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which in turn causes the uncontrolled power tool to be forced in the direction opposite of the
accessory’s rotation.
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 material 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 incorrect 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.
The operator can control kickback forces, if proper
precautions are taken.
b) Use special care when working corners, sharp edges etc. Avoid bouncing and
snagging the accessory.
Corners, sharp edges or bouncing have a tendency to snag
the rotating accessory and cause loss of control or kickback.
c) Do not attach a toothed saw blade.
Such blades create frequent kickback and loss of
control.
d) Always feed the bit into the material in the same direction as the cutting
edge is exiting from the material (which is the same direction as the chips are
thrown).
Feeding the tool in the wrong direction causes the cutting edge of the bit to
climb out of the work and pull the tool in the direction of this feed.
e) When using rotary files, cut-off wheels, high-speed cutters or tungsten carbide
cutters, always have the work securely clamped.
These wheels will grab if they
become slightly canted in the groove, and can kickback. When a cut-off wheel grabs,
the wheel itself usually breaks. When a rotary file, high-speed cutter or tungsten carbide
cutter grabs, it may jump from the groove and you could lose control of the tool .
SAFETY WARNINGS SPECIFIC FOR GRINDING AND ABRASIVE CUTTING-OFF OPERATIONS:
a) Use only wheel types that are recommended for your power tool and only for
recommended applications. For example: do not grind with the side of a cut-off
wheel.
Abrasive cut-off wheels are intended for peripheral grinding, side forces applied
to these wheels may cause them to shatter.
b) For threaded abrasive cones and plugs use only undamaged wheel mandrels
with an unrelieved shoulder flange that are of correct size and length.
Proper
mandrels will reduce the possibility of breakage.
c) Do not “jam” a 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 snagging of the wheel in the cut and the possibility of
kickback or wheel breakage.
d) Do not position your hand in line with and behind the rotating wheel.
When the
wheel, at the point of operation, is moving away from your hand, the possible kickback
may propel the spinning wheel and the power tool directly at you.
e) When wheel is pinched, snagged or when interrupting a cut for any reason,
switch off the power tool and hold the power tool motionless until the wheel
