BB 8 Drive System Parts List - Hazmit/BB-8 GitHub Wiki McMasterCarr Shaft Mounts Qt 2 3/8″ Shaft (12″) 3/8″ Shaft (3″) 3/8″ Bearings Qt. 4 1/4″ Shaft 12″ x1 Timing Pully x4 Timing Belt x2 Servo City Spin Motor x1 Continous Servo x1 Servo Blocks x1 RobotZone Servo System 90degree 7:1 x2 Clamping Hub Youll Need x2 (545588) x2 (545616) Drive Motors x2 Motor Mount E x2 1.5″ CHannel x2 Bearing Channel PIllow mount x2