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）

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.

Les flexi-coupleurs de ma LeadCNC, monobloc en aluminium casse régulièrement suites aux contraintes elevées en decoupe de bois dur. Ceux la ont lair plus solides, bien quavec un leger backlash qui nest pas geneant pour mon utilisation.

Works great for my Wanhao clone, the monoprice maker select plus

The plastic slides right out whether vertical or horizontal. The bottom of the clamping screw hole was foil thin. it wouldnt clamp on the stepper shaft

this coupler has one job: be straight. It isnt. Its off by at least 2-3 degrees, which takes considerable torque to overcome if your motor is mounted firmly. I think (think, not positive) the problem is in the rubber piece, not the aluminum. The rubber is tight fitting and allows no play, which would be good... if it were straight. I sanded the rubber ears down and introduced a bunch of slop so that my motor would quit stalling as it binds up every rotation. I used it for something that doesnt require any precision so it was good enough after I fixed it, but i would not recommend this for any kind of 3d printer or CNC.

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

These coupling did not last thru the first minor jam on m Tops cnc

The children wanted to extend the shaft of the motor and in turn, go from an 8mm to 6 mm shaft. This did the trick.

I had to add a layer of aluminum foil around my Nema 17 stepper shaft to actually get it to bite tight enough to have a firm grip. They should design these things with a D-Bottom the same shape as a Nema 17 shaft so they will actually grab....

Needes for 10mm stepper shafts amd 1605 ball screws.