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）

Took me some time to figure out what was causing the banding on my print. When I took the lead screw out and looked at the shaft coupler while it spun, you can easily see the top piece wobble, thought it was just a bad z-screw initially, but after replacing that first, it had to be the coupler.

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.

Works as should

They seem to work. Hard to test it. You have to take the Z rods out all the way to get it to go in. But thats a good time to clean them. The fitting is very loose at first and the screws are very hard to turn. I thought I was going to strip it. Then finally it turned and tightened. I thought I had the wrong size at first.

I installed these and noticed it wobbling immediately when rotating the z lead screw. So I reinstalled these in several different ways (loosening/tightening grub screws, reseating coupler on lead screw then on motor and vis versa, and tried correcting uneven coupler by taking it apart and assembling it in different ways). I looked up and watched several different videos just to make sure I wasn’t installing these wrong. Nothing worked. After spending several hours on this coupler, I reinstalled the stock coupler and wobble is completely gone. I really wanted this coupler to work but in the end I had to accept that this coupler is poorly built. I will be returning and looking for a better built coupler than this one.

Printer moves much smoother now after this upgrade, fits perfect with my ender 3, excellent quality

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.

I could not get my Z axis screw drive to remain level with the vertical frame of my Ender 3 V2. This little gem solved the issue as the gel inserts between the lower and upper halves allow flexing and the Z axis rod now remains straight. Great solution for a minor issue. 2 sets to a pack so youll always have a spare on hand.

no spring back as with the traditional couplings. Nice tight, true turns when engaged!

I like these type of coupler alot better than the set screw type because the set screw type you can never get them exactly on center. with these friction type they stay on center and nothing damages the lead screw