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INSTRUCTION MANUAL
DEWALT Industrial Tool Co., 701 East Joppa Road, Baltimore, MD 21286
(MAR11) Part No. N112900 DWS780 Copyright © 2011 DEWALT
The following are trademarks for one or more D
EWALT power tools: the yellow and black color scheme,
the “D” shaped air intake grill, the array of pyramids on the handgrip, the kit box configuration, and the
array of lozenge-shaped humps on the surface of the tool.
If you have questions or comments, contact us.
1-800-4-DEWALT • www.dewalt.com
DWS780
12" (305 mm) Double Bevel Sliding Compound Miter Saw
Definitions: Safety Guidelines
The definitions below describe the level of severity for each signal word. Please read the
manual and pay attention to these symbols.
DANGER: Indicates an imminently hazardous situation which, if not avoided, will result
in death or serious injury.
WARNING: Indicates a potentially hazardous situation which, if not avoided, could result
in death or serious injury.
CAUTION: Indicates a potentially hazardous situation which, if not avoided, may result in
minor or moderate injury.
NOTICE: Indicates a practice not related to personal injury which, if not avoided, may
result in property damage.
IF YOU HAVE ANY QUESTIONS OR COMMENTS ABOUT THIS OR ANY DEWALT TOOL, CALL
US TOLL FREE AT: 1-800-4-D
EWALT (1-800-433-9258).
IMPORTANT SAFETY INSTRUCTIONS
WARNING: Read all instructions before operating product. Failure to follow
all instructions listed below may result in electric shock, fi re and/or serious
injury.
READ ALL INSTRUCTIONS
Double Insulation
Double insulated tools are constructed throughout with two separate layers of electrical insulation
or one single layer of reinforced insulation between you and the tool’s electrical system. Tools built
with this insulation system are not intended to be grounded. As a result, your tool is equipped
with a two prong plug which permits you to use extension cords without concern for maintaining
a ground connection.
NOTE: Double insulation does not take the place of normal safety precautions when operating this
tool. The secondary insulation system is for protection against injury resulting from a possible failure
of the primary insulation within the tool.
CAUTION: WHEN SERVICING USE ONLY IDENTICAL REPLACEMENT PARTS. Repair or
replace damaged cords.
Polarized Plugs
Polarized plugs (one blade is wider than the other) are used on equipment to reduce the risk of
electric shock. When provided, this plug will fit in the 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
the proper outlet. Do not change the plug in any way.
Drive
120 volt motor
1600 watts in 15 amp motor
3800 RPM Cut helical gears
Multi-V belt Roller bearings
Automatic electric brake Carbide blade
Safety Instructions for All Tools
WARNING: To reduce the risk of eye injury, ALWAYS use eye protection when operating
the miter saw.
• KEEP GUARD IN PLACE and in working order.
• REMOVE ADJUSTING KEYS AND WRENCHES. Form habit of checking to see that keys
and adjusting wrenches are removed from spindle before turning tool on. Tools, scrap pieces,
and other debris can be thrown at high speed, causing injury.
• KEEP WORK AREA CLEAN. Cluttered areas and benches invite accidents.
• DO NOT USE THE MACHINE IN A DANGEROUS ENVIRONMENT. The use of power tools
in damp or wet locations or in rain can cause shock or electrocution. Keep your work area well-lit
to avoid tripping or placing arms, hands, and fingers in danger.
• KEEP CHILDREN AWAY. All visitors should be kept at a safe distance from work area. Your
shop is a potentially dangerous environment.
• MAKE WORKSHOP CHILDPROOF with padlocks, master switches, or by removing starter
keys. The unauthorized start-up of a machine by a child or visitor may result in injury.
• DON’T FORCE TOOL. It will do the job better and be safer at the rate for which it was
designed.
• USE RIGHT TOOL. Don’t force tool or attachment to do a job for which it was not designed.
Using the incorrect tool or attachment may result in personal injury.
• WEAR PROPER APPAREL. Do not wear loose clothing, gloves, neckties, rings, bracelets, or
other jewelry which may get caught in moving parts. Nonslip footwear is recommended. Wear
protective hair covering to contain long hair.
• ALWAYS USE SAFETY GLASSES. Everyday eyeglasses are NOT safety glasses. Also
use face or dust mask if cutting operation is dusty. ALWAYS WEAR CERTIFIED SAFETY
EQUIPMENT:
• ANSI Z87.1 eye protection (CAN/CSA Z94.3).
• ANSI S12.6 (S3.19) hearing protection.
• NIOSH/OSHA/MSHA respiratory protection.
• SECURE THE WORKPIECE. Use clamps or a vise to hold the workpiece on the table and
against the fence or when your hand will be dangerously close to the blade within 6" (152mm).
It is safer than using your hand and it frees both hands to operate tool.
