6
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 the operator.
Kickback is the result of saw misuse and/or incorrect
operating procedures or conditions and can be avoided by
taking proper precautions as given below.
a.
Maintain a firm grip with both hands on the saw and
position your arms to resist kickback forces.
Position
your body to either side of the blade, but not in line
with the blade. Kickback could cause the saw to jump
backwards, but kickback forces can be controlled by the
operator, if proper precautions are taken.
b.
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 eliminate the cause of blade binding.
c.
When restarting a saw in the workpiece, centre the
saw blade in the kerf and check that 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.
d.
Support large panels to minimise the risk of blade
pinching and kickback.
Large panels tend to sag under
their own weight. Supports must be placed under the
panel on both sides, near the line of cut and near the
edge of the panel.
e.
Do not use dull or damaged blades.
Unsharpened
or improperly set blades produce narrow kerf causing
excessive friction, blade binding and kickback.
f.
Blade depth and bevel adjusting locking levers
must be tight and secure before making cut.
If blade adjustment shifts while cutting, it may cause
binding and kickback.
g.
Use extra caution when making a “plunge cut” into
existing walls or other blind areas.
The protruding
blade may cut objects that can cause kickback.
The protruding blade may cut objects that can
cause kickback.
a.
Check lower guard for proper closing before each
use.
Do not operate the 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, 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, in all
angles and depths of cut.
b.
Check the operation 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
build-up of debris.
c.
Lower guard should be retracted manually only for
special cuts such as “plunge cuts” and “compound
cuts.”
Raise lower guard by retracting handle and as
soon as blade enters the material, the lower guard must
be released. For all other sawing, the lower guard should
operate automatically.
d.
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.
e. Do not use abrasive wheels.
