Washer 6,3x28x1,5 (for motor shaft)

When the screw is tightened, the wheel must be able to slide about 1mm on the motor shaft. If there is to little space, the wheel will not be able to release the line. If the game is too big, the wheel risks losing engagement with the motor, or pushed against the outer screw that holds the wheel in place. An combination between the washers 1mm, 1,5mm