DeWalt DW378, DW378GT, DW378G User Manual
INSTRUCTION MANUAL
GUIDE D'UTILISATION
MANUAL DE INSTRUCCIONES
INSTRUCTIVO DE OPERACIÓN, CENTROS DE SERVICIO Y PÓLIZA
DE GARANTÍA. ADVERTENCIA: LÉASE ESTE INSTRUCTIVO
ANTES DE USAR EL PRODUCTO.
DEWALT Industrial Tool Co., 701 East Joppa Road, Baltimore, MD 21286 (JUL04-CD-1)
Form No. 626676-00 DW378, DW378G, DW378GT Copyright © 1998, 2002, 2004 D
EWALT
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.
Questions? See us in the World Wide Web at www.dewalt.com
DW378, DW378G, DW378GT
7-1/4"(184 mm) Framing Saw
Scie circulaire pour la charpente de 184 mm (7 1/4 po)
Siera alternataiva de 184 mm (7-1/4")
IF YOU HAVE ANY QUESTIONS OR COMMENTS ABOUT THIS OR ANY DEWALT TOOL,
CALL US TOLL FREE AT: 1-800-4-DEWALT (1-800-433-9258)
General Safety 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.
SAVE THESE 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 adaptor 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. The DW378G and
DW378GT are 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 elim-
inates the need for the three wire grounded power cord and grounded power supply system.
Applicable only to Class II (double insulated) tools. The DW378 is a double insulated
tool.
• 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. 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 gage. The smaller the gage number, the heavier the cord.
Minimum Gage for Cord Sets
Volts Total Length of Cord in Feet
120V 0-25 26-50 51-100 101-150
240V 0-50 51-100 101-200 201-300
Ampere Rating
More Not more AWG
Than Than
10- 12 16 16 14 12
12- 16 14 12 Not Recommended
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 clothing, 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 mainte-
nance 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.
Additional Safety Instructions for Circular Saws
DANGER! Keep hands away from cutting area and blade. Keep your second hand on
auxiliary handle, or motor housing. If both hands are holding the saw, they cannot be cut by
the blade.
CAUTION: Blades coast after turn off.
• Keep your body positioned to either side of the blade, but not in line with the saw
blade. KICKBACK could cause the saw to jump backwards (see Causes and Operator
Prevention of Kickback and KICKBACK).
• Do not reach underneath the work. The guard can not protect you from the blade below
the work.
• Check lower guard for proper closing before each use. Do not operate saw if lower
guard does not move freely and close instantly. Never clamp or tie the lower guard
into the open position. If saw is accidentally dropped, the lower guard may be bent. Raise
the lower guard with the retracting handle and make sure it moves freely and does not touch
the blade or any other part, at all angles and depth of cut.
• Check the operation and condition of the lower guard spring. If the guard and the
spring are not operating properly, they must be serviced before use. Lower guard may
operate sluggishly due to damaged parts, gummy deposits, or a buildup of debris.
• Lower guard should be retracted manually only for special cuts such as “pocket cuts”
and “compound cuts.” Raise lower guard by retracting handle. As soon as blade
enters the material, lower guard must be released. For all other sawing, the lower guard
should be allowed to operate automatically.
• Always observe that the lower guard is covering the blade before placing saw down
on bench or floor. An unprotected, coasting blade will cause the saw to walk backwards,
cutting whatever is in its path. Be aware of the time it takes for the blade to stop after switch
is released.
• NEVER hold piece being cut in your hands or across your leg. It is important to support
the work properly to minimize body exposure, blade binding, or loss of control.
• 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 also
make exposed metal parts of the tool “live” and shock the operator.
• When ripping, always use a rip fence or straight edge guide. This improves the accuracy of cut and reduces the chance for blade binding.
• Always use blades with correct size and shape (diamond vs. round) arbor holes.
Blades that do not match the mounting hardware of the saw will run eccentrically, causing
loss of control.
