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）

All good as expected

Holes out of alignment. They wobble. The hole for the motor is skewed enough to be visible. Probably done free hand on cheap drill press. I payed alot for quality got junk. Shame.

If your planning to buy this to solve z axis wobble, DONT! The hole is not centered and made prints come out worse than ever before! Poor manufacturing quality and not even worth $1 Look elsewhere!

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).

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

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.

Quality of coupling itself and screws is really bad. I would avoid as it is not worth the hassle of ruining your motor is the coupling seizes and you are unable to get it off.

Semplicemente dopo averli installati sulla mia stampante 3d ho riscontrato un movimento delle aste filettate non trascurabile. Da una parte un po me lo aspettavo vista la natura del pezzo (due pezzi separati con nel mezzo del materiale plastico) ma non così tanto. Il problema secondo me deriva dal non perfetto allineamento tra il foro da 5 mm e quello da 8 e questo accentua le oscillazioni.

I should have listened to the other reviewers. Not only was the machining and tolerances pretty far off for a precision job for properly aligning a leadscrew but the small screws are super bad quality (see picture close up of the striped screw head). The 5-8mm holes are pretty far off causing you to need to extra tighten the screws to grab hold of your leadscrew and stepper shaft. After I realized how terrible the bottom screw was (to the stepper shaft) I replaced the top screw with the one that was in the factory coupler and it never stripped. At the very least if you still feel like many of us dont know what we are talking about and you still want to give this a try, replace the screws with the ones that came with your stock coupler. Its a good thing I did that or else I would have lost the stepper and the leadscrew to a wobbly, out of alignment poorly manufactured coupler. I have yet to find a solution other than properly aligning everything with custom designed 3d printed parts and the solid factory coupler. After this failure I have pulled out the calipers to make sure everything was aligned properly and my issues were fixed and I never needed this part anyway. One star for wasting my money and costing me a new stepper motor.

Definitely not a precision product, but the work for hobby applications.