IEC 60745-2-22:2011

IEC 60745-2-22 ®
Edition 1.0 2011-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Hand-held motor-operated electric tools – Safety –
Part 2-22: Particular requirements for cut-off machines

Outils électroportatifs à moteur – Sécurité –
Partie 2-22: Règles particulières pour les tronçonneuses à disques

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IEC 60745-2-22 ®
Edition 1.0 2011-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Hand-held motor-operated electric tools – Safety –
Part 2-22: Particular requirements for cut-off machines

Outils électroportatifs à moteur – Sécurité –
Partie 2-22: Règles particulières pour les tronçonneuses à disques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX T
ICS 25.140.20 ISBN 978-2-88912-394-0

– 2 – 60745-2-22 © IEC:2011
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 General requirements . 7
5 General conditions for the tests . 8
6 Void. 8
7 Classification . 8
8 Marking and instructions . 8
9 Protection against access to live parts . 11
10 Starting . 11
11 Input and current . 11
12 Heating . 11
13 Leakage current . 12
14 Moisture resistance . 12
15 Electric strength . 12
16 Overload protection of transformers and associated circuits . 12
17 Endurance . 12
18 Abnormal operation . 12
19 Mechanical hazards . 12
20 Mechanical strength . 16
21 Construction . 18
22 Internal wiring . 18
23 Components . 19
24 Supply connection and external flexible cords . 19
25 Terminals for external conductors . 19
26 Provision for earthing . 19
27 Screws and connections . 19
28 Creepage distances, clearances and distances through insulation . 19
29 Resistance to heat, fire and tracking . 19
30 Resistance to rusting . 19
31 Radiation, toxicity and similar hazards . 19
Annexes . 24
Annex K (normative) Battery tools and battery packs . 24
Annex L (normative) Battery tools and battery packs provided with mains connection
or non-isolated sources. 24
Bibliography . 25

Figure 101 – Examples of gaps and rake angles . 20
Figure 102 – Typical guard designs . 21
Figure 103 – Principal dimensions of flanges . 22
Figure 104 – Guard strength test: explanation of guard positions . 22

60745-2-22 © IEC:2011 – 3 –
Figure 105 – Guard strength test: preparation of the cut-off machine . 23
Figure 106 – Guard strength test box . 23

Table 101 – Torques for testing flanges . 15
Table 102 – Guard thickness for diamond wheels . 16

– 4 – 60745-2-22 © IEC:2011
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
HAND-HELD MOTOR-OPERATED ELECTRIC TOOLS –
SAFETY –
Part 2-22: Particular requirements for cut-off machines

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This part of International Standard IEC 60745 has been prepared by IEC technical committee
116: Safety of motor-operated electric tools.
The text of this standard is based on the following documents:
FDIS Report on voting
116/57/FDIS 116/62/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
This Part 2 is to be used in conjunction with the fourth edition of IEC 60745-1 (2006): Hand-
held motor-operated electric tools – Safety – Part 1: General requirements, and its
amendments.
60745-2-22 © IEC:2011 – 5 –
NOTE 1 When “Part 1” is mentioned in this standard, it refers to IEC 60745-1.
This part 2 supplements or modifies the corresponding clauses of IEC 60745-1, so as to
convert that publication into the IEC standard: Safety requirements for electric cut-off
machines.
When a particular subclause of Part 1 is not mentioned in this part 2, that subclause applies
as far as is reasonable. When this standard states “addition”, “modification” or “replacement”,
the relevant text in Part 1 is to be adapted accordingly.
NOTE 2 The following numbering system is used:
– subclauses, tables and figures that are numbered starting from 101 are additional to those in Part 1;
– additional annexes are lettered AA, BB, etc.
NOTE 3 in this standard, the following print types are used:
– requirements: in roman type;
– test specifications: in italic type;
– notes: in smaller roman type.
Words in bold in the text are defined in Clause 3. When a definition concerns an adjective, the adjective and the
associated noun are also in bold.
Subclauses, tables and figures which are additional to those in Part 1 are numbered starting from 101; additional
annexes are lettered AA, BB, etc.
A list of all the parts in the IEC 60745 series, published under the general title Hand-held
motor-operated electric tools – Safety, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – 60745-2-22 © IEC:2011
HAND-HELD MOTOR-OPERATED ELECTRIC TOOLS –
SAFETY –
Part 2-22: Particular requirements for cut-off machines

