DeWalt D28490 User manual

D28490, D28491
Angle Grinder
Esmeriladora Angular
INSTRUCTION MANUAL
MANUAL DE INSTRUCCIONES
INSTRUCTIVO DE OPERACIÓN, CENTROS DE SERVICIO Y PÓLIZA DE
GARANTÍA. ADVERTENCIA: LÉASE ESTE INSTRUCTIVO ANTES DE USAR
EL PRODUCTO.
Questions? See us on the World Wide Web at www.dewalt.com
¿Dudas? Visítenos en Internet: www.dewalt.com

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SAVE THESE INSTRUCTIONS
WARNING! Read and understand all instructions. Failure to
follow all instructions listed below, may result in electric shock, fire
and/or serious personal injury.
General Safety Instructions
WORK AREA
• Keep your work area clean and well lit. Cluttered benches
and dark areas invite accidents.
• Do not operate power tools in explosive atmospheres, such
as in the presence of flammable liquids, gases, or dust.
Power tools create sparks which may ignite the dust or fumes.
• Keep bystanders, children, and visitors away while operating
a power tool. Distractions can cause you to lose control.
ELECTRICAL SAFETY
• Grounded tools must be plugged into an outlet properly
installed and grounded in accordance with all codes and
ordinances. Never remove the grounding prong or modify
the plug in any way. Do not use any adapter plugs. Check
with a qualified electrician if you are in doubt as to whether
the outlet is properly grounded. If the tools should electrically
malfunction or break down, grounding provides a low resistance
path to carry electricity away from the user. Applicable only to
Class I (grounded) tools.
• Double insulated tools are equipped with a polarized plug
(one blade is wider than the other.) This plug will fit in a
polarized outlet only one way. If the plug does not fit fully
in the outlet, reverse the plug. If it still does not fit, contact
a qualified electrician to install a polarized outlet. Do not
change the plug in any way. Double insulation eliminates
the need for the three wire grounded power cord and grounded
power supply system. Applicable only to Class II (double
insulated) tools.
• Avoid body contact with grounded surfaces such as pipes,
radiators, ranges and refrigerators. There is an increased risk
of electric shock if your body is grounded.
• Don’t expose power tools to rain or wet conditions. Water
entering a power tool will increase the risk of electric shock.
• Do not abuse the cord. Never use the cord to carry the
tools or pull the plug from an outlet. Keep cord away from
heat, oil, sharp edges or moving parts. Replace damaged
cords immediately. Damaged cords increase the risk of electric
shock.
• When operating a power tool outside, use an outdoor
extension cord marked “W-A” or “W.” These cords are rated
for outdoor use and reduce the risk of electric shock.
Voltage (Volts) Total length of cord in meters (m)
120 - 127V 0 - 7 7 - 15 15 - 30 30 - 50
220 - 240V 0 - 15 15 - 30 30 - 60 60 - 100
Rated Ampere
range Minimal cross-sectional area of the cord in meters (mm2)
0 - 6A 1.0 1.5 1.5 2.5
6 - 10A 1.0 1.5 2.5 4.0
10 - 12A 1.5 1.5 2.5 4.0
12 - 16A 2.5 4.0 Not Recommended

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PERSONAL SAFETY
• Stay alert, watch what you are doing and use common
sense when operating a power tool. Do not use tool while
tired or under the influence of drugs, alcohol, or medication.
A moment of inattention while operating power tools may result
in serious personal injury.
• Dress properly. Do not wear loose clothing or jewelry.
Contain long hair. Keep your hair, clothing, and gloves
away from moving parts. Loose clothes, jewelry, or long hair
can be caught in moving parts. Air vents often cover moving
parts and should also be avoided.
• Avoid accidental starting. Be sure switch is off before
plugging in. Carrying tools with your finger on the switch or
plugging in tools that have the switch on invites accidents.
• Remove adjusting keys or wrenches before turning the tool
on. A wrench or a key that is left attached to a rotating part of
the tool may result in personal injury.
• Do not overreach. Keep proper footing and balance at all
times. Proper footing and balance enables better control of the
tool in unexpected situations.
• Use safety equipment. Always wear eye protection. Dust
mask, non-skid safety shoes, hard hat, or hearing protection
must be used for appropriate conditions.
TOOL USE AND CARE
• Use clamps or other practical way to secure and support
the workpiece to a stable platform. Holding the work by
hand or against your body is unstable and may lead to loss of
control.
• Do not force tool. Use the correct tool for your application.
The correct tool will do the job better and safer at the rate for
which it is designed.
• Do not use tool if switch does not turn it on or off. Any tool
that cannot be controlled with the switch is dangerous and must
be repaired.
• Disconnect the plug from the power source before making
any adjustments, changing accessories, or storing the tool.
Such preventative safety measures reduce the risk of starting
the tool accidentally.
• Store idle tools out of reach of children and other untrained
persons. Tools are dangerous in the hands of untrained users.
• Maintain tools with care. Keep cutting tools sharp and
clean. Properly maintained tools, with sharp cutting edges are
less likely to bind and are easier to control.
• Check for misalignment or binding of moving parts,
breakage of parts, and any other condition that may affect
the tools operation. If damaged, have the tool serviced before
using. Many accidents are caused by poorly maintained tools.
• Use only accessories that are recommended by the
manufacturer for your model. Accessories that may be
suitable for one tool may become hazardous when used on
another tool.
SERVICE
• Tool service must be performed only by qualified repair
personnel. Service or maintenance performed by unqualified
personnel could result in a risk of injury.
• When servicing a tool, use only identical replacement parts.
Follow instructions in the Maintenance section of this manual.
Use of unauthorized parts or failure to follow Maintenance
instructions may create a risk of electric shock or injury.

