SIST EN ISO 14405-3:2017

Overview

EN ISO 14405-3:2017 - "Geometrical product specifications (GPS) - Dimensional tolerancing - Part 3: Angular sizes" defines how to specify, tolerate and document angular dimensions in technical product specifications. Published by CEN and aligned with ISO 14405-3:2016, this standard provides the default specification operator for angular size and a set of special operators for common angular features such as cones (and frustums), wedges (and truncated wedges) and two opposite straight lines. It also standardizes drawing indications, specification modifiers, and how to express angular tolerances.

Key topics and requirements

• Default and special specification operators: establishes the ISO default operator for angular size and special operators for revolute (cone/frustum) and prismatic (wedge) angular features.
• Angular feature types: covers cones, frustums, wedges, truncated wedges and intersections that form two opposite straight lines.
• Angular size characteristics: defines local and global angular sizes and specific measures including:
  • local angular size
  • angular size between two lines
  • portion angular size
  • direct global angular size (least squares, minimax)
  • rank order/indirect global angular sizes (maximum, minimum, average, range, mid-range, median, standard deviation)
• Tolerance expression: permits +/− limit deviations (e.g., 0°/−0.5°), upper/lower limits (ULS/LLS, e.g., 35° max or 15° min, 34°/36°) and the use of modifiers.
• Drawing indications and symbols: specifies graphical and text conventions for indicating angular sizes and their modifiers on engineering drawings.
• Scope boundaries: provides tools to express angular characteristics but does not prescribe their relationship to function or intended use.

Practical applications

• Use EN ISO 14405-3:2017 for consistent specification of angles in mechanical design, assemblies, precision components, and mould/tool design where angular tolerances affect fit and function.
• Applicable to CAD/drafting, engineering drawing standards, metrology and inspection procedures, quality control, and production engineering.
• Beneficial for manufacturers, design engineers, metrologists, quality managers and technical drafters who need unambiguous angular dimensioning and tolerance interpretation.

Who should use this standard

• Mechanical and product designers, CAD specialists
• Metrology and inspection teams implementing measurement procedures
• Quality assurance and manufacturing engineers specifying tolerances
• Standards committees and technical authors producing drawings and specifications

Related standards

• ISO 14405-1 (Linear sizes)
• ISO 14405-2 (Dimensions other than linear sizes)
• ISO 8015 (GPS fundamentals)
• ISO 17450 series (General GPS concepts and feature definitions)

Keywords: EN ISO 14405-3:2017, angular sizes, GPS, dimensional tolerancing, angular tolerances, cones, wedges, frustums, drawing indications, least squares, minimax, metrology.