ISO 8538:1999 PDF

Aerospace — Nuts, hexagonal, self-locking, with counterbore and captive washer, with MJ threads, classifications: 1 100 MPa (at ambient temperature)/235 degrees C, 1 100 MPa (at ambient temperature)/315 degrees C and 1 100 MPa (at ambient temperature)/425 degrees C — Dimensions

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Title (English):

ISO 8538:1999

Document status:: Active
Format:: Electronic (PDF)
Number of pages:: 2
Publication date:: February 4, 1999
Edition:: ISO IS 8538 edition 2 version 1
ICS:: 49.030.30

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Description (English):

This International Standard specifies the dimensions of self-locking hexagonal nuts, with counterbore and captive washer, with MJ threads, of classifications: 1 100 MPa1)/235 °C2), 1 100 MPa1)/315 °C2), 1 100 MPa1)/425 °C2). This International Standard is only applicable for the compilation of aerospace product standards.

Technical details

Technical committee: ISO/TC 20/SC 4 - Aerospace fastener systems
SKU: ISO 8538:1999

Abstract

Overview

ISO 8538:1999 defines the dimensions for aerospace hexagonal, self-locking nuts with a counterbore and captive washer using MJ threads. It covers nuts of classification 1 100 MPa (ambient)/235 °C, 1 100 MPa (ambient)/315 °C, and 1 100 MPa (ambient)/425 °C. This International Standard is intended for the compilation of aerospace product standards and provides dimensional requirements to support procurement and manufacturing compliance.

Key topics and requirements

Scope: Dimensional specification for self-locking hexagonal nuts with counterbore and captive washer (MJ threads) for specified strength/temperature classifications.
Dimensions and tolerances: All dimensions and tolerances are given in millimetres. Values apply after any surface coating(s) but before lubricant application.
Threading: MJ thread limits and basic fit are referenced to ISO 5855‑2. Thread tolerances in the self-locking zone apply before forming out-of-round.
Self-locking feature: Achieved by localized out-of-round form in the nut (tooling marks permissible in that area). The captive washer must be free to rotate on the nut.
Form and position tolerances: Conform to ISO 8788 (tolerances of form and position for nuts).
Compatibility: Dimensions were determined to satisfy the procurement specification ISO 5858 (self-locking nuts with maximum operating temperature ≤ 425 °C).
Product configuration: Figure and table layouts define key dimensions (bearing diameter, wrench engagement, chamfer, etc.) and include notes on surface texture and manufacturing discretion where details are not specified.

Applications and users

Who uses ISO 8538:
- Aerospace design and structural engineers specifying fasteners for airframes, engines, and high-temperature assemblies.
- Fastener manufacturers producing MJ-thread hex nuts with captive washers.
- Quality and inspection teams verifying dimensional conformity.
- Procurement specialists and standards writers compiling aerospace product standards.
Practical applications:
- High-temperature aerospace joints where self-locking capability and captive washer retention are required.
- Components exposed to elevated temperatures (up to classification limits) in propulsion, bleed air systems, and hot-structure assemblies.
- Standardizing parts lists and procurement documents to ensure interchangeability and traceability.

Related standards

ISO 5855‑2 - MJ threads: limit dimensions for bolts and nuts.
ISO 5858 - Procurement specification for self-locking nuts (≤ 425 °C).
ISO 8788 - Fastener tolerances of form and position.

Keywords: ISO 8538:1999, aerospace nuts, hexagonal self-locking nuts, MJ threads, captive washer, counterbore, dimensions, high-temperature fasteners, aerospace standards.

Related standards

Standards mentioned in the description

Abstract

Overview

Key topics and requirements

Scope: Dimensional specification for self-locking hexagonal nuts with counterbore and captive washer (MJ threads) for specified strength/temperature classifications.
Dimensions and tolerances: All dimensions and tolerances are given in millimetres. Values apply after any surface coating(s) but before lubricant application.
Threading: MJ thread limits and basic fit are referenced to ISO 5855‑2. Thread tolerances in the self-locking zone apply before forming out-of-round.
Self-locking feature: Achieved by localized out-of-round form in the nut (tooling marks permissible in that area). The captive washer must be free to rotate on the nut.
Form and position tolerances: Conform to ISO 8788 (tolerances of form and position for nuts).
Compatibility: Dimensions were determined to satisfy the procurement specification ISO 5858 (self-locking nuts with maximum operating temperature ≤ 425 °C).
Product configuration: Figure and table layouts define key dimensions (bearing diameter, wrench engagement, chamfer, etc.) and include notes on surface texture and manufacturing discretion where details are not specified.

Applications and users

Who uses ISO 8538:
- Aerospace design and structural engineers specifying fasteners for airframes, engines, and high-temperature assemblies.
- Fastener manufacturers producing MJ-thread hex nuts with captive washers.
- Quality and inspection teams verifying dimensional conformity.
- Procurement specialists and standards writers compiling aerospace product standards.
Practical applications:
- High-temperature aerospace joints where self-locking capability and captive washer retention are required.
- Components exposed to elevated temperatures (up to classification limits) in propulsion, bleed air systems, and hot-structure assemblies.
- Standardizing parts lists and procurement documents to ensure interchangeability and traceability.

Related standards

ISO 5855‑2 - MJ threads: limit dimensions for bolts and nuts.
ISO 5858 - Procurement specification for self-locking nuts (≤ 425 °C).
ISO 8788 - Fastener tolerances of form and position.

Keywords: ISO 8538:1999, aerospace nuts, hexagonal self-locking nuts, MJ threads, captive washer, counterbore, dimensions, high-temperature fasteners, aerospace standards.

ISO 8538:1999 PDF

Technical details

Abstract

Overview

Key topics and requirements

Applications and users

Related standards

Related standards

Abstract

Overview

Key topics and requirements

Applications and users

Related standards

Related standards

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

Aerospace — Fasteners — Tolerances of form and position for nuts

Aerospace — Self-locking nuts with maximum operating temperature less than or equal to 425 degrees C — Procur…

Aerospace — Self-locking hexagon nuts with counterbore and captive washer, classification 1 100 MPa/235 degre…