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minute. If the wire brush has loose wires, they will be detected.
Never start the tool with a person in line with the wheel. This
includes the operator.
• In operation, avoid bouncing the wheel or giving it rough
treatment. If this occurs, stop the tool and inspect the wheel.
• Direct sparks away from operator, bystanders or flammable
materials. Sparks may be produced while using a sander or
grinder. Sparks may cause burns or start fires.
• Always use side handle. Tighten the handle securely. The
side handle should always be used to maintain control of the tool
at all times.
CAUTION: Use extra care when grinding into a corner because a
sudden, sharp movement of the grinder may be experienced when the
wheel contacts a secondary surface.
• Clean out your tool often, especially after heavy use. Dust
and grit containing metal particles often accumulate on interior
surfaces and could create an electric shock hazard.
CAUTION: Wear appropriate personal hearing protection during
use. Under some conditions and duration of use, noise from this
product may contribute to hearing loss.
WARNING: Some dust created by power 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 paints,
• crystalline silica from bricks and cement and other masonry
products, and
• arsenic and chromium from chemically-treated lumber (CCA).
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
Additional Specific Safety Instructions
for Grinders
• Always use proper guard with grinding wheel. A guard
protects operator from broken wheel fragments and wheel
contact.
• Accessories must be rated for at least the speed recom-
mended on the tool warning label. Wheels and other
accessories running over rated speed can fly apart and cause
injury. Refer to the table below. Accessory ratings are above
rated no-load tool speeds because actual tool speeds may
vary.
NOTE: The rated no load tool speed is printed on the name plate
and embossed on the gear case.
Rated
no (no load) Minimum Accessory
Tool Speed Rating
6500 RPM 6600 RPM
8500 RPM 8500 RPM
• Hold tool by insulated gripping surfaces when performing
an operation where the cutting tool may contact hidden
wiring or its own cord. Contact with a “live” wire will make
exposed metal parts of the tool “live” and shock the operator.
• Before using, inspect recommended accessory for
cracks or flaws. If such a crack or flaw is evident, discard the
accessory. The accessory should also be inspected whenever
you think the tool may have been dropped.
• When starting the tool with a new or replacement wheel, or
a new or replacement wire brush installed, hold the tool in a
well protected area and let it run for one minute. If the wheel
has an undetected crack or flaw, it should burst in less than one

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A
B
D
E
C
Features
SWITCH
The tool is controlled by a trigger switch (A). A lock-on button (B)
provides increased comfort in extended use applications.
MULTIPLE SIDE HANDLE POSITIONS
The side handle can be properly positioned in two locations based
on personal preference and application. The side handle must be
used at all times to maintain proper control of the tool.
SPINDLE LOCK C
The spindle lock pin is provided to
prevent the spindle from rotating when
installing or removing wheels. Operate
the spindle lock pin only when the tool is
turned off and unplugged from the power
source. To engage the lock, depress the
spindle lock button (C) and rotate the
spindle until you are unable to rotate it
further.
equipment, such as those dust masks that are specially designed
to filter out microscopic particles.
• Avoid prolonged contact with dust from power sanding,
sawing, grinding, drilling, and other construction activities.
Wear protective clothing and wash exposed areas with
soap and water. Allowing dust to get into your mouth, eyes, or
lay on the skin may promote absorption of harmful chemicals.
• The label on your tool may include the following symbols.
V.......... volts A ............. amperes
Hz........ hertz W ............ watts
min ......minutes ........... alternating current
....direct current no ........... no load speed
....... Class II Construction …/min..... revolutions or
........ earthing terminal ................ reciprocation per
........safety alert symbol ................ minute
FAMILIARIZATION
Large Angle Grinders and Large Angle Sanders are designed for
heavy material removal in extended use applications. The following
grinders and sanders are described in this manual.
D28490 9" Angle Grinder 6,500 rpm 2200 W
D28491 7" Angle Grinder 8,500 rpm 2200 W
Components
A. Trigger Switch D. Guard
B. Lock On Button E. Side Handle
C. Spindle Lock

