Change Gear Fitment
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  1. #1
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    Default Change Gear Fitment

    Hi Guys,

    I have a model C that i am getting back to operational. When i engage the gear train to use the power feed i have issues with the change gears coming loose. Specifically the nut that holds the gears on spins with the gear and comes off of the threaded shaft.

    Should the bronze bushing stick out past the bore of the change gear slightly so that the nuts tighten on the bushing capturing the gear, OR should the nut be tightened up against the gear.

    In my case the bushings are not long enough to stick past the gear and the nut tightens on the gear, hence it loosens when the gear starts spinning with the lathe.

    Is there a drawing for those bushings ? The lathe i got was a hodge podge of parts thrown together I am trying to sort out.

  2. #2
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    Any such rig (such as idler gear) must have free to turn gear with nut socked up tight. This is done with shoulder length on stud - and if a bronze bush provides the shoulder, so be it.

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    I have a 1936 9" Model C and there are no bronze bushings in any of the gears. Sometimes if I forget to tighten the nuts holding the gears on the nut may spin off but I've never had a gear come loose. The fact that yours have bronze bushings suggests that the gears have been modified for some reason.

  5. #4
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    You need to post a pic or two of your gear train. The idler in all gear trains should bolt tight and still turn effortlessly. It is not keyed. The stud gear is keyed and so is the screw gear. They will never spin the nut off.
    Bronze bushings in idlers gears are popular and so are steel ones. Again a few pics would be helpful.

  6. #5
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    Quote Originally Posted by tommy1010 View Post
    You need to post a pic or two of your gear train. The idler in all gear trains should bolt tight and still turn effortlessly. It is not keyed. The stud gear is keyed and so is the screw gear. They will never spin the nut off.
    Bronze bushings in idlers gears are popular and so are steel ones. Again a few pics would be helpful.
    What does the nut on the idler gear tighten up against so that the gear can spin freely ? Shoulder on the bolt ?

  7. #6
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    The bushing should be flanged on the banjo side and a little proud of the thickness of the gear on the nut side. This will allow the nut to tighten against the bushing and allow the idler to spin. I do not have one to take a picture of and show you but I am sure someone here does.

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    Quote Originally Posted by tommy1010 View Post
    The bushing should be flanged on the banjo side and a little proud of the thickness of the gear on the nut side. This will allow the nut to tighten against the bushing and allow the idler to spin. I do not have one to take a picture of and show you but I am sure someone here does.
    Ok that is exactly what i was looking for and what I thought. the bushings that sit against the banjo do not stick proud of the gears on my lathe. I suspect that they were homemade at somepoint in its life. I am going to look into making some new ones.

    Thanks.


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