SIST EN ISO 6789-1:2017

SLOVENSKI STANDARD
SIST EN ISO 6789-1:2017
01-maj-2017
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SIST EN ISO 6789:2004
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Assembly tools for screws and nuts - Hand torque tools - Part 1: Requirements and
methods for design conformance testing and quality conformance testing: minimum
requirements for declaration of conformance (ISO 6789-1:2017)
Schraubwerkzeuge - Handbetätigte Drehmoment-Werkzeuge - Teil 1: Anforderungen
und Prüfverfahren für die Typprüfung und Annahmeprüfung - Mindestanforderungen an
Kalibrierung und Kalibrierscheine (ISO 6789-1:2017)
Outils de manoeuvre pour vis et écrous - Outils dynamométriques à commande
manuelle - Exigences et méthodes d'essai pour vérifier la conformité de conception, la
conformité de qualité et la procédure de réétalonnage (ISO 6789-1:2017)
Ta slovenski standard je istoveten z: EN ISO 6789-1:2017
ICS:
25.140.30 2URGMD]DURþQRXSRUDER Hand-operated tools
SIST EN ISO 6789-1:2017 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 6789-1:2017

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SIST EN ISO 6789-1:2017


EN ISO 6789-1
EUROPEAN STANDARD

NORME EUROPÉENNE

March 2017
EUROPÄISCHE NORM
ICS 25.140.30 Supersedes EN ISO 6789:2003
English Version

Assembly tools for screws and nuts - Hand torque tools -
Part 1: Requirements and methods for design
conformance testing and quality conformance testing:
minimum requirements for declaration of conformance
(ISO 6789-1:2017)
Outils de manoeuvre pour vis et écrous - Outils Schraubwerkzeuge - Handbetätigte Drehmoment-
dynamométriques à commande manuelle - Partie 1: Werkzeuge - Teil 1: Anforderungen und Prüfverfahren
Exigences et méthodes d'essai pour vérifier la für die Typprüfung und Annahmeprüfung:
conformité de conception et la conformité de qualité: Mindestanforderungen an Konformitätserklärungen
exigences minimales pour déclaration de conformité (ISO 6789-1:2017)
(ISO 6789-1:2017)
This European Standard was approved by CEN on 14 January 2017.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6789-1:2017 E
worldwide for CEN national Members.

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SIST EN ISO 6789-1:2017
EN ISO 6789-1:2017 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 6789-1:2017
EN ISO 6789-1:2017 (E)
European foreword
This document (EN ISO 6789-1:2017) has been prepared by Technical Committee ISO/TC 29 “Small
tools”.
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 2017, and conflicting national standards
shall be withdrawn at the latest by March 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document supersedes EN ISO 6789:2003.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 6789-1:2017 has been approved by CEN as EN ISO 6789-1:2017 without any
modification.


3

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SIST EN ISO 6789-1:2017

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SIST EN ISO 6789-1:2017
INTERNATIONAL ISO
STANDARD 6789-1
First edition
2017-02
Assembly tools for screws and nuts —
Hand torque tools —
Part 1:
Requirements and methods for design
conformance testing and quality
conformance testing: minimum
requirements for declaration of
conformance
Outils de manoeuvre pour vis et écrous — Outils dynamométriques à
commande manuelle —
Partie 1: Exigences et méthodes d’essai pour vérifier la conformité
de conception et la conformité de qualité: exigences minimales pour
déclaration de conformité
Reference number
ISO 6789-1:2017(E)
©
ISO 2017

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SIST EN ISO 6789-1:2017
ISO 6789-1:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

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SIST EN ISO 6789-1:2017
ISO 6789-1:2017(E)

