Flexible coupling for Anycubic i3 mega z-axis

thingiverse

I designed this flexible coupling specifically for the Anycubic i3 mega to connect threaded rods and Z-motors because of z-wobble issues. Replacing rigid couplers with these flexible ones compensates for imperfections in threaded rods. To attach these couplers, you'll need four DIN 934 M4 nuts - standard nuts will do just fine. For attaching threaded rods, use the headless screws from the rigid couplers. On the motor side with a 5 mm bore, longer M4 screws are needed. On the right side of the printer where the Z-endstop switch is, use headless screws on top; if you use longer screws, they might collide with the endstop switch. These couplers are flexible against bending in any direction and work like springs along the Z-axis. However, they're very stiff to torsion around the Z-axis. The coupler has a side with an 8 mm bore and another with a 5 mm bore, making it potentially useful for other printer models.