One Piece Minimalistic MK8 Springed Extruder

I have a CTC Makerbot clone that I wanted to fit with a spring loaded extruder. I did not want to buy extra parts, and all I had at hand was a 5x11x4 mm ball bearing (MR115), so I took inspiration from Emmet's "minimalistic MK8 replacement" and designed a part that prints in one peace, including the spring.

I recommend that after printing and removing supports (which is fiddly), you first screw it to the motor with the original screws, which should be easy as there is no tension yet. Then pus