ISO/FDIS 17104
(Main)Rotary tools for threaded fasteners — Impulse and impulsing tools — Performance test method
Rotary tools for threaded fasteners — Impulse and impulsing tools — Performance test method
Outils rotatifs pour fixations filetées — Outils à impulsion — Méthode d'essai des caractéristiques de fonctionnement
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Standards Content (Sample)
FINAL DRAFT
International
Standard
ISO/TC 118/SC 3
Rotary tools for threaded
Secretariat: SIS
fasteners — Impulse and impulsing
Voting begins on:
tools — Performance test method
2025-11-27
Outils rotatifs pour fixations filetées — Outils à impulsion —
Voting terminates on:
Méthode d'essai des caractéristiques de fonctionnement
2026-01-22
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
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TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 118/SC 3
Rotary tools for threaded
Secretariat: SIS
fasteners — Impulse and impulsing
Voting begins on:
tools — Performance test method
Outils rotatifs pour fixations filetées — Outils à impulsion —
Voting terminates on:
Méthode d'essai des caractéristiques de fonctionnement
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
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BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 1
4 Method for measurement of performance . 5
4.1 General rules for performance tests .5
4.1.1 Measurements .5
4.1.2 Ambient conditions .5
4.1.3 Test installation . .6
4.1.4 Test tool .6
4.1.5 Test tool condition.6
4.1.6 Power media .6
4.2 Test fixtures .8
4.2.1 General .8
4.2.2 Test joint.9
4.2.3 Measuring devices . 12
4.3 Test method . 13
4.3.1 Overview of test procedure . 13
4.3.2 Determination of torque factor, K .14
4.3.3 Calculation of mean torque factor, K .
4.3.4 Reconfirmation of mean torque factor, K .
4.3.5 Performance test .17
5 Comparison with built-in torque measurement systems .18
6 Evaluation of test results .18
6.1 Correlated torque scatter .18
6.2 Correlated torque scatter over a defined range of torque adjustment .18
7 Presentation of test results . 19
7.1 Test report .19
Annex A (informative) Explanation and justification of the method .20
Annex B (informative) Explanation of electric impulsing tools .24
Annex C (informative) Non-normative use of the methods defined in this document .25
Annex D (informative) Examples of test report and worksheet for tool performance test .27
Annex E (informative) Non-normative use of the methods defined in this document .31
Bibliography .36
iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of 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 www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 118, Compressors and pneumatic tools,
machines and equipment, Subcommittee SC 3, Pneumatic tools and machines.
This first edition of ISO 17104 cancels and replaces the first edition of ISO/TS 17104:2006, which has been
technically revised and upgraded to an International Standard.
The main changes are as follows:
— Title and Scope have been modified to reflect changes in the tool types that have become available
since 2006.
— Starting point of the joint rate measurement is taken from 50 % of the target rather than 10 %.
— Several requirements are explained more in detail to increase user understanding and tool test
consistency.
— The opportunity for users to test performance at a preferred test torque level is added as an
informative annex.
— New annexes have been added to educate users in the background to the requirements.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
This document is intended to
— enable the manufacturers of power tools to offer their products under standardized technical
specifications, and
— give users of threaded fasteners a method for evaluating and specifying the performance of power
assembly tools.
This document is a fundamental test procedure, with no attempt to set acceptance criteria. Any minimum
performance requirements are the responsibility of the user to meet the demands of the particular
application for which the tool is intended for use.
Unlike the previous Technical Specification, this document is applicable to tightening tools of any power
source within its scope. However, the test does require that the tool under test is capable of being set to a
specific shut-off point.
Additional statements have been introduced to point out the differences between correlated torque derived
from clamp force and inbuilt indication or control systems that now exist in a number of tools.
Annex A explains the basis for the use of clamp force rather than torque for testing the performance of
fastener assembly tools that apply torque in a discontinuous method.
Annex B explains the principle of electric impulsing tools which operate in a different way to hydraulic
impulse tools.
Annex C includes preferred torque values that may be used for testing.
Annex D gives an example format for the test report.
Annex E provides background to the testing performed during the creation of this document.
This document includes some changes to the specifications for the test joints and for the test method. These
changes reflect the practical experience gained through the use of the previous version of the document and
are intended to improve the reproducibility of the test method.
Testing of the tools within the scope of this document present a number of challenges. New equipment
and methods are being developed and the subcommittee members responsible for its publication believe
that this document is a step closer to understanding the true performance of impulse and impulsing tools.
Further development will continue, and the experiences of users are welcomed by the subcommittee.
Results obtained using this document may differ from results obtained using the previous technical
specification.
Some of the changes in this document have been guided by the work of the VDI/VDE Committee Gesellschaft
Mess- und Automatisierungstechnik and are used with their permission.
v
FINAL DRAFT International Standard ISO/FDIS 17104:2025(en)
Rotary tools for threaded fasteners — Impulse and impulsing
tools — Performance test method
1 Scope
This document specifies a laboratory performance test method for hydraulic impulse and electric impulsing
tools for installing threaded fasteners in a laboratory environment, and for power assembly tools (referred
throughout the document as “tools”) for installing threaded fasteners. It gives instructions on the procedure,
performance parameters to test and how to evaluate and present the test data.
It also provides a method for the measurement of torque repeatability (scatter)
— over a range of torque rates as specified in this document, and
— over a range of torque adjustment as defined by the manufacturer.
It gives instructions on equipment parameters, what to test for and how to evaluate and present the test data.
It is applicable to tools
— of any power source, such as pneumatic or electric, including battery-powered,
— which apply torque in discontinuous increments, and
— within the torque range 0,5 N·m to 800 N·m. Outside this range, it is acceptable to modify the test method
providing that the modification is documented in the test report.
It is not applicable to
— impact wrenches, and
— ratchet wrenches or wrenches with ratcheting clutches.
The relationship between torque measurements and clamp force-based tests is commented on in Annex A.
The use of tools using discontinuous operation of the motor to provide torque impulses is discussed in
Annex B.
It requires manufacturers to perform tests over their defined torque range of the tool; however, it allows
users to perform single point tests in order to minimize the number of test joints necessary for a wide range
of test torque levels. A list of preferred test torque levels is provided in Annex C.
2 Normative references
No normative references are referred to in this document.
3 Terms, definitions and symbols
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
rotary tool for threaded fasteners
powered tool, the output spindle of which rotates to turn a threaded fastener
Note 1 to entry: Either a pneumatic or an electric motor can be used.
Note 2 to entry: The final movement of the spindle can be rotational and continuous or rotational and discontinuous,
depending on the type of rotary machine considered.
3.2
continuous rotation fastening tool
powered assembly tool for tightening threaded fasteners, which applies torque to a fastener in a
continuous motion
Note 1 to entry: The term is used in this document when establishing the relationship between torque and clamp force.
3.3
hydraulic impulse tool
powered assembly tool for tightening threaded fasteners, which applies torque to a fastener in discontinuous
increments through a hydraulic impulse unit between the motor and the output drive
3.4
electric impulsing tool
powered assembly tool for tightening threaded fasteners, which applies torque to a fastener in discontinuous
increments by pulsing the input to the electric motor which then delivers pulses of kinetic energy to the
output drive
Note 1 to entry: A number of variations on this tool exists. Their common distinguishing action is that the pulsing
comes from controlling the motor, rather than subsequently controlling the output of the motor.
3.5
automatic shut-off tool
powered assembly tool for tightening threaded fasteners, provided with a torque control mechanism which
shuts off or disconnects the power to the tool when the predetermined set output torque level is attained
Note 1 to entry: A number of variations on the mechanisms for achieving this feature exists.
