Okay, in the 3rd revision, I increased the gap between the ball and socket to 1.5, which allowed the ball to go in without breaking the socket. But you will need to place some sticky back foam (I used weather stripping) in the bottom of the socket to act as a spring to keep the ball in place. The socket did not crack at all this time when I put the ball in.

Customized version of http://www.thingiverse.com/thing:1085548

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=1085548

Using the following options:

screwHead = 0
neckLength = 30
ballSize = 30
ballSlop = 1.5
flangeDiameter = 84
flangeThickness = 3
socketThickness = 5
holeSize = 0