Y Axis Tensioner with looped belt

Took this design and the design i printed for the X axis http://www.thingiverse.com/thing:1820493 and tried to make one piece in Tinkercad.

For easier installation and tightening of the Y-Axis belt on a Wanhao Duplicator i3. Requires a M3x30 screw and a M3 lock nut

I'm still struggling with Tinkercad so if you can improve it please do
https://www.tinkercad.com/things/aCpalPHZSlD-magnificent-elzing-luulia/editv2?sharecode=mgflzoKH3HLP85eSMuh46-Fhsd9gq8D1rJkXbHpt4jg=

Edit: Belt didn't ca