3.6
parameter adjustable tool
hydraulic impulse tool (3.3) or electric impulsing tool (3.4) capable of customising the tightening profile, by
changing parameters such as speed, pulse rate, pulse intensity
3.7
pulse mode
settings employed in an electricimpulsing tool (3.4) to establish pulse frequency, duration and intensity
Note 1 to entry: The settings will influence the reaction force experienced by the operator.
3.8
number of pulses
number of pulses generated by the tool from the start of rundown to completion of the defined joint
3.9
operating cycle
one complete fastener tightening from start of rotation until end of rotation
3.10
joint condition
combination of torque rate (3.14) and test torque (3.26)
Note 1 to entry: The effect of lubrication viscosity, thread deformation or galling can alter the joint condition.
3.11
standard deviation
s
statistical parameter to describe a scatter range
N
s= xX−
()
i
∑
N−1
i=1
[SOURCE: ISO 3534-1:2006, 2.37]
3.12
diameter
D
nominal diameter of a bolt
Note 1 to entry: The diameter is expressed in millimetres.
3.13
angle
Ɵ
measure of the rotation through which a fastener is turned
Note 1 to entry: The angle is expressed in degrees.
3.14
torque rate
rate of increase of torque relative to rotation while tightening a fastener in a threaded joint.
Note 1 to entry: The torque rate is expressed in newton-metres per revolution.
3.15
rundown
period of angular rotation without corresponding torque increase
Note 1 to entry: This allows the tool to reach operating speed.
3.16
clamp force
F
c
axial tension acting on the bolt shank or compression acting on the clamped member
Note 1 to entry: The clamp force is expressed in newtons.
3.17
peak clamp force
F
cp
peak value of the clamp force (3.16) measured during a tightening cycle
Note 1 to entry: The peak clamp force is expressed in newtons.
3.18
target clamp force
F
ct
clamp force (3.16) required to achieve the test torque (3.26) when testing a tool on a test joint
Note 1 to entry: This is based on the following formula:
FT=×/ KD
()
ct t
where T is defined in 3.26,K is defined in 3.31 and D is defined in 3.12.
T
3.19
torque
T
product of the force turning the fastener and the perpendicular distance between the line of force and the
centre of the fastener
Note 1 to entry: Torque is expressed in newton-metres.
3.20
dynamic torque
torque (3.19) recorded during the determination of K for a test joint condition as described in 4.3.2
Note 1 to entry: For test joint analysis, dynamic torque is measured with an in-line, rotary torque and angle transducer,
placed between a continuous drive spindle and the socket/driver bit.
Note 2 to entry: Dynamic torque is expressed in newton-metres.
3.21
peak dynamic torque
T
dp
peak value of the dynamictorque (3.20) recorded during a tightening cycle performed during the procedure
described in 4.3.2
3.22
correlated torque
T
c
torque (3.19) derived from a peak clamp force (3.17) measurement
Note 1 to entry: This is based on the following formula:
TK=×DF×
ccp
where K is defined in 3.30, F is defined in 3.17 and D is defined in 3.12.
cp
Note 2 to entry: The correlated torque is expressed in newton-metres.
3.23
mean correlated torque
T
c
arithmetic mean of a number of correlatedtorque (3.22) readings on a specific joint
3.24
range of correlated torque scatter
S
range within which the actual values lie
Note 1 to entry: For a normally distributed statistical population, 99,73 % of all members of that population are
encompassed within the scatter range 6 times the standard deviation, s, (6s).
Note 2 to entry: Scatter range is expressed in the quantity measured e.g. in kN or N·m.
3.25
correlated torque scatter as a percentage of the mean correlated torque
S
p
single numerical percentage value designating the correlatedtorque (3.22) capability of a tool run on a single
joint condition under controlled conditions
3.26
test torque
T
t
torque level at which the tool's correlated torque scatter capability is determined, e.g. the torque level at
which the test is carried out
Note 1 to entry: Although nominally determined by the values of the torque adjustment range, the exact test torque is
set by the value achieved by the continuous rotation nut runners in 4.3.2.
3.27
torque adjustment range
range over which a tool can be adjusted as defined by the manufacturer
3.28
upper test torque
T
u
test torque (3.26) equal to the upper limit of the defined torque adjustment range (3.27)
3.29
lower test torque
T
l
test torque (3.26) equal to the lower limit of the defined torque adjustment range (3.27)
3.30
torque factor
K
constant relating clamp force (3.16) and dynamic torque (3.20) in a test joint
3.31
mean torque factor
K
mean of the 25 torque factor values obtained in the measurement process for each test joint at each test
torque level
3.32
tightening time
time required for a tool to tighten a specific joint, excluding the rundown
4 Method for measurement of performance
4.1 General rules for performance tests
4.1.1 Measurements
All measurements carried out in conformity with this document shall be performed by personnel trained in
the use of the equipment utilizing instrumentation, which is calibrated against existing standard methods.
4.1.2 Ambient conditions
Unless otherwise noted, the ambient conditions shall be kept within the following limits during the test:
— ambient temperature: 22 °C ± 5 °C;
— change of ambient temperature during one complete test shall be within ±2 °C;
— relative humidity: below 90 %.
4.1.3 Test installation
The test performance of a tool can be affected by improper alignment with the axis of the test joint. The tool
shall, therefore, be guided by a device and shall be aligned to the test joint to minimise operator influence.
An example of a test stand used to support the tool and align it with the test joint is shown in Figure 1 and
Figure 2.
4.1.4 Test tool
The tool under test shall be an automatic shut-off tool, equipped with a mechanism for automatically shutting
off the drive of the tool once the set point has been reached.
The test tool shall be adjusted to each joint condition specified in 4.3.2 in accordance with the manufacturer’s
instructions. The adjustment shall be such that the shut-off mechanism operates each time.
Once the tool has been adjusted for the joint-rate and test torque level, all control settings shall be constant
throughout the test.
4.1.5 Test tool condition
The test tool shall be in good working conditions and lubricated in accordance with the manufacturer’s
specification. Before the start of the test, it shall be ensured that the tool under test is at ambient temperature.
The tool shall be tested under the manufacturer’s specified input conditions and used in accordance with
the manufacturer’s instructions.
4.1.6 Power media
4.1.6.1 Pneumatic power
The air pressure shall be documented in the test report. The air supply shall include lubrication in accordance
with the manufacturer's instructions.
The performance of pneumatic tools is affected by the ambient conditions such as atmospheric pressure and
temperature. For this reason, unless otherwise specified, the following conditions shall be maintained:
— atmospheric pressure: 1 013 hPa ± 50 hPa;
— compressed air temperature: 20 °C ± 5 °C.
Actual values shall be recorded if they are outside of these limits.
During performance tests of pneumatic tools, it is necessary to state the inlet air pressure. If not stated, the
inlet air pressure is 0,6 MPa. The air supply shall be free from fluctuations that would influence the result.
During performance tests of pneumatic tools, a 3 m hose of the tool manufacturer’s specification shall be
attached to the tool inlet. The air pressure at the inlet of this hose shall be kept within the following limits:
— free-running conditions: between the static value and 2 % below;
— approaching the test torque level: ±2 % of the static value.
NOTE A lubricator with insufficient flow properties can affect these values.
No pressure adjustments shall be made to the pilot regulator during the course of a given test.
Key
1 shutoff valve
2 filter
3 pilot-operated pressure regulator
4 lubricator
5 pressure gauge
6 tool under test
7 tool support
8 clamp force measuring device
9 clamp force measuring device display
Figure 1 — Example of a suitable test installation for pneumatically powered tool
4.1.6.2 Electric power
4.1.6.2.1 Mains
This includes all tools requiring an external continuous supply. It includes both a.c. and d.c. motor driven tools.
