DeWalt DCS781 - Advanced Cutting Techniques; Large Workpieces and Mitre Crosscuts; Bevel Cuts and Cut Quality; Grooving, Rabbeting, and Clamping

15
ENGLISH
When cutting anything larger than a 51x 203mm (51 x 152at 45º mitre) use an
out‑down‑back motion with the rail lock knob loosened. Pull the saw out, toward you, lower
the saw head down toward the workpiece, and slowly push the saw back to complete the cut.
Do not allow the saw to contact the top of the workpiece while pulling out. The saw may run
toward you, possibly causing personal injury or damage to theworkpiece.
Cutting of multiple pieces is not recommended but can be done safely by ensuring that each
piece is held firmly against the table and fence.
NOTE: To provide greater crosscut capacity with reduced stroke, the blade on the DCS781
extends deeper into the table. As a result, a greater lifting force on the workpiece may be
experienced during thecut.

CAUTION: Always use a work clamp to maintain control and reduce the risk of workpiece
damage and personal injury, if your hands are required to be within 100mm of the blade
during thecut.
NOTE: The rail lock knob
30
shown in Figure A must be loose to allow the saw to slide along
its rails
24
.
Mitre crosscuts are made with the mitre arm at some angle other than zero. This angle is often
45º for making corners, but can be set anywhere from zero to 50º left or 60° right. Make the
cut as described above.
When performing a mitre cut on workpieces wider than a 51mm X 152mm that are shorter in
length, always place the longer side against the fence
12
(FigureQ).
To cut through an existing pencil line on a piece of wood, match the angle as close as possible.
Cut the wood a little too long and measure from the pencil line to the cut edge to determine
which direction to adjust the mitre angle and recut. This will take some practice, but it is a
commonly usedtechnique.
Bevel Cuts
A bevel cut is a crosscut made with the saw blade leaning at an angle to the wood. In order
to set the bevel, loosen the bevel lock
13
, and move the saw to the left or right as desired.
(It is necessary to move the fence to allow clearance.) Once the desired bevel angle has been
set, tighten the bevel lock firmly. Refer to the Controls section for detailed instructions on the
bevelsystem.
Bevel angles can be set from 49º right to 49º left and can be cut with the mitre arm set
between 50º left or 60º right. At some extreme angles, the right or left side fence might have
to be removed. To remove the left or right fence, unscrew the fence adjustment knob
16
several turns and slide the fenceout.
NOTE: Refer to Fence Adjustment in the Assembly and Adjustments section for important
information on adjusting the fences for certain bevelcuts.
Quality of Cut
The smoothness of any cut depends on a number of variables. Things like material being cut,
blade type, blade sharpness and rate of cut all contribute to the quality of thecut.
When smoothest cuts are desired for molding and other precision work, a sharp (60 tooth
carbide) blade and a slower, even cutting rate will produce the desiredresults.
Ensure that the material does not move or creep while cutting; clamp it securely in place.
Always let the blade come to a full stop before raisingarm.
If small fibers of wood still split out at the rear of the workpiece, stick a piece of masking tape
on the wood where the cut will be made. Saw through the tape and carefully remove tape
whenfinished.
For varied cutting applications, refer to the list of recommended saw blades for your saw and
select the one that best fits your needs. Refer to Saw Blades under OptionalAccessories.
Non‑Through‑Cutting (Grooving and Rabbeting)
Instructions in the Crosscuts, Bevel Cuts and Cutting Compound Mitres sections are for cuts
made through the full thickness of the material. The saw can also perform non‑through cuts to
form grooves or rabbets in thematerial.
Groove Cut (Fig.A)
Refer to Depth Stop for detailed instructions for setting depth of cut. A piece of scrap wood
should be used to verify the desired depth ofcut.
Hold the wood firmly on the table and against the fence
12
. Align the cut area underneath
the blade. Position the saw arm fully forward, with blade in down position. Turn on the saw by
squeezing the trigger switch
1
shown in FigureA. Smoothly, push saw arm rearward to cut a
groove through the workpiece.
Release the trigger switch with the saw arm down. When saw blade has completely stopped,
raise the saw arm. Always let the blade come to a full stop before raising thearm.
To widen the groove, repeat steps 1–4 until the desired width isobtained.
Clamping the Workpiece (Fig. A)

WARNING: To reduce the risk of serious personal injury, turn off the tool and
disconnect it from the power source before attempting to move it, change
accessories or make anyadjustments.

