ISO 8279:2008

Aerospace — Nuts, hexagonal, plain, normal height, normal across flats, with MJ threads, classifications: 600 MPa (at ambient temperature)/120 degrees C, 600 MPa (at ambient temperature)/235 degrees C, 900 MPa (at ambient temperature)/425 degrees C, 1 100 MPa (at ambient temperature)/235 degrees C, 1 100 MPa (at ambient temperature)/315 degrees C, 1 100 MPa (at ambient temperature)/650 degrees C, 1 210 MPa (at ambient temperature)/730 degrees C, 1 250 MPa (at ambient temperature)/235 degrees C and 1 550 MPa (at ambient temperature)/600 degrees C — Dimensions

ISO 8279:2008 specifies the dimensions of plain, hexagonal nuts, of normal height, normal across flats, with MJ threads, of classifications: 600 MPa/120 °C, 600 MPa/235 °C, 900 MPa/425 °C, 1 100 MPa/235 °C, 1 100 MPa/315 °C, 1 100 MPa/650 °C, 1 210 MPa/730 °C, 1 250 MPa/235 °C and 1 550 MPa/600 °C. Nuts provided with holes are intended to be used with lockwire in conformity with ISO 245. ISO 8279:2008 is only applicable for the compilation of aerospace product standards.

Aéronautique et espace — Écrous hexagonaux ordinaires, hauteur normale, surplats normaux, filetages MJ, classifications: 600 MPa (à température ambiante)/120 degrés C, 600 MPa (à température ambiante)/235 degrés C, 900 MPa (à température ambiante)/425 degrés C, 1 100 MPa (à température ambiante)/235 degrés C, 1 100 MPa (à température ambiante)/315 degrés C, 1 100 MPa (à température ambiante)/650 degrés C, 1 210 MPa (à température ambiante)/730 degrés C, 1 250 MPa (à température ambiante)/235 degrés C et 1 550 MPa (à température ambiante)/600 degrés C — Dimensions

General Information

• Status: Published
• Publication Date: 20-Jul-2008
• ICS: 49.030.30 - Nuts
• Technical Committee: ISO/TC 20/SC 4 - Aerospace fastener systems
• Drafting Committee: ISO/TC 20/SC 4 - Aerospace fastener systems
• Current Stage: 9093 - International Standard confirmed
• Start Date: 19-Oct-2021
• Completion Date: 14-Feb-2026

Relations

• Consolidated By: ISO 13786:2017 - Thermal performance of building components — Dynamic thermal characteristics — Calculation methods
• Effective Date: 06-Jun-2022
• Revises: ISO 8279:1997 - Aerospace — Nuts, hexagonal, plain, normal height, normal across flats, with MJ threads, classifications: 600 MPa (at ambient temperature)/120 degrees C, 600 MPa (at ambient temperature)/235 degrees C, 900 MPa (at ambient temperature)/425 degrees C, 1 100 MPa (at ambient temperature)/235 degrees C, 1 100 MPa (at ambient temperature)/315 degrees C, 1 100 MPa (at ambient temperature)/650 degrees C, 1 210 MPa (at ambient temperature)/730 degrees C, 1 250 MPa (at ambient temperature)/235 degrees C and 1 550 MPa (at ambient temperature)/600 degrees C — Dimensions
• Effective Date: 15-Apr-2008

Overview

ISO 8279:2008 is an international standard developed by the International Organization for Standardization (ISO) specifying the dimensions for plain, hexagonal, normal height nuts with normal across flats and MJ threads, intended for use in aerospace applications. These nuts are classified according to their minimum tensile strength at ambient temperature and the maximum service temperature they can withstand without permanent alteration of their characteristics. The standard supports the standardized design and interoperability of aerospace fastener systems, ensuring consistency and safety across specialized applications.

