Universal Joint for 1/4-20 threaded rods and bolts

This is a universal joint made to lock onto 1/4-20 threaded rods and bolts. I made it for a robot arm I'm designing, the rest of which will be shared when it's finalized. I've reprinted it a few times to make sure it snaps together easily but still stays together in use.

To see a description of the project it is for and a video of it in action check out the Milwaukee Makerspace blog. There is also a link if you want to vote for my project on element14:
http://milwaukeemakerspace.org/2014/01/a-robot-barista-a-new-open-source-robot-arm-design-and-a-call-for-votes/

I printed it at 100% fill from PLA with 2 shells, on a Makerbot Replicator 2 with the spring lever upgrade on a bed covered in scotch blue painters tape.