It is a proof of concept model not meant to fly for a long life
That helps, thank you Frank. I can get off my soap box now.

The grinding is hard to see in the photos (and looked more like welds!) but this is a way that the camera can tell lies.
Given the care and attention you've dedicated to your other work, I have no doubt that you carefully ground them, too.
I am curious about how you'll keep the balls well spaced unless you can come up with a cage for them too.
If you're looking for ideas on ball arrangements, I think I've heard of special ball spacers, which might inspire some ideas, but I don't think I could find the link to the article again. Just a strange thing I read once and this reminded me of it again.