Overview - ISO 14278:2002 (Aerospace gauges, metric series)
ISO 14278:2002 defines the dimensions and configuration of metric gauges used to check internal offset cruciform drives (ribbed or unribbed) in aerospace fasteners. It covers GO and NOT GO drive gauges and the drive penetration gauge assembly for metric screws with nominal thread diameters from 1.6 mm to 20 mm. The standard presents mandatory figures, tables of dimensions and tolerances (in millimetres), and guidance on materials and hardness for gauge components.
Key topics and technical requirements
- Scope and drive types: Internal offset cruciform drives (ribbed and unribbed) as defined in ISO 14275 and ISO 14276; metric series for nominal thread diameters 1.6–20 mm.
- Gauge types: Specification for Drive GO and Drive NOT GO gauges and the drive penetration gauge assembly (components: gauge body, holder, point, collar, spring).
- Dimensions and tolerances: Detailed dimension tables and figures (A, B, F, G, H, etc.) express limits and fits in millimetres; geometric tolerances (surface-profile, perpendicularity, location, run-out) follow ISO 1101 presentation conventions.
- Materials and hardness:
- Gauge points: heat-treatable corrosion-resisting steel, hardened to 58–62 HRC.
- Body, holder and collar (not gauge point): corrosion-resistant steel (e.g., 440C) heat-treated to 30–35 HRC.
- Designation and marking: Rules for GO / NOT GO gauge designations and component part coding for traceability and interchangeability.
- Assembly and calibration: Configuration and zero-position determination for drive penetration gauges; adhesive and fastener notes (Eastman 910 referenced as an example).
- Intellectual property: ISO notes a claimed patent (Phillips Screw Company) affecting some gauge elements; licensing may be required.
Practical applications and who uses it
- Aerospace manufacturers and OEMs: Ensures correct drive geometry for internal cruciform fasteners used on aircraft structures and components.
- Quality control / inspection labs: Standardizes GO/NOT GO checks and penetration gauges for production inspection and incoming fastener acceptance.
- Fastener suppliers and tooling manufacturers: Design and produce compliant gauges, gauge assemblies and inspection equipment.
- Maintenance, repair and overhaul (MRO): Confirms fastener drive integrity during service inspections.
- Calibration and metrology services: Provide gauge calibration and certification to ISO 14278 dimensional and hardness requirements.
Related standards
- ISO 14275 - Drives, internal, offset cruciform, ribbed - Metric series
- ISO 14276 - Drives, internal, offset cruciform - Metric series
- ISO 1101 - Geometrical product specifications (GPS) - Tolerancing of form, orientation, location and run-out
Keywords: ISO 14278:2002, aerospace gauges, internal offset cruciform drives, metric gauges, GO NOT GO gauges, drive penetration gauge, fastener inspection, gauge dimensions, aerospace standard.