daier 2 Set Motor Shaft Coupling,M6 5mm Axle Motor Shaft Coupler Sleeve Saw Blade Coupling Saw Chuck Adapter

Handy to connect a motor spindle to other things. The motor spindle fits into the 6mm end and is affixed using the included set screw. The other end is threaded M6 rod and comes with a washer and nut to connect whatever it is you're hoping to put on the business end of the motor (such as a saw blade or pully or spur gear or whatever). The threaded bit is on the short side, extending approximately 8 mm. Using the included nut and washer you can put on a saw blade (or other thing) that's maybe 3 mm thick. I would say you are pushing your luck with 5 mm. That said, there's a lot you can do with what you're given. The set I got even included an extra set screw, those things are small and I can't be trusted not to lose tiny bits so that's a welcome addition. Overall, if you're needing a thing like this, this product should suit the task.

No exactly what I was expecting, super small

I am building a DIY CNC-based panel cutting system for the shop and I needed to attach an arbor of some kind to the two motors that do the cutting, and these fit and are working great. They are pretty much the standard type that you get at this price point, so no frills, but they seem to be made well and are so far working perfectly. They go on the 6mm shaft nicely and they tighten down well, with no slippage so far, even when I cut some thicker aluminum panels than I will normally be cutting.