X Carriage rework type without ties

Support based on the Prusa i3 rework, but redesigned from scratch, not using nylon cable ties, bearings are introduced laterally and secured by a screw.
In the images have been used Igus bearing type, but have the same size as the LM8uu.
I include two STL files depending on the distance between bars of your "x_ends".
Based on:http://www.thingiverse.com/thing:119616.
New version released to avoid interference with a P3steel frame screw.