Befenybay 2PCS 5mm to 8mm Aluminium Plum Flexible Shaft Coupling D20 L25 Connector Flexible Coupler for 3D Printer CNC Machine and Servo Stepped Motor（5x8mm）

My printed Z couplers broke so I bought these, turns out it made crazy Z-banding on my prints, went back to printed couplers, and that solved the issue. Bought for a dual-z ender 5, might work better on ender 3 or cr10.

These are most probably planned to separate, so these do not work for my use case: couplers for cartesian 3D printer z axis leadscrew. When moving z-axis, either one of these will separate. The grip is good, too good. Now I wasted two stepper motors because I cannot get these off without bending the axis.

The machining is horrible. I dont know if its made of aluminum or plastic.

Should work fine on a 3d printer, but its horrible on a CNC machine.

Der Kunststoff ist zu weich - und die Schraubenköpfe auch. Resultat: Man braucht viel Drehmoment um die Schrauben anzuziehen, damit die Kupplung nicht auseinander rutscht, und dabei macht man die Schraubenköpfe rund. Drei von vier gingen noch vom Schaft, eine nicht mehr und musste abgeschliffen werden. Für z.b. die Z-Achse an einem 3D Drucker wäre diese Schaftkupplung noch brauchbar, aber wer hat schon einen 8mm Schaft an einem Nema 17? Geht Retour.

I like the quick delivery and i use it for my project.

I bought two sets of these and both were bad. They are cheap so I did not go through the hassle of returning them again. I strongly recommend looking elsewhere. These are NOT the ones you should get. I struggled for days trying to figure out why the printer was failing, only to find out the problem was with the coupler. Bad on me for trusting a cheap product.

I felt that these were too tight to fit the shaft on NEMA motor (without forcing), and they are really tight - not sure I could get them loose if I had to after seating on the motor. However, after comparing overall performance with several other couplers, Ive decided I prefer these. Hopefully I can avoid needing to remove these from the motor (often enough to make cost an issue at least).

hole was too large for my stepper. no matter how much I tightened it, it wouldnt lock down onto the stepper hex wrench eventually stripped from my trying to tighten

To be fair I didnt try to adjust the cheap ones that came on the printer, or re-seat them in any way, but removing the original ones and installing these got rid of all the low pitch squeaking I got when rapidly adjusting the z health on my Cartesian printer.