ISO 14405-3:2016

Overview

ISO 14405-3:2016 - Geometrical product specifications (GPS) - Dimensional tolerancing - Part 3: Angular sizes - defines how angular dimensions are specified, interpreted and drawn in technical documentation. The standard establishes the default specification operator for angular size and several special specification operators for common angular features such as cones, frustums (truncated cones), wedges (truncated or not) and two opposite straight lines. It also standardizes specification modifiers, drawing indications, and the meaning of common angular tolerance notations (e.g. ± deviations, ULS/LLS).

Key topics and technical requirements

• Default and special specification operators for angular size (cone, frustum, wedge, two-line cases).
• Types of angular size characteristics covered:
  • Local angular size (two-line, section, portion)
  • Global angular size (direct global, least squares, minmax)
  • Rank-order/indirect global (maximum, minimum, average, range, mid-range, median, standard deviation)
• Association and evaluation criteria: defines association methods such as total least squares and min–max for establishing the associated feature used to evaluate angular size (see Annexes for criteria).
• Tolerance representations: clarifies meaning of tolerances shown as + / – limit deviations, upper/lower limit of size (ULS/LLS), and sizes given with or without modifiers (e.g., 0°/–0.5°, 35° max., 34°/36°).
• Drawing indications and graphical symbols: prescribes how to indicate angular size characteristics on drawings and which modifiers to use for unambiguous interpretation.
• Scope limitation: provides tools to express angular size characteristics but does not prescribe how those characteristics relate to a part’s function or use.

Practical applications and users

Who uses ISO 14405-3:

• Mechanical and product designers specifying tapers, cone angles, wedge geometries and opposing-line features.
• Tolerancing and GD&T engineers creating unambiguous manufacturing drawings.
• Metrology and quality assurance teams defining inspection procedures and measurement algorithms.
• CAD/CAM programmers and inspection software developers implementing evaluation criteria (least squares, minmax).
• Technical drafters standardizing drawing symbols and callouts.

Why it matters:

• Ensures consistent interpretation of angular dimensions across design, manufacturing and inspection.
• Reduces ambiguity in drawings for angled features (cones, wedges, prismatic cross-sections).
• Supports reproducible measurement and clear tolerance communication for angular features.

Related standards

• ISO 14405-1 (Linear sizes) and ISO 14405-2 (Dimensions other than linear sizes) - companion parts of the ISO 14405 series.
• ISO 8015 (Fundamental GPS principles), ISO 14253-1 (decision rules), ISO 17450 series (GPS concepts), and ISO 81714 / ISO 3098 for graphical and lettering rules.

Keywords: ISO 14405-3:2016, geometrical product specifications, GPS, dimensional tolerancing, angular sizes, cone angle, wedge, frustum, two-line angular size, least squares, minmax, drawing indications, angular tolerancing.