Ender 3 ( or any 40 x 40 extrusion) cable chain mount adapter.

thingiverse

This is an add-on for the fantastic Ender 3 cable chain system by johnniewhiskey (https://www.thingiverse.com/thing:2920060). Having printed a rear-mounted electronics case (https://www.thingiverse.com/thing:3688967) designed by TeachingTech, I needed to secure the cable chain mount on my bed. This thing allows you to use the original mount that slides into the slots on the 40 x 40 extrusion - it bolts to the back of said extrusion and the original mount just glides on smoothly. To do this, you will need to tap two M5 threads in the extrusion using a sturdy tap or an M5 cap head if one is available. This process should not be difficult, but be careful not to get the M5 cap head jammed in there. You will also require a couple of M5 bolts, approximately 6-10mm long. Shorter bolts are better if you haven't tapped the holes very deeply.