Stihl TS 440 Instruction Manual page 19

Support an exposed pipe in a trench so
that it is stable and will not "sag" or
"drop". If the ends of the pipe are firmly
in the ground, the ground may act as a
support where the pipe emerges into the
open. Additional support will be needed
closer to the cut, however, to prevent
sagging (see illustration). Be alert for
pipe that is under stress that may cause
it to shift when cut; pipe in the ground
may be under stress because of uneven
pipe bed surfaces. The release of stress
or tension in the pipe can propel the cut-
off machine, causing loss of control and
resulting in severe personal injury or
death. It also can cause a binding or
pinching of the abrasive cutting wheel,
which could result in reactive forces,
including kickback
Make sure any section of pipe to be
removed is also properly supported and
will not shift. After the first cut, you may
need to move the supports or add
additional support for the second cut so
that both sides of that cut are fully
supported, including the section to be
removed.
Always pay attention in
subgrade/subsurface work areas –
supporting material can crumble or slide
away, causing the pipe to sag and pinch
the wheel.
TS 440
WARNING
Be particularly alert when cutting a
workpiece such as a pipe with a bell end
or when cutting out a section of pipe in a
trench that, if not properly supported,
can sag or drop upon completion of the
cut, creating a pinch or bind. Without
proper support, a pipe with a bell end
laying on the ground will tend to create a
ramp effect that will cause the pipe to
sag or drop as the pipe is cut. If the pinch
or bind occurs in the upper quadrant of
the abrasive cutting wheel, kickback can
result.
WARNING
Use wet-cutting whenever feasible.
Water can act as a lubricant in a pinch
situation and can reduce both the
likelihood of reactive forces occurring
and the energy of any such forces if they
do occur, making it easier to maintain
control of the machine. Please note,
however, that wet cutting should not be
used with composite wheels on the
TS 440.
WARNING
Only STIHL branded cutting
attachments are recommended. Use of
certain non-STIHL branded wheels may
be extremely dangerous. Many
substandard diamond cutting wheels
are available in the market. If they are
not manufactured with the proper quality
materials in their core, if they are not
properly hardened or tensioned, or if
other design or manufacturing problems
exist, they may begin to wobble during
use, lose segments or exhibit other
operational problems that can
substantially increase the risk of
personal injury or death from reactive
forces, thrown segments or loss of
control. If a diamond cutting wheel
begins or ceases to wobble within the
cut, the change in the behavior of the
wheel may cause a severe binding that
can lead to loss of control and/or
kickback. If the wheel you are using
begins to wobble or has ever wobbled,
discard it immediately. Although such a
wheel may temporarily cease to wobble,
e.g., if run without load, it will always be
prone to wobble again. A wheel that
wobbles is extremely dangerous.
WARNING
Some non-STIHL branded diamond
cutting wheels are manufactured with
abrasive material on their sides. Do not
use such wheels, since the abrasive
material increases frictional forces and
will lead to substantially increased
reactive forces in a pinch or side loading
situation.
WARNING
Never use chipped abrasive cutting
wheels, wheels with missing or
damaged segments, or circular saw
blades, carbide-tipped blades, rescue
blades or wood-cutting or toothed
blades of any nature on a cut-off
machine. The use of such wheels or
blades will greatly increase the risk of
loss of control and severe personal
injury or death from reactive forces,
since the chipped or damaged section of
an abrasive cutting wheel or the teeth of
a saw blade may catch in the material
English
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