Ender-3 X-Gantry Alignment Tool

This is a pair of "legs" that will hold the x-gantry perfectly level while you adjust it. This video from Alex Kenis will show how it can be used instead of the CD cases he uses.

https://www.youtube.com/watch?v=AN0MlQMMew0&t=149s

You don't need it, but I used the knob, an m3 bolt and t-slot nut to hold it to the vertical brace.