[Dominik]

Nice going! :-)

Please can someone fit the pins on a stud or bolt and turn them in a lathe or drill press.
I would like to know if they are concentric. Or how much they "run out".

You could also fit them (2) on a hub. Measure the gap with a vernier caliper between the two. Then turn them half a turn and measure again. Do that until you get the biggest difference.

Dom