Key Topics

• Hexagonal Nuts: Covers plain, hexagonal nuts of normal height and standard widths across flats, widely used in aerospace fastener assemblies.
• MJ Threads: Specifies nuts with MJ thread profiles, which are commonly used in aerospace for their optimal distribution of stress and improved fatigue resistance.
• Strength and Temperature Classifications: Defines several nut classes, including combinations such as 600 MPa at 120°C, 900 MPa at 425°C, up to 1550 MPa at 600°C, addressing a range of mechanical and thermal requirements in aerospace environments.
• Lockwire Capability: Includes provisions for nuts with holes that can be secured using lockwire in accordance with ISO 245, enhancing safety and vibration resistance in critical assemblies.
• Reference to Related Standards: Requires conformance with standards for MJ thread limits (ISO 5855-2) and nut tolerances (ISO 8788), integrating with the broader framework of aerospace fastener standards.

Applications

ISO 8279:2008 is critical for:

• Aerospace Design and Manufacturing: Guides the specification and production of hexagonal nuts for aircraft, spacecraft, and related systems, supporting reliability and interchangeability.
• Procurement Specifications: Used in conjunction with procurement standards such as ISO 9139, ensuring that supplied products meet defined mechanical and dimensional criteria.
• Maintenance and Assembly: Provides clear criteria for selecting compatible fasteners, particularly where high tensile strength or resistance to elevated temperatures is required, improving maintenance safety.
• Safety-Critical Assemblies: Supports the application of lockwire for nuts where loosening due to vibration or thermal cycling could have safety implications, as specified by ISO 245.

Related Standards

To ensure comprehensive compliance and optimal performance, ISO 8279:2008 should be applied alongside these related standards:

• ISO 245: Aerospace - Lockwire - Diameters, specifying the requirements for securing nuts using lockwire.
• ISO 5855-2: Aerospace - MJ threads - Limit dimensions for bolts and nuts, detailing thread profiles and tolerances.
• ISO 8788: Aerospace - Nuts, metric - Tolerances of form and position, defining geometric tolerances essential for reliable assemblies.
• ISO 9139: Aerospace - Nuts, plain or slotted (castellated) - Procurement specification, referenced for procurement and acceptance.
• ISO 13715: Technical drawings - Edges of undefined shape - Vocabulary and indications, for technical documentation.

By following ISO 8279:2008 and its associated standards, aerospace manufacturers, engineers, and suppliers can achieve dependable performance, international compatibility, and regulatory compliance when selecting and applying hexagonal nuts in demanding environments.

Keywords: ISO 8279:2008, aerospace hexagonal nuts, MJ threads, nut dimensions, high strength nuts, high temperature nuts, aerospace fasteners, standardization, lockwire, international standards.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 8279
Third edition
2008-08-01
Aerospace — Nuts, hexagonal, plain,
normal height, normal across flats, with
MJ threads, classifications: 600 MPa (at
ambient temperature)/120 °C, 600 MPa (at
ambient temperature)/235 °C, 900 MPa (at
ambient temperature)/425 °C, 1 100 MPa
(at ambient temperature)/235 °C,
1 100 MPa (at ambient
temperature)/315 °C, 1 100 MPa (at
ambient temperature)/650 °C, 1 210 MPa
(at ambient temperature)/730 °C,
1 250 MPa (at ambient
temperature)/235 °C and 1 550 MPa
(at ambient temperature)/600 °C —
Dimensions
Aéronautique et espace — Écrous hexagonaux ordinaires, hauteur
normale, surplats normaux, à filetages MJ, classifications: 600 MPa
(à température ambiante)/120 °C, 600 MPa (à température
ambiante)/235 °C, 900 MPa (à température ambiante)/425 °C,
1 100 MPa (à température ambiante)/235 °C, 1 100 MPa
(à température ambiante)/315 °C, 1 100 MPa (à température
ambiante)/650 °C, 1 210 MPa (à température ambiante)/730 °C,
1 250 MPa (à température ambiante)/235 °C et 1 550 MPa
(à température ambiante)/600 °C — Dimensions

Reference number
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ISO 2008
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ii © ISO 2008 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 8279 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 4,
Aerospace fastener systems.
This third edition cancels and replaces the second edition (ISO 8279:1997), which has been technically
revised.
Introduction
The dimensions specified in this International Standard have been determined to satisfy the requirements of
the procurement specification ISO 9139.

iv © ISO 2008 – All rights reserved

INTERNATIONAL STANDARD ISO 8279:2008(E)

Aerospace — Nuts, hexagonal, pl
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