1 Scope
This clause of Part 1 is applicable as follows:
Addition:
This standard applies to cut-off machines fitted with
– one bonded reinforced wheel of Type 41 or Type 42, or
– one or more diamond cut-off wheels with the peripheral gaps, if any, not exceeding
10 mm
and with
– a rated speed not exceeding a peripheral speed of the wheel of 100 m/s at rated
capacity and
– a rated wheel capacity range of 55 mm to 410 mm.
These machines are intended to cut materials such as metals, concrete, masonry, glass and
tile.
This standard does not apply to:
– grinders, sanders, or polishers, even if they can be converted to a cut-off machine, which
are covered by IEC 60745-2-3;
– circular saws which are covered by IEC 60745-2-5.
2 Normative references
This clause of Part 1 is applicable except as follows:
Addition:
ISO 603-15:1999, Bonded abrasive products – Dimensions – Part 15: Grinding wheels for
cutting-off on stationary or mobile cutting-off machines
ISO 603-16:1999, Bonded abrasive products – Dimensions – Part 16: Grinding wheels for
cutting-off on hand-held power tools
3 Terms and definitions
This clause of Part 1 is applicable, except as follows:
3.101
blotter
thin piece of an easily compressible material, between the abrasive product and flange

60745-2-22 © IEC:2011 – 7 –
3.102
flange
collar, disc, or plate between or against which wheels are mounted
3.102.1
flange outside diameter
outside diameter of the contact surface of a flange
3.102.2
backing flange
part that contacts and provides support to the back side of the wheel and is located on the
spindle between wheel and tool
3.102.3
locking flange
part that supports the front side of the wheel and secures and clamps the wheel to the spindle
and the backing flange
3.103
cut-off machine
tool driving a rotating spindle, with a guide plate or guide roller or similar means, on which a
bonded reinforced wheel or diamond wheel is mounted and used for peripheral grinding
3.104
rated capacity
maximum intended diameter of the rotating accessory to be fitted on the tool as recommended
by the manufacturer’s instruction
3.105
rated speed
maximum attainable speed as designated by the manufacturer, with any recommended
accessory installed, at rated voltage or at the upper limit of the rated voltage range
3.106
wheel guard
device which partly encloses the wheel and gives protection to the operator
3.107
guide plate
flat plate on the machine which rests on the material to be cut
3.108
guide roller
roller on the machine which rests on the material to be cut
3.109
bonded reinforced wheel
wheels for different applications in accordance with ISO 603-15 and ISO 603-16
3.110
diamond wheel
metal wheels with a continuous or segmented abrasive rim
4 General requirements
This clause of Part 1 is applicable.