• Never use damaged or incorrect blade washers or bolts. The blade washers and bolt
were specially designed for your saw, for optimum performance and safety of operation.
• Avoid cutting nails. Inspect for and remove all nails from lumber before cutting.
CAUSES AND OPERATOR PREVENTION OF KICKBACK
• Kickback is a sudden reaction to a pinched, bound or misaligned saw blade, causing an
uncontrolled saw to lift up and out of the workpiece toward the operator.
• When the blade is pinched or bound tightly by the kerf closing down, the blade stalls and the
motor reaction drives the unit rapidly back toward the operator.
• If the blade becomes twisted or misaligned in the cut, the teeth at the back edge of the blade
can dig into the top surface of the wood causing the blade to climb out of the kerf and jump
back toward operator.
• Kickback is the result of tool misuse and/or incorrect operating procedures or conditions and
can be avoided by taking proper precautions as given below:
• Maintain a firm grip with both hands on the saw and position your body and arm to
allow you to resist kickback forces. Kickback forces can be controlled by the operator, if
proper precautions are taken.
• When blade is binding, or when interrupting a cut for any reason, release the trigger
and hold the saw motionless in the material until the blade comes to a complete stop.
Never attempt to remove the saw from the work or pull the saw backward while the
blade is in motion or kickback may occur. Investigate and take corrective actions to elim-
inate the cause of blade binding.
• When restarting a saw in the workpiece, center the saw blade in the kerf and check
that the saw teeth are not engaged into the material. If saw blade is binding, it may walk
up or kickback from the workpiece as the saw is restarted.
• Support large panels to minimize the risk of blade pinching and kickback. Large panels tend to sag under their own weight. Support must be placed under the panel on both
sides, near the line of cut and near the edge of the panel.
• Do not use dull or damaged blade. Unsharpened or improperly set blades produce narrow
kerf causing excessive friction, blade binding, and kickback.
• Blade depth and bevel adjusting locking levers must be tight and secure before mak-
ing cut. If blade adjustment shifts while cutting, it may cause binding and kickback.
• Use extra caution when making a “Pocket Cut” into existing walls or other blind areas.
The protruding blade may cut objects that can cause kickback.
WARNING: Some dust created by power sanding, sawing, grinding, drilling, and other con-
struction 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 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.
WARNING: Use of this tool can generate and/or disburse dust, which may cause serious and
permanent respiratory or other injury. Always use NIOSH/OSHA approved respiratory protection
appropriate for the dust exposure. Direct particles away from face and body.
WARNING: Always use eye protection. All users and bystanders must wear eye protection
that conforms to ANSI Z87.1.
CAUTION: Wear appropriate personal hearing protection during use. Under some con-
ditions and duration of use, noise from this product may contribute to hearing loss.
CAUTION: When cutting into walls, floors or wherever live electrical wires may be encoun-
tered, DO NOT TOUCH ANY METAL PARTS OF THE TOOL! Hold the tool only by insulated
grasping surfaces to prevent electric shock if you cut into a live wire.
• The label on your tool may include the following symbols. The symbols and their definitions
are as follows:
V..........volts A ..........amperes
Hz........hertz W ..........watts
min ......minutes ........alternating current
....direct current
n
o..........no load speed
........Class II Construction ..........earthing terminal
........safety alert symbol .../min....revolutions per minute
FEATURES
A. Brush inspection cover E. Shoe
B. Trigger switch F. Blade clamping screw
C. Cutting depth adjustment
D. Bevel angle adjustment
Motor
Your DEWALT tool is powered by a DEWALT motor. Be sure your power supply agrees with
nameplate marking. 120 Volts AC/DC means your saw will operate on alternating or direct current. As little as 10% lower voltage can cause loss of power and can result in overheating. All
D
EWALT tools are factory-tested; if this tool does not operate, check the power supply.
