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）

For some reason the flexible couplers milled from a single piece of aluminum tend to shear on my DIY CNC machine on both the X and Y axis. Ive tried different brands and suppliers, including the one in the photo, with the very same results. Within 6 hours of run time it breaks on the simplest of carves, ruining my workpiece. As you can see in the photo and the pictured break, one has to question the mill stock used vs. who mills these from that stock. However, since changing to this 3 piece design, Ive been running fine without any issues or mid-carve failures!!! Thanks!

I used these on my 3D printer and they work great. Excellent quality

The pull apart, there is actually nothing that would keep them together. I installed them and not long afterwards, my printer would make some weird noise. Sounded like a door hinge that needed some form of lubrication. Took a few hours to locate the source. Turns out the piece of hard rubber, or whatever it is, in between the two metal pieces would cause the noise. Sounded really awful, like my printer would fall apart any moment. The Z lead screw(s) would sway like the Eiffel Tower. Thought my screw(s) were lose, hi, hi. So I checked them as good as I could and they ran true. Now I am using solid coupler and all is good.

worked as it should and am well pleased

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.

Works as should

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.

One of them was straight but the other was completely out of round. These were purchased for the Z axis on my 3D printer and having any wobble was not acceptable.. I didn’t have to measure the runout to see how bad these were it was visible. They’re definitely not appropriate for a 3D printer.

Unlike most couplers there is no set screw for locking this into place on the notched portion of the motor shaft. Ive found it very difficult to get a good firm lock to the motor shaft with these. Ive tightened them to the point where I feel like anymore risks stripping the threads.

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....