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NOTE: Never depress the spindle lock button while the grinder is
running. Never turn on the grinder while the spindle lock button is
depressed. Damage to your tool may result.
MOUNT
The grinder is equipped with a mount, enabling easy wheel
installation and removal.
Accessories and Attachments
It is important to choose the correct guards, backing pads
and flanges to use with grinder accessories. See the chart on
pages 5–7 for information on choosing the correct accessories.
CAUTION: Accessories must be rated for at least the speed
recommended on the tool warning label. Wheels and other
accessories running over rated speed can fly apart and cause
injury.
ATTACHMENTS
Attachments designed specifically for this grinder can be purchased
through DEWALT dealers and DEWALT Factory Service centers.
D284939 9" Type 27 guard
D284948 9" Type 28 guard
D284937 7" Type 27 guard
D284936 6" Type 11 Flaring cup guard with flange
D284934 4" Type 11 Flaring cup guard with flange
D284933 Type 11 flaring cup wheel backing flange
D284932 Type 1 Flange set
D284931 7" Type 1 Guard
054339-00 Grinding backing flange
22191-00 Clamp nut
61820-01 Wheel Wrench
445928-01 Mount spindle protector
397711-00 Rubber gear case bumper
Sanding Flap Discs
mount mount
type 27 guard
D284937/D284939
type 27 guard
D284937/D284939
hubbed sanding flap
disc
non-hubbed sanding
flap disc
clamp nut
D22191-00
backing flange
54339-00
NOTE: Wheel size must match guard size; i.e., a new 7" wheel may
not be used with a 9" guard. The bottom surface of wheel must be
inside the bend of the guard lip.

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Grinding Wheels
mount
type 27 guard
D284937/D284939
type 27 hubbed wheel
mount
type 28 guard
D284948
type 28 hubbed wheel
mount
type 27 guard
D284937/D284939
backing flange
54339-00
type 27 non-hubbed
wheel
clamp nut
D22191-00
Sanding Discs
mount
rubber backing pad
DW4947
sanding disc
clamp nut
included with
D4947
mount
type 28 guard
D284948
backing flange
54339-00
type 28 non-hubbed
wheel
clamp nut
D22191-00
NOTE: Wheel size must match guard size; i.e., a new 7" wheel may not be used with a
9" guard. The bottom surface of wheel must be inside the bend of the guard lip.

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Flaring Cup Stones
Wire Wheels
type 11 flaring cup guard
D284934 — 4"
D284936 — 6"
backing flange
608368-00
flaring cup stone
NOTE: Wheel size must match guard size; i.e., a 7" wheel may not
be used with a 9" guard.
Cutting Wheels
mount
type 1 guard
D284931
backing flange
608370-00
abrasive cutting wheel
clamp nut
608463-00
mount
type 1 guard
D284931
backing flange
608370-00
diamond cutting wheel
clamp nut
608463-00
mount
wire wheel
type 27 guard
D284937/D284939
mount
wire cup brush
type 27 guard
D284937/D284939

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trigger. Lock-on button will remain depressed and tool will remain
on.
To turn the tool off, depress and release trigger. The lock pin button
will pop out, permitting the trigger to disengage and causing the
tool to turn off.
NOTE: Allow the tool to reach full speed before touching tool to
work surface. Lift the tool from the work surface before turning the
tool off.
WARNING: Make sure the wheel has come to a complete stop
before setting the tool down.
REMOVAL OF LOCK-ON FEATURE
The lock-on button can be permanently removed without
compromising compliance with regulatory agencies shown on
the tool’s nameplate. Removal of the lock pin must be done by a
DEWALT service center.
Mounting and Using Depressed
Center Grinding Wheels and
Sanding Flap Discs
MOUNTING AND REMOVING GUARD
WARNING: Turn off and unplug tool before making any
adjustments or removing or installing accessories. Before
reconnecting the tool, depress and release the trigger switch
to ensure that the tool is off.
IMPORTANT INFORMATION
ABOUT GUARDS
Guards must be used with all grinding
wheels, sanding flap discs, wire brushes
and wire wheels. The tool may be used
without a guard only when sanding with
conventional sanding discs.
ASSEMBLY AND ADJUSTMENTS
Attaching the
Side Handle
To install the side handle, thread the
handle into one of the two positions and
tighten securely by turning clockwise.
OPERATION
Power Source
Plug the large angle grinder into
a dedicated electrical circuit.
Operating this tool on a circuit with other tools will decrease tool
performance.
Switch
WARNING: Before connecting the tool to a power source or after
a power failure, depress and release the trigger switch (A) once
without depressing the lock-on button (B) to ensure that the switch
is in the off position. If the trigger switch is locked on, the tool will
start unexpectedly when power is reconnected to the tool. Hold the
side handle and rear handle firmly to maintain control of tool at start
up and during use.
TRIGGER OPERATION
To turn the tool on, depress the trigger switch (A). The tool will
remain running while the trigger is depressed. Turn the tool off by
releasing the trigger.
TRIGGER OPERATION WITH
A
B
LOCK-ON FEATURE
To turn tool on, depress trigger. Depress
and hold lock-on button (B) while releasing

