ORIGINAL: MinnFlyer
A misaligned cylindrical hole will cause the prop to sit cockeyed, but a misaligned tapered hole will allow the prop to sit flush with the thrust plate.
Thank you for the picture Mike, that dummied it down enough so even I could understand it.
I can't recall even getting an APC prop that wouldn't balance but I'm sure it happens. I think the biggest APC I have ever used was a 17 inch. Once you get past the 12 inch the prices do go up quite a bit but still, if I had one that wouldn't balance I would pull it and buy another. I mite even send it back to APC so they could evaluate it and find the problem. I'm guessing but I bet they would make good on the bad prop too?