Parametric rostock rod-end printed u-joint jaws for hollow tubes

These are rod-ends for Rostock's printed u-joints parametric so you can use tubes of any size.

Unlike the stock Rostock ones, these are designed with a plug to fit into a tube rather than as a socket for tubes to fit into.

The current settings are for 3/8" hollow Aluminium rods.

This was inspired by http://www.thingiverse.com/thing:39662, but thingiverse seems wonky and I can't mark this piece as a remix of that so I'm just linking it for now.