Complex sentence: A worm gear, or worm wheel or worm drive, is a type of gear that consists of a cylinder with a spiral groove mounted on a shaft, it is used to greatly reduce rotational speed, or to allow higher torque to be transmitted.
Split into simpler sentences: A worm gear, or worm wheel or worm drive, is a type of gear that consists of a cylinder with a spiral groove mounted on a shaft. It is used to greatly reduce rotational speed, or to allow higher torque to be transmitted.