Mains electric tools shall be tested under rated input conditions. The supply voltage shall be documented in
the test report. The power supply shall be free from fluctuations that would influence the result.
The cable length should not exceed 10 m.
Key
1 tool under test
2 power supply with controller
3 tool support
4 clamp force measuring device
5 clamp force measuring device display
Figure 2 — Example of a suitable test installation for electrically powered tool requiring mains supply
4.1.6.2.2 Batteries
The battery pack nominal capacity and nominal voltage shall be recorded. The battery pack used shall be as
per the manufacturer’s specification, be in good condition and be fully charged at the start of the test.
4.2 Test fixtures
4.2.1 General
The torque rate of a threaded joint varies widely from application to application and can vary appreciably
on a specific assembly. All types of rotary tool for threaded fasteners can show sensitivity to the joint rate,
including hydraulic impulse tools and electric impulsing tools. The following characteristics apply:
a) On a low torque-rate joint, sometimes referred to as a “soft joint” and abbreviated to “L joint” in this
document, the tightening is usually accomplished with one full revolution or more of the fastener.
b) On a high torque-rate joint, sometimes referred to as a “hard joint” and abbreviated to “H joint” in this
document, the tightening is accomplished in a fraction of a revolution. On a high torque-rate joint, the
kinetic energy of the rotating parts of the tool may cause the torque delivered to the fastener to be
higher than that on a low torque-rate joint.
Any test of torque performance of a tool shall be conducted on joints having controlled torque rates. The test
shall include a joint having a low torque rate and a joint having a high torque rate according to 4.2.2.2. The
high and low torque rates represent the upper and lower limits of the practical range of conditions which
may affect the torque output of the tool.
4.2.2 Test joint
4.2.2.1 General
To achieve consistent joint rates and minimise changes in the torque factor, K, test fixtures for use with
this document shall be regularly inspected to ensure that the joint continues to comply with the following
requirements for the design and maintenance of the test joint.
Changes in K greater than 5 % will require part of the test to be repeated, see Figure 4. Constant attention to
the condition of the threaded joint components can reduce the risk of this happening.
Users are encouraged to read Annex A to better understand the importance of a consistent joint performance
for low correlated torque scatter.
4.2.2.2 Description of the test joint torque rate and linearity
Key
θ angle, expressed in degrees
T torque level, expressed in percentage of the test torque level
±5 % allowable deviation from theoretical torque level
±10 % allowable deviation from theoretical torque level
a) High torque-rate joint
Key
θ angle, expressed in degrees
T torque level, expressed in percentage of the test torque level
±10 % allowable deviation from theoretical torque level
±20 % allowable deviation from theoretical torque level
b) Low torque-rate joint
Figure 3 — Maximum allowable deviation from test torque
Each tool shall be tested in the high torque rate and low torque rate joint conditions, which shall meet the
following requirements:
— Up to 50 % of the test torque, the measuring points for the torque/rotary angle shall not deviate from
their theoretical straight line by more than ±10 % in the high torque rate joint condition, and by no more
than ±15 % in the low torque rate joint condition.
— Between 50 % and 100 % of the test torque, the measuring points for the torque/rotary angle shall not
deviate from their theoretical straight line by more than ±5 % in the high torque rate joint condition, and
by no more than ±10 % in the low torque rate joint condition (see Figure 3).
a) The test joint condition shall be such that the torque during rundown does not exceed 5 % of the
test torque.
b) The high torque rate test joint condition shall be such that the increase in torque between 50 % and
100 % of the test torque is associated with a change in angle of 30° ± 5°.
c) The low torque rate test joint condition shall be such that the increase in torque between 50 % and
100 % of the test torque is associated with a change in angle of 180° ± 15°.
4.2.2.3 Characteristics of test joint
The physical quantities of a threaded joint (e.g. mass, strength, surface finish and lubrication) influence
the transmission of energy from the tool to the joint. A test joint shall therefore be designed to minimise
variation.
The consistency of test measurements will be impacted by friction under the bolt head and in the thread. Design
of the fixture and lubrication should minimise variation. For the same reason, the torque rate of the test joint
shall be smooth and not show effects of quickly changing friction, e.g. from stick-slip phenomena. A surface
treatment may be utilised, provided that the performance of the joint does not change as the coating wears.
Since the document uses clamp force as a means of estimating torque, the user shall maintain the linear
relationship between the two quantities by careful design, manufacture and maintenance of the joint
components.
4.2.2.3.1 Test bolt
The test bolt shall be designed so that the coefficient of friction between bolt head and washer, and between
the threads, remains reasonably constant during the test. The test bolt shall conform at least to strength
class 12.9.
To aid comparison of correlated torque scatter, it is important that the same test bolt size is used with both
joint conditions and that the test bolt is as short as possible to achieve sufficient rigidity. Where the bolt
size for the test has not been specified by the manufacturer and the torque adjustment range overlaps two
fastener sizes in Table 1, the larger size shall be used.
NOTE Practice due to design of the test joint, a length to diameter ratio of 6 to 8 is likely. Shorter is preferred.
Table 1 — Maximum lengths for the test bolt
Fastener size
Characteristic
M4 M5 M6 M8 M10 M12 M14 M16 M18 M20 M24
5 to 15 to 30 to 55 to 90 to
Torque range (N⋅m) 1 to 3 3 to 5 150 to 200 200 to 300 300 to 450 450 to 700
15 30 55 90 150
Maximum bolt
50 50 50 60 80 80 100 100 120 120 140
length (mm)
4.2.2.3.2 Washer
The washer shall be hardened to 45 HRC to 50 HRC to ensure minimum abrasive wear of the washer and
maximum possible consistency of performance of the clamp force tester. The surface of the washer shall be
ground to obtain a roughness Rz ≤ 2,5 µm. The washer shall be properly sized for the test bolt, centred on
the axis of rotation and be locked against rotation.
4.2.2.3.3 Threaded insert
Each threaded insert can be designed as a replaceable insert or a connecting part to the clamp force-
measuring cell. To achieve an optimal contact area of the thread, the threaded insert shall be made of a
suitable material and the thread length designed to consider thread wear and friction.
4.2.2.4 Characteristics of the interface between tool and joint
The mass, inertia and stiffness of hardware used to connect the tool to the joint will influence the
transmission of energy from the tool to the joint. The interface shall therefore be designed to minimise
variation.
The moment of inertia of rotating parts between the test bolt and the tool, should be of the same order of
magnitude as for the socket normally used.
The stiffness and mechanical damping of rotating parts of the test joint should be high enough to minimise
torsional oscillations.
For tools with a square drive output, drive sockets shall be used that fit the test joint fastener and match the
tool’s square drive without adaptors. For tools with hexagon drive, a hexagon to square adaptor may be used
if required. Additional connecting shafts or couplings shall be avoided. Tool to socket connections using a
side loading retention such as a spring-loaded ball and groove shall be avoided. The tool should connect with
the socket through defined journal surfaces according to ISO/TS 21108, in addition to the square or hexagon
drive. If a socket is used which does not conform to ISO/TS 21108, this shall be recorded in the test report.
Table 2 specifies the maximum sizes for the bits and sockets.
Table 2 — Maximum sizes for the test bits and fasteners
Fastener size
Characteristic
M4 M5 M6 M8 M10 M12 M14 M16 M18 M20 M24
5 to 15 to 30 to 55 to 90 to
Torque range (N⋅m) 1 to 3 3 to 5 150 to 200 200 to 300 300 to 450 450 to 700
15 30 55 90 150
Maximum socket
16 16 22 22 30 30 36 40 46 50 60
diameter (mm)
Maximum socket
30 30 40 40 40 50 60 60 60 70 70
length (mm)
Maximum bit length
50 50 50 50 — — — — — — —
(mm)
4.2.3 Measuring devices
4.2.3.1 General
Measuring devices for use with this document shall comply with the following requirements.