11x20,DW378 7/21/04 12:51 PM Page 1
Changing Blades
CAUTION: Turn off and unplug the tool before making any adjustments or
removing/installing attachments or accessories.
TO INSTALL THE BLADE
1. Place inner clamp washer (G) on saw spindle with the large flat surface facing out toward
the blade (Fig. 1).
2. Retract the lower blade guard (H) and place blade on saw spindle against the inner clamp
washer, making sure that the blade will rotate in the proper direction (the direction of the rotation arrow on the saw blade and the teeth must point in the same direction as the direction
of rotation arrow on the saw). Do not assume that the printing on the blade will always be facing you when properly installed. When retracting the lower blade guard to install the blade,
check the condition and operation of the lower blade guard to assure that it is working properly. Make sure it moves freely and does not touch the blade or any other part, in all angles
and depths of cut.
3. Place outer clamp washer (I) on saw spindle with the large flat surface against the blade and
the wording on the outer clamp washer facing you.
4. Thread blade clamping screw (F) into saw spindle by hand (screw has left-hand threads and
must be turned counterclockwise to tighten).
5. Depress the blade lock (J) while turning the saw spindle with the blade wrench until the
blade lock engages and the blade stops rotating (Fig. 3).
6. Tighten the blade clamping screw firmly with the blade wrench.
NOTE: Never engage the blade lock while saw is running, or engage in an effort to stop the tool.
Never turn the saw on while the blade lock is engaged. Serious damage to your saw will result.
TO REPLACE THE BLADE
1. To loosen the blade clamping screw (F), depress the blade lock (J) and turn the saw spindle with the blade wrench until the blade lock engages and the blade stops rotating. With
the blade lock engaged, turn the blade clamping screw clockwise with the blade wrench
(screw has left-hand threads and must be turned clockwise to loosen).
2. Remove the blade clamping screw (F) and outer clamp washer (I) only. Remove old blade.
3. Clean any sawdust that may have accumulated in the guard or clamp washer area and check
the condition and operation of the lower blade guard as previously outlined. Do not lubricate
this area.
4. Select the proper blade for the application (see Blades). Always use blades that are the correct size (diameter) with the proper size and shape center hole for mounting on the saw
spindle. Always assure that the maximum recommended speed (rpm) on the saw blade
meets or exceeds the speed (rpm) of the saw.
5. Follow steps 2 through 6 under To Install the Blade, making sure that the blade will rotate
in the proper direction.
LOWER BLADE GUARD
WARNING: The lower blade guard is a safety feature which reduces the risk of serious
personal injury. Never use the saw if the lower guard is missing, damaged, misassembled
or not working properly. Do not rely on the lower blade guard to protect you under all circumstances. Your safety depends on following all warnings and precautions as well as
proper operation of the saw. Check lower guard for proper closing before each use as
outlined in Additional Safety Rules for Circular Saws. If the lower blade guard is missing
or not working properly, have the saw serviced before using. To assure product safety
and reliability, repair, maintenance and adjustment should be performed by an authorized service center or other qualified service organization, always using identical
replacement parts.
Cutting Depth Adjustment
CAUTION: Turn off and unplug the tool before making any adjustments or
removing/installing attachments or accessories.
Hold the saw firmly. Raise the depth adjustment lever (C) to loosen and move shoe to obtain
the desired depth of cut, as shown. Make sure the depth adjustment lever has been retightened
(lowered) before operating saw (Fig. 4).
Your saw is equipped with a carbide tipped saw blade for long life and efficient cutting.
Setting the saw at the proper cutting depth keeps blade friction to a minimum, removes saw-
dust from between the blade teeth, results in cooler, faster sawing and reduces the chance of
kickback. Align the appropriate mark on the depth adjustment strap with triangle on the upper
blade guard. Your depth is set.
For the most efficient cutting action using a carbide tipped saw blade, set the Depth Adjustment
so that about one half of a tooth projects below the surface of the wood to be cut (Figure 5).
