<P> In early 20th century automobiles prior to the introduction of power steering, the effect of a flat or blowout on one of the front wheels tended to pull the steering mechanism toward the side with the flat tire . The use of a worm screw reduced this effect . Further worm drive development led to recirculating ball bearings to reduce frictional forces, which transmitted some steering force to the wheel . This aids vehicle control and reduces wear that could cause difficulties in steering precisely . </P> <P> Worm drives are a compact means of substantially decreasing speed and increasing torque . Small electric motors are generally high - speed and low - torque; the addition of a worm drive increases the range of applications that it may be suitable for, especially when the worm drive's compactness is considered . </P> <P> Worm drives are used in presses, rolling mills, conveying engineering, mining industry machines, on rudders, and worm drive saws . In addition, milling heads and rotary tables are positioned using high - precision duplex worm drives with adjustable backlash . Worm gears are used on many lift / elevator and escalator - drive applications due to their compact size and the non-reversibility of the gear . </P> <P> In the era of sailing ships, the introduction of a worm drive to control the rudder was a significant advance . Prior to its introduction, a rope drum drive controlled the rudder . Rough seas could apply substantial force to the rudder, often requiring several men to steer the vessel--some drives had two large - diameter wheels so up to four crewmen could operate the rudder . </P>

Where is a worm gear used in everyday machines