Each measuring device shall be designed so that its capacity suits the target quantities to be expected, and
that the resolution, r, of the display is adequate.
In the measuring chain for clamp force and torque measurements, a low-pass Butterworth filter of at least
third-order with a cut-off frequency of 300 Hz shall be provided.
NOTE According to experience, higher frequencies do not add to the quality of the measurement results.
4.2.3.2 Torque and angle measurements required in 4.3
A combined torque and angle sensor shall be used. During the measurement, the sensor casing shall not be
allowed to rotate.
The uncertainty of measurement of the entire equipment for torque measurements shall be ≤2 %. The
repeatability of the torque measuring chain shall be ≤1 %.
Angle sensors shall have an angular resolution of at least 1°.
Torque and rotary angle values of the tightening curve shall be plotted synchronously on the same time
basis, taking into account the filter delays.
4.2.3.3 Clamp force measurements required in 4.3
The measurement of clamp force may be performed in different ways. Specific guidance is given for devices
employing electronic clamp force gauges and for hydraulic pressure gauges. Other forms of clamp force
measurement may be used if they comply with the requirements of 4.2.3.3.
The uncertainty of measurement of the entire equipment for clamp force measurements shall be ≤2 %. The
repeatability of the clamp force measuring chain shall be ≤1 %.
If using an electronic clamp force gauge, the clamp force, F , shall be determined using a torque compensated
c
clamp force gauge that is independent of lateral forces. Annular pressure sensors underneath the washer or
at the threaded insert shall not be used.
If using a hydraulic pressure gauge, the clamp force, F , shall be determined using either a digital clamp force
c
transducer and meter, or a digital pressure gauge in conjunction with a reference table that gives the load
exerted by the test bolt proportionate to the pressure multiplied by the pressure bearing area. The chosen
measurement device shall be capable of displaying and recording each measurement in a timely fashion to
avoid errors caused by time delays.
4.3 Test method
4.3.1 Overview of test procedure
Torque measurements of hydraulic impulse and electric impulsing tools in accordance with this document
shall be based on the measurement of clamp force in the test joint. The process for establishing the
correlation between torque and clamp force is complex and Figure 4 offers a diagrammatic representation
of the test method. Two different methods are possible in step 2 for matching the clamp force of the test tool
and the continuous rotation fastening tool.
Method A uses the manufacturer’s torque adjustment range to select the upper test torque and lower test
torque values. The continuous rotation fastening tool is set to these torque values at each joint type as
described in 4.3.2.2 to determine the target clamp force to be used in establishing K in 4.3.3.
Method B sets the individual tool under test at the maximum and minimum settings according to the
manufacturer’s instructions. The clamp force achieved at each combination of setting and joint type is then
measured. The continuous rotation fastening tool is adjusted to match this target clamp force as described
in 4.3.2.3 and the torque measured in achieving this clamp force with the continuous rotation fastening tool
is used to establish K in 4.3.3.
The user shall determine whether to use Method A or B and shall report this in the test report.
Figure 4 — Overview of the test procedure
4.3.2 Determination of torque factor, K
4.3.2.1 General
The first step of performing tool tests in accordance with this document shall be to establish the torque
factor, K, which is a constant between torque and clamp force for each test joint condition.
To determine the torque factor, K, for each test joint condition, the test bolt shall be rotated continuously
with a continuous rotation fastening tool supported in a fixture at a speed ranging between 10 r/min and
20 r/min; the speed used shall be documented. The measurement shall be carried out using a torque/rotary
angle sensor and a clamp force sensor in the test joint, see Figure 5.
Key
1 continuous rotation fastening tool with controller
2 torque transducer with measurement output device
3 tool support
4 clamp force measuring device
5 clamp force measuring device display
Figure 5 — Typical diagram for continuous rotation fastening tool used to establish torque factor, K
4.3.2.2 Matching the target clamp force – Method A
To achieve a known clamp force at a known joint rate for each torque value, it will be necessary to perform
an iterative process until the clamp force achieved by the test tool, at the desired torque value, matches that
of the continuous rotation fastening tool.
The below iterative process shall be followed:
— Take the continuous rotation fastening tool and tighten the test bolt to the test torque value at the test
joint condition. Note the target clamp force generated by that torque value.
— Set the test tool to the required settings for the test joint condition according to the manufacturer’s
instructions and tighten the test bolt. Note the clamp force result.
— Adjust the test tool until the clamp force is within ±5 % of the continuous rotation fastening tool target
clamp force.
— If the maximum achievable clamp force of the test tool is more than 5 % below that of the continuous
rotation fastening tool, the test torque shall be reduced proportionally to the difference in clamp forces.
The above three steps shall then be repeated.
— Check the tightening angle with the continuous rotation fastening tool. Adjust the joint to deliver the
desired torque rate at the test torque. Note the clamp force result.
— Take the test tool and tighten the test bolt again. Adjust this tool until the clamp force is once more
within ±5 % of the continuous- rotation fastening tool clamp force.
4.3.2.3 Matching the target clamp force – Method B
To achieve a known clamp force at a known joint rate for each torque value, it will be necessary to perform
an iterative process until the clamp force achieved by the continuous rotation fastening tool, matches the
clamp force of the test tool whi
...
ISO/TC 118/SC 3
Secretariat: SIS
Date: 2025-10-21xx
Rotary tools for threaded fasteners— — Impulse and impulsing tools
— Performance test method
Outils rotatifs pour fixations filetées — Outils à impulsion — Méthode d'essai des caractéristiques de
fonctionnement
FDIS stage
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 1
4 Method for measurement of performance . 6
4.1 General rules for performance tests . 6
4.2 Test fixtures . 9
4.3 Test method . 13
5 Comparison with built-in torque measurement systems . 18
6 Evaluation of test results . 18
6.1 Correlated torque scatter . 18
6.2 Correlated torque scatter over a defined range of torque adjustment . 19
7 Presentation of test results . 19
7.1 Test report . 19
Annex A (informative) Explanation and justification of the method . 21
Annex B (informative) Explanation of electric impulsing tools . 25
Annex C (informative) Non-normative use of the methods defined in this document . 26
Annex D (informative) Examples of test report and worksheet for tool performance test . 28
Annex E (informative) Non-normative use of the methods defined in this document . 33
Bibliography . 38
iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of 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 www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 118, Compressors and pneumatic tools,
machines and equipment, Subcommittee SC 3, Pneumatic tools and machines.
This first edition of ISO 17104 cancels and replaces the first edition of ISO/TS 17104:2006, which has been
technically revised and upgraded to an International Standard.
The main changes are as follows:
— — Title and Scope have been modified to reflect changes in the tool types that have become available
since 2006.
— — Starting point of the joint rate measurement is taken from 50 % of the target rather than 10 %.
— — Several requirements are explained more fullyin detail to increase user understanding and tool test
consistency.
— — The opportunity for users to test performance at a preferred test torque level is added as an
informative annex.
— — New annexes have been added to educate users in the background to the requirements.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
This document specifies a laboratory performance test method for hydraulic impulse and electric impulsing
tools for installing threaded fasteners in a laboratory environment. It gives instructions on the procedure,
performance parameters to test and how to evaluate and present the test data.
This document is intended to
— — enable the manufacturers of power tools to offer their products under standardized technical
specifications, and
— — give users of threaded fasteners a method for evaluating and specifying the performance of power
assembly tools.
