Stihl TSA 230 Instruction Manual page 14

English
concrete materials – leave a thin piece
uncut. For most such materials, this
piece can be easily broken afterwards.
Do not cock, jam or wedge the wheel in
the cut.
Release the pressure on the cut-off
machine as you reach the end of the cut.
Too much pressure may cause the
operator to lose control of the cut-off
machine when the abrasive wheel
completes the cut. The abrasive wheel
may contact the operator or strike some
foreign object and shatter.
Always switch off the machine, move
retaining latch to ? and be sure the
wheel has stopped rotating before
setting down the cut-off machine.
Wet Cutting with Abrasive Wheels
Before wet cutting, make sure water will
not damage the floor or building.
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:
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. 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.
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WARNING
To reduce the risk of injury from wheel
breakage when wet cutting with a
composite 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.
Reactive Forces including Kickback
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.
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. Severe
binding of the wheel can be prevented
by proper cutting techniques, e.g., not
TSA 230