Pull-In; Pushback - Stihl MSA 120 C Instruction Manual

7 Kickback and Other Reactive Forces
7.3

Pull-in

WARNING
￭ Pull-in occurs when the saw chain on the bottom of the bar
is suddenly stopped or significantly slowed when it is
pinched, caught or encounters a foreign object in the
wood. The reaction of the saw chain pulls the chain saw
forward and may cause the operator to lose control,
which, in turn, may cause serious or fatal injury. If the tip
contacts an object, kickback may occur.
￭ Pull-in usually occurs when the bumper spike of the chain
saw is not held securely against the tree or limb and when
the saw chain is not rotating at full speed before it contacts
the wood.
￭ To reduce the risk of pull-in:
– Cut with a sharp, properly tensioned chain.
– Always start a cut with the saw chain rotating at full
speed and with the bumper spike in contact with the
wood.
– Use wedges to open the kerf or cut, where possible.
– Use extreme caution when cutting small-size brush
and saplings which may easily catch the saw chain,
spring towards you or pull you off balance.
0458-716-8621-C
7.4

Pushback

WARNING
￭ Pushback occurs when the saw chain on the top of the bar
is suddenly stopped or significantly slowed when it is
pinched, caught or encounters a foreign object in the
wood. The reaction of the saw chain may drive the chain
saw rapidly straight back toward the operator, causing
loss of control which, in turn, may cause serious or fatal
injury.
￭ Pushback usually occurs when the top of the bar is used
for cutting.
￭ To reduce the risk of pushback:
– Be alert to forces or situations that may cause
material to pinch or bind the top of the saw chain.
– Do not cut more than one log at a time.
– Do not twist the chain saw when withdrawing the bar
from an underbuck cut because the saw chain can
pinch or bind.
– Cut with a sharp, properly tensioned chain.
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