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Re: Dismounting the headstock bearings

 

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Hello PR,
My experience with these bearings is that they can be hand tight, up to press tight.? On an automobile the bearing is slip fit on the spindle and press tight on the hub, so use your judgement carefully.
Do you have a 3" spindle mount or 4" spindle mount???
If you have the smaller 3" spindle, you can goto your favorite BigBox home store, (lowes, Home Depot, Menards, etc.), and buy a small piece of 4" PVC Pipe x 12" long about... and a long enough piece of all-thread rod, 30" about, + 2-3 matching nuts and washers? to create a "Screw-Press" type of press with the 4" pipe over the 3" end of the spindle, with the long screw down the middle, and a small 2x4 piece of wood, maybe 6" approx, on the other end of the 4" pipe and a bushing of sorts that you would make before beginning this process that fits just in the small end of the spindle to lock in the inner diameter and be the same as the outer diameter slightly smaller so as to pass through the bearing there.

1. Before disassembly, make a special bushing to go into the small end of the spindle so that it will grab just the edge of the spindle and still pass through the inner diameter of the bearing, include a center hole large enough to allow the threaded rod to go through as well..
2. Stack the parts collected like this....
??? a. Nut and washer on 1 end of the threaded rod, pass through a piece of 2x4, then through the 4" pvc pipe.
??? b. take this setup to the lathe and pass through the spindle from the big 3" end all through the headstock.
??? c. Place your special bushing on the small end of the spindle and over the threaded rod and install the last washer and nut.
??? d. Tighten this mess up until the spindle is drawn out of the headstock.
??? e. Examine the spindle shaft area and look for burrs or shiney spots that might indicate what your problem(s) might be.
3. Remove any burrs you find, if you see shiney spots near where the bearings ride, sand or polish or file them a little bit until the bearing will slide smoothly but snugly, don't remove too much material.
4. Reassemble in reverse of disassembly
5. If this still does not give you your desired results, do it again and look closer at the problem areas.

If you have a 4" flange, you will need a larger pipe probably, maybe a stack of 4" pvc pipe coupler fittings,(without the center pipe stop ring), to allow the spindle to be removed through their center area. Glue and tape them edge to edge carefully and allow them to dry a day or 2 before using them.

Good Luck


On 2/7/2025 10:29 AM, Pierre-Raymond Rondelle via groups.io wrote:

Jon, Interesting vids.
They tend to confirm that a press is needed for dismounting and remounting. However, no figures are provided concerning the applied forces.
Referring to the ISO286 adjustment charts and a general guide about bearings (), I see that external tolerances are very low, around 2 to 5 ?m, that the inner rings should match a k5 or k6 tolerance range arbor and the outer ring should be mounted in an H7 or K7 bore. That said, the adjustments are qualified as "temporary" meaning that they could be disassembled with a mallet. In practice, they are almost stuck. Puzzling !

From my understanding, it should be possible to push the inner ring a little bit farther with the nut. But it blocks !

Perhaps search YouTube for "mini lathe angular contact bearing" and reveal this -->? ? <--. Maybe 'click it even'. Good luck on your final answers


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