went to my local hacklab tonight to drill new tapered holes to join the three rotor plates and check the rotor friction against free spinnininh by hand. These can be welded by acrylic cement but for the prototype I need to be able to disassemble.

After some slow drillling I got 3 spaced around the rotor nut/bolts through to hold them together. I then grinded the end of the screw (scalded my finger as the screw got really hot!) .

The overall friction on the rotor is quite low and the gap against stator narrow to approx 1.5mm without scratching and axle fit quite tight. But the rotor doesn't quite free run when I spin it by hand.. There is friction that seems to come from the bearings, perhaps because some of the balls don't roll. I need to check this and perhaps file the ball cages a bit.

So for now, I need to troubleahoot the ball bearings. The design seems right but due to the limitations of laser cutting perhaps some of the balls are locked when I tightened the rotor plates together. Once solved, Then we move on to adding the magnets and coils.