Milwaukee 2680-20 User manual

OPERATOR'S MANUAL
MANUEL de L'UTILISATEUR
MANUAL del OPERADOR
TO REDUCE THE RISK OF INJURY, USER MUST READ OPERATOR'S MANUAL.
AFIN DE RÉDUIRE LE RISQUE DE BLESSURES, L'UTILISATEUR DOIT LIRE LE MANUEL DE
L'UTILISATEUR.
PARA REDUCIR EL RIESGO DE LESIONES, EL USUARIO DEBE LEER EL MANUAL DEL
OPERADOR.
Cat. No.
No de cat.
2680-20
HEAVY-DUTY 4-½" CUT-OFF / GRINDER
EXTRA ROBUSTE MEULE À TRONÇONNER DE 115 mm (4½")
AMOLADORA PARA TROCEAR DE HEAVY-DUTY 115 mm (4½")

23
PERSONAL SAFETY
GENERAL POWER TOOL SAFETY WARNINGS
WORK AREA SAFETY
ELECTRICAL SAFETY
• Keep work area clean and well lit. Cluttered or
dark areas invite accidents.
• Do not operate power tools in explosive atmo-
spheres,suchasin thepresence offlammable
liquids, gases or dust. Power tools create
sparks which may ignite the dust or fumes.
• Keep children and bystanders away while
operating a power tool. Distractions can cause
you to lose control.
• Power tool plugs must match the outlet. Never
modify the plug in any way. Do not use any
adapter plugs with earthed (grounded) power
tools. Unmodifiedplugs and matchingoutlets will
reduce risk of electric shock.
• Avoid body contact with earthed or grounded
surfaces such as pipes, radiators, ranges and
refrigerators. There is an increased risk of elec-
tric shock if your body is earthed or grounded.
• Do not expose power tools to rain or wet con-
ditions. Waterenteringapower tool willincrease
the risk of electric shock.
• Do not abuse the cord. Never use the cord for
carrying, pulling or unpluggingthe power tool.
Keep cord away from heat, oil, sharp edges
or moving parts. Damaged or entangled cords
increase the risk of electric shock.
• When operating a power tool outdoors, use
an extension cord suitable for outdoor use.
Use of a cord suitable for outdoor use reduces
the risk of electric shock.
• If operating a power tool in a damp location
is unavoidable, use a residual current device
(RCD)protected supply. Useofan RCDreduces
the risk of electric shock.
or under the influence of drugs, alcohol or
medication. Amoment of inattention while oper-
ating power tools may result in serious personal
injury.
• Use personal protective equipment. Always
wear eye protection. Protectiveequipment such
as dust mask, non-skid safety shoes, hard hat, or
hearingprotection usedforappropriate conditions
will reduce personal injuries.
• Prevent unintentional starting. Ensure the
switch is in the off-position before connecting
to power source and/or battery pack, picking
up or carrying the tool. Carrying power tools
withyour finger ontheswitch or energisingpower
tools that have the switch on invites accidents.
• Remove any adjusting key or wrench before
turning the power tool on. A wrench or a key
left attached to a rotating part of the power tool
may result in personal injury.
• Do not overreach. Keep proper footing and
balance at all times. This enables better control
of the power tool in unexpected situations.
• Dress properly. Do not wear loose clothing or
jewellery. Keep your hair, clothing and gloves
away from moving parts. Loose clothes, jewel-
lery or long hair can be caught in moving parts.
• If devices are provided for the connection of
dust extraction and collection facilities, en-
sure these are connected and properly used.
Use of these devices can reduce dust-related
hazards.
WARNING READ ALL SAFETY WARNINGS AND INSTRUCTIONS.
Failure to follow the warnings and instructions may result in electric shock, fire and/or
serious injury.
Save all warnings and instructions for future reference
The term "power tool" in all of the warnings refers to your mains-operated (corded) power
tool or battery-operated (cordless) power tool.
POWER TOOL USE AND CARE
• Do not force the power tool. Use the correct
power tool for your application. The correct
power tool will do the job better and safer at the
rate for which it was designed.
