I made a modification to the belt tensioner by Tevo Tarantula to allow the use of 6mm x 6mm x M3 square nuts to provide more strength to prevent the adjustment screw from stripping out.
I have added a thicker version for more strength. The top piece where the nut is inserted and the back has been made 1mm thicker.
I've supplied STEP and Rhino 3D (.3dm) files so you can remix and stuff if needed. Just be cool and credit me somehow. :)