Cylindrical gears — ISO system of flank tolerance classification — Part 2: Definitions and allowable values of double flank radial composite deviations

ISO 1328-2:2020

ISO 1328-2:2020


This document establishes a gear tooth classification system relevant to double flank radial composite deviations of individual cylindrical involute gears and sector gears. It specifies the appropriate definitions of gear tooth deviations, the structure of the gear tooth flank classification system, and the allowable values of the gear tooth deviations. It provides formulae to calculate tolerances for individual product gears when mated in double flank contact with a master gear. Tolerance tables are not included.

 This document is applicable to gears with three or more teeth that have reference diameters of up to 600 mm.

 This document does not provide guidance on gear design nor does it recommend tolerances.


This document was prepared by Technical Committee ISO/TC 60, Gears.

 This second edition cancels and replaces the first edition (ISO 1328-2:1997), which has been technically revised. The main changes compared to the previous edition are as follows:

  • the document title of this part has been revised to correspond to that of part 1 and better reflect the contents of this part;
  • the scope of applicability has been expanded to include sector gears;
  • revisions have been made to the formulae which define the double flank radial composite tolerances, and the range of classification numbers has been changed to clarify the independence of this classification system from that given in part 1;
  • the change in tolerance value between consecutive tolerance classes has been reduced, so two steps in the new system results in the same change as one step of the old system, but approximately the same global range of tolerance values is maintained with additional steps;
  • annexes have been added to describe complementary information and examples;
  • evaluation of runout, previously handled in this document, has been moved to ISO 1328-1:2013;
  • advice on appropriate inspection methods has been removed; the information can be found in ISO/TR 10064-2.

A list of all parts in the ISO 1328 series can be found on the ISO website.

Suggestions for improvement of this standard will be welcome. They may be submitted to [email protected]

The new publication is available for purchase through the AGMA Online Store.

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