– 8 – 60745-2-22 © IEC:2011
5 General conditions for the tests
This clause of Part 1 is applicable.
6 Void
7 Classification
This clause of Part 1 is applicable.
8 Marking and instructions
This clause of Part 1 is applicable, except as follows:
8.1 Addition:
Tools shall also be marked with:
• rated speed in revolutions per minute;
• rated capacity in mm;
• tools provided with a threaded spindle shall be marked with spindle thread size;
• “ WARNING Always wear eye protection” or the sign M004 of ISO 7010 or the following
safety sign:
The eye protection symbol may be modified by adding other personal protective
equipment such as ear protection, dust mask, etc.
8.101 Tools shall also be marked with an indication of direction of rotation of the spindle.
This shall be indicated by an arrow, raised or sunk, or by any other means no less visible and
indelible.
8.6 Addition:
n . rated speed
8.12.1.1 Addition:
8.12.1.1.101 Safety instructions for abrasive cutting-off operations
Cut-off machine safety warnings
a) The guard provided with the tool must be securely attached to the power tool and
positioned for maximum safety, so the least amount of wheel is exposed towards
the operator. Position yourself and bystanders away from the plane of the rotating
wheel. The guard helps to protect operator from broken wheel fragments and accidental
contact with wheel.
b) Use only bonded reinforced or diamond cut-off wheels for your power tool. Just
because an accessory can be attached to your power tool, it does not assure safe
operation.
60745-2-22 © IEC:2011 – 9 –
NOTE Use the wording “bonded reinforced” or “diamond” as applicable depending on the designation of the tool.
c) The rated speed of the accessory must be at least equal to the maximum speed
marked on the power tool. Accessories running faster than their rated speed can break
and fly apart.
d) Wheels must be used only for recommended applications. For example: do not grind
with the side of cut-off wheel. Abrasive cut-off wheels are intended for peripheral
grinding, side forces applied to these wheels may cause them to shatter.
e) Always use undamaged wheel flanges that are of correct diameter for your selected
wheel. Proper wheel flanges support the wheel thus reducing the possibility of wheel
breakage.
f) Do not use worn down reinforced wheels from larger power tools. Wheels intended
for a larger power tool are not suitable for the higher speed of a smaller tool and may
burst.
NOTE The above warning does not apply for tools only designated to be used with diamond wheels.
g) The outside diameter and the thickness of your accessory must be within the
capacity rating of your power tool. Incorrectly sized accessories cannot be adequately
guarded or controlled.
h) The arbour size of wheels and flanges must properly fit the spindle of the power
tool. Wheels and flanges with arbour holes that do not match the mounting hardware of
the power tool will run out of balance, vibrate excessively and may cause loss of control.
i) Do not use damaged wheels. Before each use, inspect the wheels for chips and
cracks. If power tool or wheel is dropped, inspect for damage or install an
undamaged wheel. After inspecting and installing the wheel, position yourself and
bystanders away from the plane of the rotating wheel and run the power tool at
maximum no load speed for one minute. Damaged wheels will normally break apart
during this test time.
j) Wear personal protective equipment. Depending on application, use face shield,
safety goggles or safety glasses. As appropriate, wear dust mask, hearing
protectors, gloves and shop apron capable of stopping small abrasive or workpiece
fragments. The eye protection must be capable of stopping flying debris generated by
various operations. The dust mask or respirator must be capable of filtrating particles
generated by your operation. Prolonged exposure to high intensity noise may cause
hearing loss.
k) Keep bystanders a safe distance away from work area. Anyone entering the work
area must wear personal protective equipment. Fragments of workpiece or of a broken
wheel may fly away and cause injury beyond immediate area of operation.
l) Hold the power tool by insulated gripping surfaces only, when performing an
operation where the cutting accessory may contact hidden wiring or its own cord.
Cutting accessory contacting a "live" wire may make exposed metal parts of the power
tool "live" and could give the operator an electric shock.
m) Position the cord clear of the spinning accessory. If you lose control, the cord may be
cut or snagged and your hand or arm may be pulled into the spinning wheel.
n) Never lay the power tool down until the accessory has come to a complete stop. The
spinning wheel may grab the surface and pull the power tool out of your control.
o) Do not run the power tool while carrying it at your side. Accidental contact with the
spinning accessory could snag your clothing, pulling the accessory into your body.
p) Regularly clean the power tool’s air vents. The motor’s fan will draw the dust inside the
housing and excessive accumulation of powdered metal may cause electrical hazards.
q) Do not operate the power tool near flammable materials. Sparks could ignite these
materials.
r) Do not use accessories that require liquid coolants. Using water or other liquid
coolants may result in electrocution or shock.
NOTE The above warning does not apply for power tools specifically designed for use with a liquid system.

