DeWalt DHS790 - Cutting Techniques for Moldings and Frames; PRETESTING WITH SCRAP MATERIAL IS EXTREMELY IMPORTANT!

13
ENGLISH
Non-Through-Cutting (Grooving and Rabbeting)
Instructions in the Crosscuts, Bevel Cuts and Cutting Compound Miters 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 Hold the wood firmly on the table
and against the fence
14
. 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
2
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

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 your hands are required to be within 4" (100mm) of the blade
during thecut.
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 4" (100 mm) from the blade, a clamp or other fixture must
beused.
Use the material clamp provided with your saw. To purchase the material clamp, contact 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 or right fence will slide from side to side to aid inclamping.
To Install Clamp
1. Insert it into the hole (
27
, Fig.A) behind the fence. The clamp should be facing toward the
back of the miter saw. The groove on the clamp rod should be fully inserted into the base.
Ensure this groove is fully inserted into the base of the miter saw. If the groove is visible, the
clamp will not besecure.
2. Rotate the clamp 180º toward the front of the mitersaw.
3. Loosen the knob to adjust the clamp up or down, then use the fine adjust knob 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 tool off and remove
the battery packs or power supply before transporting, making any adjustments,
cleaning, repairing, or removing/installing attachments or accessories. An accidental
start-up can causeinjury.
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 miter saw table or to help feed, support or pull
theworkpiece.
For best results, use the DW7080 extension work support to extend the table width of your saw,
available from your dealer at extra cost. 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.Z,AA)
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 mitering corners like the one shown in FigureZ. Sketch 1 in
FigureAA 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 miter 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
mitering right and left with the broad surface against thefence.
Fig. Z
1
Fig. AA
1
2
Cutting Trim Molding And Other Frames (Fig.AA)
Sketch 2 in FigureAA shows a joint made by setting the miter arm at 45º to miter the two boards
to form a 90º corner. To make this type of joint, set the bevel adjustment to zero and the miter
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AA are for four-sided objectsonly.
As the number of sides changes, so do the miter and bevel angles. The chart below gives the
proper angles for a variety ofshapes.
– EXAMPLES –
NUMBER OF SIDES MITER 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 miter (if the material is
cut vertically) or bevel angle (if the material is cut laying flat).
Cutting Compound Miters (Fig.BB)
A compound miter is a cut made using a miter 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BB.
NOTE: If the cutting angle varies from cut to cut, check that the bevel lock knob and the miter
lock handle are securely locked. These must be locked after making any changes in bevel
ormiter.
The chart at the end of this manual (Table 1) will assist you in selecting the proper bevel and
miter settings for common compound miter cuts. To use the chart, select the desired angleA
(Fig.BB) 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 miterangle.
Fig. BB
Angle “A”
Set your saw to the prescribed angles and make a few trial cuts. Practice fitting the cut pieces
together until you develop a feel for this procedure and feel comfortable withit.
Example: To make a 4-sided box with 26º exterior angles (Angle A, Fig.BB), use the upper right
arc. Find 26° on the arc scale. Follow the horizontal intersecting line to either side to get miter
angle setting on saw (42°). Likewise, follow the vertical intersecting line to the top or bottom to
get the bevel angle setting on the saw (18°). Always try cuts on a few scrap pieces of wood to
verify the settings on thesaw.
Cutting Base Molding (Fig.K, CC)
ALWAYS MAKE A DRY RUN WITHOUT POWER BEFORE MAKING ANYCUTS.
Straight 90º cuts:
Position the wood against the fence and hold it in place as shown in FigureCC. Turn on the saw,
allow the blade to reach full speed and lower the arm smoothly through thecut.
Cutting Base Molding from 3" UP TO 6.75" (76 mm to 171 mm) High Vertically Against
the Fence
NOTE: Use the slide lock lever
43
, shown in FigureK, when cutting base molding measuring
from 3" to 6.75" (76 mm to 171 mm) high vertically against thefence.
Position material as shown in FigureCC.