This document is a fundamental test procedure, with no attempt to set acceptance criteria. Any minimum
performance requirements are the responsibility of the user to meet the demands of the particular application
for which the tool is intended for use.
Unlike the previous Technical Specification, this document is applicable to tightening tools of any power
source within its scope. However, the test does require that the tool under test is capable of being set to a
specific shut-off point.
Additional statements have been introduced to point out the differencedifferences between correlated torque
derived from clamp force and inbuilt indication or control systems that now exist in a number of tools.
Annex AAnnex A explains the basis for the use of clamp force rather than torque for testing the performance
of fastener assembly tools that apply torque in a discontinuous method.
Annex BAnnex B explains the principle of electric impulsing tools which operate in a different way to hydraulic
impulse tools.
Annex CAnnex C includes preferred torque values that may be used for testing.
Annex DAnnex D gives an example format for the test report.
Annex EAnnex E provides background to the testing performed during the creation of this document.
This document includes some changes to the specifications for the test joints and for the test method. These
changes reflect the practical experience gained through the use of the previous version of the document and
are intended to improve the reproducibility of the test method.
Testing of the tools within the scope of this document present a number of challenges. New equipment and
methods are being developed and the sub-committeesubcommittee members responsible for its publication
believe that this document is a step closer to understanding the true performance of impulse and impulsing
tools. Further development will continue, and the experiences of users are welcomed by the sub-
committeesubcommittee.
Results obtained using this document may differ from results obtained using the previous technical
specification.
Some of the changes in this document have been guided by the work of the VDI/VDE Committee Gesellschaft
Mess- und Automatisierungstechnik and are used with their permission.
v
Rotary tools for threaded fasteners - — Impulse and impulsing tools -
— Performance test method
1 Scope
This document specifies a laboratory performance test method for hydraulic impulse and electric impulsing
tools for installing threaded fasteners in a laboratory environment, and for power assembly tools (referred
throughout the document as “tools”) for installing threaded fasteners. It gives instructions on the procedure,
performance parameters to test and how to evaluate and present the test data.
It also provides a method for the measurement of torque repeatability (scatter)
— — over a range of torque rates as specified in this document, and
— — over a range of torque adjustment as defined by the manufacturer.
It gives instructions on equipment parameters, what to test for and how to evaluate and present the test data.
It is applicable to tools
— — of any power source, such as pneumatic or electric, including battery-powered,
— — which apply torque in discontinuous increments, and
— — within the torque range 0,5 N·m to 800 N·m. Outside this range, it is acceptable to modify the test
method providing that the modification is documented in the test report.
It is not applicable to
— — impact wrenches, and
— — ratchet wrenches or wrenches with ratcheting clutches.
The relationship between torque measurements and clamp force-based tests is commented on in
Annex AAnnex A.
The use of tools using discontinuous operation of the motor to provide torque impulses is discussed in
Annex BAnnex B.
It requires manufacturers to perform tests over their defined torque range of the tool; however, it allows users
to perform single point tests in order to minimize the number of test joints necessary for a wide range of test
torque levels. A list of preferred test torque levels is provided in Annex CAnnex C.
2 Normative references
No normative references are referred to in this document.
3 Terms, definitions and symbols
For the purposes of this document, the following terms and definitions apply. Symbols are shown where they
are used in this document.
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 3.1
rotary tool for threaded fasteners
powered tool, the output spindle of which rotates to turn a threaded fastener
Note 1 to entry: Either a pneumatic or an electric motor can be used.
Note 2 to entry: The final movement of the spindle can be rotational and continuous or rotational and discontinuous,
depending on the type of rotary machine considered.
3.2 3.2
continuous rotation fastening tool
powered assembly tool for tightening threaded fasteners, which applies torque to a fastener in a continuous
motion
Note 1 to entry: The term is used in this document when establishing the relationship between torque and clamp force.
3.3 3.3
hydraulic impulse tool
powered assembly tool for tightening threaded fasteners, which applies torque to a fastener in discontinuous
increments through a hydraulic impulse unit between the motor and the output drive
3.4 3.4
electric impulsing tool
powered assembly tool for tightening threaded fasteners, which applies torque to a fastener in discontinuous
increments by pulsing the input to the electric motor which then delivers pulses of kinetic energy to the output
drive
Note 1 to entry: A number of variations on this tool existexists. Their common distinguishing action is that the pulsing
comes from controlling the motor, rather than subsequently controlling the output of the motor.
3.5 3.5
automatic shut-off tool
powered assembly tool for tightening threaded fasteners, provided with a torque control mechanism which
shuts off or disconnects the power to the tool when the predetermined set output torque level is attained
Note 1 to entry: A number of variations on the mechanisms for achieving this feature existexists.
3.6 3.6
parameter adjustable tool
hydraulic impulse tool (3.3(3.3)) or electric impulsing tool (3.4(3.4)) capable of customising the tightening
profile, by changing parameters such as speed, pulse rate, pulse intensity etc.
3.7 3.7
pulse mode
settings employed in an electric impulsingelectricimpulsing tool (3.4(3.4)) to establish pulse frequency,
duration and intensity
Note 1 to entry: The settings will influence the rectionreaction force experienced by the operator.
3.8 3.8
number of pulses
number of pulses generated by the tool from the start of rundown to completion of the defined joint
3.9 3.9
operating cycle
one complete fastener tightening from start of rotation until end of rotation
3.10 3.10
joint condition
combination of torque rate (3.14(3.14)) and test torque (3.26(3.26))
Note 1 to entry: The effect of lubrication viscosity, thread deformation or galling etc. can alter the joint condition.
3.11 3.11
standard deviation
s
statistical parameter to describe a scatter range
𝑁𝑁
¯
𝑠𝑠 = (𝑥𝑥 −𝑋𝑋)
� �
𝑖𝑖
𝑁𝑁− 1
𝑖𝑖=1
[SOURCE: ISO 3534-1:2006, 2.37]
3.12 3.12
diameter
D
nominal diameter of a bolt
Note 1 to entry: The diameter is expressed in millimetres.
3.13 3.13
angle
Ɵ
measure of the rotation through which a fastener is turned
Note 1 to entry: The angle is expressed in degrees.
3.14 3.14
torque rate
rate of increase of torque relative to rotation while tightening a fastener in a threaded joint.
Note 1 to entry: The torque rate is expressed in newton-metres per revolution.
3.15 3.15
rundown
period of angular rotation without corresponding torque increase
Note 1 to entry: This allows the tool to reach operating speed.
3.16 3.16
clamp force
F
c
axial tension acting on the bolt shank or compression acting on the clamped member
Note 1 to entry: The clamp force is expressed in Newtonnewtons.
3.17 3.17
peak clamp force
F
cp
peak value of the clamp force (3.16(3.16)) measured during a tightening cycle
Note 1 to entry: The peak clamp force is expressed in Newtonnewtons.
3.18 3.18
target clamp force
F
ct
clamp force (3.16(3.16)) required to achieve the test torque (3.26(3.26)) when testing a tool on a test joint
Note 1 to entry: This is based on the following formula:
¯
𝐹𝐹 =𝑇𝑇 /(𝐾𝐾 ×𝐷𝐷)
𝑐𝑐𝑐𝑐 𝑐𝑐
¯
where T is defined in 3.263.26 ,𝐾𝐾 is defined in 3.313.31, and D is defined in 3.123.12.
T
3.19 3.19
torque
T
product of the force turning the fastener and the perpendicular distance between the line of force and the
centre of the fastener
Note 1 to entry: Torque is expressed in newton·metre-metres.
