Help Clock Mainspring Arbor Hook

Discussion in 'Clock Repair' started by timbo19, Feb 17, 2020.

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  1. timbo19

    timbo19 Registered User

    Dec 28, 2019
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    As a beginner, I am having problems winding a new spring on to this arbor. Is the hook too worn or should I just keep trying to bend the end of the new spring to fit around the arbor. The posts I have read say that it can take a long time to get the new spring attached but I was wondering if anyone could tell me if it is worth keeping on trying or if I need a new hook. Is there an easy way of fitting a new hook? I see there are many posts on this but not sure of the best approach. Many thanks.

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  2. Uhralt

    Uhralt Registered User
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    That arbor hook should be able to grip the spring. Probably you need to form the inner end of the spring so that it nicely fits on the arbor. If you want, you can clean up the area under the hook a bit with a needle file to make it less rounded but I think it should work as is.

    Uhralt
     
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  3. heifetz17

    heifetz17 Registered User
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    I have issues with this as well from time to time. What's the best method to form the inner end of the spring? Often I find they're rigid enough that I can't actually manipulate the end because the spring just coils up when I try.
     
  4. timbo19

    timbo19 Registered User

    Dec 28, 2019
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    Thanks Uhralt - I will try to clean the hook a little then re-align the spring around the arbor - I'll let you know how I get on. Thanks again. Tim
     
  5. Willie X

    Willie X Registered User

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    Use round nose pliers and make sure there are no burrs on the spring, where it hooks on. The curve of that inner coil should be snug (or even tight) around the arbor. A perfect fit would require some effort to push the inner coil over the arbor hook and should actually 'click' into place. Willie X
     
  6. timbo19

    timbo19 Registered User

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    Thanks Willie X, I will do as you suggest and let you know the result. Timbo 19
     
  7. shutterbug

    shutterbug Moderator
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    When you finally get it to hook, wind it up all the way. That will shape it, and you shouldn't have any more issues.
     
  8. timbo19

    timbo19 Registered User

    Dec 28, 2019
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    Thanks Shutterbug - certainly looking forward to hearing that 'click' and getting my mantle clock working again - had to make a main spring winder so finger's crossed it goes well from now on. Timbo19
     
  9. TEACLOCKS

    TEACLOCKS Registered User
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    You should make a deeper notch on the hook on the arbor.
    Use a file or Jewelers saw and make a deeper notch on the hook.
    The hook needs to pull the spring into the center, & you don't want the spring it slip off the hook.
    Good luck

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  10. timbo19

    timbo19 Registered User

    Dec 28, 2019
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    Thanks for all your help, I now have the new spring safely attached to the arbor after a bit of sawing and filing - my delay in getting this far has been visits by family but now back on the clock.
    I have run into another slight problem that someone might be able to help with. I built a ratchet type spring winder and purchased a set of mainspring sleeves but one of the sleeves is too small for the new spring and the next size up is too large for the barrel. The internal barrel size is 30.62mm and the o/d of the sleeves are 25mm or 31mm - I really need a sleeve of about 28mm but cannot see that it is possible to buy individual sleeves. Could I just wind the spring on the arbor and wire it again and push it into the barrel? Sounds tricky but I can't think of another way. My Grand-daughter and I have taken the mantle clock to pieces and re-assembled it but the springs were broken and this is the last part before we get it all working again. I checked the size of the new spring and it appears from the suppliers catalogue to be correct. Many thanks for any ideas
     
  11. shutterbug

    shutterbug Moderator
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    You can make sleeves from plumbing materials (copper) or even better the pipes used for auto/gas pipes. Cut out the open area with a Dremel cut off disk or similar. Be sure the material you choose is strong enough to capture the spring. A visit to a repair shop or machine shop might get you something in the size you need for free ;)
     
  12. R. Croswell

    R. Croswell Registered User

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    Occasionally I find a spring that doesn't want to fit any sleeve in the "set" but the problem is usually that the spring isn't wound all the way tight, or the spring is not the right size. If the broken spring is original that is your best indicator of size. If the original spring is in pieces just add the length of all the pieces together. I've made a few odd size sleeves thin wall EMT electrical conduit and plumber's pipe. Plumber's pipe is too thick but if you have a lathe it can be turned to reduce thickness. I've never tried to insert a "wired spring" into a barrel but I believe you would be asking for trouble. You would need to remove the wire with the spring in the barrel and the almost explosive release of a tightly wound spring would likely damage the barrel and bulge the side of the barrel by forcing the spring attachment into the side of the barrel. With all the coils expanded against the outer wall of the barrel it will be difficult to impossible to get the spring end hooked, and especially so if the attachment point is flattened of recessed into a bulge in the side of the barrel.