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90˚ 90˚
CAUTION: When using a grinding wheel with a type 27, 28 or 29
guard, be sure that the bottom surface of the grinding wheel is
inside the the guard lip.
MOUNTING AND REMOVING HUBBED WHEELS
Hubbed wheels install directly on the threaded spindle.
1. Thread the wheel on the spindle by hand, seating the wheel
against the mount.
2. Depress the spindle lock button and use a wrench to tighten the
hub of the wheel.
3. Reverse the above procedure to remove the wheel.
CAUTION: Failure to properly seat the wheel against the mount
before turning the tool on may result in damage to the tool or the
wheel.
MOUNTING NON-HUBBED WHEELS
Depressed center, Type 27 grinding wheels must be used with
available accessory flanges. See the charts on pages 5–7 of this
manual for more information.
G
E
H
1. Install the metal backing flange (G) on spindle (E) against the
mount.
2. Place wheel against the backing flange, centering the wheel on
the backing flange pilot.
3. While depressing the spindle lock button, thread the clamp nut
(H) on spindle, piloting the raised hub on clamp nut in the center
of grinding wheel.
4. Tighten the clamp nut with a wrench.
5. Reverse the above procedure to remove the wheel.
SURFACE GRINDING WITH GRINDING WHEELS
1. Allow the tool to reach full speed before touching tool to work
surface.
2. Apply minimum pressure to work surface, to allow the tool to
operate at high speed.
3. Maintain a 20˚ to 30˚ angle between the tool and work
surface.
4. Continuously move the tool in a forward and back motion to
avoid creating gouges in the work surface.
5. Remove the tool from work surface before turning tool off. Allow
the tool to stop rotating before setting it down.
EDGE GRINDING WITH GRINDING WHEELS
CAUTION: Wheels used for cutting and edge grinding may
break if they bend or twist while the tool is being used to do
cut-off work or deep grinding. To reduce the risk of serious injury,
limit the use of these wheels with a standard type 27 guard to
shallow cutting and notching (less than 1/2" in depth). The open
side of the guard must be positioned away from the operator. For
deeper cutting with a type 1 wheel, use a closed, type 1 guard.
Type 1 guards are available at extra cost from your local dealer or
authorized service center.

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1. Allow the tool to reach full speed before touching the tool to the
work surface.
2. Apply minimum pressure to work surface, to allow the tool to
operate at high speed.
3. Protect yourself during edge finishing by directing the open side
of the guard away from you.
4. Move the tool continuously in a forward and back motion to
avoid creating gouges in the work surface.
5. Remove tool from work surface before turning the tool off. Allow
the tool to stop rotating before setting it down.
WARNING: Do not use edge grinding wheels for surface grinding
applications because edge grinding wheels are not designed for
side pressures encountered with surface grinding. Wheel breakage
and injury may result.
SURFACE FINISHING WITH SANDING FLAP DISCS
1. Allow the tool to reach full speed before touching tool to work
surface.
2. Apply minimum pressure to work surface, to allow the tool to
operate at high speed.
3. Maintain a 5˚ to 10˚ angle between the tool and work surface.
4. Continuously move the tool in a forward and back motion to
avoid creating gouges in the work surface.
5. Remove the tool from work surface before turning tool off. Allow
the tool to stop rotating before setting it down.
Mounting and Using Sanding
Backing Pads
Sanding pads and sanding discs must be rated above minimum
accessory speed as shown on tool. Recommended sanding
backing pads and sanding discs are available at extra cost from
DEWALT service centers and DEWALT dealers.
NOTE: Guard may be removed for sanding applications with
backing pads and sanding discs. Sanding flap discs are considered
grinding wheels by ANSI standards and require the use of a guard.
(See Mounting and Using Depressed Center Grinding Wheels
and Sanding Flap Discs).
MOUNTING SANDING BACKING PADS
WARNING: Turn off and unplug tool before making any
adjustments or removing or installing accessories. Before
reconnecting the tool, depress and release the trigger switch
to ensure that the tool is off.
CAUTION: Proper guard must be re-installed for grinding wheel,
sanding flap disc, wire brush, or wire wheel applications after
sanding applications are complete. J
I
1. Place or appropriately thread rubber
backing pad (I) down to mount.
2. Place the sanding disc on the rubber
backing pad.
3. While depressing spindle lock, thread
clamp nut (J) on spindle, piloting the
raised hub on the clamp nut into the
center of sanding disc and backing
pad.
4. Tighten the clamp nut with the proper wrench.
5. To remove the wheel, reverse the above procedure.
USING SANDING BACKING PADS
Choose the proper grit sandpaper for your application. Sandpaper
is available in various grits. Coarse grits yield faster material
removal rates and a rougher finish. Finer grits yield slower material
removal and a smoother finish.

