ISO/DIS 1328-4:2026

This document establishes a tolerance classification system relevant to manufacturing and conformity assessment of individual worm and worm wheel of cylindrical worm gear pair with manufacturing specification parameters, mathematically defined for each of the five worm flank profiles A, C, I, K and N as defined in ISO/TR 10828. This standard can also be applied to modified flank shapes which can be produced using the same manufacturing processes as the flank shapes mentioned. This standard relates to analytical measurement methods and single flank composite measurement methods(add later for double flank). It specifies definitions for worm and worm wheel gear flank tolerance terms, manufacturing specifications data to be reported in the drawing, and verification parameters for conformity assessment, with tolerance classification formulae, the structure of the flank tolerance class system, allowable values. Double flank measurement methods are not covered in this document. Gear design is beyond the scope of this document.