That's awesome man! Good luck!
Time for another update! A colleague helped me in the CNC-grinder. Grinding the spindle housing, outside and the front bearing seat is now done. Will grind the back bearing seat hopefully next weekend.
Attachment 247738
Doing some test fitting.
Attachment 247740
Attachment 247742
Now it's time to grind the spacer-rings to the correct size, not today tho.
Attachment 247744
So I did some run-out testing(without the roller bearing), the run-out on the back bearing seat was around 0.02mm, and the run-out 200mm away from the tool taper was 0.02mm. Note that I didn't adjust the run-out in the AC-bearings when testing it today, when I do the final assembly I should be able to get lesser run-out on the back bearing seat and therefore lesser run-out on the tool taper. I'm still aiming for a maximum run-out of 0.01mm, 200mm away from the taper.
Here's a video showing the run-out testing.
https://www.youtube.com/watch?v=EsOjSYLWJHc
Still a lot of work left, but I'm getting closer to a finished spindle!