Overview

ISO 9609:2016 defines the dimensions for aerospace hexagonal nuts that are plain, reduced height, and normal across flats with MJ threads. Published by ISO (second edition, 2016), this standard covers nuts of strength/temperature classifications such as 450 MPa/120 °C, 600 MPa/425 °C, 900 MPa/235 °C, 1 100 MPa/730 °C, and others up to 1 250 MPa/600 °C. It is intended for compilation of aerospace product standards and ensures dimensional interchangeability for aerospace fasteners.

Key topics and technical requirements

Scope and classifications: Specifies nuts with MJ thread codes (MJ4 to MJ24) across multiple tensile-strength and maximum-temperature classifications. NOTE: the MPa values indicate minimum tensile stress at ambient temperature; temperature ratings indicate maximum service temperature without permanent alteration (surface treatment dependent).
Dimensions and tolerances: Includes configuration drawings (Figure 1) and a dimensional table (Table 1). Dimensions are given in millimetres and apply after any surface coating(s) but before the application of any lubricant.
Form and position tolerances: Tolerances of form and position shall conform to ISO 8788.
Thread and lockwire compatibility: Thread details reference ISO 5855‑2 (MJ thread limit dimensions). Nuts with holes are intended for use with lockwire in conformity with ISO 245.
Optional features and marking: Provision for lockwire holes and marking locations are shown; form of contour within limiting dimensions is left to manufacturer discretion.

Applications and users

ISO 9609:2016 is primarily used by:

Aerospace fastener manufacturers for tooling, quality control, and production of reduced-height MJ hex nuts.
Aircraft and spacecraft designers and engineers specifying fasteners in structural and non-structural assemblies.
Procurement/specification writers compiling aerospace product standards and purchase documents.
Quality assurance, inspection, and maintenance teams ensuring dimensional conformity and interchangeability. Practical applications include component design, parts procurement, assembly specification, inspection criteria, and certification requirements where reliable, standardized nut dimensions are required.

Related standards

ISO 245 - Aerospace - Lockwire - Diameters (lockwire hole usage)
ISO 5855-2 - Aerospace - MJ threads - Limit dimensions for bolts and nuts
ISO 8788 - Aerospace - Nuts, metric - Tolerances of form and position

Keywords: ISO 9609:2016, aerospace nuts, hexagonal nuts, MJ threads, reduced height nuts, nut dimensions, aerospace fastener standards, tensile stress classifications, lockwire.

ISO 9609:2016 PDF

Похожие стандарты

Abstract

Overview

Key topics and technical requirements

Applications and users

Related standards

Технические детали

ISO 8788:1987

Aerospace — Fasteners — Tolerances of form and position for nuts

ISO 5855-2:1988

Aerospace — MJ threads — Part 2: Limit dimensions for bolts and nuts

BS ISO 24569:2023

Ships and marine technology. External firefighting system test methods.