Moore #3 spindle bearings - Page 2
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  1. #21
    Join Date
    May 2003
    Walla Walla Wine and Wild Turkey
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    The preload spec should be on the spindle drawing.
    As I mentioned before, cant gain in one area without losing in another.
    Loading up the bearings like that shortens their life, they even installed a thermometer on later machines so you could watch them degrade a little easier as you use the machine.
    How long the bearings last, depends on use, or non use. Not using the machine is bad because normal vibrations in the shop, traffic out side, causes the balls to vibrate though the thin grease film, and divot the races.
    The best advice from the factory, is to manually rotate the spindle daily to restore the grease film, and place the balls in a different position. When you are not using the machine.
    The preload listed on the spindle drawing are specific right down to the pound, the nose pair around 250lbs, and the drive end pair somewhere between medium and heavy preload. The spindle tech that helped me a couple of decades ago said, the preloads are balanced between the nose and the tail pair for vibration.
    Lowering the preloads, I was told, the spindle wonders all over the place.

    It is not that hard to do the spindle bearing replacement, but you have to make a bearing holder to .0001" of the housing bore, and a plug to fit the bearing ID, to the same tolerance, or ,0001" of the spindle shaft.
    And a surface grinder, lapping machine, or method to adjust the length of the spacers between the bearing pairs as needed for the preload.
    For the bearing OD holder, I sized the hole with a Sunnen hone. For the plug that fits the bearing, I cut in a lathe, and ring lapped it to size.
    You have to make those parts, so they are solid and fit on an arbor press, and allow an indicator to be able to be on the plug in the bearings ID to measure the deflection when the pressure is applied.
    The hydraulic scale is easy to make, I have a photo of that.

    The main problem you will face custom preloading the bearings is the increased exposure to the air/dust and even extra handling of the bearings is a huge risk, you need a clean as possible space, and work precisely and quickly, it is suggested to write up a plan for each stage, of the repair and follow it.
    The spindle itself is very simple, but on disassembly, you must index the spindle and housing, observe and mark the locations of all the bearings "4" of them inner and outer race high spots.
    Then upon assembly, place the new bearings high spots in the same positions as the old bearings were.
    Then perhaps you made a successful field repair of a Moore spindle.

    I wanted to add, the bearing press fits were all close to line to line, so just a little heat is all that is needed in assembly, but, an arbor press with the proper pushers needs to be on hand just in case!
    Last edited by donie; 04-08-2021 at 05:09 PM.

  2. #22
    Join Date
    Sep 2020
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    Wonderful post ! Thank you !

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