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Begin with coarser grit discs for fast, rough material removal.
Move to a medium grit paper and finish with a fine grit disc for
optimal finish.
Coarse 16 - 30 grit
Medium 36 - 80 grit
Fine Finishing 100 - 120 grit
Very Fine Finishing 150 – 180 grit
1. Allow the tool to reach full speed before touching tool to work
surface.
2. Apply minimum pressure to work surface, allowing tool to
operate at high speed.
3. Maintain a 5˚ to 15˚ angle between the tool and work surface.
The sanding disc should contact approximately one inch of
work surface.
4. Move the tool constantly in a straight line to prevent burning and
swirling of work surface. Allowing the tool to rest on the work
surface without moving, or moving the tool in a circular motion
causes burning and swirling marks on the work surface.
5. Remove the tool from the work surface before turning the tool
off. Allow the tool to stop rotating before setting it down.
Mounting and Using Wire Brushes and
Wire Wheels
WARNING: Turn off and unplug tool before making any
adjustments or removing or installing accessories. Before
reconnecting the tool, depress and release the trigger switch
to ensure that the tool is off.
Wire brushes and wire wheels must be rated above minimum
accessory speed as shown on tool. Use only wire brushes and
wheels provided with a 5/8"–11 or M-14 threaded hub. A type 27
guard is required when using wire brushes and wheels.
CAUTION: Wear work gloves when handling wire brushes or
wheels. Wire brushes and wheels can become sharp.
MOUNTING WIRE BRUSHES AND WIRE WHEELS
1. Thread the wheel on the spindle by hand, seating the wheel
against the mount.
2. Depress the spindle lock button and use a wrench on the hub
of the wire brush or wheel to tighten the wheel.
3. To remove the wheel, depress the spindle lock button and use
a wrench on the hub of the wire brush or wheel to loosen it.
NOTE: Failure to properly seat the wheel hub against the mount
before turning the tool on may result in damage to the tool or
wheel.
USING WIRE CUP BRUSHES AND WIRE WHEELS
Wire wheels and brushes can be used for removing rust, scale and
paint, and for smoothing irregular surfaces.
1. Allow tool to reach full speed before touching tool to work
surface.
2. Apply minimum pressure to work surface, to allow the tool to
operate at high speed.
3. Maintain a 5˚ to 10˚ angle between the tool and work surface for
wire cup brushes.
4. Maintain contact between the edge of the wheel and the work
surface with wire wheels.
5. Continuously move the tool in a forward and back motion to
avoid creating gouges in the work surface. Allowing the tool to
rest on the work surface without moving, or moving the tool in a
circular motion causes burning and swirling marks on the work
surface.
6. Remove the tool from the work surface before turning the tool
off. Allow the tool to stop rotating before setting it down.

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Mounting and Using Flaring Cup
(Type 11) Wheel
MOUNTING FLARING CUP WHEEL GUARD
WARNING: The flaring cup wheel guard is not included with this
tool. Flaring cup wheels require proper flanges and guards. 4"
flaring cup wheel guard D284934 and 6" flaring cup wheel guard
D284936 are available as accessories and include proper flange.
Failure to use the proper flange and guard can result in injury
resulting from wheel breakage and wheel contact.
WARNING: Turn off and unplug tool before making any
adjustments or removing or installing accessories. Before
reconnecting the tool, depress and release the trigger switch
to ensure that the tool is off.
1. Install the guard as shown.
2. Guard body should be positioned between the spindle and the
operator to provide maximum operator protection.
3. Securely tighten the two clamping screws supplied with the
guard.
G
K
F
MOUNTING FLARING CUP WHEEL
1. Remove the mount (F).
2. Install the flaring cup wheel backing flange, aligning the flats on
spindle (K) with the flats on backing flange (G).
3. Thread the flaring cup wheel on spindle by hand, seating wheel
against backing flange.
4. Depress the spindle lock button and tighten the wheel by
hand.
5. To remove the wheel, reverse the above procedure.
CAUTION: Failure to properly seat the wheel against backing
flange before turning the tool on may result in damage to the tool or
the wheel.
NOTE: Adjust the guard skirt so that only 1/8" of the wheel is
exposed below the skirt.
USING A FLARING CUP WHEEL
Flaring cup wheels are designed for heavy material removal.
1. Allow the tool to reach full speed before touching tool to work
surface.
2. Apply minimum pressure to work surface, allowing the tool to
operate at high speed.
3. Maintain a 5˚ to 10˚angle between the tool and the work
surface.
4. Continuously move the tool in a forward and back motion to
avoid creating gouges in the work surface.
5. Remove the tool from work surface before turning tool off. Allow
the tool to stop rotating before setting it down.
Mounting and Using Cutting
(Type 1) Wheels
Cutting wheels include diamond wheels and abrasive discs.
Abrasive cutting wheels for metal and concrete use are available.
Diamond blades for concrete cutting can also be used.
WARNING: A closed, cutting wheel guard is not included with
this tool. Cutting wheels require proper flanges and guards. A
7" cutting guard, D284931, is available as an accessory and

