No End Shake on 2nd Wheel

Discussion in '400-Day & Atmos' started by KurtinSA, Jun 30, 2018.

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  1. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    In the process of reassembling a Becker. It has nice thick plates...it was built in 1905. Plus various parts have matching numbers stamped on them, so an indication they go together. The clock has never run...not hugely dirty but it needed the usual going over.

    I was doing the spin tests of each arbor by itself. All are OK except for the 2nd wheel...it wouldn't spin freely. That's when I noticed no end shake. First thing I looked at was for bowing in the plates. Not readily obvious. I don't have a lot of straight edges, but I have a two-sided 90-degree ruler...I even used the long shank on my digital micrometer. I don't see anything that jumps out at me as a huge bend or variation. Again, these are thick plates...would take a lot to bend them.

    I measured the length of each arbor on the first three wheels...not to the end of the pivots but to the shoulders of the arbor. Using my micrometer, I'm seeing that the 2nd wheel arbor length is around 0.1mm longer than the 1st or 3rd. That has to be the problem. Which suggests that this clock never worked.

    What's the remedy for something like this?

    Kurt
     
  2. roughbarked

    roughbarked Registered User

    Dec 2, 2016
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    Either turn the arbor down in the lathe or rebush it's hole with a bush slightly thinner than the plate, sinking it so that the outside is flush with the plate but the inside is recessed enough to give the desired endshake.
     
  3. MartinM

    MartinM Registered User

    Jun 24, 2011
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    Is the wheel stamped with the same number as the other parts?
    If so, I'd guess your presumption is correct.
    If not, it might be a replacement wheel that should be easy to turn down to get the clearance needed.
    Make sure to check it with the barrel and with the 3rd wheel, individually, to be sure they mesh cleanly.
     
  4. shimmystep

    shimmystep Registered User

    Mar 5, 2012
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    A simple strategy is to use a oil sink cutter, and give it a turn on the pivot hole on the inside of the plate. This can be enough to free the arbour.
    When I bush a hole, the inside will always get a very small chamfer cut with one of these cutters., they do a very clean job.
     
  5. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    Yes, the wheels are stamped with the same number, so they go together as a set.

    As for turning the shoulder of the arbor in a lathe, I thought about that...I've not encountered this before so not familiar with doing it nor have the tools. Haven't done bushings and no equipment. I also don't have an oil sink cutter. All good ideas. Just need to figure out what I can handle.

    Thanks...Kurt
     
  6. MartinM

    MartinM Registered User

    Jun 24, 2011
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    Do you have a drill? you can chuck up the wheel in that and use a fine file to cut the shoulder if you don't have a graver.
    Just don't get into the existing pivot surface any more than absolutely necessary and polish it as smooth as you can.
     
  7. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    I have a jeweler's lathe. I was certainly wondering about how to stay away from the pivot.

    I like the idea of dealing with the arbor first as it does less "alteration" to the original clock. Maybe an oil sink cutter next, followed by replacing the bushing.

    Kurt
     
  8. Harry Hopkins

    Harry Hopkins Registered User
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    Nov 16, 2011
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    Do you have a tip over tee rest for your jewelers lathe? If so buy a hand graver... something like this.. (I prefer one with a wooden handle) watch a Youtube video or 2 on using a hand graver then practice on a scrap piece similar in size to your arbor. I think you will find it easier to do that you imagine and then you will have confidence to do more difficult jobs in the future.
     
  9. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    I had a member of our club with a much better lathe setup take off a bit of the shoulder on the arbor. Worked great...clock is together and going through initial stages of check out. I guess it came down to which part I wanted to "change". Once you take metal off, you can't put it back, so the option was to work on the arbor. If we took off took much of the arbor, I could add back a thin washer.

    I still don't know how this left the factory this way. I suppose if the pillars between the plates weren't tightened down completely, it could have allowed for the additional space needed. From now on, I think I'm going to check end shake before I take a clock apart.

    Kurt
     
  10. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    These clocks still leave me a bit bewildered!! I had it running well with no motion works...270 deg of rotation with a good 40 deg of over swing. I decided to put the motion works on with no dial. The clock stopped fairly quickly. I took off the hour pipe and the clock then ran for hours. So, I figured I've got some kind of meshing problem although I didn't sense that when I was first assembling the clock. I spent a day trying to see if there was one spot that things didn't mesh well...I put marks on the three wheels/pinions to see if they kept realigning together. In the end, it kept stopping fairly quickly, and the marks didn't consistently show up together.

    Hmmm...what to do?? I decided to drop the fork and ended up going about 2mm...there's no suspension unit shown for this clock in the guide...I had just left the fork where it was from the previous owner. I also rechecked the fork-pin clearance...looked like it needed to be opened up since the piece of paper wouldn't fit. Restarted the clock and it's been running strong again for at least 12 hours.

    I wish I knew what "fixed" the clock? Since the amount of rotation/over swing didn't change significantly with the fork lowering (still 270 and 40-45 over swing), I'm guessing the spacing of the fork was more critical.

    And if that were the case, how could that spacing be the difference between with and without the hour pipe? What's the interaction there?

    Kurt
     
  11. roughbarked

    roughbarked Registered User

    Dec 2, 2016
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    I think you need to look at action to explain interaction. Could polishing the inside of the hour wheel have changed anything?
     

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