3.20 3.20
dynamic torque
torque (3.19(3.19)) recorded during the determination of K for a test joint condition as described in 4.3.24.3.2
Note 1 to entry: For test joint analysis, dynamic torque is measured with an in-line, rotary torque and angle transducer,
placed between a continuous drive spindle and the socket/driver bit.
Note 2 to entry: Dynamic torque is expressed in newton-metremetres.
3.21 3.21
peak dynamic torque
Tdp
peak value of the dynamictorque (3.20dynamic torque (3.20)) recorded during a tightening cycle performed
during the procedure described in 4.3.24.3.2
3.22 3.22
correlated torque
T
c
torque (3.19(3.19)) derived from a peak clamp force (3.17(3.17)) measurement
Note 1 to entry: This is based on the following formula:
¯
𝑇𝑇 =𝐾𝐾 ×𝐷𝐷 ×𝐹𝐹
𝑐𝑐 𝑐𝑐𝑐𝑐
where K is defined in 3.303.30,, Fcp is defined in 3.173.17 and D is defined in 3.123.12.
Note 2 to entry: The correlated torque is expressed in newton-metremetres.
3.23 3.23
mean correlated torque
¯
𝑻𝑻
c
arithmetic mean of a number of correlatedtorque (3.22correlated torque (3.22)) readings on a specific joint
3.24 3.24
range of correlated torque scatter
S
range within which the actual values lie
Note 1 to entry: For a normally distributed statistical population, 99,73 % of all members of that population are
encompassed within the scatter range 6 times the standard deviation, s, (6s).
Note 2 to entry: Scatter range is expressed in the quantity measured e.g. in kN or N·m.
3.25 3.25
correlated torque scatter as a percentage of the mean correlated torque
S
p
single numerical percentage value designating the correlatedtorque (3.22correlated torque (3.22)) capability
of a tool run on a single joint condition under controlled conditions
3.26 3.26
test torque
Tt
torque level at which the tool's correlated torque scatter capability is determined, e.g.,. the torque level at
which the test is carried out
Note 1 to entry: Although nominally determined by the values of the torque adjustment range, the exact test torque is
set by the value achieved by the continuous rotation nutrunnersnut runners in 4.3.24.3.2.
3.27 3.27
torque adjustment range
range over which a tool can be adjusted as defined by the manufacturer
3.28 3.28
upper test torque
T
u
test torque (3.26(3.26)) equal to the upper limit of the defined torque adjustment range (3.27(3.27))
3.29 3.29
lower test torque
T
l
test torque (3.26(3.26)) equal to the lower limit of the defined torque adjustment range (3.27(3.27))
3.30 3.30
torque factor
K
constant relating clamp force (3.16(3.16)) and dynamic torque (3.20(3.20)) in a test joint
3.31 3.31
mean torque factor
¯
𝑲𝑲
mean of the 25 torque factor values obtained in the measurement process for each test joint at each test torque
level
3.32 3.32
tightening time
time required for a tool to tighten a specific joint, excluding the rundown
4 Method for measurement of performance
4.1 General rules for performance tests
4.1.1 Measurements
All measurements carried out in conformity with this document shall be performed by personnel trained in
the use of the equipment utilizing instrumentation, which is calibrated against existing standard methods.
4.1.2 Ambient conditions
Unless otherwise noted, the ambient conditions shall, during the test, be kept within the following limits
during the test:
— — ambient temperature: 22 °C ± 5 °C;
— — change of ambient temperature during one complete test shall be within ±2 °C;
— — relative humidity: below 90 %.
4.1.3 Test installation
The test performance of a tool can be affected by improper alignment with the axis of the test joint. The tool
shall, therefore, be guided by a device and shall be aligned to the test joint to minimise operator influence.
An example of a test stand used to support the tool and align it with the test joint is shown in Figure 1Figures 1
and Figure 22.
4.1.4 Test tool
The tool under test shall be an automatic shut-off tool, equipped with a mechanism for automatically shutting
off the drive of the tool once the set point has been reached.
The test tool shall be adjusted to each joint condition specified in 4.3.24.3.2 in accordance with the
manufacturer’s instructions. The adjustment shall be such that the shut-off mechanism operates each time.
Once the tool has been adjusted for the joint-rate and test torque level, all control settings shall be constant
throughout the test.
4.1.5 Test tool condition
The test tool shall be in good working conditionconditions and lubricated in accordance with the
manufacturer’s specification. Before the start of the test, it shall be ensured that the tool under test is at
ambient temperature.
The tool shall be tested under the manufacturer’s specified input conditions and used in accordance with the
manufacturer’s instructions.
4.1.6 Power media
4.1.6.1 Pneumatic power
The air pressure shall be documented in the test report. The air supply shall include lubrication in accordance
with the manufacturer's instructions.
The performance of pneumatic tools is affected by the ambient conditions such as atmospheric pressure and
temperature. For this reason, unless otherwise specified, the following conditions shall be maintained:
— — atmospheric pressure: 1 013 hPa ± 50 hPa;
— — compressed air temperature: 20 °C ± 5 °C.
Actual values shall be recorded if they are outside of these limits.
During performance tests of pneumatic tools, it is necessary to state the inlet air pressure. If not stated, the
inlet air pressure is 0,6 MPa. The air supply shall be free from fluctuations that would influence the result.
During performance tests of pneumatic tools, a 3- m hose of the tool manufacturer’s specification shall be
attached to the tool inlet. The air pressure at the inlet of this hose shall be kept within the following limits:
— — free-running conditions: between the static value and 2 % below;
— — approaching the test torque level: ±2 % of the static value.
NOTE A lubricator with insufficient flow properties can affect these values.
No pressure adjustments shall be made to the pilot regulator during the course of a given test.
17104_ed2fig1.EPS
Key
1 shutoff valve
2 filter
3 pilot-operated pressure regulator
4 lubricator
5 pressure gauge
6 tool under test
7 tool support
8 clamp force measuring device
9 clamp force measuring device display
Figure 1 — Example of a suitable test installation for pneumatically powered tool
4.1.6.2 Electric power
4.1.6.2.1 Mains
This includes all tools requiring an external continuous supply. It includes both a.c. and d.c. motor driven tools.
Mains electric tools shall be tested under rated input conditions. The supply voltage shall be documented in
the test report. The power supply shall be free from fluctuations that would influence the result.
The cable length should not exceed 10 m.
17104_ed2fig2.EPS
Key
1 tool under test
2 power supply with controller
3 tool support
4 clamp force measuring device
5 clamp force measuring device display
Figure 2 — Example of a suitable test installation for electrically powered tool requiring mains
supply
4.1.6.2.2 Batteries
The battery pack nominal capacity and nominal voltage shall be recorded. The battery pack used shall be as
per the manufacturer’s specification, be in good condition and be fully charged at the start of the test.
4.2 Test fixtures
4.2.1 General
The torque rate of a threaded joint varies widely from application to application and can vary appreciably on
a specific assembly. All types of rotary tool for threaded fasteners can show sensitivity to the joint rate,
including hydraulic impulse tools and electric impulsing tools. The following characteristics apply:
a) a) On a low torque-rate joint, sometimes referred to as a “soft joint” and abbreviated to “L joint”
in this document, the tightening is usually accomplished with one full revolution or more of the fastener.
b) b) On a high torque-rate joint, sometimes referred to as a “hard joint” and abbreviated to “H joint”
in this document, the tightening is accomplished in a fraction of a revolution. On a high torque-rate joint,
the kinetic energy of the rotating parts of the tool may cause the torque delivered to the fastener to be
higher than that on a low torque-rate joint.
Any test of torque performance of a tool shall be conducted on joints having controlled torque rates. The test
shall include a joint having a low torque rate and a joint having a high torque rate according to 4.2.2.24.2.2.2.
