Makita 8420V User manual

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ENGLISH (Original instructions)
INSTRUCTION MANUAL
IMPORTANT: Read Before Using.
Hammer Drill
8420V
012949

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ENGLISH (Original instructions)
SPECIFICATIONS
Model 8420V
Concrete 20 mm
Metal 13 mm
Capacities
Wood 30 mm
No load speed (min-1) 0 - 1,400
Blows per minute 0 - 21,000
Overall length 368 mm
Net weight 2.9 kg
Safety class Class I
• Due to our continuing program of research and development, the specifications herein are subject to change without notice.
• Specifications may differ from country to country.
• Weight according to EPTA-Procedure 01/2003
END224-1
Symbols
The following show the symbols used for the equipment.
Be sure that you understand their meaning before use.
･Read instruction manual.
･Only for EU countries
Do not dispose of electric equipment
together with household waste material!
In observance of European Directive
2002/96/EC on waste electric and
electronic equipment and its
implementation in accordance with
national law, electric equipment that
have reached the end of their life must
be collected separately and returned to
an environmentally compatible recycling
facility.
ENE039-1
Intended use
The tool is intended for impact drilling in brick, concrete
and stone as well as for drilling without impact in wood,
metal, ceramic and plastic.
ENF001-1
Power supply
The tool should be connected only to a power supply of
the same voltage as indicated on the nameplate, and can
only be operated on single-phase AC supply. This tool
should be grounded while in use to protect the operator
from electric shock. Use only three-wire extension cords
which have three-prong grounding-type plugs and
three-pole receptacles which accept the tool's plug.
GEA005-3
General Power Tool Safety
Warnings
WARNING Read all safety warnings and all
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 the warnings refers to your
mains-operated (corded) power tool or battery-operated
(cordless) power tool.
Work area safety
1. Keep work area clean and well lit. Cluttered or
dark areas invite accidents.
2. 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.
3. Keep children and bystanders away while
operating a power tool. Distractions can cause
you to lose control.
Electrical safety
4. 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. Unmodified plugs and matching outlets will
reduce risk of electric shock.
5. Avoid body contact with earthed or grounded
surfaces such as pipes, radiators, ranges and
refrigerators. There is an increased risk of
electric shock if your body is earthed or grounded.
6. Do not expose power tools to rain or wet
conditions. Water entering a power tool will
increase the risk of electric shock.

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7. Do not abuse the cord. Never use the cord for
carrying, pulling or unplugging the power tool.
Keep cord away from heat, oil, sharp edges or
moving parts. Damaged or entangled cords
increase the risk of electric shock.
8. 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.
9. If operating a power tool in a damp location is
unavoidable, use a residual current device
(RCD) protected supply. Use of an RCD reduces
the risk of electric shock.
10. Use of power supply via a RCD with a rated
residual current of 30mA or less is always
recommended.
Personal safety
11. 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 or
under the influence of drugs, alcohol or
medication. A moment of inattention while
operating power tools may result in serious
personal injury.
12. Use personal protective equipment. Always
wear eye protection. Protective equipment such
as dust mask, non-skid safety shoes, hard hat, or
hearing protection used for appropriate conditions
will reduce personal injuries.
13. 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 with
your finger on the switch or energising power tools
that have the switch on invites accidents.
14. 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.
15. Do not overreach. Keep proper footing and
balance at all times. This enables better control
of the power tool in unexpected situations.
16. Dress properly. Do not wear loose clothing or
jewellery. Keep your hair, clothing, and gloves
away from moving parts. Loose clothes,
jewellery or long hair can be caught in moving
parts.
17. If devices are provided for the connection of
dust extraction and collection facilities,
ensure these are connected and properly used.
Use of dust collection can reduce dust-related
hazards.
Power tool use and care
18. 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.
19. Do not use the power tool if the switch does
not turn it on and off. Any power tool that cannot
be controlled with the switch is dangerous and
must be repaired.
20. 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.
21. Store idle power tools out of the reach of
children and do not allow persons unfamiliar
with the power tool or these instructions to
operate the power tool. Power tools are
dangerous in the hands of untrained users.
22. Maintain power tools. Check for misalignment
or binding of moving parts, breakage of parts
and any other condition that may affect the
power tool’s operation. If damaged, have the
power tool repaired before use. Many accidents
are caused by poorly maintained power tools.
23. Keep cutting tools sharp and clean. Properly
maintained cutting tools with sharp cutting edges
are less likely to bind and are easier to control.
24. 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. Use of the power
tool for operations different from those intended
could result in a hazardous situation.
Service
25. Have your power tool serviced by a qualified
repair person using only identical replacement
parts. This will ensure that the safety of the power
tool is maintained.
26. Follow instruction for lubricating and
changing accessories.
27. Keep handles dry, clean and free from oil and
grease.