• DON’T OVERREACH. Keep proper footing and balance at all times. Loss of balance may
cause personal injury.
• MAINTAIN TOOLS WITH CARE. Keep tools sharp and clean for best and safest performance.
Follow instructions for lubricating and changing accessories. Poorly maintained tools and
machines can further damage the tool or machine and/or cause injury.
• TURN THE MACHINE “OFF”, AND DISCONNECT THE MACHINE FROM THE POWER
SOURCE before installing or removing accessories, before adjusting or changing set-ups, when
making repairs or changing locations. An accidental start-up can cause injury. Do not touch the
plug’s metal prongs when unplugging or plugging in the cord.
• REDUCE THE RISK OF UNINTENTIONAL STARTING. Make sure that the switch is in the
“OFF” position before plugging in the power cord.
• USE PROPER EXTENSION CORD. Make sure your extension cord is in good condition.
When using an extension cord, be sure to use one heavy enough to carry the current your
product will draw. An undersized cord will cause a drop in line voltage resulting in loss of power
and overheating. The following table shows the correct size to use depending on cord length
and nameplate ampere rating. If in doubt, use the next heavier gauge. The smaller the gauge
number, the heavier the cord.
Minimum Gauge for Cord Sets
Ampere Rating
Volts Total Length of Cord in Feet (meters)
120V 25 (7.6) 50 (15.2) 100 (30.5) 150 (45.7)
240V 50 (15.2) 100 (30.5) 200 (61.0) 300 (91.4)
More
Than
Not More
Than
AWG
0 6 18 16 16 14
610 18161412
10 12 16 16 14 12
12 16 14 12 Not Recommended
• CHECK FOR DAMAGED PARTS. Before further use of the tool, a guard or other part that is
damaged should be carefully checked to determine that it will operate properly and perform its
intended function—check for alignment of moving parts, binding of moving parts, breakage of
parts, mounting and any other conditions that may affect its operation. A guard or other part
that is damaged should be properly repaired or replaced. Do not use tool if switch does not turn
it on and off.
• USE RECOMMENDED ACCESSORIES. Use only accessories that are recommended by the
manufacturer for your model. Accessories that may be suitable for one tool may be hazardous
when used on another tool. Consult the instruction manual for recommended accessories. The
use of improper accessories may cause risk of injury to persons.
• NEVER STAND ON TOOL. Serious injury could occur if the tool is tipped or if the cutting tool
is unintentionally contacted.
• NEVER LEAVE TOOL RUNNING UNATTENDED. TURN POWER OFF. Don’t leave tool until
it comes to a complete stop. Serious injury can result.
• DO NOT OPERATE ELECTRIC TOOLS NEAR FLAMMABLE LIQUIDS OR IN GASEOUS
OR EXPLOSIVE ATMOSPHERES. Motors in these tools may spark and ignite fumes.
• STAY ALERT, WATCH WHAT YOU ARE DOING, AND USE COMMON SENSE. DO NOT
USE THE MACHINE WHEN YOU ARE TIRED OR UNDER THE INFLUENCE OF DRUGS
OR ALCOHOL. A moment of inattention while operating power tools may result in injury.
Additional Safety Rules For Miter Saws
WARNING: Do not allow familiarity (gained from frequent use of your saw) to replace safety rules.
Always remember that a careless fraction of a second is sufficient to inflict severe injury.
• DO NOT OPERATE THIS MACHINE until it is completely assembled and installed according
to the instructions. A machine incorrectly assembled can cause serious injury.
• OBTAIN ADVICE from your supervisor, instructor, or another qualified person if you are not
thoroughly familiar with the operation of this machine. Knowledge is safety.
• STABILITY. Make sure the miter saw is placed on a secure supporting surface and does not
slip or move during use.
• FOLLOW ALL WIRING CODES and recommended electrical connections to prevent shock or
electrocution. Protect electric supply line with at least a 15 ampere time-delay fuse or a circuit
breaker.
• MAKE CERTAIN the blade rotates in the correct direction. The teeth on the blade should point
in the direction of rotation as marked on the saw.
• TIGHTEN ALL CLAMP HANDLES, knobs and levers prior to operation. Loose clamps can
cause parts or the workpiece to be thrown at high speeds.
• BE SURE all blade and blade clamps are clean, recessed sides of blade clamps are against
blade and arbor screw is tightened securely. Loose or improper blade clamping may result in
damage to the saw and possible personal injury.
• ALWAYS USE A SHARP BLADE. Check the blade to see if it runs true and is free from
vibration. A dull or a vibrating blade can cause damage to the machine and/or serious injury.
• DO NOT OPERATE ON ANYTHING OTHER THAN THE DESIGNATED VOLTAGE for the
saw. Overheating, damage to the tool and personal injury may occur.
