Belt tentioner for MF126zz bearing for the Prusa i3 Hephestos

I made some modifications to get this to work with a 2 MF126zz bearing that I purchased here. http://www.amazon.com/gp/product/B00HHHDQLE?psc=1&redirect=true&ref_=oh_aui_detailpage_o08_s00

Assembly parts are
0) 2x MF126zz
Parts below were purchased at Ace Hardware:
1) M6 x 25 mm button head cap screw
2) M6 nylon locking nut
3) M6 Washer - Goes under M5 washer not on bearing axis
3) M5 x 30 mm socket head cap screw
4) M5 nut
5) M5 Washer

The M5 nut is set into the back end of the id