Makita 9521NB, Original Instructions Manual

Page: 7 / 12

7
Kickback and Related Warnings
Kickback is a sudden reaction to a pinched or snagged
rotating wheel, backing pad, brush or any other acces-
sory. Pinching or snagging causes rapid stalling of the
rotating accessory which in turn causes the uncontrolled
power tool to be forced in the direction opposite of the
accessory’s rotation at the point of the binding.
For example, if an abrasive wheel is snagged or pinched
by the workpiece, the edge of the wheel that is entering
into the pinch point can dig into the surface of the mate-
rial causing the wheel to climb out or kick out. The wheel
may either jump toward or away from the operator,
depending on direction of the wheel’s movement at the
point of pinching. Abrasive wheels may also break under
these conditions.
Kickback is the result of power tool misuse and/or incor-
rect operating procedures or conditions and can be
avoided by taking proper precautions as given below.
a) Maintain a firm grip on the power tool and
position your body and arm to allow you to
resist kickback forces. Always use auxiliary
handle, if provided, for maximum control
over kickback or torque reaction during start-
up.
The operator can control torque reactions or
kickback forces, if proper precautions are taken.
b) Never place your hand near the rotating
accessory. Accessory may kickback over your
hand.
c) Do not position your body in the area where
power tool will move if kickback occurs. Kick-
back will propel the tool in direction opposite to
the wheel’s movement at the point of snagging.
d) Use special care when working corners,
sharp edges etc. Avoid bouncing and snag-
ging the accessory.
Corners, sharp edges or
bouncing have a tendency to snag the rotating
accessory and cause loss of control or kickback.
e) Do not attach a saw chain woodcarving blade
or toothed saw blade. Such blades create fre-
quent kickback and loss of control
Safety Warnings Specific for Grinding and Abrasive
Cutting-Off Operations:
a) Use only wheel types that are recommended
for your power tool and the specific guard
designed for the selected wheel.
Wheels for
which the power tool was not designed cannot
be adequately guarded and are unsafe.
b) The guard must be securely attached to the
power tool and positioned for maximum
safety, so the least amount of wheel is
exposed towards the operator.
The guard
helps to protect the operator from broken wheel
fragments, accidental contact with wheel and
sparks that could ignite clothing.
c) Wheels must be used only for recommended
applications. For example: do not grind with
the side of cut-off wheel.
Abrasive cut-off
wheels are intended for peripheral grinding, side
forces applied to these wheels may cause them
to shatter.
d) Always use undamaged wheel flanges that
are of correct size and shape for your
selected wheel.
Proper wheel flanges support
the wheel thus reducing the possibility of wheel
breakage. Flanges for cut-off wheels may be dif-
ferent from grinding wheel flanges.
e) Do not use worn down wheels from larger
power tools. Wheel intended for larger power
tool is not suitable for the higher speed of a
smaller tool and may burst.
Additional Safety Warnings Specific for Abrasive
Cutting-Off Operations:
a) Do not “jam” the cut-off wheel or apply
excessive pressure. Do not attempt to make
an excessive depth of cut.
Overstressing the
wheel increases the loading and susceptibility to
twisting or binding of the wheel in the cut and the
possibility of kickback or wheel breakage.
b) Do not position your body in line with and
behind the rotating wheel. When the wheel, at
the point of operation, is moving away from your
body, the possible kickback may propel the spin-
ning wheel and the power tool directly at you.
c) When wheel is binding or when interrupting a
cut for any reason, switch off the power tool
and hold the power tool motionless until the
wheel comes to a complete stop. Never
attempt to remove the cut-off wheel from the
cut while the wheel is in motion otherwise
kickback may occur.
Investigate and take cor-
rective action to eliminate the cause of wheel
binding
d) Do not restart the cutting operation in the
workpiece. Let the wheel reach full speed
and carefully re-enter the cut.
The wheel may
bind, walk up or kickback if the power tool is
restarted in the workpiece.
e) Support panels or any oversized workpiece
to minimize the risk of wheel pinching and
kickback.
Large workpieces tend to sag under
their own weight. Supports must be placed under
the workpiece near the line of cut and near the
edge of the workpiece on both sides of the
wheel.
f) Use extra caution when making a “pocket
cut” into existing walls or other blind areas.
The protruding wheel may cut gas or water
pipes, electrical wiring or objects that can cause
kickback.
Safety Warnings Specific for Sanding Operations:
a) Do not use excessively oversized sanding
disc paper. Follow manufacturers recommen-
dations, when selecting sanding paper.
Larger sanding paper extending beyond the
sanding pad presents a laceration hazard and
may cause snagging, tearing of the disc or kick-
back.
Safety Warnings Specific for Wire Brushing Opera-
tions:
a) Be aware that wire bristles are thrown by the
brush even during ordinary operation. Do not
overstress the wires by applying excessive
load to the brush.
The wire bristles can easily
penetrate light clothing and/or skin.
b) If the use of a guard is recommended for wire
brushing, do not allow interference of the
wire wheel or brush with the guard.
Wire
wheel or brush may expand in diameter due to
work load and centrifugal forces.