Gears, Gear Boxes, Speed Changers, Ball or Roller Screws, and Torque Converters

Ball screws and roller screws are explicitly classified at 8483408000. They differ from conventional lead screws in that they use recirculating balls or planetary rollers between the screw and nut to achieve high efficiency and low backlash—characteristics essential for CNC and precision positioning applications. A standard lead screw relying on sliding contact between screw and nut would not classify here; it would more likely fall under a general mechanical parts heading depending on its material and application.

To support classification under the wind turbine gearbox line, importers should retain the manufacturer's application specification confirming the unit is designed and rated for wind turbine service, along with the purchase order or contract referencing the turbine model. CBP may also consider whether the gearbox's torque rating, mounting interface, and lubrication system are specific to wind turbine duty cycles. A general-purpose industrial gearbox that happens to be installed in a wind turbine would not automatically qualify for this dedicated line.