• Do not use the power tool if the switch does
not turn it on and off.Anypower toolthat cannot
be controlled with the switch is dangerous and
must be repaired.
• Disconnect the plug from the power source
and/or the battery pack from the power tool
before making any adjustments, changing
accessories, or storing power tools. Such
preventive safety measures reduce the risk of
starting the power tool accidentally.
• Store idle power tools out of the reach of chil-
dren and do not allow persons unfamiliar with
the power tool or these instructions to operate
the power tool. Powertools are dangerousin the
hands of untrained users.
• Maintain power tools. Check for misalignment
or binding of moving parts, breakage of parts
and any other condition that may affect the
power tool operation. If damaged, have the
powertool repaired before use. Manyaccidents
are caused by poorly maintained power tools.
• Keep cutting tools sharp and clean. Properly
maintained cutting tools with sharp cutting edges
are less likely to bind and are easier to control.
• Use the power tool, accessories and tool bits
etc., in accordance with these instructions,
taking into account the working conditions
and the work to be performed. Useof the power
tool for operations different from those intended
could result in a hazardous situation.
BATTERY TOOL USEAND CARE
SERVICE
• Have your power tool serviced by a qualified
repair person using onlyidentical replacement
parts. Thiswill ensure thatthe safetyof the power
tool is maintained.
• Recharge only with the charger specified by
the manufacturer. A charger that is suitable for
one type of battery pack may create a risk of fire
when used with another battery pack.
• Use power tools only with specifically desig-
nated battery packs. Use of any other battery
packs may create a risk of injury and fire.
• When battery pack is not in use, keep it away
from other metal objects like paper clips,
coins, keys, nails, screws,or other small metal
objects that can make a connection from one
terminal to another. Shorting the battery termi-
nals together may cause burns or a fire.
• Under abusive conditions, liquid may be eject-
ed from the battery, avoid contact. If contact
accidentally occurs, flush with water. If liquid
contacts eyes, additionally seek medical help.
Liquid ejected from the battery may cause irrita-
tion or burns.
SPECIFIC SAFETY RULES
• Stay alert, watch what you are doing and use
common sense when operating a power tool.
Do not use a power tool while you are tired
Safety Warnings Common for Grinding, Sand-
ing, Wire Brushing or Abrasive Cutting-Off
Operations:
• This power tool is intended to function as a
grinder, sander, wire brush or cut-off tool.
Read all safety warnings, instructions, il-
lustrations and specifications provided with
this power tool. Failure to follow all instructions
listed below may result in electric shock, fire and/
or serious injury.
• Operations such as polishing are not recom-
mended to be performed with this power tool.
Operations for which the power tool was not de-
signed may create a hazard and cause personal
injury.
• Do not use accessories which are not specifi-
cally designed and recommended by the tool
manufacturer. Just because the accessory can
be attached to your power tool, it does not assure
safe operation.
• 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.
• The outside diameterand thethickness ofyour
accessory must be within the capacity rating
ofyour power tool. Incorrectlysizedaccessories
cannot be adequately guarded or controlled.
• The arbour size of wheels, flanges, backing
pads or any other accessory must properly
fit the spindle of the power tool. Accessories
witharbourholes that do notmatchthe mounting
hardware of the power tool will run out of bal-
ance, vibrate excessively and may cause loss of
control.
• Do not use a damaged accessory. Before each
use inspect the accessory such as abrasive
wheels for chips and cracks, backing pad for
cracks, tear or excess wear, wire brush for
loose or cracked wires. If power tool or acces-
sory is dropped, inspect for damage or install
an undamaged accessory. After inspecting
and installing an accessory, position yourself
and bystanders away from the plane of the
rotating accessory and run the power tool
at maximum no-load speed for one minute.
Damaged accessories will normally break apart
during this test time.
• Wear personal protective equipment. Depend-
ing on application, use face shield, safety
goggles or safety glasses. As appropriate,

45
wear dust mask, hearing protectors, gloves
and work shop apron capable of stopping
small abrasive or workpiece fragments. The
eye protection must be capable of stopping
flying debris generatedby 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.