Contents Page
Foreword .iv
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 1
3.1 Terms and definitions . 1
3.2 Symbols, designations and units . 3
4 Classification . 3
5 Requirements . 3
5.1 Design conformance testing . 3
5.1.1 General. 3
5.1.2 Maximum torque values . 4
5.1.3 Specified torque range . 4
5.1.4 Scales, dials and displays . 4
5.1.5 Maximum permissible deviation . 5
5.1.6 Overloading test . 5
5.1.7 Endurance test . 5
5.1.8 Effect of geometric changes . . 6
5.2 Quality conformance testing . 7
5.3 Conformance test during use . 7
6 Torque measurement . 7
6.1 Torque measurement system . 7
6.2 Application of torque . 8
6.3 Ambient conditions . 8
6.4 Measurement requirements . 9
6.5 Measurement sequence .11
6.5.1 General.11
6.5.2 Indicating torque tools, Type I .11
6.5.3 Setting torque tools, Type II .11
7 Calculation of deviation .12
7.1 General .12
7.2 Calculation example 1 .12
7.3 Calculation example 2 .13
8 Declaration of conformance .14
9 Marking .15
Annex A (normative) Examples of indicating torque tools (Type I) .16
Annex B (normative) Examples of setting torque tools (Type II) .17
Annex C (informative) Measurement sequence flowchart for torque tools .19
Bibliography .22
© ISO 2017 – All rights reserved iii

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SIST EN ISO 6789-1:2017
ISO 6789-1:2017(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 29, Small tools, Subcommittee SC 10,
Assembly tools for screws and nuts, pliers and nippers.
This first edition of ISO 6789-1, together with ISO 6789-2, cancels and replaces ISO 6789:2003 which
has been technically revised with changes as follows.
a) ISO 6789:2003 has been divided into two parts. This document specifies the requirements for
design and manufacture including the content of a declaration of conformance. ISO 6789-2 specifies
the requirements for traceable certificates of calibration. It includes a method for calculation of
uncertainties and provides a method for calibration of the torque measurement device used for
calibrating hand torque tools.
b) The output drive designation of torque tools is expanded to include hexagonal and other output
drives.
c) The definition of the torque range of the tools has been changed.
d) The rate of loading (shown by the time to achieve the last 20 %) has been changed.
e) The importance of avoiding parasitic forces has been emphasized.
f) Explanatory flowcharts for the measurement sequence of different torque tools have been added in
Annex C.
g) The requirement for a “declaration of conformance” that the torque tool conforms with this
document has been added.
h) The requirement for a “certificate of calibration” has been removed, recognizing that
manufacturers’ calibration certificates have not previously contained enough information to be
traceable calibration certificates.
i) ISO 6789 has been editorially updated and restructured.
iv © ISO 2017 – All rights reserved

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SIST EN ISO 6789-1:2017
ISO 6789-1:2017(E)

j) Figures B.2, B.3, B.5 and B.6 have been changed.
A list of all parts in the ISO 6789 series can be found on the ISO website.
© ISO 2017 – All rights reserved v

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SIST EN ISO 6789-1:2017
ISO 6789-1:2017(E)

Introduction
The revision of ISO 6789:2003 has been designed to achieve the following improvements.
ISO 6789 has been split to provide two levels of documentation. It recognizes the different needs of
different users of the standard.
This document continues to provide designers and manufacturers with relevant minimum requirements
for the development, production and documentation of hand torque tools.
ISO 6789-2 provides detailed methods for calculation of uncertainties and requirements for calibrations.
This will allow users of calibration services to more easily compare the calibrations from different
laboratories. Additionally, minimum requirements for the calibration of torque measurement devices
are described in ISO 6789-2:2017, Annex C.
vi © ISO 2017 – All rights reserved

