Ryobi P2507 Manuel D'utilisation page 19

„ Never cut through to the notch. Always leave a band of
wood between the notch and backcut (approximately 2 in.
or 1/10 the diameter of the tree). This is called "hinge" or
"hingewood." It controls the fall of the tree and prevents
slipping or twisting or shoot-back of the tree off the stump.
See Figures 14 - 15.
„ On large diameter trees, stop the back cut before it is
deep enough for the tree to either fall or settle back on
the stump. Then insert soft wooden or plastic wedges
into the cut so they do not touch the chain. The wedges
can be driven in, little by little, to help jack the tree over.
See Figure 16.
„ As tree starts to fall, stop the chain saw and put it down
immediately. Retreat along the cleared path, but watch
the action in case something falls your way. Be alert for
overhead limbs or branches that may fall and watch your
footing.
WARNING:
Never cut through to the notch when making a backcut.
The hinge controls the fall of the tree, this is the section
of wood between the notch and backcut.
BUCKING
See Figures 17 - 20.
Bucking is the term used for cutting a fallen tree to the de-
sired log length.
„ Always make sure your footing is secure and your weight
is distributed evenly on both feet.
„ Cut only one log at a time.
„ Support small logs on a saw horse or another log while
bucking.
„ Keep a clear cutting area. Make sure that no objects can
contact the guide bar nose and chain during cutting, this
can cause kickback. Refer to Kickback earlier in this
manual.
„ When bucking on a slope, always stand on the uphill side
of the log. To maintain complete control of the chain saw
when cutting through the log, release the cutting pres-
sure near the end of the cut without relaxing your grip on
the chain saw handles. Do not let the chain contact the
ground. After completing the cut, wait for the saw chain
to stop before you move the chain saw. Always stop the
motor before moving from tree to tree.
„ Sometimes it is impossible to avoid pinching (with just
standard cutting techniques) or difficult to predict which
way a log will settle when cut. To avoid pinching while cut-
ting, rotate or move the log so that the pinch is eliminated.
BUCKING LOGS UNDER STRESS
See Figures 19 - 20.
When the log is supported along its entire length, it should
be cut from the top or overbucking.
OPERATION
When the log is supported on one end, cut 1/3 the diameter
from the underside or underbucking. Then make the finishing
cut by overbucking to meet the first cut.
As the log is being cut, it will tend to bend. The saw can
become pinched or hung in the log if you make the first cut
deeper than 1/3 of the diameter of the log.
Give special attention to logs under stress to prevent the
bar and chain from pinching.
When bucking on a slope, always stand on the uphill side
of the log as shown in figure 18. When "cutting through,"
to maintain complete control of the chain saw, release the
cutting pressure near the end of the cut without relaxing your
grip on the chain saw handles. Do not let the chain contact
the ground. After completing the cut, wait for the saw chain
to stop before you move the chain saw. Always stop the
motor before moving from tree to tree.
TYPES OF CUTTING USED
See Figure 20.
OVERBUCKING
Begin on the top side of the log with the bottom of the saw
against the log; exert light pressure downward. Note that
the saw will tend to pull away from you.
UNDERBUCKING
Begin on the under side of the log with the top of the saw
against the log; exert light pressure upward. During under-
bucking, the saw will tend to push back at you. Be prepared
for this reaction and hold the saw firmly to maintain control.
LIMBING
See Figure 21.
WARNING:
Never climb into a tree to limb or prune. Do not stand on
ladders, platforms, a log, or in any position which can
cause you to lose your balance or control of the saw,
which could result in death or other serious personal
injury.
Limbing is removing branches from a fallen tree.
„ Work slowly, keeping both hands on the chain saw with
a firm grip. Always make sure your footing is secure and
your weight is distributed evenly on both feet.
„ Leave the larger support limbs under the tree to keep the
tree off the ground while cutting.
„ Limbs should be cut one at a time. Remove the cut limbs
from the work area often to help keep the work area clean
and safe.
„ Branches under tension should be cut from the bottom
up to avoid binding the chain saw.
13 - English