Stihl MS 172 User Manual

► If the wood is sound and long-fibered:
Observe the following points when making
sapwood cuts:
–
The cuts must be the same on both sides.
–
The cuts must be at the same height as the
bottom of the felling notch.
–
The width of the cuts is 1/10 of the trunk
diameter.
The trunk does not splinter when the tree falls.
11.4.5 Plunge cutting
Plunge cutting is a technique required for felling.
3.
1.
2.
0000-GXX-1252-A0
► Begin cut with the lower portion of the guide
bar nose – with chain running at full speed.
► Cut until depth of kerf is twice the width of the
guide bar.
► Swing the saw into plunge-cutting position.
► Perform the plunge cut
11.4.6 Selecting the Appropriate Felling Cut
The choice of appropriate felling cut depends on
the following conditions:
–
The natural inclination of the tree
–
The tree’s branch formation
–
Damage to the tree
–
The tree’s state of health
–
If there is snow on the tree: the snow load
–
The direction of slope
–
Wind direction and speed
–
Nearby trees, if any
There are different features of these conditions.
Only two features are described in this Instruc‐
tion Manual.
0000-GXX-1253-A0
1
2
1 Normal tree
A normal tree is vertical and has an even
crown.
2 Leaner
A leaner stands at an angle and the crown
faces in the direction of fall.
11.4.7 Felling normal, small diameter tree
A normal tree is felled with a felling cut and stabi‐
lizing strap. This felling cut must be performed if
the tree diameter is less than the guide bar’s
length.
► Shout a warning.
0000-GXX-1254-A0
1.
2.
► Plunge the guide bar into the felling cut until it
is visible at the other side of the trunk,
11.4.5.
► Apply the spiked bumper behind the hinge and
use it as a pivot.
► Enlarge felling cut in direction of hinge.
► Enlarge felling cut in direction of stabilizing
strap.
0000-GXX-1255-A0
3.
► Insert a felling wedge. The felling wedge must
match the tree diameter and the width of the
felling cut.
► Shout a warning.
► With outstretched arms, cut through the stabi‐
lizing strap horizontally from outside at the
same level as the felling cut.
The tree falls.
11.4.8 Felling normal, large diameter tree
A normal tree is felled with a felling cut and stabi‐
lizing strap. This felling cut must be performed if
the tree diameter is greater than the guide bar’s
length.
11 Operating the Saw English
0458-200-0121-B 21

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)