– 10 – 60745-2-22 © IEC:2011
8.12.1.1.102 Further safety instructions for abrasive cutting-off operations
Kickback and related warnings
Kickback is a sudden reaction to a pinched or snagged rotating wheel. Pinching or snagging
causes rapid stalling of the rotating wheel which in turn causes the uncontrolled power tool to
be forced in the direction opposite of the wheel’s rotation at the point of the binding.
For example, if an abrasive wheel is snagged or pinched by the workpiece, the edge of the
wheel that is entering into the pinch point can dig into the surface of the material causing the
wheel to climb out or kick out. The wheel may either jump toward or away from the operator,
depending on direction of the wheel’s movement at the point of pinching. Abrasive wheels
may also break under these conditions.
Kickback is the result of power tool misuse and/or incorrect operating procedures or
conditions and can be avoided by taking proper precautions as given below.
a) Maintain a firm grip on the power tool and position your body and arm to allow you
to resist kickback forces. Always use auxiliary handle, if provided, for maximum
control over kickback or torque reaction during start-up. The operator can control
torque reactions or kickback forces, if proper precautions are taken.
b) Never place your hand near the rotating accessory. Accessory may kickback over your
hand.
c) Do not position your body in line with the rotating wheel. Kickback will propel the tool
in direction opposite to the wheel’s movement at the point of snagging.
d) Use special care when working corners, sharp edges etc. Avoid bouncing and
snagging the accessory. Corners, sharp edges or bouncing have a tendency to snag the
rotating accessory and cause loss of control or kickback.
e) Do not attach a saw chain, woodcarving blade, segmented diamond wheel with a
peripheral gap greater than 10 mm or toothed saw blade. Such blades create frequent
kickback and loss of control.
f) Do not “jam” the wheel or apply excessive pressure. Do not attempt to make an
excessive depth of cut. Overstressing the wheel increases the loading and susceptibility
to twisting or binding of the wheel in the cut and the possibility of kickback or wheel
breakage.
g) When wheel is binding or when interrupting a cut for any reason, switch off the
power tool and hold the power tool motionless until the wheel comes to a complete
stop. Never attempt to remove the wheel from the cut while the wheel is in motion
otherwise kickback may occur. Investigate and take corrective action to eliminate the
cause of wheel binding.
h) Do not restart the cutting operation in the workpiece. Let the wheel reach full speed
and carefully re-enter the cut. The wheel may bind, walk up or kickback if the power tool
is restarted in the workpiece.
i) Support panels or any oversized workpiece to minimize the risk of wheel pinching
and kickback. Large workpieces tend to sag under their own weight. Supports must be
placed under the workpiece near the line of cut and near the edge of the workpiece on
both sides of the wheel.
j) Use extra caution when making a “pocket cut” into existing walls or other blind
areas. The protruding wheel may cut gas or water pipes, electrical wiring or objects that
can cause kickback.
60745-2-22 © IEC:2011 – 11 –
8.12.2 a) Addition:
101) Permitted wheel construction (diamond or bonded reinforced, if diamond segmented,
maximum peripheral gap between segments is 10 mm, only with a negative rake angle,
see Figure 101), wheel diameter and wheel thickness
102) Explanation of the term “bonded reinforced wheel” or type designation, if applicable
8.12.2 b) Addition:
101) Proper use of blotters, when they are provided with a bonded reinforced product
102) Mounting of accessories and use of the correct flanges, use and care of the abrasive
product. For reversible flanges, the correct method of fitting the flanges
103) Instruction for the mounting and securing of the guard identifying allowable
adjustments to ensure maximum protection of the operator
104) Instruction to the operator on the use of all the different types of wheels specified in
the instructions in accordance with 8.12.2 a) 101), e.g. bonded wheel, diamond wheel
105) Proper support for the workpiece
106) If the guide roller or guide plate is removable or adjustable, instructions on its use
and settings
8.12.2 c) Addition:
101) Storage and handling of accessories
9 Protection against access to live parts
This clause of Part 1 is applicable.
10 Starting
This clause of Part 1 is applicable.
11 Input and current
This clause of Part 1 is applicable.
12 Heating
This clause of Part 1 is applicable, except as follows:
12.4 Replacement:
The tool is operated for 30 min. The temperature rises are measured at the end of the 30 min.

