6Pack Treehobby Aluminium Alloy Shaft Coupling Rigid Stepper Motor Wheel Coupler Joint Connector for DIY Car Boat Airplane 3D Printers, 5mm to 5mm

I like the quantity and the quality for the price.

We needed to connect two 5 mm rods in one of our inventions and these worked exactly as we needed them to.

Product shipped fast and arrived on time. Parts arrived in factory packaging with good finish on products. Dimensions are to spec as stated with no visible defects. Unfortunately mine arrived without any set screws. Had some extra M4 screws but was annoying getting the little wrench to install them without getting the screws. Couplings are otherwise performing perfectly so far.

With a full machine shop in my basement, for this price and quality, I would be a fool to make my own. These are very good couplings, and I put them on 1/2 my commercial printers already.

Does exactly what I needed. Good value.

I bought the wrong size

the inside diameter is not 8mm. its 8.25mm. using these on a NEMA 23 Shaft is worthless. they wont give you a precise fit.

The idea of using setscrews is that you have two screws that push the top and bottom rods onto the same corner on the top and bottom couplings.You have to do a total of 4 drilling and 4 tapping operations to accomplish this. The setscrews can be any angle to each other as long as the two screws that grab the 5mm rod are at the same angle and on the same side as the corresponding screws for the 8mm rod. This way they hold the two rods concentric and you get the full friction of the rods on the surface of the coupling.Having the screws 180 degrees apart cuts the drilling and tapping operations in half, unfortunately now the screws push the rods out of concentrically. Furthermore instead of having the friction of the whole rod surface against the whole coupling surface, you only have the friction of the rod on the two setscrews as the rods are held off of the side walls.