A method of checking for the correct cutting depth is shown in Figure 6. Lay a piece of the material you plan to cut along the side of the blade, as shown in the figure, and observe how much
tooth projects beyond the material.
Bevel Angle Adjustment
CAUTION: Turn off and unplug the tool before making any adjustments or
removing/installing attachments or accessories.
The full range of the bevel adjustment is from 0 TO 50 DEGREES. The quadrant is graduated
in increments of 5 degrees.
On the front of the saw is a bevel angle adjustment mechanism (Fig. 8) consisting of a calibrated
quadrant (L) and a lever (M). To set the saw for a bevel cut, raise to loosen the Bevel Adjustment
lever and tilt shoe to the desired angle by aligning the pointer (N) with the desired angle mark.
Retighten lever firmly by lowering it.
KERF INDICATOR
The front of the saw shoe has a kerf indicator (Figure 10) for vertical and bevel cutting. This indicator enables you to guide the saw along cutting lines penciled on the material being cut. The
indicator lines up with the left (outer) side of the saw blade, which makes the slot or “kerf” cut
by the moving blade fall to the right of the indicator. The ribs on the front of the shoe are at 1/2"
(13mm) spacing.
OPERATION
Switch (Fig. 1)
Pull the trigger switch (B) to turn the motor ON. Releasing the trigger turns the motor OFF. This
tool has no provision to lock the switch in the ON position, and should never be locked ON in
any way.
Workpiece Support
Figure 11 and 13 show proper sawing position. Figure 12 and 14 show an unsafe condition.
Hands should be kept away from cutting area, and power cord is positioned clear of the cutting
area so that it will not get caught or hung up on the work.
To avoid kickback, DO support board or panel NEAR the cut, (Fig. 11, 13). DON’T support board
or panel away from the cut (Fig. 12, 14). When operating the saw, keep the cord away from the
cutting area and prevent it from becoming hung up on the work piece.
WARNING: It is important to support the work properly and to hold the saw firmly to prevent
loss of control which could cause personal injury; Figure 14 illustrates typical hand support of
the saw.
ALWAYS DISCONNECT SAW BEFORE MAKING ANY ADJUSTMENTS! Place the work with
its “good” side - the one on which appearance is most important - down. The saw cuts upward,
so any splintering will be on the work face that is up when you saw it.
Cutting
Support the work so that the waste will be on your left. Place the wider portion of the saw shoe
on that part of the work piece which is solidly supported, not on the section that will fall off when
the cut is made. As examples, Figure 13 illustrates the RIGHT way to cut off the end of a board,
and Figure 14 the WRONG way. Always clamp work. Don’t try to hold short pieces by hand!
Remember to support cantilevered and overhanging material. Use caution when sawing material from below.
Be sure saw is up to full speed before blade contacts material to be cut. Starting saw with blade
against material to be cut or pushed forward into kerf can result in kickback.
Push the saw forward at a speed which allows the blade to cut without laboring. Hardness and
toughness can vary even in the same piece of material, and knotty or damp sections can put a
heavy load on the saw. When this happens, push the saw more slowly, but hard enough to keep
it working without much decrease in speed.
Sawhook
Your saw has a convenient saw hook to allow you to hang the saw on a joist or rafter. The
sawhook folds flat against the tool handle when not in use.
To use the sawhook, push down on the hook and rotate it outwards from the handle. It will latch
into position. (Fig.15)
To return the sawhook to its stored position, push down on the hook and rotate it back towards
the handle. It will latch into position.
Kickback
When the saw blade becomes pinched or twisted in the cut, kickback can occur. The saw is
thrust rapidly back toward the operator. When the blade is pinched or bound tightly by the kerf
closing down, the blade stalls and the motor reaction drives the unit backward. When the blade
becomes twisted or misaligned in the cut, the teeth at the back edge of the blade can dig into
the top surface of the wood causing the blade to climb out of the kerf and jump back toward the
operator.
