Hey Jim @Webb, hey Bob, hey all,
what I wanted to add is that what I was paying attention to when buying are things like runout, and that the bearings meet ABEC 7 / P4S.
Among other things, I relied on that when buying.
(Source: Datenblatt_HFSAC-8022-24-ER16.pdf)
This CNC Depot spindle meets the ABEC 7 requirement, that’s fine. And ISO 30 Tool Changer, that’s nice.
(Source: CNC Depot: S Series Spindles)
Note that Mechatron spindle has at least 3 bearings.
That’s what I relied on too. My Mechatron spindle is manufactured where I live, they have good support and I have a warranty.