ender5_belt_tensioner_y_axis_nut_plug

thingiverse

This is a plug that will prevent the lock nut from spinning freely. It is a tight fit. The nut I was using did not lock itself so I had to use pliers every time I wanted to adjust tension to stop the the nut from moving. I made this plug to be inserted from the top or bottom and fit snug. Print with supports. Your fingers should be able to fit in the cut out grooves to remove the plug if needed. If the edges are too sharp, consider filing them down with nail file. They were fine for my fingers. If you happen to have large gorilla fingers then you can use the center hole with an allen or screwdriver to remove the plug. I am using an M4 carbon steel lock nut with nylon center. Nut width is 0.2665 inch between flat edges.