Interfering Gears Stop My Clock

Discussion in 'Clock Repair' started by WDHewson, Feb 11, 2015.

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  1. WDHewson

    WDHewson Registered User

    Nov 27, 2013
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    Gentlemen:

    I believe the movement I'm working on is a Smiths Enfield from the 1950s, but I'm unsure.

    I've managed to correct a few faults with this seemingly high quality movement, but the gears in the accompanying image are ever so slightly touching and the friction stops the clock. This is the time drive train.

    One gear is on the spring drum, and the other gear is just below the escapement wheel, so it is a very low torque gear. I tried to get a feeler gauge between these two gears and even the 0.0015 inch (yes 0.0015 inch) won't fit.

    The time mainspring drum has a lot of clearance between the drum and the front plate, so something seems amiss here.

    I might be able to shim this whole drum assembly forward toward the front plate with a shim at the rear plate.

    How would you gents recommend I remedy this fine old clock?

    With appreciation....................
     

    Attached Files:

  2. harold bain

    harold bain Registered User
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    Well, it didn't come from the factory like that. Look for worn bushings in either the barrel or the plates.
     
  3. dad1891

    dad1891 Registered User

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    Any chance that the spring drum arbors were switched during the cleaning process?
     
  4. Tinker Dwight

    Tinker Dwight Registered User

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    #4 Tinker Dwight, Feb 11, 2015
    Last edited: Feb 12, 2015
    It looks like he is missing the barrel cap.
    There should be a cover over spring. This
    centers the side of the barrel.
    If the end cap is there, the bushing at the center
    is shot. Either replace the bushing or make a
    new end cap.
    Tinker Dwight

    barrel3.jpg
     
  5. shutterbug

    shutterbug Moderator
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    You can buy caps. Get one that's slightly over-sized, and you can cut it down with a lathe fairly easily.
     
  6. Burkhard Rasch

    Burkhard Rasch Registered User
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    look at all gears:all wheels seem to be in direct contact with their respective lantern pinions,but there seems tzo be a gap between 3rd wheel and pinion.Could it be that the wheel once loose has been reinstalled too closely to the barrel?In any case:if there is a gap between wheel and pinion You could use it to shift the wheel away from the barrel.
    Just a thought..
    Burkhard
     
  7. WDHewson

    WDHewson Registered User

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    Many thanks Harold. Much of this Smiths Enfield has been rebushed, and it's not excellent work, but not a travesty either.

    I like this old movement. It runs with a soft shuffle rather than the loose clatter of most clocks.

    I don't give up easily.
     
  8. WDHewson

    WDHewson Registered User

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    Thanks dad. I would not have thought of that. Both time and chime drums wind CW. By eye, these two drum are identical, but my calipers show the time drum at 0.914 inches wide and the chime drum at 0.992 inches. This difference of 0.078 inches seems to about the difference between their gaps with the back side of the front plate.

    Both drums have covers that are flush with the drum edge, to a few thou.

    But I'll need to disassemble to inspect their arbors. Great suggestion.
     
  9. WDHewson

    WDHewson Registered User

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    Thanks Tinker. Great suggestion.

    There is an end cap, but I'll direct my attention to the bushing. I've recently wound down the time spring entirely by lifting the recoil completely away from the escapement wheel.

    If I understand your comment well, with the spring relaxed, I should be able manually to wobble the drum around on the worn bushing.

    I've watched this drum carefully when rewinding the completely relaxed drum, and don't recall seeing a wobble. But I need to look again.

    There's a fair amount of wear on the square of the winding arbor, so I this nice old movement has had an insensitive owner at one time, and some novice attention.

    Much thanks for your helpful reply with picture.
     
  10. WDHewson

    WDHewson Registered User

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    Thanks shutterbug. I do have the lathe at hand if need be.
     
  11. WDHewson

    WDHewson Registered User

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    Thanks Burkhard. I also noticed that gap between the 3rd wheel and the lantern on the same shaft. If the 3rd wheel's hub can butt against the latern's hub, that'll be sufficient clearance. That third wheel runs very true with no visual wobble, so I don't need much clearance. I suspect that the 3rd wheel is a friction fit on the shaft, and a few minor taps might shift it over.

    Many thanks............
     
  12. shimmystep

    shimmystep Registered User

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    You mention it has much re-bushing before now. Perhaps the bushing for the intermediate wheel in the front plate is not flush at the non pinion end, but may be sunk, so causing the issue. and the pinion end bushing may be too proud.
    If these have been re-bushed and this is the issue, you could replace them correctly.
    It only needs fractional clearance of the drum.
     
  13. WDHewson

    WDHewson Registered User

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    Thanks shimmy. The rebushed locations on this clock do look a little ragged. For the 3rd wheel that's sitting too close to the winding drum, the bushes are not too bad axially, so I think that the 3rd wheel is about where it should be.

    Another clue I've discovered in this situation is that the teeth of the winding drum are not centered on the lantern they engage, but are set much rearward in that lantern toward the backplate.

    This fact, the big gap from the front plate, and the interference with the 3rd wheel makes me believe that this whole winding drum assembly is set reward too much.

    I'll have to get that drum assembly out and figure out a way to locate the drum forward about 2 millimeters.
     
  14. shimmystep

    shimmystep Registered User

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    Apologies, I meant the bushings on the 3rd wheel, not intermediate!

    I'm looking again at the picture of the barrel in the movement. There is a big difference in the distance from the barrel edge to the front plate, from the top of the barrel and the bottom. i think Tinker has probably got it right. The barrel looks far from parallel to the plate with some wind on the spring.
     
  15. Tinker Dwight

    Tinker Dwight Registered User

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    Of course, Shimmystep, it could be camera angle that
    is distorting our perspective. It does look like it
    is not square with the plates but I could imagine it
    is just a perspective issue as well.
    If it isn't perfectly square, it is a bushing issue.
    Tinker Dwight
     
  16. bangster

    bangster Moderator
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    It sure looks tilted to me.
     
  17. Tinker Dwight

    Tinker Dwight Registered User

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    Me too Bang. Still I've been fooled before.
    Tinker Dwight
     
  18. WDHewson

    WDHewson Registered User

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    Thanks for the continued help guys.

    My camera has a very fish eye lens in the macro mode and it does distort lines away from the center of the image.

    The barrel is parallel with the front plate.


    As an update, I disengaged the escapement recoil, and let her wind down to little or no spring tension. The barrel flops around too much (I believe) and has too much axial play (about 1.5 mm). So I'll need to get this barrel out and do some shimming or turn out a new arbor.

    Stay tuned.
     
  19. Nicko

    Nicko Registered User

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    I can just recall having something similar on a Smiths clock. It turned out to be the 2nd wheels on the time and time and strike side being interchanged. Might be worth a quick look.
     
  20. Tinker Dwight

    Tinker Dwight Registered User

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    That is why I mentioned the end cap bushing. They
    often get ignored when lubricationing and can be
    quite warn.
    Tinker Dwight
     
  21. WDHewson

    WDHewson Registered User

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    Thanks tinker.

    Your cover bushing diagnosis nailed it. A correction and the old Smiths Enfield has been shuffling along for many days now.

    I like this movement. High quality and a slick beat adjustment with no crude wire bending.

    With appreciation to all..................
     
  22. shimmystep

    shimmystep Registered User

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    Good news:thumb: Did you rebush the cap?
     

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