MS 194 C
English
15
DANGER
REACTIVE FORCES INCLUDING 
KICKBACK
WARNING
Reactive forces may occur any time the 
chain is rotating. Reactive forces can 
cause serious personal injury.
The powerful force used to cut wood can 
be reversed and work against the 
operator. If the rotating saw chain is 
suddenly and significantly slowed or 
stopped by contact with any solid object 
such as a log or branch or is pinched, the 
reactive forces may occur instantly. 
These reactive forces may result in loss 
of control, which, in turn, may cause 
serious or fatal injury. An understanding 
of the causes of these reactive forces 
may help you avoid the element of 
surprise and loss of control. Surprise 
contributes to accidents.
The most common reactive forces are:
– kickback,
– pushback,
– pull-in.
WARNING
Kickback:
When this occurs, the energy driving the 
saw chain can create a force that moves 
the chain saw in a direction opposite to 
the saw chain movement at the point 
where the saw chain is slowed or 
stopped. This may fling the bar up and 
back in a lightning fast reaction mainly in 
the plane of the bar and can cause 
severe or fatal injury to the operator.
Kickback may occur, for example, when 
the saw chain near the upper quadrant 
of the bar nose contacts the wood or is 
pinched during limbing or when it is 
incorrectly used to begin a plunge or 
boring cut.
The greater the force of the kickback 
reaction, the more difficult it becomes for 
the operator to control the chain saw. 
Many factors influence the occurrence 
and force of the kickback reaction. 
These include saw chain speed, the 
speed at which the bar and saw chain 
contact the object, the angle of contact, 
the condition of the saw chain and other 
factors.
The type of bar and saw chain you use 
is an important factor in the occurrence 
and force of the kickback reaction. Some 
STIHL bar and saw chain types are 
designed to reduce kickback forces. 
STIHL recommends the use of reduced 
kickback bars and low kickback chains.
Do not rely on the chain 
saw ’s insulation against 
electric shock. To reduce 
the risk of electrocution, 
never operate this chain 
saw in the vicinity of any 
wires or cables (power, 
etc.) which may be carry-
ing electric current.To 
reduce risk of electrocu-
tion, take extra 
precautions when cutting 
near power lines. Have 
the power switched off 
before starting cutting 
work in the immediate 
vicinity of power lines.
Kickback may occur 
when the moving saw 
chain near the upper 
quadrant of the bar nose 
contacts a solid object or 
is pinched.