• Keep bystanders a safe distance away from
work area. Anyone entering the work area
must wear personal protective equipment.
Fragmentsof workpiece orof a brokenaccessory
may fly away and cause injury beyond immediate
area of operation.
• Hold power toolby insulatedgripping 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 shock the operator.
• Position the cord clear of the spinning acces-
sory. If you lose control, the cord may be cut or
snaggedand your handor armmaybe pulledinto
the spinning accessory.
• Never lay the power tool down until the ac-
cessory has come to a complete stop. The
spinningaccessory may grabthe surfaceandpull
the power tool out of your control.
• 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.
• 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.
• Do not operate the power tool near flammable
materials. Sparks could ignite these materials.
• Do not use accessories that require liquid
coolants. Using water or other liquid coolants
may result in electrocution or shock.
Kickback and Related Warnings
Kickback is a sudden reaction to a pinched or
snagged rotating wheel, backing pad, brush or
anyother accessory. Pinchingor snaggingcauses
rapid stalling of the rotating accessory which in
turn causes the uncontrolled power tool to be
forcedin the directionopposite of theaccessory’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
Cat. No. Volts DC No Load RPM Spindle Thread Size Wheel Size
2680-20 18 9000 5/8”-11 4-1/2”
Specifications
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.
Kickbackis the resultof power toolmisuse and/or
incorrect operating procedures or conditions and
can be avoided by taking proper precautions as
given below.
• 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.
• Neverplace yourhand nearthe rotatingacces-
sory. Accessory may kick back over your hand.
• Do not position your body in the area where
power tool will move if kickback occurs. Kick-
back will propel the tool in direction opposite to
the wheel’s movement at the point of snagging.
• Use special care whenworking 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.
• Do not attach a saw chain woodcarving blade
or toothed saw blade. Such blades create fre-
quent kickback and loss of control.
Safety Warnings Specific for Grinding and
Abrasive Cutting-Off Operations:
• Use only wheel types that are recommended
for your power tool and the specific guard
designed for the selected wheel. Wheels for
which the power tool was not designed can not
be adequately guarded and are unsafe.
• The guard must be securely attached to the
power tool andpositioned formaximum safety,
so the least amount of wheel is exposed to-
wards the operator. The guard helps to protect
operator from broken wheel fragments and ac-
cidental contact with wheel.
• Wheels must be used only for recommended
applications. For example: do not grind with
theside ofcut-off wheel.Abrasive cut-offwheels
areintendedforperipheralgrinding, sideforcesap-
plied to these wheels may cause them to shatter.
• Alwaysuse undamaged wheel flanges that are
of correct size and shape for your selected
wheel. Proper wheel flanges support the wheel
thus reducing the possibility of wheel breakage.
Flanges for cut-off wheels may be different from
grinding wheel flanges.
• Do not use worn down wheels from larger
powertools. Wheelintended forlarger powertool
is not suitable for the higher speed of a smaller
tool and may burst.
Additional Safety Warnings Specific for Abra-
sive Cutting-Off Operations:
• Do not jamthe cut-offwheel orapply excessive
pressure. Do notattempt to makean excessive
depth of cut. Overstressing the wheel increases
the loading and susceptibility to twisting or bind-
ing of the wheel in the cut and the possibility of
kickback or wheel breakage.
• Do not position your body in line with and
behind the rotating wheel. When the wheel, at
the point of operation, is moving away from your
body, the possible kickback may propel the spin-
ning wheel and the power tool directly at you.
• 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 cut-off wheel from the
cutwhile thewheel isin motion otherwisekick-
back may occur. Investigate and take corrective
action to eliminate the cause of wheel binding.
• Do not restart the cutting operation in the
workpiece. Let the wheel reach full speed and
carefully reenter the cut. The wheel may bind,
walk up or kickback if the power tool is restarted
in the workpiece.
• Support panels or any oversized workpiece to
minimize the risk of wheel pinching and kick-
back. 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.
