A nod to Integza on this one. It evolved or devolved from his Mk4 version.

I had imperial size shaft & bearings so used a .125" reamer in hub & a .375" reamer in bearing bores. Or you can use 3mm shaft & 10mm OD bearings. Either way the holes are tight after shrinkage & need to be reamed to final size. Similar, I tapped for 4-40 threads but M3 are OK too.

I designed the end caps to be printed with the concave side down & no support. The concave surface is like an "as cast" surface vs. a machined surface so some imperfections are OK