrel to ensure that there was a lip to catch the mainspring. What could I have done to prevent the head of the nail from getting closer to the inner wall of the barrel? Did I make the nail too short (should I have left it a bit longer-knowing it would have shortened itself during the peening)? I did use a penny nail to ensure that it was beveled (for lack of a better word) at the tip of the nail head. Any opinions are welcome.

    Chris Beattie
     
  2. David Robertson

    David Robertson Registered User

    Jan 6, 2003
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    Chris,

    Sounds like you are getting the hang of things and not afraid to try new things.

    I don't know what tools you have, but I have done this task two ways. One requires a lathe, one doesn't.

    The easiest and least tool intensive is to use a small flat head bolt (countersink type head) . Drill the appropriate size hole in the barrel wall, thread the hole to match the bolt, screw in the bolt from the inside. This will leave a tapered screw head exposed inside the barrel. Then, cut off the screw on the outside, peen it so it wont come unscrewed and file off to make it look nice. Then, dress up the inside to make the hook the right size and shape. You might actually want to do the inside shaping before you cut and peen the screw on the outside. This way you can take it out to work on it if need be or start over if you mess something up.

    The second way is similar except it would use a suitable piece of steel turned in the lathe to make the proper shape for inside the barrel. A small shoulder can be cut so that the head won't pull too close to the inside of the barrel during peening.

    I personally like using the small bolt because it gives two lines of defense against pulling out (threads and peening). You really don't want one of these things to fail. It can cause all sorts of damage further up the train... and then you will be learning some other new skills!!!
     
  3. clockdaddy

    clockdaddy Guest

    Chris,
    Any time a piece of metal of uniform length is use to make a catch for the mainspring, it's rather difficult to judge ahead of time, how long to make the piece. You might want to consider using a rivot with a shoulder for your new catch. Like the ones most commonly used for replacing clicks. Your hole (even if you must redrill it) must fit the small portion of the rivot.
    After placing the rivot on the inside of the barrel with the small end through the hole, use something like you bench vise (real small!) to support the rivot head while you champer the small end on the outside of the barrel.
    It doesn't matter how the top of the rivot is turned, it always has an edge that'll catch the spring hole.

    CD
     
  4. David Robertson

    David Robertson Registered User

    Jan 6, 2003
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    Chris,

    I forgot to mention... when you are dressing the inside of the hook, be sure to remove the "lip" from the side of the hook that won't be catching the spring hole. This way the spring can slide over the hook from the "back side" if it needs to and still catch on the front side. Make it look like the one that was originally there. You will also want to make it thinner (distance from the flat on the screw head to the barrel wall) since most flat head bolt heads stick up higher than a typical barrel hook. The main advantage of the flat headed screw is that it gives you an inverse taper to start with and requires less shaping work.
     
  5. clockdaddy

    clockdaddy Guest

    Good idea David!

    I hadn't thought about the screw idea. Not bad.....!

    I did not know the other post had come through...

    CD
     
  6. harold bain

    harold bain Registered User
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    Nov 4, 2002
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    Chris, I use basically the same method as David. I usually make a new hole 180 degrees from the old hook. A dremel type tool speeds up the shaping process, which is easier done before permanent installation.
    I wouldn't trust the strength of either a nail or a rivet for this job.
     
  7. ChrisBeattie

    ChrisBeattie Registered User
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    Dec 9, 2004
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    Very nice suggestion David! I never would have thoght to use a bolt instead of a nail...I will have to try that the next time.

    As far as the tools, I have just about everything I need (love my dremel) with the exception of a lathe :bang: (this will be my biggest and last large $$$ tool purchase) :clap:.

    Thanks for the suggestions guys!

    Chris
     
  8. Kevin W.

    Kevin W. Registered User
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    Apr 11, 2002
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    Just my thinking.But i would imagine a nail or rivet is soft, compared to a bolt.also you could get different materials, bolts are made of.For instance a stainless stell bolt would be tough.
     
  9. Tom Kloss

    Tom Kloss Registered User
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    Dec 5, 2003
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    Hi,
    I agree with Veritas on this one. I think the steel used in a nail is a bit soft for this purpose.

    Tom :cool:

    [colour=blue]“Sometimes you really don’t know if your being rewarded or punished”[/colour]



     

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