Overview
EN ISO 1938-2:2017 - adopted from ISO 1938-2:2017 - is a Geometrical Product Specification (GPS) standard that specifies the principal metrological and design characteristics of reference disk gauges used for verifying gap gauges. The standard covers linear sizes of the gauge up to 500 mm and is intended for use in dimensional measuring equipment and gauge-setting workflows within quality assurance and metrology.
Key Topics
- Scope and purpose: Defines what a reference disk gauge is and its role in determining the working size (WS) of a gap gauge.
- Design characteristics: Permits two basic gauge types - full form cylindrical plug gauges (type A) and segmental cylindrical bar gauges (type B) - with design rules referenced to ISO 1938-1.
- Metrological characteristics: Describes essential characteristics such as size S, form deviations (e.g., cylindricity), and available modifiers per ISO 14405-1 and symbols from ISO 1101. By default, the two-point size and form deviation are required.
- Maximum permissible limits (MPL): Specifies the placement of tolerance limits for reference disk gauges relative to workpiece tolerances (illustrated in the standard’s figures) and defines how parameters like H, z, α, and y link to gauge specification limits. Table values for H and calculation rules are provided for standard tolerance grades.
- Marking and documentation: Requires marking and identification details so gauges can be used reliably in inspection and calibration chains.
- Normative references and GPS alignment: Integrates with the GPS matrix and general GPS rules (e.g., ISO 14978, ISO 8015, ISO 14253-1) and cross-references key metrology standards.
Applications
- Calibration and setting of GO/NO-GO gap gauges and gap-type measuring tools.
- Production quality control where gap gauges are used to validate part clearances and fits.
- Metrology laboratories and gauge manufacturers creating or certifying reference disk gauges for use up to 500 mm.
- Quality engineers and inspectors applying GPS principles to ensure consistent, traceable measurement and conformity decisions.
Who would use it: metrology labs, gauge manufacturers, quality/inspection engineers, standards bodies and procurement specialists specifying dimensional measurement equipment.
Related Standards
Key normative references included in EN ISO 1938-2:2017:
This standard is essential for anyone involved in dimensional measuring equipment and GPS-based gauge verification.