The high and low torque rates represent the upper and lower limits of the practical range of conditions which
may affect the torque output of the tool.
4.2.2 Test joint
4.2.2.1 General
To achieve consistent joint rates and minimise changes in the torque factor, K, test fixtures for use with this
document shall be regularly inspected to ensure that the joint continues to comply with the following
requirements for the design and maintenance of the test joint.
Changes in K greater than 5 % will require part of the test to be repeated, see Figure 4Figure 4. Constant
attention to the condition of the threaded joint components can reduce the risk of this happening.
Users are encouraged to read Annex AAnnex A to better understand the importance of a consistent joint
performance for low correlated torque scatter.
4.2.2.2 Description of the test joint torque rate and linearity
17104_ed2fig3a.EPS
Key
θ angle, expressed in degrees
T torque level, expressed in percentage of the test torque level
±5 % allowable deviation from theoretical torque level
±10 % allowable deviation from theoretical torque level
a) High torque-rate joint
17104_ed2fig3b.EPS
Key
θ angle, expressed in degrees
T torque level, expressed in percentage of the test torque level
±10 % allowable deviation from theoretical torque level
±20 % allowable deviation from theoretical torque level
b) Low torque-rate joint
Figure 3 — Maximum allowable deviation from test torque
Each tool shall be tested in the high torque rate and low torque rate joint conditions, which shall meet the
following requirements:
— — Up to 50 % of the test torque, the measuring points for the torque/rotary angle shall not deviate from
their theoretical straight line by more than ±10 % in the high torque rate joint condition, and by no more
than ±15 % in the low torque rate joint condition.
— — Between 50 % and 100 % of the test torque, the measuring points for the torque/rotary angle shall
not deviate from their theoretical straight line by more than ±5 % in the high torque rate joint condition,
and by no more than ±10 % in the low torque rate joint condition (see Figure 3Figure 3).).
a) a) The test joint condition shall be such that the torque during rundown does not exceed 5 % of
the test torque.
b) b) The high torque rate test joint condition shall be such that the increase in torque between 50 %
and 100 % of the test torque is associated with a change in angle of 30° ± 5°.
c) c) The low torque rate test joint condition shall be such that the increase in torque between 50 %
and 100 % of the test torque is associated with a change in angle of 180° ± 15°.
4.2.2.3 Characteristics of test joint
The physical quantities of a threaded joint (e.g. mass, strength, surface finish and lubrication) influence the
transmission of energy from the tool to the joint. A test joint shall therefore be designed to minimise variation.
The consistency of test measurements will be impacted by friction under the bolt head and in the thread.
Design of the fixture and lubrication should minimise variation. For the same reason, the torque rate of the
test joint shall be smooth and not show effects of quickly changing friction, e.g. from stick-slip phenomena. A
surface treatment may be utilised, provided that the performance of the joint does not change as the coating
wears.
Since the document uses clamp force as a means of estimating torque, the user shall maintain the linear
relationship between the two quantities by careful design, manufacture and maintenance of the joint
components.
4.2.2.3.1 Test bolt
The test bolt shall be designed so that the coefficient of friction between bolt head and washer, and between
the threads, remains reasonably constant during the test. The test bolt shall conform at least to strength class
12.9.
To aid comparison of correlated torque scatter, it is important that the same test bolt size is used with both
joint conditions and that the test bolt is as short as possible to achieve sufficient rigidity. Where the bolt size
for the test has not been specified by the manufacturer and the torque adjustment range overlaps two fastener
sizes in Table 1Table 1,, the larger size shall be used.
NOTE Practice due to design of the test joint, a length to diameter ratio of 6 to 8 is likely. Shorter is preferred.
Table 1 — Maximum lengths for the test bolt
Fastener size
Characteristi
M M1 M1 M1
c
M4 M6 M8 M16 M18 M20 M24
5 0 2 4
3 t 15 t 30 t 55 t 90 t
Torque range 1 to 5 to 150 t 200 t 300 t 450 t
o o o o o
(N⋅m) 3 15 o 200 o 300 o 450 o 700
5 30 55 90 150
Max.Maximum
bolt length 50 50 50 60 80 80 100 100 120 120 140
(mm)
4.2.2.3.2 Washer
The washer shall be hardened to 45 HRC to 50 HRC to ensure minimum abrasive wear of the washer and
maximum possible consistency of performance of the clamp force tester. The surface of the washer shall be
ground to obtain a roughness Rz ≤ ≤ 2,5 µm. The washer shall be properly sized for the test bolt, centred on
the axis of rotation and be locked against rotation.
4.2.2.3.3 Threaded insert
Each threaded insert can be designed as a replaceable insert or a connecting part to the clamp force-measuring
cell. To achieve an optimal contact area of the thread, the threaded insert shall be made of a suitable material
and the thread length designed to consider thread wear and friction.
4.2.2.4 Characteristics of the interface between tool and joint
The mass, inertia and stiffness of hardware used to connect the tool to the joint will influence the transmission
of energy from the tool to the joint. The interface shall therefore be designed to minimise variation.
The moment of inertia of rotating parts between the test bolt and the tool, should be of the same order of
magnitude as for the socket normally used.
The stiffness and mechanical damping of rotating parts of the test joint should be high enough to minimise
torsional oscillations.
For tools with a square drive output, drive sockets shall be used that fit the test joint fastener and match the
tool’s square drive without adaptors. For tools with hexagon drive, a hexagon to square adaptor may be used
if required. Additional connecting shafts or couplings shall be avoided. Tool to socket connections using a side
loading retention such as a spring-loaded ball and groove shall be avoided. The tool should connect with the
socket through defined journal surfaces according to ISO/TS 21108, in addition to the square or hexagon
drive. If a socket is used which does not conform to ISO/TS 21108, this shall be recorded in the test report.
Table 2Table 2 specifies the maximum sizes for the bits and sockets.
Table 2 — Maximum sizes for the test bits and fasteners
Fastener size
Characteristi
M1 M1 M1
c
M4 M5 M6 M8 M16 M18 M20 M24
0 2 4
15 t 30 t 55 t 90 t
Torque range 1 to 3 to 5 to 150 t 200 t 300 t 450 t
o o o o
(N⋅m) 3 5 15 o 200 o 300 o 450 o 700
30 55 90 150
Max.Maximum
socket
16 16 22 22 30 30 36 40 46 50 60
diameter
(mm)
Max.Maximum
socket length 30 30 40 40 40 50 60 60 60 70 70
(mm)
Max.Maximum
bit length 50 50 50 50 — — — — — — —
(mm)
4.2.3 Measuring devices
4.2.3.1 General
Measuring devices for use with this document shall comply with the following requirements.
Each measuring device shall be designed so that its capacity suits the target quantities to be expected, and that
the resolution, r, of the display is adequate.
In the measuring chain for clamp force and torque measurements, a low-pass Butterworth filter of at least
third-order with a cut-off frequency of 300 Hz shall be provided.
NOTE According to experience, higher frequencies do not add to the quality of the measurement results.
4.2.3.2 Torque and angle measurements required in 4.34.3
A combined torque and angle sensor shall be employedused. During the measurement, the sensor casing shall
not be allowed to rotate.
The uncertainty of measurement of the entire equipment for torque measurements shall be ≤ 2 %. The
repeatability of the torque measuring chain shall be ≤ 1 %.
Angle sensors shall have an angular resolution of at least 1°.
Torque and rotary angle values of the tightening curve shall be plotted synchronously on the same time basis,
taking into account the filter delays.