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SIST EN ISO 6789-1:2017
INTERNATIONAL STANDARD ISO 6789-1:2017(E)
Assembly tools for screws and nuts — Hand torque tools —
Part 1:
Requirements and methods for design conformance testing
and quality conformance testing: minimum requirements
for declaration of conformance
1 Scope
This document specifies the conformance testing and marking requirements for hand torque tools used
for controlled tightening of screws and nuts. It also specifies the minimum requirements for declaration
of conformance for hand torque tools.
This document applies to hand torque tools which are classified as indicating torque tools (Type I) and
setting torque tools (Type II).
NOTE Hand torque tools covered by this document are those identified in ISO 1703:2005 by reference
numbers 6 1 00 11 0, 6 1 00 11 1 and 6 1 00 12 0, 6 1 00 12 1 and 6 1 00 14 0, 6 1 00 15 0. ISO 1703 is currently
under revision. In the next edition, torque tools will be moved to an own clause, and with this change the
reference numbers will also change and additional reference numbers will be added.
This document does not specify requirements of calibration certificates for hand torque tools. These
are described in ISO 6789-2.
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.
ISO 1173, Assembly tools for screws and nuts — Drive ends for hand- and machine-operated screwdriver
bits and connecting parts — Dimensions, torque testing
ISO 1174-1, Assembly tools for screws and nuts — Driving squares — Part 1: Driving squares for hand
socket tools
ISO 6789-2:2017, Assembly tools for screws and nuts — Hand torque tools — Part 2: Requirements for
calibration and determination of measurement uncertainty
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
© ISO 2017 – All rights reserved 1

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SIST EN ISO 6789-1:2017
ISO 6789-1:2017(E)

3.1.1
design conformance test
technical examination of conformance with those requirements to be met during design or modification
of hand torque tools
3.1.2
quality conformance test
technical examination of conformance with those requirements to be met during manufacture of hand
torque tools
3.1.3
declaration of conformance
documented information provided by the manufacturer that the torque tool complies with the
requirements of this document
3.1.4
maximum permissible deviation
maximum value of relative measurement deviation of the observed torque value on the torque
measurement device measured as a percentage of the target torque value on the torque tool
Note 1 to entry: Sometimes the term “accuracy” is still used in place of the term “maximum permissible deviation”
which is, however, not technically correct. The concept “measurement accuracy” is not a quantity and is not given
a numerical quantity value. A measurement is said to be more accurate when it offers a smaller measurement
deviation.
Note 2 to entry: Maximum permissible deviation is different from measurement error which is used in ISO 6789-2
and defined in ISO/IEC Guide 99.
3.1.5
torque measurement system
combination of a torque measurement device and the loading system for application of torque that acts
as the measurement standard for the hand torque tool
Note 1 to entry: A calibration system as defined in ISO 6789-2 can also be used as a torque measurement system
in this document.
3.1.6
torque measurement device
working measurement standard provided either mechanically or by an electronic torque transducer
and display
3.1.7
indicating torque tool (Type I)
tool that indicates by means of a mechanical scale, dial or electronic display, the value of torque exerted
by the tool at the output drive
3.1.8
setting torque tool (Type II)
tool sensing torque transmitted by comparing the torque applied with a self-contained standard and
signalling the transmission of the pre-selected value by a physical impulse, with or without audible
signal, causing a temporary reduction in the torque applied
3.1.9
adjustable graduated torque tool (Type II, Class A, Class D and Class G)
tool designed to be adjusted by the user, which has a scale or a display to assist adjustment
3.1.10
adjustable non-graduated torque tool (Type II, Class C and Class F)
tool designed to be adjusted by the user with the aid of a torque measurement system
2 © ISO 2017 – All rights reserved

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SIST EN ISO 6789-1:2017
ISO 6789-1:2017(E)

3.1.11
torque tool with fixed adjustment (Type II, Class B and Class E)
tool not designed to be adjusted by the user, i.e. having a single setting
3.2 Symbols, designations and units
The designations used in this document are indicated in Table 1.
Table 1 — Symbols, designations and units
Symbol Designation Unit
a Relative deviation of the torque tool from the target torque %
d
Value of torque desired, which may be the indicated, set, nominal value, depending on
X N ⋅ m
t
the type and class of the torque tool
X Observed value shown by the torque measurement device N ⋅ m
o
4 Classification
The hand torque tools to which this document applies are classified as follows.
a) Indicating torque tools (Type I; see Annex A):
1) Class A: Wrench, torsion or flexion bar;
2) Class B: Wrench, rigid housing, with scale or dial or display;
3) Class C: Wrench, rigid housing and electronic measurement;
4) Class D: Screwdriver, with scale or dial or display;
5) Class E: Screwdriver, with electronic measurement;
b) Setting torque tools (Type II; see Annex B):
1) Class A: Wrench, adjustable, graduated or with display;
2) Class B: Wrench, fixed adjustment;
3) Class C: Wrench, adjustable, non-graduated;
4) Class D: Screwdriver, adjustable, graduated or with display;
5) Class E: Screwdriver, fixed adjustment;
6) Class F: Screwdriver, adjustable, non-graduated;
7) Class G: Wrench, flexion bar, adjustable, graduated
5 Requirements
5.1 Design conformance testing
5.1.1 General
The manufacturer shall verify that the torque tool is in conformity with 5.1.2 to 5.1.8.
© ISO 2017 – All rights reserved 3

