You could redesign the one you have by using precision angular contact Bearings, you would have to make a spacer to go between the ( 2 ) Bearings this spacer you machine to give you the right amount of Preload Here is a spindle I made recently
And another spindle I built some years ago on the Zone, to give you an idea of how you could change the spindle you have with just bearings and a spacer
Or even just adding a spacer between the Bearings you already have, this will then not allow the preload to change once you have made the spacer the correct size
https://www.cnczone.com/forums/cnc-w...dle-build.html