ISO 6413:2018

Overview

ISO 6413:2018 - Technical product documentation - Representation of splines and serrations defines standardized rules and graphical symbols for showing splines and serrations in technical product documentation. The standard specifies two methods of depiction - complete representation and simplified representation - and applies to detail drawings of parts (shafts and hubs) and to assembly drawings of spline joints. Its purpose is to reduce drawing complexity, increase uniformity and improve clarity in mechanical drawings and CAD documentation.

Key topics and technical requirements

• Two representation methods:
  • Complete representation: full tooth geometry shown (used only when necessary).
  • Simplified representation: common, preferred method that represents parts as solids with selected reference lines.
• Graphical symbols and designation: specific symbols for straight-sided splines, involute splines and serrations; symbols are linked to contours by leader lines (see Clause 4).
• Representation rules for details (shafts and hubs) (Clause 6):
  • Parts shown as solid without teeth, with the root surface or pitch surface indicated by specified line types (references to ISO 128-24 line types).
  • Usable length shown with continuous wide line.
  • Tool run-out, position of teeth, and optional detailed tooth profile if designation is insufficient.
• Assembly drawings: rules to depict joints (male spline representation in sections) and combined designation of hub and shaft.
• Graphic proportions and dimensions (Annex A): sizing rules for symbol height, line thickness (line thickness d′ = one-tenth of lettering height h) and permitted symbol sizes to harmonize with drawing lettering (per ISO 3098-2).

Practical applications

• Use ISO 6413:2018 when creating or reviewing:
  • Mechanical drawings and CAD models that include spline joints or serrations
  • Detail drawings for shafts and hubs
  • Assembly drawings showing torque-transmitting joints
• Benefits include clearer documentation, reduced drawing time (by avoiding complex tooth detail where not needed), improved cross-team and cross-supplier consistency, and easier interpretation for manufacturing and inspection.

Who should use this standard

• Mechanical designers and CAD engineers
• Technical drafters and documentation specialists
• Manufacturing and quality engineers
• Standards and compliance teams specifying drawing practices

Related standards

• ISO 128-24 (lines on mechanical drawings) - referenced for line types
• ISO 3098-2 (lettering) - lettering rules for symbols and dimensions
• ISO 4156-1, ISO 14, ISO 81714-1 - related spline definitions and graphical symbol design

Keywords: ISO 6413:2018, representation of splines and serrations, technical product documentation, spline joint, simplified representation, graphical symbols, shaft and hub drawings.