rackwork

/ˈrækˌwɜrk/
noun
  1. A mechanical system using a rack (a bar with teeth) and a pinion (a small gear) to convert rotational motion into linear motion.
    • Rackwork is common in industrial machinery for precise movement.
    • The steering in many cars uses rackwork to turn the wheels.
    • The old clock's rackwork needed oiling to keep it running smoothly.