Robot chassis, partially assembled.
(2) Parallax continuous rotation servos
(8) pan-head screws, 3/8″ #4-40
(8) Nylon core locknuts - OR - regular steel hex nuts
Parallax screwdriver
Parallax wrench
masking tape (optional)
pen (optional)
With both servos mounted, your chassis will look like this:
Note: You may mount the servos the other ways instead.
Mounting the servos with the servo shaft closer to the front of the robot is also possible. This design may cause some turning difficulty on “sticky” floor surfaces unless the front of the robot has increased weight. The benefit of mounting the servos this way is that the potentiometer hole in the servo case is more accessible (from the front of the robot). If the servos need to be re-centered, you would not need to remove them from the chassis.
You may also mount the servos with the tabs on the inside of the chassis for a narrower wheel base. This allows for the tightest turns pivoting on one wheel. But, it is easier to remove and replace the servos when they are mounted from the outside.
Throughout this tutorial you may see cyber:bot examples with different servo mounting positions.