Bushing issue with model 2038 Gilbert tambour clock

Discussion in 'Clock Repair' started by Rockin Ronnie, Mar 19, 2019.

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  1. Rockin Ronnie

    Rockin Ronnie Registered User
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    Any suggestions as to how to tackle this motion works bushing on a Gilbert time and strike mantel clock model 2038, made in 1925? It is the only bad bushing on the movement but there is not much to work with.

    Ron

    RS P3195052.jpg
     
  2. Willie X

    Willie X Registered User

    Feb 9, 2008
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    Luckily you can leave that one like it is.

    Center shafts and motion works on American clocks work well with way more slop the that.

    Willie X
     
  3. Bruce Alexander

    Bruce Alexander Registered User
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    If I had to bush that pivot hole I think I would dove-tail into the plate and "square-up" that rounded corner so that the next person (probably long after I'm gone) could bush routinely. That assumes that there are no parts of the movement in that vicinity which need clearance. It's kind of hard to understand why they would lay out the pivot hole like this with no good reason. It takes more time but it can be done. I agree with Willie. it doesn't look that bad in your photo. Clean, smooth and lubricated appears to be all that's needed.
     
  4. Jerry Kieffer

    Jerry Kieffer Registered User
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    Ron
    For those who use a milling machine for bushing, this is not an issue if they wish to bush it. It can be done as follows.

    (1) Locate the spindle centered over the original pivot hole and record the hand wheel settings.

    (2) Then machine a bushing hole with a center cutting Endmill per attached sketch and install a blank bushing.

    (3) Return the slides to the recorded hand wheel settings for the original pivot hole and spot drill/drill a new pivot hole.

    (4) If desired, the ring around the pivot hole can be restamped using closing punches per second photo or similar tools. Again if desired, dress the repair invisible.

    Jerry Kieffer

    fullsizeoutput_383.jpeg fullsizeoutput_381.jpeg
     
  5. R. Croswell

    R. Croswell Registered User

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    I agree with others, from the picture it doesn't look that bad as it is. You have a few options depending on your skill level and what tools are available if you decide to do something about it. I'm guessing that what we see is not really a bushing but just a stamped mark around the hole. You could ream the hole short of going through the side and install a bushing which would likely need to be broached considerably to fit the pivot. You would have a rather thin wall bushing but should be OK and not much loading here. Another option for an invisible repair, broach the existing hole just enough to restore it to round, and then simply replace the pivot with a slightly oversize one to fit the worn hole.

    Why did they make it this way? Well why not? It lasted 100 years and that's longer than the company lasted. So now its your problem and no one to compline to and perhaps they saved a few milligrams of brass. God only knows, they were not thinking about anyone rebuilding a hundred years later for sure.

    RC
     
  6. Bruce Alexander

    Bruce Alexander Registered User
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    #6 Bruce Alexander, Mar 20, 2019
    Last edited: Mar 20, 2019
    I've seen similar placement of pivot holes in chiming Herschede Movements but the design/layout was for clearance of regulation or activation levers.

    These movements were made to be serviceable so it seems excessively frugal to have made such a placement to save such a small quantity of brass in a clock which probably cost the equivalent of several hundred dollars today. I'm not that familiar with Gilbert clocks so I don't know if they were cheaply made. Fortunately for us "Fixers", it doesn't seem to have been a widespread practice to layout movements in this way.

    Please let us know what you decide to do.
     
  7. R&A

    R&A Registered User

    Oct 21, 2008
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    There isn't much power transfer at this location. You may consider taking the pivot down and putting in a smaller bushing. Or I would make a bushing for this as to not cut through the side wall. Between a 2 and 3 KWM reamer size.
     
  8. Jim_Miller

    Jim_Miller Registered User
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    Here’s a hypothetical question, what would happen, or is it possible, if the pivot was turned down to accept a smaller bushing?
     
  9. RJSoftware

    RJSoftware Registered User

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    The minute arbor on this isnt free/passive part of motion works so it does require a bushing and !ooks to have sffered enough wear for replacement.

    Probably your just afraid to break open the edge, the kwm hand reamers designed for prefab bushings can be easily directed to broach out hole any direction because it only cuts on one side.

