About this 3D model

Customized version of http://www.thingiverse.com/thing:53451 Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=53451 I printed the original 0.15 tol and it was completely locked up on the outer edge. I rounded out the center hex trying to get it to break free. Additionally, I am using a shorter one to save on materials until I find a tolerance that works for my machine. I will be attempting a number of other tolerances until I get it right.