Kickback is more likely to occur when any of the following conditions exist.
1. IMPROPER WORKPIECE SUPPORT
A. Sagging or improper lifting of the cut off piece causing pinching of the blade. (Figure 12)
B. Cutting through material supported at the outer ends only (see Figure 12). As the mater-
ial weakens it sags, closing down the kerf and pinching the blade.
C.Cutting off a cantilevered or overhanging piece of material from the bottom up in a verti-
cal direction. The falling cut off piece can pinch the blade.(Figure 14)
D.Cutting off long narrow strips (as in ripping). The cut off strip can sag or twist closing the
kerf and pinching the blade.
FIG. 2
FIG. 3
FIG. 4
C
FIG. 7
FIG. 5
J
FIG. 6
FIG. 8
K
M
L
FIG. 9
N
FIG. 10
0˚
45˚
1/2”
13 mm
B
C
A
E
F
FIG. 12
FIG. 13
FIG. 14
FIG. 15
FIG. 11
TIGHTEN
(counterclockwise)
SERRER
(vers la gauche)
AJUSTAR
(dirección contraria
a las manillas
del reloj)
LOOSEN
(clockwise)
DESSERRER
(vers la droite)
AFLOJAR
(dirección de las
manillas del reloj)
FIG. 1
D
F
I
G
J
E. Snagging the lower guard on a surface below the material being cut momentarily reduc-
ing operator control. The saw can lift partially out of the cut increasing the chance of blade
twist.
2. IMPROPER DEPTH OF CUT SETTING ON SAW
Using the saw with an excessive depth of cut setting increases loading on the unit and susceptibility to twisting of the blade in the kerf. It also increases the surface area of the blade
available for pinching under conditions of kerf close down. See CUTTING DEPTH
ADJUSTMENT.
3. BLADE TWISTING (MISALIGNMENT IN CUT)
A. Pushing harder to cut through a knot, a nail, or a hard grain area can cause the blade to
twist.
B. Trying to turn the saw in the cut (trying to get back on the marked line) can cause blade
twist
C.Extended reach or operating saw with poor body control (out of balance), can result in
twisting the blade.
D.Changing hand grip or body position while cutting can result in blade twist.
E. Backing unit up to clear blade can lead to twist if not done carefully.
4. MATERIALS THAT REQUIRE EXTRA ATTENTION
A. Wet lumber
B. Green lumber (material freshly cut or not kiln dried)
C.Pressure treated lumber (material treated with preservatives or anti-rot chemicals)
5. USE OF DULL OR DIRTY BLADES
Dull blades cause increased loading of the saw. To compensate, an operator will usually
push harder which further loads the unit and promotes twisting of the blade in the kerf. Worn
blades may also have insufficient body clearance which increases the chance of binding and
increased loading.
6. LIFTING THE SAW WHEN MAKING BEVEL CUTS
Bevel cuts require special operator attention to proper cutting techniques - especially guidance of the saw. Both blade angle to the shoe and greater blade surface in the material
increase the chance for binding and misalignment (twist) to occur.
7. RESTARTING A CUT WITH THE BLADE TEETH JAMMED AGAINST THE MATERIAL
The saw should be brought up to full operating speed before starting a cut or restarting a cut
after the unit has been stopped with the blade in the kerf. Failure to do so can cause stalling
and kickback.
Any other conditions which could result in pinching, binding, twisting, or misalignment of the
blade could cause kickback. Refer to the sections on “Adjustments And Set-Up” and “Operation”
for procedures and techniques that will minimize the occurrence of kickback.
MAINTENANCE
Lubrication
Your saw has a sealed gear housing filled to the proper level with a high-performance gear lubricant. Adding excessive amounts of lubricant, or adding improper lubricant can cause leakage or
premature gear failure.
H
H
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