Working With The Chain Saw - Makita BUC250 Manual De Instrucciones

WORKING WITH THE CHAIN SAW

The first time user should, as a minimum practice, do cut-
ting logs on a saw-horse or cradle.
Pruning trees
CAUTION:
• Keep all parts of the body away from the saw chain
when the motor is operating.
• Hold the chain saw firmly with both hands when the
motor is running.
• Do not overreach. Keep proper footing and balance at
all times.
Bring the lower guide into contact with the branch to be
cut before switching on. Cutting without bringing the
lower guide into contact with the branch may cause the
guide bar to wobble, resulting in injury to operator.
(Fig. 23)
When cutting thick branches, first make a shallow under-
cut and then make the finish cut from the top. (Fig. 24)
If you try to cut off thick branches from the bottom, the
branch may close in and pinch the saw chain in the cut. If
you try to cut off thick branches from the top without a
shallow undercut, the branch may splinter. (Fig. 25)
If you cannot cut the timber right through with a single
stroke:
Apply light pressure to the handle and continue sawing
and draw the chain saw back a little; then apply the spike
a little lower and finish the cut by raising the handle.
(Fig. 26)
Bucking
For bucking cuts, rest the serrated rail shown in the figure
on the wood to be cut. (Fig. 27)
With the saw chain running, saw into the wood, using the
top handle to raise the saw and the front one to guide it.
Use the serrated rail as a pivot.
Continue the cut by applying slight pressure to the front
handle, easing the saw back slightly. Move the serrated
rail further down the timber and raise the front handle
again.
When making several cuts, switch the chain saw off
between cuts.
CAUTION:
• If the upper edge of the bar is used for cutting, the
chain saw may be deflected in your direction if the
chain becomes trapped. For this reason, cut with the
lower edge, so that the saw will be deflected away from
your body. (Fig. 28)
Cut wood under tension on the pressure side (A) first.
Then make the final cut on the tension side (B). This pre-
vents the bar from becoming trapped. (Fig. 29)
Limbing
CAUTION:
• Limbing may only be performed by trained persons. A
hazard is presented by the risk of kick-back.
When limbing, support the chain saw on the trunk if pos-
sible. Do not cut with the tip of the bar, as this presents a
risk of kickback.
Pay particular attention to branches under tension. Do
not cut unsupported branches from below.
Do not stand on the felled trunk when limbing.
Burrowing and parallel-to-grain cuts
CAUTION:
• Burrowing and parallel-to-grain cuts may only be car-
ried out by persons with special training. The possibility
of kickback presents a risk of injury.
Perform parallel-to-grain cuts at as shallow an angle as
possible. Carry out the cut as carefully as possible, as
the serrated rail cannot be used. (Fig. 30)
Felling
CAUTION:
• Felling work may only be performed by trained persons.
The work is hazardous.
Observe local regulations if you wish to fell a tree.
- Before starting felling work, ensure that: (Fig. 31)
(1) Only persons involved in the felling operation are in
the vicinity;
(2) Any person involved has an unhindered path of
retreat through a range of approximately 45° either
side of the felling axis. Consider the additional risk
of tripping over electrical cables;
(3) The base of the trunk is free of foreign objects,
roots and branches;
(4) No persons or objects are present over a distance
of 2 1/2 tree lengths in the direction in which the
tree will fall.
- Consider the following with respect to each tree:
• Direction of lean;
• Loose or dry branches;
• Height of the tree;
• Natural overhang;
• Whether or not the tree is rotten.
- Consider the wind speed and direction. Do not carry
out felling work if the wind is gusting strongly.
- Trimming of root swellings: Begin with the largest swell-
ings. Make the vertical cut first, then the horizontal cut.
(Fig. 32)
- Cut a scarf: The scarf determines the direction in which
the tree will fall, and guides it. It is made on the side
towards which the tree is to fall. Cut the scarf as close
to the ground as possible. First make the horizontal cut
to a depth of 1/5 – 1/3 of the trunk diameter. Do not
make the scarf too large. Then make the diagonal cut.
- Cut any corrections to the scarf across its entire width.
- Make the back cut a little higher than the base cut of
the scarf. The back cut must be exactly horizontal.
Leave approximately 1/10 of the trunk diameter
between the back cut and the scarf.
The wood fibers in the uncut trunk portion act as a
hinge. Do not cut right through the fibers under any cir-
cumstances, as the tree will otherwise fall unchecked.
Insert wedges into the back cut in time. (Fig. 33)
- Only plastic or aluminum wedges may be used to keep
the back cut open. The use of iron wedges is prohib-
ited.
- Stand to the side of the falling tree. Keep an area clear
to the rear of the falling tree up to an angle of 45° either
side of the tree axis (refer to the "felling area" figure
(Fig. 31)). Pay attention to falling branches.
- An escape path should be planned and cleared as nec-
essary before cuts are started. The escape path should
extend back and diagonally to the rear of the expected
line of fall as illustrated in figure. (Fig. 34)
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