Ryan Carlyle made a nice design of u-joints to replace the traxxas joints on delta printers. Since I had bought different sized ballbearings I made a similar design in OpenSCAD where you can modifu the ball bearing dimensions.I've just begun learning OpenSCAD so I'm sure there are a lot of improvements that can be made to my design.Further information: https://groups.google.com/forum/#!topic/deltabot/eu1ScVehuCERyan's design: http://www.thingiverse.com/thing:849794