SIST EN 3711:2008

Aerospace series - Wrench-double ended, bi-hexagonal - Straight, cranked, offset

This standard specifies the properties of the following types of double end box wrenches: double head flat, double head offset and double end modified offset.

Luft- und Raumfahrt - Doppelringschlüssel, Doppelsechskant - Gerade, abgewinkelt, flach gekröpft

Diese Norm legt die Eigenschaften der folgenden Ausführungen von Doppelringschlüsseln fest: gerade, abgewinkelt und flach gekröpft.

Série aérospatiale - Clé bihexagonale, double, droite, inclinée, contre coudée

Aeronavtika - Ključi za vijake - Obojestranski, biheksagonalni - Ravni, kolenasti, zviti

General Information

• Status: Published
• Publication Date: 26-May-2008
• ICS: 49.030.99 - Other fasteners
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 09-May-2008
• Due Date: 14-Jul-2008
• Completion Date: 27-May-2008
• Ref Project: EN 3711:2008 - Aerospace series - Wrench-double ended, bi-hexagonal - Straight, cranked, offset

Overview

SIST EN 3711:2008 is a European Standard developed by the Aerospace and Defence Industries Association of Europe (ASD-STAN) and adopted by CEN that specifies the properties and technical requirements for aerospace series double-ended, bi-hexagonal wrenches. This standard covers three main types: double head flat, double head offset, and double end modified offset wrenches. It ensures uniformity in configuration, dimensions, tolerances, hardness, material quality, and surface treatment for these specialized wrenches used predominantly in aerospace applications.

Key highlights include strict dimensional tolerances based on ISO 691, specific hardness requirements, and protective nickel-chromium surface coatings to optimize tool durability and performance in demanding environments.

Key Topics

• Scope and Types
  Defines three wrench configurations:

  • Double head flat
  • Double head offset (15° offset)
  • Double end modified offset

• Dimensions and Tolerances
  Stipulates dimensions for wrench openings with tolerances in accordance with ISO 691 to ensure precise fit and reliable torque transmission.

• Material and Hardness Requirements

  • Allows manufacturer discretion for material selection to suit intended use.
  • Requires hardness between 42 and 54 HRC for double head flat wrenches per EN 3709 standards, ensuring appropriate strength and wear resistance.

• Surface Treatment
  Specifies a nickel-chromium deposit finish with a minimum nickel thickness of 5 µm and chrome thickness of 0.25 µm to provide corrosion resistance and enhanced tool lifespan.

• Marking and Identification
  Uses EN 2424 guidelines for marking, ensuring wrenches are clearly identified by standard number, shape code, and size across flats for traceability and quality confirmation.

Applications

SIST EN 3711:2008 double-ended bi-hexagonal wrenches are essential tools in the aerospace industry for assembly and maintenance tasks involving high-precision fasteners. Their design supports optimal torque application in:

• Aircraft engine assembly and maintenance
• Aerospace structural fastener operations
• Precision mechanical systems requiring reliable wrench configurations (flat, cranked offset, and modified offset designs) for access to confined spaces
• Quality assurance processes demanding standardized tooling to meet safety and performance requirements in aerospace manufacturing

The consistent material hardness and protective coatings also make these wrenches suitable for use in other high-performance engineering sectors requiring durability, corrosion resistance, and tool reliability.

Related Standards

• ISO 691 – Assembly tools for screws and nuts: Tolerances for wrench and socket openings, which establishes dimensional accuracy criteria referenced in SIST EN 3711:2008.
• EN 3709 – Aerospace series: Technical specification for bi-hexagonal wrenches and sockets, providing complementary technical requirements on hardness, material, and functionality.
• EN 2424 – Aerospace series: Marking of aerospace products, defining marking styles and visibility, crucial for proper tool identification in compliance with aerospace standards.

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This standard provides aerospace manufacturers and tool producers with a detailed framework to ensure that double-ended bi-hexagonal wrenches meet rigorous quality and performance benchmarks critical to aerospace safety and efficiency. Adhering to SIST EN 3711:2008 supports consistent tooling quality, compatibility, and operational reliability across the aerospace supply chain.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.]YLWLLuft- und Raumfahrt - Doppelringschlüssel, Doppelsechskant - Gerade, abgewinkelt, flach gekröpftSérie aérospatiale - Clé bihexagonale, double, droite, inclinée, contre coudéeAerospace series - Wrench-double ended, bi-hexagonal - Straight, cranked, offset49.030.99Drugi vezni elementiOther fastenersICS:Ta slovenski standard je istoveten z:EN 3711:2008SIST EN 3711:2008en01-julij-2008SIST EN 3711:2008SLOVENSKI
STANDARD
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 3711April 2008ICS 25.140.30 English VersionAerospace series - Wrench-double ended, bi-hexagonal -Straight, cranked, offsetSérie aérospatiale - Clé bihexagonale, double, droite,inclinée, contre coudéeLuft- und Raumfahrt - Doppelringschlüssel,Doppelsechskant - Gerade, abgewinkelt, flach gekröpftThis European Standard was approved by CEN on 21 December 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2008 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 3711:2008: ESIST EN 3711:2008

Figures Figure 1 — Box wrench flat.5 Figure 2 — Box wrench 15° offset.
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