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SIST EN ISO 6789-1:2017
ISO 6789-1:2017(E)

5.1.2 Maximum torque values
The size of the output drive limits the maximum torque value of the respective torque tool. The
assignment is carried out according to the values given in Table 2. For outputs not specified in Table 2,
the size of the output drive is determined by the maximum torque of the respective torque tool and
shall comply with the requirements given in 5.1.6 and 5.1.8.
Table 2 — Maximum torque values of the torque tool
Square output Hexagonal output
Maximum torque value
drive drive
a b
nominal size nominal size N⋅m
— 3 4
— 4 10
— 5,5 25
6,3 6,3 30
— 8 70
10 — 135
— 11,2 200
12,5 12,5 340
20 — 1 000
25 — 2 100
a
Dimensions in accordance with ISO 1174-1.
b
Dimensions in accordance with ISO 1173.
5.1.3 Specified torque range
The requirements and methods in this document cover a specified torque range, where the range
depends on type and class of the torque tool.
The torque range or value is selected for the different torque tools as follows.
— Indicating torque tools of Type I (Classes A, B and D): From the lowest marked value to 100 % of the
maximum torque value of the respective tool.
— Indicating torque tools of Type I (Classes C and E): As specified by the manufacturer.
— Setting torque tools of Type II (Classes A, D and G): From the lowest marked value to 100 % of the
maximum torque value of the respective tool.
— Setting torque tools of Type II (Classes B, C, E and F): As specified by the manufacturer.
5.1.4 Scales, dials and displays
For scales and dials, the increment between two graduation marks shall not exceed 5 % of the maximum
torque value of the torque tool.
For electronic displays, the resolution shall not exceed 1/4 of the maximum permissible relative
deviation of the torque tool at each target value.
For indicating torque tools of Type I (Classes A, B and D), the scales or dials shall be marked with a zero
position. The range between zero and the lowest specified torque value shall be marked on or near the
dial or scale in a way to make clear to the user that this range is not within the specified torque range.
Alternatively, the scale, dial or display shall be identified in some way to indicate the specified torque
range to the user.
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SIST EN ISO 6789-1:2017
ISO 6789-1:2017(E)

For indicating torque tools of Type I (Classes C and E), the range between zero and the lower value of
the range specified by the manufacturer shall be identified in some way to make clear to the user that
this range is not in the specified range.
The design of scales, dials and displays has a significant influence on the calibration uncertainty of a
torque tool. Designers are recommended to take guidance from ISO 6789-2:2017, 6.2.1.
5.1.5 Maximum permissible deviation
Each result for a torque tool, recorded in accordance with Clause 6 and calculated in accordance with
Clause 7, shall lie within the respective maximum permissible relative deviation for the type and class
of that tool stated in Tables 3 and 4.
Where a manufacturer claims a smaller maximum permissible relative deviation than stated in Tables 3
and 4, each result shall lie within the claimed maximum permissible relative deviation.
For determining conformance with this subclause, the influence of the uncertainty of the torque tool
and of the torque measurement device shall not be considered.
Table 3 — Maximum permissible relative deviation (Type I)
Maximum torque value
Class
≤10 N⋅m >10 N⋅m
A and D ±6 %
B, C and E ±6 % ±4 %
If a tool is operating in both directions, the maximum
permissible relative deviation shall be met in each direction
specified by the manufacturer.
Table 4 — Ma
...