Working safely with cut-off machines
English
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power available for the actual cutting
work. It could also damage the abrasive
wheel.
STIHL recommends the use of the cart
for longer cuts in a straight line.
Wet Cutting with Abrasive Wheels
Before wet cutting, make sure water will
not damage the floor or building.
1.
Make certain water does not flow on
a wheel that is not running, since the
wheel will absorb water, which will
affect wheel balance.
2.
Be certain water is applied to both
sides of wheel, since uneven
distribution can cause "one sided"
wear.
3.
After finishing work, run the cutting
wheel at normal operating speed for
about 3 to 6 seconds without water
so that the remaining water is flung
off.
Reactive Forces including Kickback
An understanding of the causes of these
reactive forces may help you avoid loss
of control. Reactive forces are exerted in
a direction opposite to the direction in
which the wheel is moving at the point of
contact or of pinching / binding. If the
wheel is slowed solely by frictional
contact with a solid object, such as the
workpiece, the resulting reactive forces
are normally moderate and readily
controllable by an operator who is
holding the machine properly. If,
however, the wheel is abruptly slowed or
stopped by a pinch or severe bind, the
reactive forces may be substantially
greater. The greater the force
generated, the more difficult it will be for
the operator to control the cut-off
machine. Loss of control can result in
severe personal injury or death.
Pull-away, Climbing, Pinching and
Rotational Kickback Forces
The most common reactive forces are
pull-away and climbing. If the contact is
at the bottom of the wheel, a cut-off
machine will try to pull away from the
operator (pull-away.) If the contact is at
the front of the wheel, the wheel may
attempt to climb the object being cut
(climbing.)
Pinching occurs when the piece being
cut closes on the wheel. A severe
binding may also occur if the wheel is
substantially sideloaded in the kerf or if
an improper or damaged diamond wheel
begins or ceases to wobble in the kerf. If
the wheel is severely pinched or bound
in the upper quadrant, the wheel may be
instantly thrown up and back towards
the operator with great force in a
rotational kickback motion. Such
kickback situations can and should
always be avoided. Pinching of the
wheel can be prevented by proper
support of the workpiece. (See below.)
Severe binding of the wheel can be
prevented by proper cutting techniques,
e.g., not sideloading the wheel, and by
the use of properly designed,
manufactured and maintained wheels.
Warning!
To reduce the risk of electrocution to
you or bystanders, do not allow water or
sludge to contact live electric wires.
Warning!
To reduce the risk of injury from wheel
breakage when wet cutting with any
composite wheel:
Warning!
To reduce the risk of injury from wheel
breakage when wet cutting with a com-
posite wheel that is not specifically
designed for wet cutting, never store
and reuse such a wheel that has been
used with water. Use these wheels up
the same day.
Warning!
Reactive forces may
occur at any time the cut-
ting wheel on a cut-off
machine is rotating. The
powerful force used to
cut through a workpiece
can be reversed and work against the
operator. If the wheel is slowed or
stopped by frictional contact with any
solid object or by a pinch or binding,
reactive forces can occur instantly and
may result in the operator losing control
of the cut-off machine, which, in turn,
may result in serious or fatal injury.
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