Stihl HT 100 Instruction Manual page 14

The most common reactive forces are:
– kickback,
– pushback,
– pull-in.
Kickback
Kickback may occur when the moving
saw chain near the upper quadrant of
the bar nose contacts a solid object or is
pinched.
The reaction of the cutting force of the
chain causes a rotational force on the
chainsaw in the direction opposite to the
chain movement. This may cause the
bar to move upward.
HT 100, HT 101, HT 130, HT 131
To avoid kickback
The best protection from kickback is to
avoid kickback situations:
1. Be aware of the location of the guide
bar nose at all times.
2. Never let the nose of the guide bar
contact any object. Do not cut limbs
with the nose of the guide bar. Be
especially careful near wire fences
and when cutting small, tough
limbs, which may easily catch the
chain.
3. Cut only one limb at a time.
A = Pull-in
Pull-in occurs when the chain on the
bottom of the bar is suddenly stopped
when it is pinched, caught or encounters
a foreign object in the wood. The
reaction of the chain pulls the saw
forward.
Pull-in frequently occurs when the chain
is not rotating at full speed before it
contacts the wood.
To avoid pull-in
1. Be alert to forces or situations that
may cause material to pinch the
chain at the bottom of the bar.
2. Always start a cut with the chain
rotating at full speed
B = Pushback
Pushback occurs when the chain on the
top of the bar is suddenly stopped when
it is pinched, caught or encounters a
foreign object in the wood. The reaction
of the chain may drive the saw rapidly
A
straight back toward the operator.
Pushback frequently occurs when the
top of the bar is used for cutting.
To avoid pushback
1. Be alert to forces or situations that
may cause material to pinch the
chain at the top of the bar.
2. Do not cut more than one limb at a
time.
3. Do not twist the bar when
withdrawing it from an underbuck
cut because the chain can pinch.
English / USA
B
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