• DO NOT WEDGE ANYTHING AGAINST THE FAN to hold the motor shaft. Damage to tool
and possible personal injury may occur.
• DO NOT FORCE CUTTING ACTION. Stalling or partial stalling of motor can cause damage
to the machine or blade and/or serious injury.
• ALLOW THE MOTOR TO COME TO FULL SPEED prior to starting cut. Starting the cut too
soon may cause damage to the machine or blade and/or serious injury.
• NEVER CUT FERROUS METALS (those with any iron or steel content) or masonry. Either of
these can cause the carbide tips to fly off the blade at high speeds causing serious injury.
• DO NOT USE ABRASIVE WHEELS. The excessive heat and abrasive particles generated by
them may damage the saw and cause personal injury.
• NEVER HAVE ANY PART OF YOUR BODY IN LINE WITH THE PATH OF THE SAW
BLADE. Personal injury will occur.
• NEVER APPLY BLADE LUBRICANT TO A RUNNING BLADE. Applying lubricant could
cause your hand to move into the blade resulting in serious injury.
• DO NOT place either hand in the blade area when the saw is connected to the power source.
Inadvertent blade activation may result in serious injury.
• DO NOT PERFORM FREEHAND OPERATIONS (workpiece not supported by table and
fence). Hold the work firmly against the fence and table. Freehand operations on a miter saw
could cause the workpiece to be thrown at high speeds, causing serious injury.
• NEVER REACH AROUND OR BEHIND THE SAW BLADE. A blade can cause serious injury.
• DO NOT REACH UNDERNEATH THE SAW unless it is unplugged and turned off. Contact
with saw blade may cause personal injury.
• SECURE THE MACHINE TO A STABLE SUPPORTING SURFACE. Vibration can possibly
cause the machine to slide, walk, or tip over, causing serious injury.
• USE ONLY CROSSCUT SAW BLADES recommended for miter saws. For best results, do
not use carbide tipped blades with hook angles in excess of 7 degrees. Do not use blades with
deep gullets. These can deflect and contact the guard, and can cause damage to the machine
and/or serious injury.
• USE ONLY BLADES OF THE CORRECT SIZE AND TYPE specified for this tool to prevent
damage to the machine and/or serious injury.
• INSPECT BLADE FOR CRACKS or other damage prior to operation. A cracked or damaged
blade can come apart and pieces can be thrown at high speeds, causing serious injury. Replace
cracked or damaged blades immediately.
• CLEAN THE BLADE AND BLADE CLAMPS
prior to operation. Cleaning the blade and
blade clamps allows you to check for any damage to the blade or blade clamps. A cracked
or damaged blade or blade clamp can come apart and pieces can be thrown at high speeds,
causing serious injury.
• DO NOT use lubricants or cleaners (particularly spray or aerosol) in the vicinity of the plastic
guard. The polycarbonate material used in the guard is subject to attack by certain chemicals.
• ALWAYS USE THE KERF PLATE AND REPLACE THIS PLATE WHEN DAMAGED. Small
chip accumulation under the saw may interfere with the saw blade or may cause instability of
workpiece when cutting.
• USE ONLY BLADE CLAMPS SPECIFIED FOR THIS TOOL to prevent damage to the
machine and/or serious injury.
• CLEAN THE MOTOR AIR SLOTS of chips and sawdust. Clogged motor air slots can cause
the machine to overheat, damaging the machine and possibly causing a short which could
cause serious injury.
• KEEP ARMS, HANDS, AND FINGERS AWAY FROM THE BLADE to prevent severe cuts.
Clamp all workpieces that would cause your hand to be within 6"(152mm) of the saw blade.
• NEVER LOCK THE SWITCH IN THE “ON” POSITION. Severe personal injury may result.
• TURN OFF THE MACHINE and allow the blade to come to a complete stop before raising
the arm and prior to cleaning the blade area, removing debris in the path of the blade, before
servicing or adjusting tool. A moving blade can cause serious injury.
• PROPERLY SUPPORT LONG OR WIDE WORKPIECES. Loss of control of the workpiece
can cause injury.
• NEVER CROSS ARMS IN FRONT OF BLADE while using tool. Always make a dry run
(unpowered) before making a finish cut so that you can check the path of the blade or severe
personal injury may result.
• ADDITIONAL INFORMATION regarding the safe and proper operation of power tools (i.e.,
a safety video) is available from the Power Tool Institute, 1300 Sumner Avenue, Cleveland,
OH 44115-2851 (www.powertoolinstitute.com). Information is also available from the National
Safety Council, 1121 Spring Lake Drive, Itasca, IL 60143-3201. Please refer to the American
National Standards Institute ANSI 01.1 Safety Requirements for Woodworking Machines and
the U.S. Department of Labor OSHA 1910.213 Regulations.
WARNING: Do not connect unit to electrical power source until complete instructions are read
and understood.