Rod adapter for Xnaron Printable Magnetic u-joint for Rostocks

* Updated to add a 4mm rod version.

This is an adapter I made so I can use some carbon fiber rods I already had and that are readily available from Hobbytownusa locally. The original files were for 3/8" rods. Mine are about 5.5mm / .188" OD from http://www.hobbytown.com/Shop/Carbon-Fiber-Tube-24-188-OD/