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includes proper, matching flanges. Failure to use proper flange
and guard can result in injury resulting from wheel breakage and
wheel contact.
MOUNTING CLOSED (TYPE 1) GUARD
WARNING: Turn off and unplug tool before making any
adjustments or removing or installing accessories. Before
reconnecting the tool, depress and release the trigger switch
to ensure that the tool is off.
1. Align the lugs with slots on the gear case cover. Position the
guard facing backward, as shown.
2. Push the guard down until the guard lug engages and rotates
freely in the groove on the gear case hub.
3. Rotate guard into desired working position. The guard body
should be positioned between the spindle and the operator to
provide maximum operator protection.
4. Secure the guard on the gear case cover. You should be
unable to rotate the guard by hand when the latch is in closed
position. Do not operate grinder with a loose guard or clamp
lever in open position.
NOTE: The guard is pre-adjusted to the diameter of the gear case
hub at the factory. If, after a period of time, the guard becomes
loose, tighten the adjusting screw.
MOUNTING CUTTING WHEELS
1. Remove mount.
2. Install wheel backing flange, aligning flats on spindle with flats
on backing flange.
3. Place the wheel on the backing flange, centering the wheel on
the backing flange pilot.
4. Install the clamp nut, ensuring that the wheel remains centered
on the backing flange.
5. Depress the spindle lock button and tighten clamp nut with
wrench.
6. Reverse the above procedure to remove the wheel.
USING CUTTING WHEELS
1. Allow tool to reach full speed before touching tool to work
surface.
2. Apply minimum pressure to work surface, allowing tool to
operate at high speed.
3. Once you begin a cut, maintain the angle of the cutting wheel
to the work surface. This will keep you from bending the wheel
which could result in wheel breakage and injury.
4. Remove the tool from work surface before turning tool off. Allow
the tool to stop rotating before setting it down.
MAINTENANCE
WARNING: Turn off and unplug tool before making any
adjustments or removing or installing accessories. Before
reconnecting the tool, depress and release the trigger switch
to ensure that the tool is off.
Cleaning
WARNING: Blow dirt and dust out of the main housing with dry
air as often as dirt is seen collecting in and around the air vents.
Wear approved eye protection and approved dust mask when
performing this procedure.
WARNING: Never use solvents or other harsh chemicals for
cleaning the non-metallic parts of the tool. These chemicals may
weaken the materials used in these parts. Use a cloth dampened
only with water and mild soap. Never let any liquid get inside the
tool; never immerse any part of the tool into a liquid.

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Lubrication
DEWALT tools are properly lubricated at the factory and are ready
for use.
Repairs
To assure product SAFETY and RELIABILITY, repairs, maintenance
and adjustment should be performed by authorized service
centers or other qualified service personnel. Always use identical
replacement parts.
Motor Brushes
When brushes become worn, the tool will automatically stop,
preventing damage to the motor. Brush replacement should be
performed by DEWALT authorized service centers or other qualified
service personnel. Qualified service personnel should follow the
procedures below when replacing motor brushes.
Turn off and unplug tool before making any adjustments or
removing or installing accessories. Before reconnecting the
tool, depress and release the trigger switch to ensure that the
tool is off.
1. Remove the brush doors located on the sides of motor
housing.
2. To remove the brush, hold the female terminal, which is
attached to the brush lead wire, and disconnect the female
terminal from the male terminal.
3. Pull the brush straight up out of the brush holder.
4. Replace brushes, in pairs, with original DEWALT brushes
available from DEWALT authorized service centers.
5. Ensure that the brushes slide freely in brush box.
6. Reconnect the brush lead wire to brush box terminal.
7. Re-install the brush doors before using the tool. Torque screws
to 10 in-lbs, maximum. Overtightening may cause screws to
strip.
Purchasing Accessories
WARNING: Since accessories, other than those offered by
DEWALT, have not been tested with this product, use of such
accessories with this tool could be hazardous. To reduce the risk of
injury, only DEWALT, recommended accessories should be used
with this product.
Recommended accessories for use with your tool are available at
extra cost from you local dealer or authorized service center.

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Medidas generales de seguridad
¡ADVERTENCIA! Lea y comprenda todas las instrucciones.
El no cumplir con todas las advertencias a continuación podría
resultar en el riesgo de un choque eléctrico, incendio o de
lesiones graves.
CONSERVE ESTAS INSTRUCCIONES
Instrucciones generales de seguridad
ÁREA DE TRABAJO
• Conserve el área de trabajo limpia y bien iluminada. Las
bancas desordenadas y las zonas oscuras podrían ocasionar
accidentes.
• No opere herramientas eléctricas en atmósferas
explosivas, como en presencia de líquidos, gases o polvos
inflamables. Las herramientas eléctricas producen chispas que
pueden incendiar el polvo o los vapores.
• Mantenga a los niños, visitantes y demás personas
alejadas mientras opera una herramienta eléctrica. Las
distracciones pueden hacer que pierda el control.
SEGURIDAD ELÉCTRICA
• Las herramientas de conexión a tierra deben conectarse a
una toma de corriente instalada puesta a tierra debidamente
en conformidad con todos los códigos y regulaciones
locales. Nunca retire la clavija de conexión a tierra, no
modifique el enchufe ni utilice adaptadores. Consulte
con un electricista calificado si tiene dudas acerca de la
conexión a tierra apropiada de su toma de corriente. En el
caso que la herramienta tuviese una falla eléctrica, la puesta
a tierra proporciona una vía de baja resistencia para alejar la
electricidad del usuario. Aplicable únicamente a herramientas
clase I (puestas a tierra).
• Las herramientas con doble aislamiento están equipadas
con una clavija polarizada (con una pata más ancha que
la otra.) Esta clavija se acoplará únicamente en una toma de
corriente polarizada en un sentido. Si la clavija no se acopla
al contacto, inviértala. Si aún así no se ajusta, comuníquese
con un electricista calificado para que le instalen una toma de
corriente polarizada apropiada. El doble aislamiento elimina la
necesidad de cables con tres hilos y sistemas de alimentación
de conexión a tierra. Aplicable a herramientas clase II (con
doble aislamiento).
• Evite el contacto corporal con las superficies puestas
a tierra incluyendo las tuberías radiadores, hornos y
refrigeradores. Existe un gran riesgo de choque eléctrico si su
cuerpo hace tierra.
• No exponga las herramientas eléctricas a la lluvia o a
condiciones de mucha humedad. El agua que penetra
las herramientas eléctricas aumenta el riesgo de un choque
eléctrico.
• No maltrate el cable. Nunca sujete el cable para transportar
la herramienta ni para desconectarla de la toma de corriente.
Mantenga el cable alejado del calor, aceite, bordes afilados
o del calor. Cambie inmediatamente los cables dañados. Los
cables dañados aumentan el riesgo de choque eléctrico.
• Cuando opere una herramienta eléctrica a la intemperie,
utilice una extensión con el sello “W-A” o “W”. Estas
extensiones están clasificadas para uso a la intemperie y para
reducir el riesgo de choques eléctricos.

