Stihl MS 171 Instruction Manual page 16

English
The tree is felled with the felling cut (E).
Cut horizontally.
–
1/10 (at least 3 cm) of width of
–
hinge (D) higher than bottom of
felling notch (C).
The holding strap (F) or stabilizing
strap (G) supports the tree and helps
prevent it from falling prematurely.
Width of strap: about 1/10 to 1/5 of
–
tree diameter.
Do not cut into the strap while
–
making the felling cut.
Leave a broader strap on rotten
–
trees.
Plunge cutting
For relieving cuts during bucking
–
For wood carving
–
1.
2.
Use a low kickback chain and
N
exercise particular caution
14
1. Begin cut by applying the lower
portion of the guide bar nose – do
not use upper portion because of –
risk of kickback. Start cutting at full
throttle until depth of kerf is twice the
width of the guide bar.
2. Swing saw slowly into plunge-
cutting position – take care because
of the risk of kickback or pushback.
3. Make the plunge cut very carefully.
Danger of pushback.
Use the plunge-cutting sight if possible.
The plunge-cutting sight and the top and
bottom of the guide bar are parallel.
When making the plunge cut, the sight
helps keep the hinge horizontal, i.e. the
same thickness all round. To do this,
hold the plunge-cutting sight parallel to
the chord of the felling notch.
Felling wedges
Make use of wedges as soon as
possible, i.e. providing they do not
interfere with cutting. Drive wedge into
felling cut with a suitable tool.
3.
Use only aluminum or plastic wedges –
never steel. Steel wedges can seriously
damage the saw chain and cause
dangerous kickback.
Select felling wedges that suit the
diameter of the tree and width of the kerf
(felling cut (E)).
Contact your STIHL dealer for advice on
selecting the right felling wedge (length,
width and height).
Choosing Right Felling Cut
The criteria for choosing the right felling
cut are the same as those for
determining the direction of fall and the
escape path.
There are many different variations of
these characteristics. Only the two most
common characteristics are described in
this manual:
Left:
Right:
Felling Cut with Stabilizing Strap
(Normal Tree)
A) Small diameter trees
Perform this felling cut when the tree
diameter is smaller than the length of the
guide bar.
MS 171, MS 171 C, MS 181, MS 181 C, MS 211, MS 211 C
Normal tree – vertical trunk
with uniform tree crown.
Leaner – tree crown leans in
direction of fall.