ISO 14405-1:2016

Overview - ISO 14405-1:2016 (Geometrical Product Specifications - Linear Sizes)

ISO 14405-1:2016 is a Geometrical Product Specification (GPS) standard that defines how to specify and tolerate linear sizes on engineering drawings and related documentation. It establishes the default specification operator (referencing ISO 17450‑2) and a set of special specification operators for common features of size such as cylinders, spheres, torus, circles, two parallel planes, and parallel straight lines. The standard also defines specification modifiers and the graphical drawing indications used to communicate linear size requirements.

Key topics and technical requirements

• Types of linear size characteristics covered:
  • Local sizes: two‑point size, spherical size, section size, portion size
  • Global sizes: direct global (least‑squares, maximum inscribed, minimum circumscribed, minimax) and indirect global sizes
  • Calculated sizes: circumference diameter, area diameter, volume diameter
  • Rank‑order sizes: maximum, minimum, average, median, mid‑range, range, standard deviation
• Tolerancing formats accepted:
  • Plus/minus limit deviations (e.g., 0/−0.019)
  • Upper limit of size (ULS) and/or lower limit of size (LLS) (e.g., 15.2 max., 12 min.)
  • ISO tolerance class codes per ISO 286‑1 (e.g., 10 h6), with optional modifiers
• Drawing and specification rules:
  • Graphical rules and modifiers for indicating special operators and size characteristics
  • Rules to indicate the toleranced portion of a feature (whole feature, restricted portion, specific section)
• Scope constraint: provides tools to express size characteristics but does not prescribe how a given function or usage maps to a particular size characteristic.

Practical applications and users

ISO 14405-1 is essential for professionals involved with dimensional specification, tolerancing, and inspection:

• Design engineers and CAD/drafting teams - for unambiguous dimensioning of parts (shafts, bores, tubes, spherical features)
• Quality and metrology engineers - for defining which size characteristic to measure and how to interpret limits
• Manufacturing and process engineers - to translate functional requirements into producible tolerances
• Technical drafters and standards managers - to ensure drawings comply with GPS and ISO drawing conventions

Use cases include specifying tolerances for mating parts, defining inspection criteria for features of size, and standardizing drawing indications across suppliers.

Related standards

• ISO 17450‑2 (default specification operator and GPS concepts)
• ISO 286‑1 (ISO code system for tolerances on linear sizes)
• ISO 8015 (GPS fundamentals)
• ISO 17450 series (general GPS concepts)
• ISO 14253‑1 and ISO 14638 (decision rules and GPS matrix model)

Keywords: ISO 14405-1:2016, geometrical product specifications, GPS, dimensional tolerancing, linear sizes, size characteristic, feature of size, ISO tolerance class.