Ball of Death: or How I Learned to Stop Worrying and Love Apple Pro Speakers

Step 6 Screw it

I mean BOLT it, of course. the most important thing here is that the shaft of the motor not touch the sides of the hole in the core. Believe it or not, there's a LOT of maneuverability built into this step. You can either file/ream out the holes more for the bolts to slide down into them, or you can loosen one side and tighten the other 2. Either way, it's not too difficult to manage to center it almost dead on. Hindsight being 20/20, and according to the pic, I think I need to adjust it a little myself!

Note: you don't want bolts that are too long. Make sure they JUST go into the motor housing. Too deep and you'll damage the motor.