WARNING: A workpiece that is clamped, balanced and secure before a cut may become
unbalanced after a cut is completed. An unbalanced load may tip the saw or anything the
saw is attached to, such as a table or workbench. When making a cut that may become
unbalanced, properly support the workpiece and ensure the saw is firmly bolted to a
stable surface. Personal injury mayoccur.

WARNING: The clamp foot must remain clamped above the base of the saw whenever
the clamp is used. Always clamp the workpiece to the base of the saw–not to any other
part of the work area. Ensure the clamp foot is not clamped on the edge of the base of
thesaw.

CAUTION: Always use a work clamp to maintain control and reduce the risk of workpiece
damage and personalinjury.
If you cannot secure the workpiece on the table and against the fence by hand, (irregular
shape, etc.) or your hand would be less than 100mm from the blade, a clamp or other fixture
must beused.
For best results use the vertical material clamp
23
provided with your saw. Additional clamps
can be purchased at your local retailer or DeWALT servicecenter.
Other aids such as spring clamps, bar clamps or C‑clamps may be appropriate for certain sizes
and shapes of material. Use care in selecting and placing these clamps. Take time to make a
dry run before making the cut. The left fence will slide from side to side to aid in clamping
To Install Clamp (Fig.A)
1. Insert clamp post into the hole behind the fence
12
.
2. Adjust the clamp up turning the knob counterclockwise. And clamp down by turning the
knob clockwise. Make sure to firmly clamp theworkpiece.
NOTE: Place the clamp on the opposite side of the base when beveling. ALWAYS MAKE DRY
RUNS (UNPOWERED) BEFORE FINISH CUTS TO CHECK THE PATH OF THE BLADE. ENSURE THE
CLAMP DOES NOT INTERFERE WITH THE ACTION OF THE SAW ORGUARDS.
Support for Long Pieces

WARNING: To reduce the risk of serious personal injury, turn off the tool and
disconnect it from the power source before attempting to move it, change
accessories or make anyadjustments.
ALWAYS SUPPORT LONGPIECES.
Never use another person as a substitute for a table extension; as additional support for a
workpiece that is longer or wider than the basic mitre saw table or to help feed, support or
pull theworkpiece.
Support long workpieces using any convenient means such as sawhorses or similar devices to
keep the ends fromdropping.
Cutting Picture Frames, Shadow Boxes and Other Four‑Sided
Projects (Fig. R)
To best understand how to make the items listed here, we suggest that you try a few simple
projects using scrap wood until you develop a “feel” for yoursaw.
Your saw is the perfect tool for mitreing corners like the one shown in FigureR. Sketch 1in
FigureR shows a joint made by using the bevel adjustment to bevel the edges of the two
boards at 45º each to produce a 90º corner. For this joint the mitre arm was locked in the
zero position and the bevel adjustment was locked at 45º. The wood was positioned with the
broad flat side against the table and the narrow edge against the fence. The cut could also be
made by mitreing right and left with the broad surface against thefence.
Cutting Trim Molding and Other Frames (Fig. R)
Sketch 2in FigureR shows a joint made by setting the mitre arm at 45º to mitre the two
boards to form a 90º corner. To make this type of joint, set the bevel adjustment to zero and
the mitre arm to 45º. Once again, position the wood with the broad flat side on the table and
the narrow edge against thefence.
The two sketches in FigureR are for four‑sided objectsonly.
As the number of sides changes, so do the mitre and bevel angles. The chart below gives the
proper angles for a variety ofshapes.
– EXAMPLES –
NUMBER OF SIDES Mitre OR BEVEL ANGLE
4 45°
5 36°
6 30°
7 25.7°
8 22.5°
9 20°
10 18°
The chart assumes that all sides are of equal length. For a shape that is not shown in the
chart, use the following formula: 180º divided by the number of sides equals the mitre (if the
material is cut vertically) or bevel angle (if the material is cut layingflat).
Cutting Compound Mitres (Fig. S)
A compound mitre is a cut made using a mitre angle and a bevel angle at the same time.
This is the type of cut used to make frames or boxes with slanting sides like the one shown in
FigureT.

WARNING: If the cutting angle varies from cut to cut, check that the bevel lock knob and
the mitre lock handle are securely locked. These must be locked after making any changes
in bevel ormitre.
The chart shown below will assist you in selecting the proper bevel and mitre settings for
common compound mitrecuts.
• Select the desired angle A (Fig.S) of your project and locate that angle on the appropriate
arc in thechart.
• From that point follow the chart straight down to find the correct bevel angle and straight
across to find the correct mitreangle.
• Set your saw to the prescribed angles and make a few trial cuts. Practise fitting the cut
piecestogether.