ISO 14:1982

Overview

ISO 14:1982 - "Straight-sided splines for cylindrical shafts with internal centering - Dimensions, tolerances and verification" is an International Standard that defines the dimensional system, tolerance rules and inspection (gauging) methods for straight‑sided (parallel‑flank) splines on cylindrical shafts and mating hubs. It covers nominal dimensions in millimetres for light and medium series, tolerance tables, symmetry limits and the prescribed approaches to gauge design and use for acceptance testing.

Key topics and technical requirements

• Scope and dimensions
  • Nominal spline dimensions (minor diameter d, major diameter D and spline width B) for light and medium series are given in the standard’s tables.
  • Part designation includes the number of splines and the nominal dimensions (e.g., examples in the standard show formats such as 6 x 23 x 26).
• Tolerances
  • Dimensional tolerances for holes and shafts are specified in tables (including separate cases for treated vs untreated workpieces).
  • Tolerances on symmetry and alignment (concentricity, angular position, etc.) are specified separately.
• Gauging and verification
  • Defines GO and NOT‑GO gauging principles: GO full‑form gauges (plug or ring) check several features simultaneously; NOT‑GO segmental gauges check elements individually.
  • Specifies gauging conditions: reference temperature (20 °C), measuring force (zero force by default), number and distribution of gauging positions (e.g., three angular positions for GO checks).
  • Prescribes types of gauges and measurement methods (spline GO plug/ring, segmental NOT‑GO elements, plug/plate/calliper gauges for individual features).
  • Addresses gauge wear limits, permissible form errors for gauges, and the influence of active length and engagement length on alignment tolerances.
• Inspection control
  • Guidance on gauge calibration, mutual checking between manufacturer and customer gauges, and referral to calibration authorities in disputes.

Applications and practical value

• Useful for mechanical designers, manufacturing engineers, quality and inspection teams who specify, produce or accept splined shafts and hubs.
• Commonly applied in power transmission components, gearboxes, coupling interfaces and machinery where internal centering and accurate spline fit are critical.
• Helps ensure interchangeability, functional fit (sliding, close‑sliding or fixed mountings), and reliable gauge‑based pass/fail inspection procedures.

Who should use this standard

• Mechanical designers and drafting engineers specifying spline profiles.
• Tooling and broaching/milling manufacturers preparing spline tools.
• Metrology, QA and inspection personnel responsible for acceptance testing and gauge procurement.
• Procurement and supplier quality engineers managing supplier calibration and disputes.

Related standard (referenced)

• ISO/R 1938 (ISO system of limits and fits - Part 2: inspection of plain workpieces) - referenced for gauge tolerance principles and inspection rules.

Keywords: ISO 14:1982, straight‑sided splines, cylindrical shafts, internal centering, spline dimensions, tolerances, gauging, GO/NOT‑GO gauges, spline verification.