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Ténsion (Volts) Longitud del cable en metros (m)
120 - 127V 0 - 7 7 - 15 15 - 30 30 - 50
220 - 240V 0 - 15 15 - 30 30 - 60 60 - 100
Corriente nominal
(Ampéres) Sección nominal mínima del cable en milímetros cuadrados (mm2)
0 - 6A 1.0 1.5 1.5 2.5
6 - 10A 1.0 1.5 2.5 4.0
10 - 12A 1.5 1.5 2.5 4.0
12 - 16A 2.5 4.0 No recomendado
SEGURIDAD PERSONAL
• Esté alerta, concéntrese en lo que está haciendo. Recurra
al sentido común cuando opere una herramienta eléctrica.
No opere ninguna herramienta si se encuentra fatigado o
bajo la influencia de drogas, alcohol o medicamentos. Un
momento de desatención mientras se operan herramientas
eléctricas puede ocasionar lesiones graves.
• Vístase apropiadamente. No use ropa holgada ni joyería.
Cubra o recójase el cabello. Mantenga el cabello, la ropa y
los guantes alejados de las partes en movimiento. La ropa
floja, joyería o el cabello largo podría quedar atrapado en las
partes móviles. Los escapes de aire algunas veces cubren las
partes en movimiento y también deben ser evitadas.
• Evite el encendido accidental. Asegúrese que el interruptor
esté apagado antes de conectar. El sujetar una heramienta con
el dedo en el interruptor o conectarla sin fijarse si el interruptor
está en posición de encendido podría ocasionar un accidente.
• Retire las llaves de ajuste antes de encender la herramienta.
Una llave que se deja en una pieza giratoria puede ocasionar
lesiones personales.
• No se sobre extienda. Mantenga siempre los pies bien
apoyados, al igual que el equilibrio. La posición correcta de los
pies y el equilibrio permiten controlar mejor la herramienta en
situaciones inesperadas.
• Utilice equipo de seguridad. Siempre utilice protección
para los ojos. Se deben utilizar mascarillas contra polvo,
zapatos antideslizantes, casco o protectores para los oídos
conforme sea necesario.
USO Y CUIDADOS DE LA HERRAMIENTA
• Utilice prensas u otros medios prácticos para asegurar y
apoyar la pieza de trabajo en una plataforma estable. Sujetar
las piezas con la mano o contra su cuerpo es inestable y puede
originar la pérdida de control.
• No fuerce la herramienta. Utilice la herramienta apropiada
según la aplicación. La herramienta apropiada hará el trabajo
mejor y de manera más segura bajo las especificaciones para
las que se diseñó.
• No utilice la herramienta si el interruptor no enciende
ni apaga. Cualquier herramienta que no pueda controlarse
por medio de interruptores antideslizantes peligrosa y debe
repararse.
• Desconecte el enchufe de la toma de corriente antes de
hacer cualquier ajuste, cambio de accesorios o de guardar la
herramienta. Tales medidas preventivas de seguridad reducirán
el riesgo de que la herramienta se encienda accidentalmente.
• Guarde las herramientas fuera del alcance de los niños y
de otras personas no capacitadas. Las herramientas son
peligrosas en manos de personas no capacitadas.
• Cuide sus herramientas. Conserve las herramientas de
corte afiladas y limpias. Las herramientas que reciben un

