uxcell 8mm to 8mm Bore Rigid Coupling Set Screw L22XD14 Stainless Steel,Shaft Coupler Connector for 3D Printers, Motor Accessories,2pcs

Honestly it would be hard not to make a good set of shaft couplers like these. They work great, and will probably be reusable forever unless you make the mistake of stripping the threads somehow. The set screws (grub screws) included could be a mm or more longer depending on how you use the part, but if you are coupling shafts that fill the holes entirely then they will work just fine. In my case I was trying to grip a shaft that was undersized and this was the closest coupler I could find for my application.

size was excellent, they fit what I used them for. They feel tight with no slipping and did not strip out .

Yep, I said "Almost". But it's my shortcomings not the product's shortcomings that make me say "almost". The set screws are really small and hard to see or insert. You have to put them in the right way or you cannot use an allen wrench to tighten them. In my younger days, before cataracts, I wouldn't have had any problem seeing these set screws. But today, it was difficult getting them screwed in and tightened. I would have liked the set screws to be locked into the holes so I only had to tighten them and couldn't take them out or lose them.I am building a linear stage which uses a 5/16" threaded rod and a 12VDC motor with a 4mm shaft. I needed to connect them together. I talked with employees at the big box hardware stores and department stores -- they had no idea what to use to make the connection. It wasn't until I realized that the motor manufacturer would probably have good ideas for how to make the connection that I found these connectors.

made quick work of connecting two shafts of different diameters

I figured that I would give this a shot to join a 1/4 to 3/8 inch shaft for a drill. 3/8 is about half a millimeter smaller than the 10mm spec but I managed to get it set just fine. After a few tests I noticed a slight wobble. This was quickly resolved with a thin shim to steady and center the 3/8 in shaft in the 10mm hole. Precision demands such things. Now I know how tolerances are important if you want a quality tool.I’m really happy with how it turned out. Good coupling sleeve for mating two odd shafts. If I need another one in the future, I wouldn’t hesitate to order more of the same.Highly recommended.

For great for attaching the windshield wiper motor to the bicycle rim. Secured very tightly

It Shows 2 items in the picture , only came with one. I just needed one ,thought it would be good to have a back up though . Quality of the one item is good.

Was well made and glad it came with the 90 degree set screws. I used this on a focuser project for my telescope. It was replacing a previous plastic part so this is much sturdier and less slop in the coupling. The extra set screws work well to hold it into place. The bore does scale out per my micrometer. Seems very well made and the screws went in easily so the taps are clean.