• Use extra caution when making a “pocketcut”
into existing walls or other blind areas. The
protrudingwheel maycut gasor waterpipes, elec-
trical wiring or objects that can cause kickback.
Safety Warnings Specific for Sanding Opera-
tions:
• Do not useexcessively oversized sandingdisc
paper. Follow manufacturers recommenda-
tions, when selecting sanding paper. Larger
sanding paper extending beyond the sanding
pad presents a laceration hazard and may cause
snagging, tearing of the disc or kickback.
Safety Warnings Specific for Wire Brushing
Operations:
• Be aware that wire bristles are thrown by the
brush even during ordinary operation. Do not
over stress the wires by applying excessive
load to the brush. The wire bristles can easily
penetrate light clothing and/or skin.
• If the use of a guard is recommended for wire
brushing, do not allow any interference of the
wire wheel or brush with the guard. Wirewheel
orbrush may expandin diameter dueto workload
and centrifugal forces.
Additional Safety Warnings
•Maintain labels and nameplates. These carry
important information. If unreadable or missing,
contact a MILWAUKEE service facility for a free
replacement.
• WARNING: Some dustcreated bypower sanding,
sawing, grinding, drilling, and other construction
activities contains chemicals known to cause
cancer, birth defects or other reproductive harm.
Some examples of these chemicals are:
• lead from lead-based paint
• crystallinesilica frombricks and cementand other
masonry products, and
• arsenic and chromium from chemically-treated
lumber.
Your risk from these exposures varies, depending
on how often you do this type of work. To reduce
your exposure to these chemicals: work in a well
ventilated area, and work with approved safety
equipment,such asthosedust masksthat arespe-
cially designed to filter out microscopic particles.
Symbology
Direct Current
Underwriters Laboratories, Inc.
United States and Canada
No Load Revolutions
per Minute (RPM)

67
ASSEMBLY
WARNING To reduce the risk of injury,
always remove battery pack before changing
or removing accessories. Only use accesso-
ries specifically recommended for this tool.
Others may be hazardous.
Inserting/Removing Battery Pack
Insert the battery pack by sliding battery pack into
the body of the tool. Insert the battery pack until
the battery latches lock.
To remove the battery pack, press in both battery
latches and slide the battery pack off of the tool.
WARNING Recharge only with the
charger specified for the battery. For specific
charging instructions, read the operator’s
manual supplied with your charger and
battery. This tool is not compatible with V™-
technology or NiCd systems.
Functional Description
1. Side handle
2. Spindle lock
3. Side handle sockets
4. Paddle switch
5. Switch lock-off
6. Guard
7. Guard lock lever
Installing Side Handle
The side handle may be installed on either side
or the top of gear case. Position side handle in
the location which offers best control and guard
protection. To install, thread side handle into side
handle socket and tighten securely.
Installing, Removing and Adjusting the Guard
This tool is shipped with a guard.A guard must be
used when using the tool as a grinder. The guard
may be removed when using tool as a sander.
1. To remove the guard, remove the battery pack
and remove any accessories from spindle.
2. Press in the lock lever and rotate the guard to
line up the tabs on the grinder with the slots in
the guard.
3. Press in the lock lever and lift the guard straight
up and away from the tool.
4. To install the guard, remove the battery pack
and remove any accessories from the spindle.
5. Line up the tabs on the grinder with the slots in
the guard.
6. Press in the lock lever and press the guard onto
the tool.
7. To adjust the guard, press in the lock lever and
rotate the guard to one of five detent slots.
WARNINGTo reduce the risk of injury
when grinding:
• ALWAYS use the proper guard.
• ALWAYS properly install the guard.
• ALWAYS hold the tool firmly with both
hands using the handles provided before
and during grinding.
• NEVER use a wheel that has been dropped.
• NEVER bang grinding disc onto work.
• NEVER grind without proper safety
equipment.
1
4
5
6
7
3
2
Tab
slots
Fig. 1
Detent
slots
OPERATION
WARNING To reduce the risk of injury,
wear safety goggles or glasses with side
shields.