    That or simply drill suitable hole for round stock and peen in place a whole new surface to bush.
     
  10. Rockin Ronnie

    Rockin Ronnie Registered User
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    Thanks for all the suggestions. Thought a video would show the issue a little better.
    Ron
     
  11. Bruce Alexander

    Bruce Alexander Registered User
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    #11 Bruce Alexander, Mar 20, 2019
    Last edited: Mar 20, 2019
    Yes, I see what your concern is RR. How you address it depends on what you have in the shop. Another low cost method (which DISCLAIMER I've only read about on the board) would be the use of a Preacher to index the location of the original center. I believe the marks could be made on the inside surface of the plate. Then drill or mill out the pivot hole and a small amount of surrounding brass. Plug the hole. Mark the location with your Preacher, drill/mill the new pivot hole and finish. If you don't have a Lathe to turn a plug, you can match up sizes of your round brass stock and drill/mill bit sizes.
     
  12. R. Croswell

    R. Croswell Registered User

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    Yes, it does need attention.
     
  13. Willie X

    Willie X Registered User

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    It does look worse in the video than in the still but still within the 'what will work' zone for a motion works.

    If you do decide to repair it, you will probably find an extremely bad finish on the pivot. After you do the machine work on that, you should have room for a #2 KWM bushing applied in the usual manner.

    Willie X
     
  14. Bruce Alexander

    Bruce Alexander Registered User
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    Strange how that low torque pivot hole is the only one which needs a bushing. Again, I agree with Willie.
    Please do let us know what you find and how you solve the problem.
     
  15. shutterbug

    shutterbug Moderator
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    I would use the smallest bushing I could and enlarge the center hole of it to accept the pivot.
     
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  16. Rockin Ronnie

    Rockin Ronnie Registered User
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    I am leaning towards using the smallest bushing. And Willie X what is the equivalent in Bergeon?
    Ron
     
  17. Bruce Alexander

    Bruce Alexander Registered User
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    See post #7 in this thread :Bergeon Bushing size? but you can get smaller ODs with KWM's system I think.
     
  18. Rockin Ronnie

    Rockin Ronnie Registered User
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    The movement has 13 new bushings but I think whoever worked on the movement previously avoided that one bushing for the very reason of this discussion.

    I think I am going to go with the smallest diameter bushing and broach to fit. Once I get it apart I'll also see what condition the pivot is in.

    Ron
     
  19. Willie X

    Willie X Registered User

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    #2 KWM bushings have a 1.8mm OD. The 1.4 height will usually look good inside the factory circle and need no furthur finishing, other than broaching for the pivot fitment. Willie X
    Example:
    20170518_204409.jpg
     
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  20. Rockin Ronnie

    Rockin Ronnie Registered User
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    Thanks, very helpful.
    Ron
     
  21. Bruce Alexander

    Bruce Alexander Registered User
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    You have a lot of movement in the Pivot Hole. If the Pivot itself is much larger than 1 mm, and they usually seem to be in 20th Century American Mantels, you won't have a lot of brass to work with if your KWM OD is only 1.8 mm. Interesting problem. I look forward to reading about how you solve it.
     
  22. bangster

    bangster Moderator
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    I yam with Willie. Leave it alone.
     
  23. Rockin Ronnie

    Rockin Ronnie Registered User
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    #23 Rockin Ronnie, Mar 26, 2019
    Last edited: Mar 26, 2019
    Decided to go for it. Put in a smaller 3mm Bergeon bushing (#46) with a thin bit of plate to spare. Broached out to fit leaving a 0.8mm sidewall. There's not a lot of torque on this gear so I think I am okay.

    Ron
     
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  24. R. Croswell

    R. Croswell Registered User

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    The bushing looks fine, just make sure the pivot hole isn't too tight. I could not see any movement in the video.

    RC
     
  25. Rockin Ronnie

    Rockin Ronnie Registered User
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    Thanks, RC. The movement has been running for a couple of hours now and everything seems fine. There is a wee bit of movement that the video does not show.
    Ron
     
  26. shutterbug

    shutterbug Moderator
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    Good job. It's going to be fine ;)
     
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