    Regarding the earlier problem of hooking the main spring to the arbor, one thing that's often overlooked that was not mentioned is the second inner coil. If the 2nd. coil lays tight over the first coil it can obstruct the hole in the 1st. coil. The arbor hook needs to go through the hole in order to get a good hook.

    RC
     
  13. timbo19

    timbo19 Registered User

    Dec 28, 2019
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    Thanks RC and Shutterbug - I did wonder if the spring was too long - I will measure the old one again to make sure. I'll see if I have some strong pipe around of the right size and try maing my own sleeve. When done I'll let you know!! I used my jewellers saw to make a deeper cut in the arbor hook - brilliant. Lets hope same success with the sleeve.
     
  14. timbo19

    timbo19 Registered User

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    Having measured the old spring I am now confused - it is 1014mm in length. Its width is 25mm, thickness 0.27/28mm and barrel size 30.62mm. Looking at available springs of this size they are 1250mm long. Should I shorten the mainspring? I believe I would need to anneal it and punch a new hole - it might then fit the sleeve that I have or I must continue to find a pipe to make a sleeve to my dimensions.
     
  15. shutterbug

    shutterbug Moderator
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    Yes, shorten it just as you mentioned. Let us know on the sleeve :)
     
  16. R. Croswell

    R. Croswell Registered User

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    Yes, anneal, and shorten to approx 1044 mm. I usually drill the hole after the spring end is annealed and do the final shaping with with files and/or Dremel tool.

    RC
     
  17. timbo19

    timbo19 Registered User

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    Thanks for all these replies. I have just tried winding the spring again to make sure it was fully wound and it will nearly fit into the sleeve but just before it is fully wound it starts to slip but does not come fully unwound - I can see the arbor lug is engaged in the spring hole. Maybe I just need to manipulate the end of the spring a little more with my round needle pliers to see what is making it slip at the last few turns?
     
  18. Willie X

    Willie X Registered User

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    In my books, with your measurements, that barrel should take a spring of about 1,270mm.

    Are you sure about the the spring's thickness?

    Willie X
     
  19. R. Croswell

    R. Croswell Registered User

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    If the spring slips in the winder before becoming fully wound you can be sure that it will slip once it is in the barrel unless you fix the problem first. I'm, guessing that you need to do more work on the arbor spring hook. See the picture below. The backside of the hook should be flat and slop up to the end of the hook without curving over. The tip of the hook should be sharp and the hook should be undercut at an angle that will pull the spring under the hook. The symptoms you describe indicate that the the spring is catching on the tip of the hook and the hook isn't going all the way through the spring. The tightness of the wrap allows it to hold for a partial wind but at some point the spring slips off of the hook. If your spring is under the hook instead of on the tip it should not slip.

    That arbor hook is somewhat worn down and by the time you take out the curved over end there won't be a lot left. If there isn't enough hook to go completely through the spring you may have to replace the hook entirely./

    RC

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  20. Uhralt

    Uhralt Registered User
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    Willie X, are you sure about that? The barrel is only 30 mm. 1.27 mm appears terribly strong. Did you mean 0.27 mm, which would be a quite usual strength for a French clock.

    Uhralt
     
  21. Uhralt

    Uhralt Registered User
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    It is also possible that the edge of the hole in the spring has become rounded, preventing the spring to sit flat on the arbor. Make sure that the spring around the hole is flat.

    Uhralt
     
  22. gmorse

    gmorse Registered User
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    Hi Uhralt,

    The comma isn't the decimal point in our notation, it's the thousands separator . . .

    Regards,

    Graham
     
  23. Uhralt

    Uhralt Registered User
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    Hi Graham,

    You are right, sorry. Living in the US since 19 years I seem to merge inch and mm notations....A 1,2 cm thick spring would qualify for a car axel...

    Uhralt
     
  24. Willie X

    Willie X Registered User

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    Yep, spring should be about 50 inches long. IOWs, I wouldn't cut the spring just yet ...

    RC is 'on it' with his picture showing the 60° angle, which translates directly to using the ole 3 corner file. It just needs a tiny amount of metal removed, right at the tip. This rounded tip is normal wear for a hook used with a thin spring. The tip of the spring wears over from action against the second coil rubbing on it.