Controlled Start
The controlled start feature reduces the torque
reaction "jerk" when its trigger is pulled.
Paddle Switch Operation
To start the tool, grasp the handle and side handle
firmly. Pull the lock-off button back and squeeze
the paddle switch.
To stop the tool, release the paddle switch. Make
sure the tool comes to a complete stop before lay-
ing the tool down.
General Operation
1. If you have just installed an accessory or are
beginninga periodof work, testit byletting itspin
forone minutebeforeapplying itto theworkpiece.
Out-of-balanceor damagedaccessories canmar
workpiece, damage the tool, and cause stress
that may cause accessory failure.
2. Use a clamp, vise or other practical means to
hold your work, freeing both hands to control the
tool.
3. Hold tool securely with both hands.
4. Start the tool.
5. Allow accessory to come to full speed before
beginning work.
6. Control pressure and surface contact between
accessory and workpiece. Too much pressure
slows speed.
If the tool stalls, release the trigger to reset.
Lighten pressure to avoid stalling.
7. When finished, turn off the tool and make sure
it comes to a complete stop before laying it
down.
Installing/Removing Accessories
Make sure the wheel does not extend beyond the
bottomof the guard.Threaded hubgrinding wheels
may require a deeper guard (see "Accessories").
1. Remove the battery pack.
2. Properly position the guard (Fig. 2).
WARNING Only use accessories with
Maximum Safe Operating Speed rated at
least equal to the maximum speed marked
on the power tool. This speed is based on
the strength of the wheel, allowing for a
reasonable measure of safety. It is not meant
to imply a best or most efficient operating
speed. Do not exceed the Maximum Safe
Operating Speed.
Fig. 2 Operator's Zones Flange nut
position for
1/8" thick or less wheels
Spindle
Flange
Wheel
Flange nut
Fig. 4
Fig. 3
1/8"
1/4"
3. Wipe the flange, flange nut and spindle to
remove dust and debris. Inspect the parts for
damage. Replace if needed.
5. Place the selected wheel on the spindle and
align it with the flange.
6. Position the flange nut over the spindle accord-
ing to wheel thickness (Fig. 4).
7. Pressin the spindlelock button whileturning the
flange nut clockwise. Tighten securely using a
spanner wrench.
8. To remove wheel, remove the battery pack and
reverse the procedure.
Flange nut
position for
1/4" thick or more wheels
4. Place the flange on spindle, as shown.
WARNING To reduce the risk of injury,
always remove battery pack before changing
or removing accessories or making adjust-
ments. Use only specifically recommended
accessories. Others may be hazardous.

89
Wire
Wheel
Brush
Fig. 8 Guard
WARNING To reduce the risk of injury,
the operator should be instructed in the use,
care and protection of grinding wheels.
Fig. 5
For best result use only this portion of disc
Hold at a
Hold at a
5° to 15°
5° to 15°
angle
angle
USING GRINDING WHEELS
Care of Grinding & Cut-Off Wheels
Grinding/cut-off wheels should be protected from:
• wetness and extreme humidity
• any type of solvent
• extreme changes in temperature
• dropping and bumping
Grinding and cut-off wheels should be stored:
• in an organized way so wheels can be removed
without disturbing or damaging other wheels
• with their safety information
Grindingandcut-offwheelsshouldNOTbe dropped,
rolled or bumped.
Discard wheels that have been dropped, rolled,
bumped, subjected to extreme changes in tempera-
ture, or come into contact with solvents or wetness.
Grinding
When grinding, hold tool at a 5oto 15oangle, using
constantpressure for auniformfinish. Toogreat an
anglecauses concentratedpressure onsmall areas
which may gouge or burn work surface.
Grinding Wheel Selection
Use grinding wheels, and accessories that are:
•correct size as written on tool’s nameplate.
•rated at or above the RPM listed on the tool’s
nameplate.
•correct accessory, wheel type and grit for the job.
