It's a remix of Y tensioner for the  Ender 3 Pro with 40x40 V-sot Profile. I want to thank Cornely_Cool as he generously shared step files with me. That helped me to adapt his work for wide 10mm idler pulleys. I used W10T20B5 idler pulley. It fits perfectly for wide 9 mm GT2 belts.
See also
This work contains two parts: this Y-tensioner and Y-mount for huge 48 mm NEMA17 step motor.
Assembly notes
I suggest using a litle bit of lubricant over the screw surface. It will help to insert it into the mount and will also make knob rotation easier.
This is a remix from https://www.thingiverse.com/thing:398515