    Willie X
     
  25. timbo19

    timbo19 Registered User

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    Thanks all - what a great community! I will try to reshape the hook a little before taking further action - am sure I'll get it to work very soon - then I start on the chime spring that has also broken but have not taken that one out yet - one at a time! Timbo.
     
  26. R. Croswell

    R. Croswell Registered User

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    You may get lucky and find that this one has just slipped off the hook. If it is broken at the outer end at or close to the hole you may be able to repair it by annealing the end and forming a new hole. The loss of an inch or so in length should have no significant effect. If it is broken at the inner coil or in the middle then it needs to be replaced.

    RC
     
  27. bangster

    bangster Moderator
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    Check HERE for tips on shortening mainspring.
     
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  28. timbo19

    timbo19 Registered User

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    Thanks for your replies; So far I have not had success in reshaping the hook but will keep trying. At the same time I am considering installing a new hook - I have read several articles on how to do this, does anyone have specifics on the type of nail/screw that is best to use - I read that a finish nail is good to use, what is this, I am not familiar with the term. I am also searching for a tube of the correct diameter so that I can make a new sleeve of the correct size.
     
  29. shutterbug

    shutterbug Moderator
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    You want something soft enough to peen into pace, and with enough build-up under the head to keep it elevated. I think I remember that Harold Baine liked a threaded screw, while others are fine with a nail.
     
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  30. R. Croswell

    R. Croswell Registered User

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    Personally, I would not use a screw. The strength of a screw in this application is much less than an unthreaded nail of the same diameter. A "finishing nail" is a nail with a very small diameter head just a little larger than the diameter of the shaft of the nail. Used for attaching wood trim etc. where the head is punched below the surface of the wood and the hole filled and painted over. Any hardware store will have these. You will need to drill a hole all the way through the arbor (I would not place it where the existing hook is). File a flat spot on one end of the hole and chamfer the other end. The nail should fit snug in the hole. Drive the nail in from the flattened end of the hole and cut it off just above the chamfer. Peen the end into the chamfer and smooth it off with a file. You will then face the same task as with the existing hook - shape it so it slops to a point, then undercut so the spring will be pulled onto the hook. Make sure the new hook is long enough to extend through the hole in the spring. You will still need to shape the inner coil properly. I usually turn a piece of steel on the lathe for this rather than using a nail, that way I can control the diameter for a nice fit in the drilled hole.

    [Just for future reference, the above is for an arbor with a gouged in and pushed up one-piece arbor and hook. Where the original hook went through the arbor, the head would be ground off and the old hook punched out and the "nail" or pin replaced in the same hole.]

    RC
     
  31. Willie X

    Willie X Registered User

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    I do this job about the same as RC. A 1/16" hole is good in most cases and a regular steel tapered pin, as used for plate pins is good for making the hook.

    Note, don't drive the pin in to hard, you can split the arbor. The arbor nor the pin is made with hardened steel.

    Willie X
     
  32. Uhralt

    Uhralt Registered User
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    Given your existing hook I wouldn't recommend to replace it. It should be much easier and less risky to re-shape it. Can you show us a picture of the file you used in your attempts? It may not be small enough. Use a triangular needle file to remove a bit of material from underneath the hook.

    Uhralt
     
  33. timbo19

    timbo19 Registered User

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    Thanks for that Uhralt. I attach photos of the file I have been using and of the arbor hook as it is at the moment - to me it looks better then when I started but maybe not right yet. I have found some metal tubing from a friend which I will turn into a sleeve - what would you recommend as the slot length and a slot width of 3/8ths seems to be a good size? I am wondering if I might try with a another new spring - I have messed around with the first new spring so much I may have created a problem with it!

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  34. Uhralt

    Uhralt Registered User
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    That hook looks good to me. It should be able to grab the spring. Make sure that the spring hole is located properly and not bent outwards.

    Uhralt
     
  35. timbo19

    timbo19 Registered User

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    Thanks - will let you know how it goes
    Timbo19
     
  36. R. Croswell

    R. Croswell Registered User

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    I don't understand what you plan to do with a 3/8 steel sleeve.

    Your hook, the back side is still curved. Make the back slope flat, be sure the spring conforms to the arbor, make sure the hook actually goes through the hole all the way and it should hook.

