15
English
Blade
Diameter
Teeth
Application
DWA7770 5-1/2" (140 mm)
30
General purpose ferrous
metal cutting
If you need assistance regarding blades, please call 1-800-4-D
E
WALT
(1-800-433-9258).
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 material 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
exists.
1. IMPROPER WORKPIECE SUPPORT
A.
Sagging or improper lifting of the cut off piece can cause
pinching of the blade and lead to kickback (Fig. 9).
B.
Cutting through material supported at the outer ends only can
cause kickback. As the material weakens it sags, closing down
the kerf and pinching the blade (Fig. 9).
C.
Cutting off a cantilevered or overhanging piece of material from
the bottom up in a vertical direction can cause kickback. The
falling cut off piece can pinch the blade.
D.
Cutting off long narrow strips can cause kickback. The cut off
strip can sag or twist closing the kerf and pinching the blade.
E.
Snagging the lower guard on a surface below the material being
cut momentarily reduces 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
To make the most efficient cut, the blade should protrude only far
enough to expose a tooth as shown in Figure 8. This allows the
shoe to support the blade and minimizes twisting and pinching in
the material. See the section titled
Cutting Depth Adjustment
.
3. BLADE TWISTING (MISALIGNMENT IN CUT)
A.
Pushing harder to cut 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.
Overreaching or operating the 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 up the saw to clear blade can lead to twist.
4. 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.
5. 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
Further Safety Instructions for All Saws
and
Blades
for procedures and techniques that will minimize the occurrence of
kickback.
