Stihl MS 172 User Manual

■ Obstacles in the work area and on the escape
path can hinder the user. The user may trip
and fall. This may result in serious or fatal
injury to the user.
►
Remove all obstacles from the work area
and escape path.
■ If you cut into or through the hinge, stabilizing
strap or holding strap too soon, the intended
direction of fall cannot be controlled or the tree
may fall prematurely. Persons may be seri‐
ously or fatally injured and property may be
damaged.
►
Do not cut into or through the hinge.
► Cut through the stabilizing strap or holding
strap last.
► If the tree begins to fall too soon: Abandon
the felling cut and retreat along the escape
path.
■
Kickback can occur if the rotating chain in the
upper quadrant of the bar nose makes contact
with a hard felling wedge and is suddenly
braked. There is a risk of serious or fatal
injury.
►
Use aluminum or plastic felling wedges.
■ If the tree does not fall all the way to the
ground or gets caught on another tree, the
operator cannot finish the operation in a con‐
trolled manner.
►
Stop the felling operation and use a cable
winch or suitable vehicle to pull the tree to
the ground.
4.9 Reactive Forces
4.9.1 Kickback
0000-GXX-2732-A0
Kickback can be caused for the following rea‐
sons:
–
The rotating saw chain in the upper quadrant
of the bar nose makes contact with a hard
object and is suddenly braked.
–
The rotating saw chain is pinched at the bar
nose.
The chain brake cannot prevent kickback.
WARNING
0000-GXX-4119-A0
■
If kickback occurs, the saw can be thrown up
in the direction of the operator. The operator
can lose control of the saw and be seriously or
fatally injured.
►
Hold the saw firmly with both hands.
► Always keep your body out of the plane of
the cutting attachment.
► Use the working techniques described in
this instruction manual.
► Do not cut with the upper quadrant of the
bar nose.
► Always cut with a properly sharpened and
tensioned saw chain.
► Use a reduced kickback saw chain.
► Use a guide bar with a narrow radius nose.
► Always cut with the chain running at full
speed.
4.9.2 Pull-in
0000-GXX-1348-A0
The saw is pulled away from the operator when
the bottom of the bar is used for cutting.
WARNING
■
If the rotating chain makes contact with a hard
object and is suddenly pinched, the saw is
abruptly jerked away from the operator. The
operator can lose control of the saw and be
seriously or fatally injured.
►
Hold the saw firmly with both hands.
► Operate the saw as described in this
instruction manual.
► Keep the guide bar straight in the cut.
► Apply the spiked bumper properly.
► Always cut with the chain running at full
speed.
4 Safety Precautions English
0458-200-0121-B 9

Stihl MS 172 Specifications

General

Sound pressure level	100 dB(A)
Sound power level	113 dB(A)
Displacement	31.8 cc (1.9 cu in)
Saw chain pitch	3/8"
Recommended bar length	30-35 cm (12-14 in)