4.2.3.3 Clamp force measurements required in 4.34.3
The measurement of clamp force may be performed in different ways. Specific guidance is given for devices
employing electronic clamp force gauges and for hydraulic pressure gauges. Other forms of clamp force
measurement may be used if they comply with the requirements of 4.2.3.34.2.3.3.
The uncertainty of measurement of the entire equipment for clamp force measurements shall be ≤ 2 %. The
repeatability of the clamp force measuring chain shall be ≤ 1 %.
If using an electronic clamp force gauge, the clamp force, F , shall be determined using a torque compensated
c
clamp force gauge that is independent of lateral forces. Annular pressure sensors underneath the washer or
at the threaded insert shall not be used.
If using a hydraulic pressure gauge, the clamp force F , F , shall be determined using either a digital clamp
C c
force transducer and meter, or a digital pressure gauge in conjunction with a reference table that gives the
load exerted by the test bolt proportionate to the pressure multiplied by the pressure bearing area. The chosen
measurement device shall be capable of displaying and recording each measurement in a timely fashion to
avoid errors caused by time delays.
4.3 Test method
4.3.1 Overview of test procedure
Torque measurements of hydraulic impulse and electric impulsing tools in accordance with this document
shall be based on the measurement of clamp force in the test joint. The process for establishing the correlation
between torque and clamp force is complex and Figure 4Figure 4 offers a diagrammatic representation of the
test method. Two different methods are possible in step 2 for matching the clamp force of the test tool and the
continuous rotation fastening tool.
Method A uses the manufacturer’s torque adjustment range to select the upper test torque and lower test
torque values. The continuous rotation fastening tool is set to these torque values at each joint type as
¯
described in 4.3.2.24.3.2.1 to determine the target clamp force to be used in establishing 𝐾𝐾 in 4.3.34.3.3.
Method B sets the individual tool under test at the maximum and minimum settings according to the
manufacturer’s instructions. The clamp force achieved at each combination of setting and joint type is then
measured. The continuous rotation fastening tool is adjusted to match this target clamp force as described in
4.3.2.34.3.2.2 and the torque measured in achieving this clamp force with the continuous rotation fastening
¯
tool is used to establish 𝐾𝐾 in 4.3.34.3.3.
The user shall determine whether to use Method A or B and shall report this in the test report.
17104_ed2fig4.EPS
Figure 4 — Overview of the test procedure
4.3.2 Determination of torque factor, K
4.3.2.1 General
The first step of performing tool tests in accordance with this document shall be to establish the torque factor,
K, which is a constant between torque and clamp force for each test joint condition.
To determine the torque factor, K, for each test joint condition, the test bolt shall be rotated continuously with
a continuous rotation fastening tool supported in a fixture at a speed ranging between 10 r/min and 20
revolutions per minute r/min; the speed used shall be documented. The measurement shall be carried out
using a torque/rotary angle sensor and a clamp force sensor in the test joint, see Figure 5.
17104_ed2fig5.EPS
Key
1 continuous rotation fastening tool with controller
2 torque transducer with measurement output device
3 tool support
4 clamp force measuring device
5 clamp force measuring device display
Figure 5 — Typical diagram for continuous rotation fastening tool used to establish torque factor, K
4.3.2.14.3.2.2 Matching the target clamp force – Method A
To achieve a known clamp force at a known joint rate for each torque value, it will be necessary to perform an
iterative process until the clamp force achieved by the test tool, at the desired torque value, matches that of
the continuous rotation fastening tool.
The below iterative process shall be followed as below.:
— — Take the continuous rotation fastening tool and tighten the test bolt to the test torque value at the test
joint condition. Note the target clamp force generated by that torque value.
— — Set the test tool to the required settings for the test joint condition according to the manufacturer’s
instructions and tighten the test bolt. Note the clamp force result.
— — Adjust the test tool until the clamp force is within ±5 % of the continuous rotation fastening tool target
clamp force.
— — If the maximum achievable clamp force of the test tool is more than 5 % below that of the continuous
rotation fastening tool, the test torque shall be reduced proportionally to the difference in clamp forces.
The above three steps shall then be repeated.
— — Check the tightening angle with the continuous rotation fastening tool. Adjust the joint to deliver the
desired torque rate at the test torque. Note the clamp force result.
— — Take the test tool and tighten the test bolt again. Adjust this tool until the clamp force is once more
within ±5 % of the continuous- rotation fastening tool clamp force.
4.3.2.24.3.2.3 Matching the target clamp force – Method B
To achieve a known clamp force at a known joint rate for each torque value, it will be necessary to perform an
iterative process until the clamp force achieved by the continuous rotation fastening tool, matches the clamp
force of the test tool which has been set according to manufacturer’s instructions.
The below iterative process shall be followed as below.:
— — Set the test tool to the required settings for the test joint condition according to the manufacturer’s
instructions and tighten the test bolt. Note the target clamp force generated by that test tool setting
— — Take the continuous rotation fastening tool and tighten the test bolt. Adjust the continuous rotation
fastening tool torque value until the clamp force is within ±5 % of the test tool target clamp force.
— — Check the tightening angle. Adjust the joint to deliver the desired torque rate.
— — Tighten the test bolt again with the test tool and record the new clamp force on the adjusted joint.
— — Take the continuous rotation fastening tool and tighten the test bolt again. Adjust the continuous
fastening tool torque value until the clamp force is once more within ±5 % of the test tool clamp force.
— — Check the torque rate again. Adjust if necessary.
— — Repeat the process until the clamp force of the continuous rotation fastening tool is within 5 % of the
clamp force result of the test tool at the joint condition.
4.3.2.34.3.2.4 Calculation of torque factor, K
The continuous rotation fastening tool shall be used to tighten the joint 25 times and the dynamic peak torque
and resultant peak clamp force values shall be recorded for each tightening.
The torque factor, K, for each tightening shall be calculated using Formula (1)Formula (1)::
𝐾𝐾 =𝑇𝑇 /(𝐹𝐹 ⋅ 𝐷𝐷) (1)
𝑑𝑑𝑐𝑐 𝑐𝑐𝑐𝑐
¯
4.3.3 Calculation of mean torque factor, 𝑲𝑲
¯
The mean torque factor , 𝐾𝐾, shall be calculated from 25 measurements of the torque factor, K, using
Formula (2)Formula (2)::
𝑛𝑛
¯
𝐾𝐾 = ∑ 𝐾𝐾 (2)
𝑖𝑖=1 𝑖𝑖
𝑛𝑛
¯
The mean torque factor, ,𝐾𝐾, for the joint condition shall be calculated from the 25 values of K. The 6s scatter of
these 25 torque factor values shall not exceed 5 % of the mean value.
¯
4.3.4 Reconfirmation of mean torque factor, 𝑲𝑲
The torque factor K shall be reconfirmed after a tool test by repeating 4.3.2.44.3.2.3 and 4.3.34.3.3. The
¯
difference between the values of mean torque factor , 𝐾𝐾, before and after the test shall not exceed 5 %. A
deviation greater than 5 % indicates that the test joint conditions may have changed and the tool performance
test shall be repeated having reviewed the joint condition.
4.3.5 Performance test
4.3.5.1 Sequence of test
¯
The test for a given joint condition shall be performed between the activities for calculating the value of 𝐾𝐾 and
of checking that value after the test. Only after that sequence can the next joint condition be tested.
Prior to a performance test, the test device shall undergo at least 25 preliminary cycles to reach a stable state.
A different tool to the tool under test should be used to perform these cycles. If this is not the case, the fact
shall be stated on the test report.
4.3.5.2 Test torque values
In order to determine the correlated torque scatter of a tool over the defined torque adjustment range, the
test shall be carried out in both the H and L joint conditions at the upper limit of the defined torque adj
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