The 3d-printed collar needs to be fixed on the shaft. In fact there is a smaller metal collar sitting inside. The set-screw needs to be quite long and extend into the plastic collar. The collar has 4 additional holes, which can be used to directly mount a pulley or a propeller. There is also a collar available with two internal metal collars. This version can transfer more torque from the rotor to the shaft (see last step with possible variations). Insert the shaft into the rotor and fit the collar into the rotor spokes.

Slide the completed stator into the rotor. Maybe you first try to close the motor without that large 3d-printed washer. If the stator doesn’t slide forth or back, you’re done. In my case the washer was needed - probably the clearance depends on the printer calibration calibration.

Turn the rotor by hand, and carefully listen, if there is some noise from cables, which are touching the rotor. Remove the stator again, and find the reason. Cables are maybe not properly in their slots. Maybe the cables are touching the air-sealing ring of the rotor (see highlighted spot in the drawing).

Basically the rotor is already well fixed when the lid is closed, but if there is a heavy load directly attached to the shaft, I recommend to fix another metal collar on the side of the stator mount.

I also strongly recommend to build a simple, wooden test-stand for the motor. The four threaded rods are used to fix the stator. Don’t tighten the nuts too much, because there is only plastic on the other side. If the nuts come loose while the motor is running, you should use locking nuts instead.

Connect the three wires from the motor to a regular ESC. I’m using my homemade arduino-based servo-tester for generating the control signal. It’s also a good idea to alternatively use an RC transmitter and a receiver - then you can do the initial tests from a safe distance. For the very first test you should really use a battery with a voltage much lower than the nominal voltage of the motor. The motor will spin not as fast, and in case something goes wrong, the damage is less severe. With 8 volts from the battery the motor should be slower than 2000 rpm.

Without a load the motor draws much less than 1 amp. I’m attaching a propeller and let it run in reverse direction, because I want to test the current and not the thrust. For this test I’m initially using again the small battery. Tests at low RPM with the small battery can safely be done indoor, but with the higher voltage from a bigger battery, I recommend to do the tests outdoor.