It's working! In this video, everything was assembled very quickly. Nothing is tight, but you can see that I can turn the steering wheel while stationary with the wheels on the ground with just one finger. It's on my PVC garage floor, which is less grippy than asphalt, but the power assist setting is in the middle, so I'll be able to increase or decrease it after some real road testing.
It took longer than expected because the first U-joint I ordered didn't fit, so I had to order another double-D one and mill two flats on the output shaft. I also damaged the first assembly, which stopped working, probably when I hammered the first U-joint in. I've since learned that the torque sensor is quite fragile and that you have to be very careful. Luckily, I found another assembly in Poland for €50, including shipping.
