RE: RClander T33 for 90 or 120mm edf
My friend opened the rotor adapter from 6mm to 8mm on his lathe. This technique provides a true center and is easy to duplicate. The short 8mm motor shaft will provide excellent stability to the rotor.
I used some removable thread locker on the motor shaft and set screws. One set screw was lined up with the shaft flat side. We filed a small dimple in the round side of the shaft so that the second set screw would prevent the adapter from getting pulled out under force.
The smaller motor holes aligned perfectly to the DF housing and I used some metric screws to mount it from a Kyosho racing kit. I mounted the thin metal plate that covers the rotor base but I am not certain what it does. It may be a leftover from the original design that had a forced air fan.
Both the rotor and spinner mount like well fitting gloves. You can see the amount of shaft area reserved for the rotor on the adapter. These design areas all help create vibration-free performance. The finished unit was ready to mount onto my test stand.