For our next model, we will build a gearbox that contains a worm gear. Every time the worm gear makes one complete rotation, the spur or straight gear meshed to it will progress by one tooth. We are using a 24-tooth spur gear in this model. Notice how this spur gear does not have any bevels. You will find that our spur gear will rotate very slowly, but we have a mechanical advantage of 24! Speed is not always the goal of a gearbox. Besides greater torque, one feature I like about using a worm gear is the greater amount of control. If you are building an arm where great precision is required, the worm gear will allow you to align your output appendage with a high degree of accuracy. The EV3 shaft encoders can guide the motors themselves to within one degree of accuracy. So with this combination of gears, we have an accuracy of 1/24 of a degree.
In the following seven steps, we will build the gearbox with a worm gear:
First insert two long friction pins into your medium motor. The...
