[Frankie4Fingers]

I doubt the shaft is damaged beyond repair. It is hardened steel, and the fan hub is cast aluminum.

There is a half moon key way in the OHLA shaft to keep the fan hub from spinning. It probably long gone in your situation but make sure when you replace the hub you use a key.

I’m not sure I understand what you mean by a key.  Do you mean a notch where it connects with a notch on the fan assembly?