EN 2943:2024

SLOVENSKI STANDARD
01-maj-2024
Aeronavtika - Žični navojni vložki, vijačni navoji MJ in M - Tehnična specifikacija
Aerospace series - Inserts, MJ and M screw threads, helical coil - Technical specification
Luft- und Raumfahrt - Draht-Gewindeeinsätze, MJ- und M-Gewinde - Technische
Lieferbedingungen
Série aérospatiale - Filets rapportés, filetages MJ et M - Spécification technique
Ta slovenski standard je istoveten z: EN 2943:2024
ICS:
49.030.20 Sorniki, vijaki, stebelni vijaki Bolts, screws, studs
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 2943
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2024
EUROPÄISCHE NORM
ICS 49.030.30 Supersedes EN 2943:2019
English Version
Aerospace series - Insert, MJ and M screw threads, helical
coil - Technical specification
Série aérospatiale - Filets rapporté, filetages MJ et M - Luft- und Raumfahrt - Draht-Gewindeeinsätz, MJ- und
Spécification technique M-Gewinde - Technische Lieferbedingungen
This European Standard was approved by CEN on 15 January 2024.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC 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
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 2943:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Quality assurance . 6
4.1 Approval of manufacturers . 6
4.2 Qualification . 6
4.3 Acceptance. 6
4.3.1 Purpose . 6
4.3.2 Conditions . 6
4.3.3 Responsibility . 6
4.3.4 Inspection and test report . 7
5 Requirements . 7
Annex A (normative) Specification of maximum and minimum test bolts for the permanent set
test . 15
Annex B (normative) Assembly for reusability tests . 17
Annex C (normative) Specification of test bolt for reusability test . 18
Annex D (normative) Specification of spacer for reusability tests . 19
Bibliography . 21

European foreword
This document (EN 2943:2024) has been prepared by ASD-STAN.
After enquiries and votes carried out in accordance with the rules of this Association, this document has
received the approval of the National Associations and the Official Services of the member countries of
ASD-STAN, prior to its presentation to CEN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by September 2024, and conflicting national standards shall
be withdrawn at the latest by September 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 2943:2019.
This document includes the following significant technical changes with respect to EN 2943:2019:
a) normative references updated;
b) subclauses 4.1 and 4.2 updated;
c) Table 1 “Technical requirements and test methods” revised;
d) Table 3 “Test equipment” revised;
e) Table 4 “Values of breakaway torque, self-locking torque and seating torque” and Table 5 “Values of
breakaway torque, self-locking torque and seating torque” extended by more thread types;
f) Annex A extended in accordance with the revised Table 4 and Table 5;
g) document editorially revised.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
1 Scope
This document specifies the characteristics, qualification and acceptance requirements for helical coil
screw thread inserts.
It is applicable whenever referenced.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 2398, Aerospace series — Heat resisting steel FE-PA2601 (X6NiCrTiMoV26-15) — R ≥ 900 MPa —
m
Bars for machined bolts — D ≤ 25 mm
EN 2945, Aerospace series — Inserts, screw thread, helical coil, self-locking — Assembly procedure
EN 3044, Aerospace series — Installation holes for inserts, screw thread, helical coil, self-locking — Design
standard
EN 3219, Aerospace series — Heat resisting nickel base alloy (NI-P100HT) — Cold worked and softened —
Bar and wire for continuous forging or extrusion for fasteners — 3 mm ≤ D ≤ 30 mm
EN 9138, Aerospace Series — Quality Management Systems — Statistical Product — Acceptance
Requirements
ISO 965-2, ISO general purpose metric screw threads — Tolerances — Part 2: Limits of sizes for general
purpose external and internal screw threads — Medium quality
ISO 3353 (all parts), Aerospace — Lead and runout threads
ISO 5855-1, Aerospace — MJ threads — Part 1: General requirements
ISO 5855-2, Aerospace — MJ threads — Part 2: Limit dimensions for bolts and nuts
ISO 21920-3, Geometrical product specifications (GPS) — Surface texture: Profile — Part 3: Specification
operators
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
batch
quantity of finished thread inserts, of the same type and same diameter, produced from a material
obtained from the same melt, manufactured in the course of the same production cycle, following the
same manufacturing route and having undergone all the relevant heat treatments and surface treatments
3.2
surface discontinuities
3.2.1
crack
rupture in the material which may extend in any direction and which may be intercrystalline or
transcrystalline in character
3.2.2
seam
open surface defect
3.2.3
lap
surface defect caused by folding over metal fins or sharp corners and then compressing them into the
surface
3.2.4
inclusions
non-metallic particles originating from the material manufacturing process
Note 1 to entry: These particles may be isolated or arranged in strings.
3.3
test temperature
ambient temperature, unless otherwise specified
3.4
simple random sampling
sampling where a sample of n sampling units is taken from a population in such a way that all the possible
combinations of n sampling units have the same probability of being taken
3.5
finished thread insert
thread insert ready for use, inclusive of any possible treatments and/or surface coatings, as specified in
the product standards or specification document
3.6
specification document
document specifying all the requirements for finished thread inserts
3.7
self-locking torque
torque to be applied to the associated bolt to maintain its movement of rotation in relation to the thread
insert assembly which is under no axial load and the thread insert locking zone being completely engaged
with the bolt (minimum protrusion of two pitches, including the end chamfer)
3.8
seating torque
tightening torque to be applied to the thread insert and bolt assembly to introduce or to increase the axial
load in the assembly
3.9
unseating torque
untightening torque to be applied to the thread insert and bolt assembly to reduce or remove the axial
load in the assembly
3.10
breakaway torque
torque required to start unscrewing the associated bolt with respect to the installed thread insert, with
the insert locking zone still fully engaged on the bolt, but after the axial load in the assembly has been
removed by unscrewing half a turn followed by a halt in rotational movement
4 Quality assurance
4.1 Approval of manufacturers
The manufacturer’s operations shall be an approved production organization for aerospace products and
shall demonstrate that it has implemented and is able to maintain a quality management system (e.g.
according to EN 9100 or an equivalent aerospace accepted and established quality management system).
4.2 Qualification
The qualification procedure for aerospace standard products (e.g. according to EN 9133 or an equivalent
aerospace accepted and established qualification procedure) may be used and documented according to
the specified tests if not otherwise agreed between customer and supplier.
Qualification inspections and tests (requirements, methods, numbers of thread inserts) are specified in
Table 1. They shall be carried out on
— each type and diameter of thread insert and
— 26 thread inserts selected from a single batch by simple random sampling.
The test programme may possibly be reduced, or the qualification be granted without inspection or
testing: any such decision shall be based on the results obtained on similar types and diameters of thread
inserts provided that the design and manufacturing conditions are identical.
4.3 Acceptance
4.3.1 Purpose
The purpose of acceptance inspections and tests is to check, as simply as possible, by a method
representative of actual use conditions, with the uncertainty inherent to statistical sampling, that the
thread inserts constituting the batch satisfy the requirements of this standard.
4.3.2 Conditions
Acceptance inspections and tests (requirements, methods, numbers of thread inserts) are specified in
Table 1. They shall be carried out on each batch. Thread inserts from the batch to be tested shall be
selected by simple random sampling.
Each thread insert may be submitted to several inspections or tests.
4.3.3 Responsibility
Acceptance inspections and tests shall be carried out by the manufacturer, or under his responsibility.
4.3.4 Inspection and test report
A test report showing actual numerical values shall be provided if specified in the purchase order.
5 Requirements
Requirements are according to Table 1.
Sampling test and examinations shall be in accordance with the requirements of EN 9138. Acceptance
quality
...