The .5mm is likely an errant artifact left behind from my tinkering to get the model generated. The hole will be tapped as an M3x8 - cut through is fine if that's easier! I just blew out a WheelsMan (the replacement hanger) on Thursday. The unit they produce now is x8 depth and doesn't go through completely. I think I blew it and removed some of the sketches that had the radius markings listed. I'm not sure how to best answer the question about the max radius ... perhaps what the tooling allows? I have an acquaintance that did a quick draft from the file I created in order to help me learn more about modeling - he accomplished it in 8 steps. There is one image showing the diameter of the hanger as 27.5mm (radius of 13.75) at the transition. I'll check to see what the radius is on the axle portion - I'm sure he kept the file.