– 12 – 60745-2-22 © IEC:2011
13 Leakage current
This clause of Part 1 is applicable.
14 Moisture resistance
This clause of Part 1 is applicable.
15 Electric strength
This clause of Part 1 is applicable.
16 Overload protection of transformers and associated circuits
This clause of Part 1 is applicable.
17 Endurance
This clause of Part 1 is applicable.
18 Abnormal operation
This clause of Part 1 is applicable, except as follows:
18.10 Addition:
When evaluating the tool in accordance with 18.10, an electronic soft start or a restart
prevention device need not operate.
18.10.4 Addition:
During these tests, the speed of the spindle shall not exceed 120 % of the rated speed. The
accessory in accordance with 8.12.2 a) 101) that results in the maximum speed shall be
installed.
19 Mechanical hazards
This clause of Part 1 is applicable, except as follows:
19.4 Addition:
For tools provided with a detachable guide plate or guide roller(s), two handles are required
for a rated capacity exceeding 100 mm.
The motor casing, if suitably shaped, may be considered as a second handle.
Compliance is checked by inspection.

60745-2-22 © IEC:2011 – 13 –
19.6 Replacement:
The tool shall be designed so as to prevent excessive speed under normal use. The speed of
the tool shall not exceed the rated speed under any operating condition.
Compliance is checked by inspection and by measuring the speed after the tool is operated
for a period of 5 min. The permitted accessory that produces the maximum speed shall be
installed.
If the tool is provided with a load sensitive speed control, then an accessory need not be
installed to load the tool to find maximum speed.
19.101 Tools shall be provided with a wheel guard to protect the user during normal use
against:
– accidental contact with the abrasive product;
– ejection of fragments of the abrasive product;
– sparks and other debris.
The guard shall fulfil the following requirements:
• to change the wheel, it shall not be necessary to remove the guard from the tool;
• be designed to facilitate easy replacement of the wheel. For this purpose, parts of the
guard may be opened without the aid of a tool provided these parts remain attached to the
guard together with any fasteners. An example of such guard is shown in Figure 102;
• be designed so that the risk of an accidental contact between the operator and the wheel
during normal use is minimized e.g. by a possibility of adjustment;
To prevent the installation of an oversized wheel, the clearance between the inside of the
guard and the periphery of a new abrasive product shall in at least one location be 8 mm
maximum for tools with a rated capacity not exceeding 130 mm and 10 mm maximum for
tools with a rated capacity exceeding 130 mm.
A minimum opening for the plunging movement of the motor with respect to the upper guard
may be provided between the guide plate and the lower side of the motor.
For tools designed for bonded reinforced wheels, the guard shall cover the periphery and
both sides of the abrasive wheel for at least 175°, except that the guard need not cover the
spindle end, nut and the locking flange. See Figure 102.
For tools designed only for diamond wheels, the guard shall cover
– the periphery and the spindle side for at least 175°;
– at least the outer 20 % of the maximum recommended wheel radius of the side where the
nut and locking flange are located for at least 175°.
Compliance is checked by inspection and by measurement.

