This is a remix of eXthemaX's Ender 3 X axis belt tensioner. I made the main body and screw to fit jyjblrd's 4 axis polar core r-theta printer. I wanted to reuse as much of my old Ender 3 as possible while building this project. With the longer main body a 760 mm belt can be used to drive the X and B axis. The updated screw/carriage uses the original idlers from the Ender 3, but I added a spacer to fit a M5 x 20.
https://www.youtube.com/watch?v=VEgwnhLHy3g
https://github.com/jyjblrd/Core-R-Theta-4-Axis-Printer?tab=readme-ov-file
The author remixed this model.
I made the main body longer to accommodate a 760mm belt. I added a spacer to use a M5 instead of a M8 so the original Ender 3 X-axis idlers can be used.