ISO 12261:2023

Aerospace - Screws, pan head, internal offset cruciform ribbed or unribbed drive, pitch diameter shank, long length MJ threads, metallic material, coated or uncoated, strength classes less than or equal to 1 100 MPa - Dimensions

This document specifies the dimensions of pan head screws with internal offset cruciform ribbed or unribbed drive, pitch diameter shank and long length MJ threads, in metallic material, coated or uncoated, with strength classes less than or equal to 1 100 MPa. This document is applicable to the compilation of aerospace product standards.

Aéronautique et espace — Vis à tête cylindrique, à empreinte cruciforme déportée, avec ou sans saillies antidérapantes, à tige de diamètre égal au diamètre sur flancs et filetage MJ long, en matériau métallique, revêtues ou non revêtues, des classes de résistance inférieures ou égales à 1 100 MPa — Dimensions

General Information

• Status: Published
• Publication Date: 31-Oct-2023
• ICS: 49.030.20 - Bolts, screws, studs
• Technical Committee: ISO/TC 20/SC 4 - Aerospace fastener systems
• Drafting Committee: ISO/TC 20/SC 4 - Aerospace fastener systems
• Current Stage: 6060 - International Standard published
• Start Date: 01-Nov-2023
• Due Date: 26-Oct-2023
• Completion Date: 01-Nov-2023

Relations

• Revises: ISO 12261:2016 - Aerospace - Screws, pan head, internal offset cruciform ribbed or unribbed drive, pitch diameter shank, long length MJ threads, metallic material, coated or uncoated, strength classes less than or equal to 1 100 MPa - Dimensions
• Effective Date: 06-Jun-2022

Overview

ISO 12261:2023 is an international standard developed by the International Organization for Standardization (ISO) that specifies the precise dimensions and configurations of aerospace screws. This edition focuses on pan head screws featuring an internal offset cruciform drive, which may be either ribbed or unribbed. It covers screws with pitch diameter shank and long length MJ threads made from metallic materials, available in coated or uncoated forms. The strength classes addressed are those with tensile strength less than or equal to 1,100 MPa.

Specifically tailored for the aerospace sector, this standard forms a crucial part of aerospace product standards, ensuring uniformity and reliability in fastener components used in aircraft and space vehicles. By adhering to ISO 12261:2023, manufacturers and engineers can guarantee compatibility and performance benchmarks essential for safety-critical aerospace applications.

Key Topics

• Screw Configuration and Dimensions
  The standard provides detailed measurements in millimeters, including head diameter, thread size, length increments, and tolerances. These dimensions are specified post surface coating but prior to lubricants to maintain consistency across manufacturing processes.

• Drive Design
  The internal offset cruciform drive offers enhanced torque transfer and reduced cam-out risk. The drive can be ribbed or unribbed, with specifications aligned with ISO 14275 and ISO 14276 standards, ensuring compatibility with aerospace tooling and installation requirements.

• Thread Specifications
  Long length MJ threads conform to ISO 5855-2, ensuring thread dimensions and quality meet strict aerospace tolerances. Lead and runout threads follow ISO 3353 series guidelines, further supporting thread integrity.

• Material and Strength Classes
  This standard applies to metallic materials with strength classes up to 1,100 MPa, which identifies the screws’ mechanical performance thresholds, vital for load-bearing aerospace fasteners.

• Tolerances and Quality Control
  Form and position tolerances align with ISO 7913, providing rigorous quality control to minimize deviations that could compromise fastener efficacy in aerospace assemblies.

Applications

ISO 12261:2023 screws are primarily used in the aerospace industry, where safety, reliability, and dimensional precision are mandatory. Common applications include:

• Aircraft Structural Assemblies
  Fastening components where high-strength pan head screws are required for durable and load-resistant joints.

• Space Vehicles and Satellites
  Components exposed to extreme conditions demand screws standardized under ISO 12261 to maintain performance over time.

• Aerospace Maintenance and Repair
  Replacement and retrofitting of fasteners adhere to this standard to ensure consistency with original equipment manufacturer (OEM) specifications.

• Aerospace Manufacturing
  Production lines utilize these standardized screws for component uniformity, interchangeability, and enhanced quality assurance processes.

Related Standards

This standard cross-references several key ISO documents critical for aerospace fastener systems:

• ISO 3353 (All parts) – Aerospace lead and runout threads, relevant for thread profile and quality.
• ISO 5855-2 – MJ threads limit dimensions for bolts and nuts, essential for thread compatibility.
• ISO 7913 – Tolerances of form and position for bolts and screws, crucial for manufacturing precision.
• ISO 14275 and ISO 14276 – Internal offset cruciform drives, defining drive geometry and design.

These interconnected standards ensure that aerospace fasteners, including those defined by ISO 12261:2023, meet comprehensive dimensional, mechanical, and performance criteria necessary for modern aerospace applications.

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Keywords: ISO 12261:2023, aerospace screws, pan head screws, internal offset cruciform drive, MJ threads, aerospace fasteners, metallic screws, coated screws, thread dimensions, aerospace manufacturing standards, high-strength screws, aerospace product standards

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 12261
Third edition
2023-11
Aerospace — Screws, pan head,
internal offset cruciform ribbed or
unribbed drive, pitch diameter shank,
long length MJ threads, metallic
material, coated or uncoated, strength
classes less than or equal to 1 100 MPa
— Dimensions
Aéronautique et espace — Vis à tête cylindrique, à empreinte
cruciforme déportée, avec ou sans saillies antidérapantes, à tige de
diamètre égal au diamètre sur flancs et filetage MJ long, en matériau
métallique, revêtues ou non revêtues, des classes de résistance
inférieures ou égales à 1 100 MPa — Dimensions
Reference number
© ISO 2023
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ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Configuration and dimensions . 1
iii
Foreword
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