– 14 – 60745-2-22 © IEC:2011
19.102 The tool shall be designed so as to prevent the abrasive product coming loose under
normal use.
Spindle and flange shall be designed so that they secure and locate wheels to the cut-off
machine. At least one of the flanges shall be keyed, screwed, shrunk-on or otherwise
secured to prevent rotation relative to the tool spindle.
Either the direction of the spindle threads shall be such that any clamping device or wheel
with threaded hole tend to tighten during cutting or the locking flange shall have positive
locking to the spindle.
Compliance is checked by inspection.
19.103 In order to limit the unbalance of any rotating accessory, the eccentricity of the
spindle shall be less than 0,1 mm.
For tools that provide for mounting of the accessory through the flange or similar clamping
and locating device, the total eccentricity of the combination of the spindle, the diameter of
the flange bore and the diameter of the part of the flange which locates and guides the
accessory shall be less than:
–1
• 0,30 mm for rated speeds less than 15 000 min ;
–1 –1
• 0,15 mm for rated speeds from 15 000 min to less than 25 000 min ;
–1
• 0,10 mm for rated speeds 25 000 min and higher.
Compliance is checked by measurement.
For tools with flanges, the eccentricity of the flange in the worst off-centre position allowed
by the mounting procedure is measured.
For tools with collets and chucks, a true concentric steel pin is mounted and its eccentricity is
measured at 10 mm and at 20 mm from the mounting location.
19.104 Flanges shall be flat and have no sharp edges.
Flanges for bonded reinforced wheels shall meet the dimensional requirements in 19.104.1.
Flanges for diamond wheels shall meet the dimensional requirements in 19.104.2.
Compliance is checked by inspection and by measurement.
19.104.1 Flanges for bonded reinforced wheels shall have the following dimensions
illustrated in Figure 103, where D is the outside diameter of the wheel, G and W are the
dimensions of the recess and D is the outside diameter of the flange clamping surface.
f
D ≥ 0,25 D
f
For 55 mm ≤ D < 80 mm and for 80 mm ≤ D < 105 mm for wheels with a bore diameter of
10 mm (3/8 in UNC), a wheel flange with D ≥ 19 mm is acceptable.
f
For 80 mm ≤ D < 105 mm for wheels with a bore diameter of 16 mm (5/8 in UNC), a wheel
flange with D ≥ 28 mm is acceptable.
f
For 105 mm ≤ D ≤ 230 mm, a wheel flange with D ≥ 40 mm is acceptable.
f
The backing and the locking flange shall have the same diameter D or the overlap of the
f
backing and locking flange bearing surfaces shall be at least equal to dimension C.

60745-2-22 © IEC:2011 – 15 –
The dimensions C, G and W in Figure 103 shall be:
C ≥ 3 mm
W ≥ G ≥ 1 mm for D < 50 mm
f
W ≥ G ≥ 1,5 mm for D ≥ 50 mm
f
Compliance is checked by measurement.
19.104.2 Flanges for diamond wheels shall have the following dimensions illustrated in
Figure 103, where D is the outside diameter of the wheel, G and W are the dimensions of the
recess and D is the outside diameter of the flange clamping surface.
f
D ≥ 0,15 D
f
The backing and the locking flange shall have the same diameter D or the overlap of the
f
backing and locking flange bearing surfaces shall be at least equal to dimension C, with
C ≥ 1,5 mm.
Dimensions G and W shall be:
W ≥ G ≥ 0
Compliance is checked by measurement.
19.105 Flanges shall be designed so that they are of adequate strength.
Compliance is checked by the following test.
The cut-off machine shall be fitted with a steel disc having an equal thickness and shape as
the wheel suitable for the tool.
The clamping nut shall be tightened with a first test torque according to Table 101. A feeler
gauge of a thickness of 0,05 mm shall be used to test whether the flanges are in contact with
the disc all around the circumference. The test is satisfactory if at no place the feeler gauge
can be pushed underneath the flanges.
The clamping nut shall be further tightened to the second test torque according to Table 101.
A feeler gauge of a thickness of 0,05 mm shall be used to test the deflection of the flanges.
The result is satisfactory if at no place the feeler gauge can be pushed underneath the
flanges by more than 1 mm.
Table 101 – Torques for testing flanges
Thread First test torque Second test torque
Metric UNC Nm Nm
2 2 8
≤ 8
10 3/8 4 15
12 ½ 7,5 30
14 11 45
16 5/8 17,5 70
¾ 35 140
– 16 – 60745-2-22 © IEC:2011
19.106 Tools shall be provided with a guide plate or guide roller for assisting normal
operation. The guide plate or guide roller may be removable or adjustable.
Compliance is checked by inspection.
20 Mechanical strength
This clause of Part 1 is applicable, except as follows:
20.101 The wheel guard, as required by 19.101, shall have sufficient mechanical strength to
withstand a wheel breakage.
For tools designed for bonded reinforced wheels or designed for both diamond wheels and
bonded reinforced wheels, compliance is checked by submitting three samples of any
recommended guard to the test specified in 20.101.1 to 20.101.4. At the manufacturer’s
discretion, the test may be conducted with three guards but less than three separate cut-off
machines. After the test, the tool shall meet the acceptance criteria of 20.101.5.
For tools designed only for diamond wheels, compliance is checked either:
– by submitting three samples of any recommended guard to the test specified in 20.101.1
to 20.101.4, also using bonded reinforced wheels. After the test, the tool shall meet the
acceptance criteria of the first paragraph in 20.101.5.
– or by meeting the design requirements in Table 102.
Table 102 – Guard thickness for diamond wheels
Material of guard Ultimate tensile Minimum fracture Minimum thickness
strength elongation
mm
N/mm²
Steel 350 - 1,50
Steel 380 - 1,25
Light alloy 160 - 2,50
Light alloy 200 - 2,00
Polycarbonate 60 80 % 3,00
Other plastic material shall have a minimum thickness resulting in an impact strength equal or better
than polycarbonate of 3 mm thickness.
20.101.1 The guard shall be securely mounted to the cut-off machine in accordance with
the instructions (see Figure 104).
Regardless the intended wheel construction, a bonded reinforced wheel with the maximum
thickness recommended in 8.12.2 a) 101) and with a diameter equal to the rated capacity of
the cut-off machine shall be mounted to the spindle in accordance with the instructions. For
tools where more than one diamond wheel can be fitted, only one bonded reinforced wheel
is mounted.
The cut-off machine shall be operated at rated voltage for a minimum of 5 min. The speed of
the wheel is measured and recorded.

