Got started on motorizing the tracks on the crane. Going to see how far it can rotate using the kidney shaped holes in the base and cab. I have not yet figured out how to secure the top to the base without the center screw. Not enough stub poking down onto the base for threads, or I would be all over that, using a audio plug in the screw hole.
Crown gear and pinion on shaft of the drive servo. Drilled out the hole in the frame and bushed it with 1/8" brass to make a better fit for the axel shaft.
Switch to a smaller crown, and added a lock nut as a jam nut on the threaded rod, up against the spline of the servo.
I'm going to try the single servo and drive parallel and see how that works first. I have started the second servo setup, but I will need to cut the shaft on the other end as well to isolate the left from right.
Jim