Grinding is the cutting action of thousands of abra-
sive grains on the face of a grinding wheel. When
grinding metals such as steel and iron, choose an
aluminum oxide grinding wheel. Select a silicon
carbidegrinding wheel forstone and concrete.Use
cotton reinforced wheels for non-ferrous metals.
Type 27 Reinforced 1/8" thick or less Cut-Off
Wheels are suited for small cut-off and shallow
notching operations only. Always handle wheels
carefully to avoid damage. Before installing any
wheel, always inspect it for cracks. If wheel is
cracked, discard it to prevent others from using it.
Fig. 6
WARNING A Type "1" guard must be
installed when usinga cut-off wheelto provide
maximum protection for the operator if the
wheel should break.
WARNING Using the face of a Cut-Off
Wheel (as in grinding) will cause the Wheel
to crack and break, resulting in serious per-
sonal injury.
USING CUT-OFF WHEELS
Type "1"Cut-Off Wheelsare suited forsmallcut-off
and shallow notching operations only.
Whenusing a cut-offwheel,holdthe toolas shown,
using only the edge of the wheel.
Fig. 7 Wire Cup Brush
Aluminum Oxide
For fast cutting, general purpose discs for most
metal jobs. Best for cold-rolled steel, stainless
steel or metals requiring tough, fast cutting, long
lasting abrasives.
Aluminum Zirconia Bi-Cut
Uniquegrit pattern isarranged in clustersfor fast-
erstock removal andcleaning. Ideal forremoving
paint from cars, boats, etc. without clogging.
Ceramic
Lasts up to 3 times longer than Aluminum Ox-
ide Discs. For general metal working. Ideal for
tough jobs.
WARNING Everyone in the area must
wear protective clothing and safety goggles
or face shields. Fatigued wires and residue
will fly off the brush with considerable force,
causing potential for serious injury.
WARNING Never exceed Maximum
Safe Operating Speed of brush. Do not use
a damaged brush or one that is functioning
improperly (throwing wires, out-of-balance,
etc.). These conditions increase the pos-
sibility of further brush failure and possible
injury. Discard and replace damaged brushes
immediately.
Sanding Disc Selection
Use sanding discs and accessories that are:
• correct size as written on tool’s nameplate.
• rated at or above the RPM listed on the tool’s
nameplate.
• correct accessory, wheel type and grit for the job.
Refer to the table below to select the correct type
of sanding disc for your job. Generally, use 24 or
36 grit for heavy stock removal; 50, 60, or 80 grit
formedium stock removaland 120 gritfor finishing.
Alwaysbegin with acoarse grit, usingsuccessively
finer grits to obtain the desired finish. See your
MILWAUKEE Electric Tool Catalog for a complete
list of sanding discs.
USING WIRE BRUSHES USING SANDING DISCS
Wire brushes are useful for removing rust, scale,
burrs, weld slag, etc.
Always install wire cup brushes according to the
accessory manufacterer’s instructions.
Testwheel for balanceand looseor damaged wires
by letting it spin for one minute before applying it
to the workpiece. During this time, no one should
stand in front of or in line with it.
Control pressure and surface contact between
wheel and workpiece. Too much pressure causes
over-bending of wires and heat build-up causing
prematurewire breaking, rapiddulling and reduced
brushlife. Insteadof morepressure, trya wirewheel
withmore aggressive cuttingaction (increasedwire
size, decreased wire length or different brush type
(knot type vs.crimped wire type).
Installing Backing Pad and Sanding Discs
1. Remove the battery pack.
2. Wipe the accessories, disc nut and spindle to
remove dust and debris. Inspect the parts for
damage. Replace if needed.
3. Slipbackingpad ontospindle with flatside away
from gear case.
Fig. 9
Spindle
Backing
pad
Disc nut
Sanding
disc
When using a wire wheel brush, install guard ac-
cording to "Installing/Removing Accessories".
4. Place sanding disc on backing pad and secure
assembly to spindle with disc nut.
WARNING Because the wires on wire
wheel brushes are directed towards the op-
erator, a guard must be used to protect the
operator when fatigued wires break.