DeWalt DWS520 Instruction Manual page 14

KICKBACK
When t hesaw blade becomes pinched ortwisted i nthe cut, k ickback
canoccur. The saw isthrust rapidly back t oward t heoperator. When
theblade ispinched orbound t ightly b ythekerr c losing d own, the
blade stalls and themotor r eaction drives t heunit b ackward. When
theblade becomes twisted o rmisaligned inthecut, t he teeth atthe
back e dge o fthe blade c an dig into the top surface ofthe wood c ausing
the blade t oclimb out o fthekerr a nd jump back toward theoperator.
Kickback ismore likely t ooccur when a nyofthe following conditions
exist.
1.IMPROPER WORKPIECE SUPPORT
A.Sagging or improper lifting ofthecutoffpiece cancause
pinching oftheblade andlead tokickback.
B.Cutting t hrough m aterial supported attheouter e nds only
can cause kickback. Asthematerial weakens itsags, closing
down t hekerr a nd pinching theblade.
C.Cutting offa cantilevered oroverhanging piece of material
from thebottom upinavertical direction can cause kickback.
The falling cutoffpiece canpinch t heblade.
D.Cutting off longnarrow strips(asin ripping) c ancause
kickback. The cutoffstrip cansag ortwist c losing thekerr a nd
pinching theblade.
E.Snagging thelower g uard ona surface b elow thematerial
being cutmomentarily reduces o perator control. Thesaw
canliftpartially outofthecutincreasing thechance o fblade
twist.
2.IMPROPER DEPTH O FCUT SETTING ONSAW
Tomake themost e fficient cut, t heblade should p rotrude only
farenough t oexpose 1 /2ofa tooth. This allows t heshoe to
support theblade andminimizes twisting a ndpinching i nthe
material. See thesection titled
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. Over-reaching 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 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 kerr. Worn blades
may also have insufficient body clearance which increases the
chance of binding and increased loading.
6. LIFTING THE SAW WHEN MAKING BEVEL CUT
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
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