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mantenimiento adecuado, con piezas de corte afiladas,
difícilmente se atascan y son más fáciles de controlar.
• Verifique la alineación de las piezas móviles, busque
fracturas en las piezas demás condiciones que puedan
afectar la operación de las herramientas. Si está dañada,
lleve su herramienta a servicio antes de usarla de nuevo.
Muchos accidentes se deben a herramientas con mantenimiento
pobre.
• Solamente use accesorios que el fabricante recomiende
para su modelo de herramienta. Los accesorios que han
sido diseñados para utilizarse con cierto tipo de herramientas,
pueden ocasionar peligro al emplearse con otras.
SERVICIO
• El servicio a las herramientas lo debe efectuar únicamente
personal calificado. El servicio o mantenimiento realizado por
personal no calificado puede ocasionar el riesgo de lesiones
personales.
• Cuando efectúe servicio a una herramienta, utilice
únicamente refacciones idénticas. Siga las instrucciones de
la sección de mantenimiento de este manual. El uso de piezas
no autorizadas o no seguir las instrucciones de mantenimiento
puede ocasionar riesgo de choque eléctrico o lesiones.
Instrucciones adicionales de seguridad
específicas para esmeriladoras
• Siempre utilice la guarda apropiada con el disco de
esmeril. Las guardas protegen al usuario contra los fragmentos
de los discos rotos y del contacto con los discos.
• Los accesorios deberán estar clasificados por lo menos
la velocidad recomendada en la etiqueta de advertencia
de la herramienta. Las discos y demás accesorios que
funcionen a una velocidad mayor a la clasificada, pueden
romperse y causar lesiones. Consulte la tabla a continuación. La
clasificación de los accesorios está sobre la clasificación de
velocidad sin carga de la herramienta, ya que las velocidades
reales pueden variar.
NOTA: la velocidad sin carga de la herramienta está impresa en la
placa de identificación y está grabada en la caja de engranajes.
• Sujete la herramienta por las superficies aislantes cuando
efectúe una operación en la que la herramienta de corte
pueda hacer contacto con cableado oculto o con su
propio cable. El contacto con un cable “vivo” hará que las
partes expuestas de la herramienta “vivan” y descarguen en el
usuario.
• Antes de usar los accesorios recomendados, revíselos
siempre en busca de quebraduras o defectos. Descártelos
si tienen un desperfecto de esta clase. Deberá revisar, de la
misma manera, los accesorios cuando sospeche que la unidad
se ha dejado caer.
• Al accionar la herramienta (con un disco o con un cepillo
nuevo de reemplazo), sujétela bien dentro de una zona
protegida adecuadamente y déjela funcionar durante un
minuto. Si el disco estuviese quebrado o dañado, se rompería
en pedazos en menos de un minuto. El usuario jamás deberá
accionar la herramienta con el disco dirigido hacia otra persona
ni hacia si mismo.
Velocidad sin carga Clasificación mínima
de la herramienta del accessorio
6500 RPM 6600 RPM
8500 RPM 8500 RPM

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• Evite que el disco opere a saltos o se maltrate mientras
funciona. Si sucediera así, apague y desconecte la herra-
mienta y revise el disco.
• Dirija las chispas lejos del operador, demás personas o
materiales inflamables. Se pueden producir chispas al utilizar
una lijadora o esmeriladora. Las chispas pueden ocasionar
quemaduras u ocasionar incendios.
• Utilice siempre el mango lateral. Apriete el mango con
firmeza. El mango lateral debe utilizarse siempre para mantener
el control de la unidad en todo momento.
PRECAUCIÓN: Tenga mucho cuidado al esmerilar cerca de una
esquina, ya que puede experimentarse un movimiento repentino,
violento de la esmeriladora al hacer contacto el disco con una
segunda superficie.
• Limpie la herramienta periódicamente. El polvo y el esmeril
contienen partículas metálicas que se acumulan con frecuencia
en las superficies interiores y pueden ocasionar riesgos de
choque eléctrico.
PRECAUCIÓN: utilice la protección auditiva apropiada durante
el uso de la herramienta. Bajo ciertas condiciones y duración de
uso, el ruido producido por este producto puede contribuir a la
pérdida auditiva.
ADVERTENCIA: Parte del polvo originado al lijar, cortar, esme-
rilar, taladrar y otras actividades constructivas contiene químicos
que se sabe causan cáncer, defectos congénitos y otros daños
reproductivos. Algunos ejemplos de estos químicos son:
• plomo de pinturas con base de plomo.
• sílice cristalino de ladrillos, cemento y otros productos de
albañilería, y
• arsénico y cromo de madera tratada químicamente (CCA).
El riesgo a estas exposiciones varía, dependiendo de la frecuencia
con la que efectúe este tipo de trabajos. Para reducir su exposición
a estos químicos, trabaje en un área bien ventilada, y trabaje con
equipo de seguridad aprobado, como aquéllas máscaras que están
diseñadas especialmente para filtrar partículas microscópicas.
• Evite el contacto prolongado con el polvo originado por lijar,
cortar, esmerilar, taladrar, y otras actividades constructivas.
Vista ropas protectoras y lave las zonas expuestas con
jabón y agua. Permitir que el polvo se introduzca en su boca,
ojos, o quede sobre su piel promueve la absorción de químicos
nocivos.
• La etiqueta de su herramienta puede incluir los siguientes
símbolos.
V............ volts A .........amperios
Hz.......... hertz W ........watts
.../min .... minutos .......corriente alterna
....... corriente directa no .......velocidad sin carga
......... construcción clase II /min.....revoluciones por
.......... terminales de ............minuto
.............. conexión a tierra .......símbolo de advertencia
CONOCIMIENTO DEL PRODUCTO
Las esmeriladoras y lijadoras angulares grandes están diseña-
das para la remoción pesada de material en aplicaciones de uso
prolongado. Las siguientes esmeriladoras y lijadoras aparecen
descritas en este manual.
D28490 Esmeriladora angular de 9" (230 mm) 6,500 rpm 2200 W
D28491 Esmeriladora angular de 7" (180 mm) 8,500 rpm 2200 W