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

Fits like it ahould

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.

Good quality

works as expected

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.

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

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.

Connectors came in a small plastic bag inside a sealed box. Fortunately for me, I had other set screws to compensate for the missing part but unfortunate for you if you do not.