A worm gear is a gear consisting of a shaft with a spiral thread that engages with and drives a toothed wheel. ... It changes the rotational movement by 90 degrees, and the plane of movement also changes due to the position of the worm on the worm wheel (or simply "the wheel").

What is an example of a worm gear?

Worm drives are used as the tuning mechanism for many musical instruments, including guitars, double basses, mandolins, bouzoukis, and many banjos (although most high-end banjos use planetary gears or friction pegs). A worm drive tuning device is called a machine head.

What are worm gear used for?

The worm and worm gear, which are illustrated in Figure 57.21, are used to transmit motion and power when a high-ratio speed reduction is required. They accommodate a wide range of speed ratios (60:1 and higher can be obtained from a single reduction and can go as high as 500:1).