Quad Rod Z-Axis

this is a Z-Axis for the root 2 cnc 2.1. I designed it around stuff I had around the house...

Parts :

4 - 8mm rod : https://www.amazon.com/BQLZR-Vertical-Bearing-Support-Optical/dp/B01K4MWQ0A/ref=as_li_ss_tl?ie=UTF8&qid=1485143748&sr=8-6&keywords=8mm+bearing+rod+300mm&linkCode=sl1&tag=wwwbethnchris-20&linkId=865621b33f6cb7e1768364b3d188efc5
8 - lm8uu bearings : https://www.amazon.com/BQLZR-Vertical-Bearing-Support-Optical/dp/B01K4MWQ0A/ref=as_li_ss_tl?ie=UTF8&qid=1485143748&sr=8-6&keyword