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GEB099-1
HAMMER DRILL SAFETY
WARNINGS
1. Wear ear protectors when impact drilling.
Exposure to noise can cause hearing loss.
2. Use auxiliary handle(s), if supplied with the
tool. Loss of control can cause personal injury.
3. Always be sure you have a firm footing.
Be sure no one is below when using the tool in
high locations.
4. Hold the tool firmly with both hands.
5. Keep hands away from rotating parts.
6. Do not leave the tool running. Operate the tool
only when hand-held.
7. Do not touch the bit or the workpiece
immediately after operation; they may be
extremely hot and could burn your skin.
8. Some material contains chemicals which may
be toxic. Take caution to prevent dust
inhalation and skin contact. Follow material
supplier safety data.
SAVE THESE INSTRUCTIONS.
WARNING:
DO NOT let comfort or familiarity with product
(gained from repeated use) replace strict adherence
to safety rules for the subject product. MISUSE or
failure to follow the safety rules stated in this
instruction manual may cause serious personal
injury.
FUNCTIONAL DESCRIPTION
CAUTION:
• Always be sure that the tool is switched off and
unplugged before adjusting or checking function on
the tool.
Switch action
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012954
CAUTION:
• Before plugging in the tool, always check to see
that the switch trigger actuates properly and returns
to the "OFF" position when released.
• Switch can be locked in "ON" position for ease of
operator comfort during extended use. Apply
caution when locking tool in "ON" position and
maintain firm grasp on tool.
Tool speed is increased by increasing pressure on the
switch trigger.
To start the tool, simply pull the switch trigger. Tool speed
is increased by increasing pressure on the switch trigger.
Release the switch trigger to stop.
For continuous operation, pull the switch trigger and then
push in the lock button.
To stop the tool from the locked position, pull the switch
trigger fully, then release it.
A speed control screw is provided so that maximum tool
speed can be limited (variable). Turn the speed control
screw clockwise for higher speed, and counterclockwise
for lower speed.
Selecting the action mode
Rotation with hammering:
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012955
For drilling in concrete, granite, tile, etc., move the
change lever to the position.
1. Change lever
1. Speed control
screw
2. Switch trigger
3. Lock button

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Be sure to use concrete and masonry drilling bit.
Rotation only:
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012956
For drilling in wood, metal or plastic metals, move
change lever to the position.
Use a conventional bit for drilling in wood or metal.
ASSEMBLY
CAUTION:
• Always be sure that the tool is switched off and
unplugged before carrying out any work on the tool.
Installing side grip (auxiliary handle)
1
012950
To install the side grip, fit the teeth on the side grip into
the grooves on the tool. Then tighten the wing nut
securely.
The position of the side grip can be changed in 30°
increments. Simply loosen the wing nut and slip out the
side grip teeth from the grooves on the tool. Swing the
side grip to the desired position and then slip the side grip
teeth back into the grooves on the tool. Then tighten the
wing nut securely.
Installing or removing drill bit
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012951
To install the bit, place it in the chuck as far as it will go.
Tighten the chuck by hand. Place the chuck key in each
of the three holes and tighten clockwise. Be sure to
tighten all three chuck holes evenly.
To remove the bit, turn the chuck key counterclockwise in
just one hole, then loosen the chuck by hand.
After using the chuck key, be sure to return it to the
original position.
Depth gauge
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2
012952
Loosen the wing bolt and adjust the depth gauge to the
desired depth. After adjusting, tighten the wing bolt.
OPERATION
CAUTION:
• Always use the side grip (auxiliary handle) and
firmly hold the tool by both side grip and switch
handle during operations.
Hammer drilling operation
012957
Position the bit at the desired location for the hole, then
pull the switch trigger. Do not force the tool. Light
pressure gives best results. Keep the tool in position and
prevent it from slipping away from the hole.
Do not apply more pressure when the hole becomes
clogged with chips or particles. Instead, run the tool at an
idle, then remove the bit partially from the hole. By
repeating this several times, the hole will be cleaned out.
Drilling operation
Drilling in wood
When drilling in wood, the best results are obtained with
wood drills equipped with a guide screw. The guide
screw makes drilling easier by pulling the bit into the
workpiece.
1. Depth gauge
2. Wing nut
1. Tighten
2. Chuck key
1. Wing nut
1. Change lever

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Drilling in metal
To prevent the bit from slipping when starting a hole,
make an indentation with a center-punch and hammer at
the point to be drilled. Place the point of the bit in the
indentation and start drilling.
Use a cutting lubricant when drilling metals. The
exceptions are iron and brass which should be drilled dry.
CAUTION:
• Pressing excessively on the tool will not speed up
the drilling. In fact, this excessive pressure will only
serve to damage the tip of your bit, decrease the
tool performance and shorten the service life of the
tool.
• There is a tremendous force exerted on the tool/bit
at the time of hole break through. Hold the tool
firmly and exert care when the bit begins to break
through the workpiece.
• A stuck bit can be removed simply by setting the
reversing switch to reverse rotation in order to back
out. However, the tool may back out abruptly if you
do not hold it firmly.
• Always secure small workpieces in a vise or similar
hold-down device.
MAINTENANCE
CAUTION:
• Always be sure that the tool is switched off and
unplugged before attempting to perform inspection
or maintenance.
• Never use gasoline, benzine, thinner, alcohol or the
like. Discoloration, deformation or cracks may
result.
To maintain product SAFETY and RELIABILITY, repairs,
carbon brush inspection and replacement, any other
maintenance or adjustment should be performed by
Makita Authorized Service Centers, always using Makita
replacement parts.

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Makita Corporation
www.makita.com
883328D9