http://igor.chudov.com/projects/Brid...e-Servo-Motor/

I looked inside one of the servo motors (Y axis).
Inside, I was surprised to see a circlip (retaining ring) and a
setscrew. It is as if the encoder shaft was inserted into the actual
motor shaft and held by a setscrew. Could that be true? If it is so, I
could make any encoder shaft as long as it could fit inside the main
shaft?