60745-2-22 © IEC:2011 – 17 –
20.101.2 The wheel as specified in 20.101.1 shall be notched into four equal segments
(quadrants). The cut is directed from the outer edge radially towards the centre (see
Figure 105). The width of each notch shall not exceed 2,5 mm. The extend of the notches
shall allow for the centrifugal forces to cause the wheel to disintegrate at a speed equal to or
greater than either the speed established in 20.101.1 or 90 % of the rated speed of the cut-
off machine, whichever is higher. The notched wheel is mounted to the spindle in accordance
with the instructions.
20.101.3 Using a flexible nylon braded rope, the cut-off machine is suspended at the
extreme right and left side of the front handle(s) and at the midpoint of the switch handle. At
each suspension point of the front handle a mass of 0,5 kg and at the midpoint of the switch
handle as mass of 1 kg shall be attached (see Figure 105). For tools with other handle
designs, other equivalent suspension means may be used.
The three suspension ropes are anchored to a single point and the tool is positioned inside a
test box.
The test box, preferably a hexagonal, octagonal or round, approximately 1 m in interior
diameter and approximately 1 m deep, shall have an outer shell capable of restraining the
disintegrating wheel segments and the interior walls, lined with 25 mm to 35 mm of modelling
clay, backed by additional 25 mm to 35 mm thick layer of cork (see Figure 106). The function
of the modelling clay and cork is to absorb the energy of wheel segments. The modelling clay
and cork may be replaced by other materials performing the same function.
The test box is turned on its side, thus the axis of the box is horizontal. The cut-off machine
is positioned with the wheel approximately in the centre of the box, with the plane of the
wheel perpendicular to the clay walls of the box, the long axis of the tool in the horizontal
plane and the guard in neutral position (see Figure 106). To restrain the cut-off machine
from excessive movement during the wheel’s acceleration, the switch handle is secured with a
force less than 5 N to the box. After securing, the movement of the midpoint of the switch
handle shall not exceed 30 mm from side to side.
NOTE One possible method to achieve the force necessary is the use of permanent magnets.
As an alternative method, the use of a high-speed camera is allowed to fix the position of the
tool just prior to the wheel burst.
20.101.4 While monitoring the wheel speed with a tachometer, the voltage to the tool is
gradually increased until the speed specified in 20.101.2 is achieved. If the wheel does not
disintegrate, the cut-off machine is stopped, the length of the pre-cuts increased and the test
above repeated until the wheel bursts.
NOTE Typically, the wheel will burst within 5 min.
20.101.5 The guard and the fasteners or the guard’s mounting hardware shall remain in
place. Deformation, hairline cracks or scratches and gouges to the guard and mounting
hardware are acceptable.
As a result of the wheel’s disintegration, the guard shal
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