ISO 1328-1:2013

Overview - ISO 1328-1:2013 (Cylindrical gears - Flank tolerance classification)

ISO 1328-1:2013 defines an ISO system of flank tolerance classification for individual cylindrical involute gears. It establishes clear definitions, the structure of flank tolerance classes, and allowable values of deviations relevant to the tooth flanks. The standard provides a mutually agreed reference for gear manufacturers and buyers to specify and verify uniform flank tolerances during manufacturing and conformity assessment.

Key facts:

• Defines 11 flank tolerance classes (numbered 1 to 11, increasing tolerance).
• Provides formulae for calculating tolerance values (Clause 5.3).
• Applicable geometric ranges: z = 5…1 000 (teeth), d = 5…15 000 mm (reference diameter), m = 0.5…70 mm (normal module), b = 4…1 200 mm (facewidth), β ≤ 45° (helix angle).
• Gear design and surface texture are outside the scope; inspection and measurement practice is referenced.

Key technical topics and requirements

• Terms, definitions and symbols for flank-related deviations (profile, helix, pitch, single/cumulative pitch, runout, composite deviations).
• Tolerance class system structure and the numeric tolerance classes with associated formulas for allowable deviations.
• Measurement and evaluation: guidance on geometrical parameters to verify, equipment verification, measurement uncertainty and elemental measurement considerations (Clause 4).
• Tolerance values and formula usage (Clause 5) including normative annexes for evaluation methods:
  • Annex A: Zone-based tolerance evaluation (normative)
  • Annex B: Second-order analysis for profile/helix (normative)
  • Annex E: Allowable values of runout (normative)
  • Informative annexes cover filtering, single-flank composite testing, sector pitch deviation, adjacent pitch differences.
• Strong recommendation to use ISO/TR 10064-1 inspection practices when applying this part.

Practical applications and users

ISO 1328-1:2013 is used to:

• Prepare purchase specifications and contractual tolerance requirements for gears.
• Define quality control and acceptance criteria in gear production and inspection.
• Guide metrology labs and inspection engineers in verifying flank deviations and reporting.
• Support process engineers and manufacturers in setting machining/grinding tolerances.
• Serve as a reference for product assurance, conformity assessment, and comparison between suppliers.

Typical users:

• Gear manufacturers and suppliers
• Buyers and procurement engineers
• Quality and metrology laboratories
• Design and application engineers specifying gear tolerances
• Standards committees and testing organizations

Related standards

• ISO 1328-2 - radial composite deviations and runout (complements Part 1)
• ISO/TR 10064-1 - inspection code of practice (recommended)
• ISO 21771, ISO 701, ISO 1122-1, ISO 16610 series - related geometry, terminology and filtration methods

By using ISO 1328-1:2013, organizations gain a consistent, internationally harmonized approach to specifying and assessing gear flank tolerances, improving interchangeability, quality control, and supplier communication.