    RC
     
  37. Uhralt

    Uhralt Registered User
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    Maybe a stupid question: Are you sure that you inserted the spring in the correct direction? The tip of the arbor hook should point at the inner end of the spring. If you turned the spring around inadvertently, the hook will slip out of the hole.

    Uhralt
     
  38. Willie X

    Willie X Registered User

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    That hook looks fine.

    I'm pretty sure your spring is not curved properly, to fit snug against the arbor.

    The spring is not supposed to be folded around the hook. It should be made to fit tightly around the arbor (or slightly smaller) and then pushed (endwise) over the hook, re-read post #5 and others.

    Willie X
     
  39. timbo19

    timbo19 Registered User

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    Hi RC - the 3/8ths is the width of the slot I am cutting into the sleeve which has a diameter of 29mm. The length of the slot is just a little longer than the width of the spring
    Timbo19
     
  40. timbo19

    timbo19 Registered User

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    Hi - I attach some photos of the spring, the arbor and my new sleeve. I think I have the arbor in the right way and I have filed the back of the hook a little (didn't want to do too much as there is not much thickness there) - do you think the spring is shaped OK? Thanks. (Probably have more time now as France is getting slowly shut-down due to Caronavirus!)
    Timbo19
     
  41. timbo19

    timbo19 Registered User

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    Photos not attached in previos post P3130082.JPG P3130084.JPG P3130086.JPG P3130087.JPG P3130088.JPG
     
  42. Uhralt

    Uhralt Registered User
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    In principle it doesn't look bad. Unfortunately I can't see the hole in the spring. With the spring out of the barrel like this, can you insert the hook into the hole? You should be able to see then if it catches the spring securely. The spring is securely caught if the tip of the hook is clearly located on top of the spring.

    Uhralt
     
  43. R. Croswell

    R. Croswell Registered User

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    Timbo, The shape of your spring looks good, but the shape of your hook will never work, As shown in your picture the tip of the hook is blunt and has a negative drawl that will tend to force the spring off the hook. See the photo below. Trim the areas shown so the "front" of the hook slants to a knife edge leading edge, and flatten the back slope as shown and it should work fine.

    RC

    blunt.JPG
     
  44. timbo19

    timbo19 Registered User

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    Hi Uhralt - I think I must be doing something very stupid. I put the spring in the winder and it wound all the way up until, I guess about the last 2 turns and then it slipped. But it doesn't continue slipping it seems to catch again and if I wind again the same is repeated. I attach a couple of photos of the arbor in the spring and you can just see the hook showing through the spring. I know I have treid to bend the spring several times but surely it should catch and stay caught? Is the second turn of the spring over the hook in some way causing the first turn to slip off the hook? Thanks for your time. P3130095.JPG P3130096.JPG P3130098.JPG
     
  45. shutterbug

    shutterbug Moderator
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    Are you sure it's slipping off your hook, is are you talking about it slipping on the other end, in the barrel? Take some needle nose pliers and really tighten up that center coil.
     
  46. timbo19

    timbo19 Registered User

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    Thanks RC. I have treid to make some adjustments to the hook as you suggested - do you think I've done enough? P3130103.JPG P3130104.JPG P3130105.JPG
     
  47. timbo19

    timbo19 Registered User

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    Thanks Shuttbug - I think it is slipping on the arbor - I haven't got to putting it in the barrel yet!
    Timbo19
     
  48. Willie X

    Willie X Registered User

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    The hook looks 'plenty good enough' to me. I think you have some problem with the spring that is preventing it from pulling down on the hook as it tightens up. Maybe work a bit on the second coil, it could be kicking the holed area upward when it tightens. Or the inner coil may not to annealed properly, or the hole may not be wide enough.

    What is the history of the spring you are dealing with there?

    Willie X
     
  49. R. Croswell

    R. Croswell Registered User

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    That looks a lot better but you still don't quite have a sharp leading edge. I understand that there isn't a lot of metal there to work with and you do not want to shorten the over all height of the hook. I think I would give it a try and see. If it doesn't catch, file the back of the hook to get a sharper leading edge. The undercut looks good. Once you get the spring drawn under the hook it will tend to form itself around the arbor the first time you get a full wind (before putting it in the barrel). If it slips after it is in the barrel it could damage the barrel.

    RC

    Yes, check what Willie said about the spring especially the second inner coil.
     
  50. Uhralt

    Uhralt Registered User
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    Good suggestions!

    Uhralt
     

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