Quadcopter Center Hub

Here is version 1.0 of quad cener hub. Built for 1/2x1/2 quare dowel arms. This version is a bit desiel but will hold up to just about any abouse you plan.
Checkout the full build over at http://backyardrc.wordpress.com/

https://backyardrc.wordpress.com/2013/08/13/3d-printed-quad-build/

And checkout the complete series of BackyardRC's Quadcopter parts on Thingiverse:

Center Hub: http://www.thingiverse.com/thing:136209
ESC Mount: http://www.thingiverse.com/thing:122363
Motor Mount: http://www.thingiverse.com/thing:128477
Quadcopter Leg: http://www.thingiverse.com/thing:136208
Ardupilot top plate: http://www.thingiverse.com/thing:136213