Term Description
Threaded groove The threaded space between the screw and the nut where the balls rotate.
Lead of Ball Screw The distance that the nut advances in the axial direction while the screw rotates one week
Lead of Ball Screw The axial distance between two adjacent threads on the same helix at two points on the center diameter line.
Base lead called nominal lead
Actual lead The lead measured from the actual Ball Screw.
Accumulated reference lead Accumulated lead when the reference lead is rotated at any number of revolutions.
Accumulated actual lead The average tendency obtained from the graph of accumulated leads measured continuously, or the accumulated lead measured on any cross-section including the screw shaft.
Cumulative representative lead  straight line representing the tendency of the actual lead.
Lead error The difference between the actual lead and the reference lead. The difference between the actual lead and the reference lead is positive when it is larger than the reference lead, and negative when it is smaller.
Cumulative Actual Lead Error The difference between the cumulative actual lead minus the cumulative reference lead.
Variation Two parallel lines parallel to the cumulative representative lead, containing the maximum value of the cumulative actual lead, with respect to the following three representative items
a) The value corresponding to the effective travel distance of the nut or the effective length of the screw thread.
b) The value corresponding to any 300mm within the range of effective thread length.
c) The value corresponding to one rotation of any point within the range of effective thread length.