Pictures are at the bottom. Thought it was walnut then discovered it was poplar after I cut and started shaping it. So it is incredibly light. Way too light (34g!!!). About 36.5mm wide, 60mm diameter, 1/4" walnut axle. Better luck next time with a known wood.
It also has an intense, visible, and pulsating vibe, though it looks pretty decent rolling across the table. Going to try some calipers all around to see if anything is off. Trying to attribute it to one of the following for next time:
Hole centering: I marked a circle while it was on the screw chuck I made and tried to hit the center of the circle with a regular bit (7/32" bit). Got a brad point bit for better accuracy next time and I don’t plan on drilling the hole all the way through for the chuck so I can mark the center better as well.
Drill press angle: I don’t know how to tell if the platform is a true 90 degrees: This is my father-in-law’s drill press and it is very, very old. Many decades. Likely this?
Assembly: I ever-so-slightly shaved the edges of the walnut axle and just gently tapped it in with hammer. 1/4" dowel into a 7/32" hole, no glue. I assumed the 16.5 mm hole in each half would be plenty to straighten it out. Was this a bad assumption?
Wood expansion: This stuff has been around for a while. I thought it would have been seasoned.
Any other ideas? What is likely? Pictures below (and the screw chuck with the poplar block on it).