Overview
ISO 19632:2015 is an ISO aerospace design standard that specifies the configuration, dimensions, tolerances and required characteristics of a flareless fitting end with a 24° internal cone and external extra‑fine thread (inch series) for aerospace hydraulic and fluid systems. The standard covers sizes ‑04 to ‑20 (tube diameters 6.35 mm to 31.75 mm / 1/4" to 1 1/4") and is intended for systems rated to 35 000 kPa (5 080 psi). ISO 19632:2015 is a design standard (not a test procedure) and includes drawings (Figures 1–5) and dimensional tables (Tables 1–2).
Key topics
- Fitting geometry and styles: configuration details for styles G, B, E and optional F; notes on which styles are suitable for port fittings (e.g., style E appropriate for port fitting; some styles are not).
- Sealing surface and 24° internal cone: definition of the cone sealing interface essential to flareless fitting performance.
- Thread specification: external thread “T” per ISO 3161 (UNJ threads) with extra‑fine pitch (inch series); thread class and gauge references shown in tables and notes.
- Dimensions and tolerances: tabulated diameters and feature dimensions in both millimetre and inch with specified tolerances - linear ±0.25 mm (±0.010 in), angular ±0°30′, and tighter tolerances on critical diameters (see Table 1).
- Wrench pad sizing: recommended and possible wrench sizes, tolerances and weight‑saving recommendations (Table 2).
- Designation and documentation: rules for designation and reference to normative documents.
Applications
ISO 19632:2015 is used to design and specify aerospace hydraulic/fluid fittings where interchangeability, pressure integrity and precise thread/cone mating are critical. Typical applications include:
- Aerospace hydraulic hose ends, adapters and connectors
- Aircraft fluid distribution systems (actuation, landing gear, flight controls)
- Component design for aerospace OEMs and suppliers
- Engineering drawings, CAD models and parts lists requiring compliant dimensions
Who uses it:
- Aerospace design engineers and CAD designers
- Component manufacturers and CNC tooling engineers
- Quality, inspection and metrology personnel (gauge reference points are defined)
- Procurement and specification writers ensuring part conformity
Related standards
- ISO 3161 - referenced for UNJ thread general requirements and limit dimensions (normative reference).
- ISO/TC 20 (Aircraft and space vehicles) committee publications and ISO/IEC Directives for units and drafting conventions.
Keywords: ISO 19632:2015, aerospace fittings, 24° internal cone, flareless fitting, extra fine thread, UNJ thread, hydraulic systems, design standard, dimensions and tolerances.