Pololu 1083 Universal Aluminum MOUNTING HUB for 6mm Shaft Pair, 4-40 Holes

This is a fairly specific item, so I'll assume you have a use in mind for this. For my use, it worked great (as an interface between a small motor shaft and a halloween prop) I'm happy with this purchase, very nice quality.

My first purchase was a cheaper hub that had set screws on opposite sides of the central sleeve and no set screw in the flange part of the hub. The problem with this is that the set screws bear all of the force of keeping the hub from spinning on the shaft, and there are precious few threads against which to distribute that force. When I saw this hub with a wider flange that is threaded and on the same side as the second set screw I knew I'd found the right hub. (Short of finding a hub with a D-Shaped hole, anyway.) Since both screws are on the same side both of them positioned on the flat part of the shaft is MUCH stronger than the other approach. The long thread path through the flange also provides lots of surface area for the threads to distribute force against and hold the hub securely. Like I said above, a hub with a D-shaped hole would be best since it would be impossible for the shaft to slip and the set screw's job is merely to keep the hub from falling off. Unfortunately, these are so far impossible to find in the 6mm size I needed. Short of that this hub is the best design I've yet found for high-torque use cases.

These are beautifully machined. My only complaint is that tightening the set screw using the included wrench tight enough to avoid loosening on the shaft causes the wrench to get stuck in the head of set screw. To get it out you have to reverse the wrench, and that just causes the screw to loosen. You might be able to use regular 4-40 screws, but the ends aren't cupped like a set screw, so they might not hold either. Maybe with loctite?

Perfect for my needs. Fit an finish were great. The threads were clean and smooth. these fr perfctly on the "uxcell DC 12V 5RPM Micro Gear Box Motor". I will be ordering more

Worked as described

Honestly, the set screws kept coming loose and I did not want to use lock tite to secure them down due to the size of the shaft / motor did not want to risk letting it flow where it shouldn't. Thankful for the extra screw included because we inevitably lost one on the shop floor... hehe

The hub fits the electric motor shaft as advertised.

Works good