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）

After a few uses the coupler was stripped and kept coming off the z motor.

Of the two in my package One is mis-sized and doesnt grip no matter how tight I put it. The other seems to be assembled with very poor tolerances as it wiggles and introduces artifacts into my system. Its not 180 degrees straight, more like 175 degrees.

Such a simple upgrade elevated the z axis binding o had after upgrading to dual z axis motors

My CNC came with solid aluminum spiral-cut shaft couplings. This lasted for quite some time but one finally broke. I replaced with flexible urethane couplings which are widely used in heavy manufacturing applications. I am confident this product will have a long service.

Just what I was wanting

The bottom of the clamping screw hole was foil thin. Couldnt figure out why it wouldnt clamp on the stepper shaft, got to looking a little harder and saw the bolt bottomed out on the other side of the slot.

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.

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.

worked as it should and am well pleased

Works well on Z-axis lead screw for my Ender 3, and is a definite upgrade to the stock coupler. The finish is decent, and seems pretty solid. My only complaint is that the coupler will come apart fairly easily if you apply any form of tension pulling on the coupler, which can get very annoying if youre used to pulling up on the X-axis gantry to manually raise it. Thats 100% a design shortcoming specific to my application, and not a fault from manufacturing.