HyperCube XY_Joiner for 8mm rods on X-Gantry

If you are unable to find 10mm anodised aluminium for the X-Gantry, then the next best solution is 8mm steel rods instead.

Requires:
* 2 x [LM8LUU linear bearings](http://www.banggood.com/LM8LUU-8mm-Long-Type-Linear-Motion-Ball-Bearing-Slide-Bushing-CNC-Part-p-994394.html?p=9X051049165582016063)

Print this thing to hold the linear bearings to the X-Carriage:
http://www.thingiverse.com/thing:1771522

**Print 2 of the XY_Joiners**