the ZK type dual-lead worm is widely used in indexing mechanisms.Based on the actual cutting process and using the gear meshing theory
the spiral surface equation of ZK type dual-lead worm is derived and the derivation process of the right flank equation is presented in detail.Using the translation of Z axis
the spiral surface equations of both the right and left flank are united in the same coordination system.These equations can be used as the base for the further research of this kind of worm.