Several people I know have adapted the turning mechanism from those cheap pedestal fans.My next incubator will definitely have an Auto turning system. The ideal system will turn tilt the eggs 90 degrees on the hour.
I amthinking of trying an actuator that is used in AC ducting. It powers the arm to raise it and then a spring lowers it when power is cut. A single timer is required. the key would be to balance the load so its not strained
xxx M