Maintenance - Makita DOLMAR AS-3726 Betriebsanleitung

Felling (Fig. 26, 27, 28 & 29)
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:
(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
swellings. Make the vertical cut first, then the hori-
zontal cut.
– 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
circumstances, as the tree will otherwise fall
unchecked. Insert wedges into the back cut in time.
– Only plastic or aluminum wedges may be used to
keep the back cut open. The use of iron wedges is
prohibited.
– 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). Pay attention to falling branches.
– An escape path should be planned and cleared as
necessary 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.
Carrying tool (Fig. 30)
Always remove the battery cartridge from the tool and
overlap the guide bar with the guide bar cover before
carrying the tool. Also cover the battery cartridge with the
battery cover.

MAINTENANCE

CAUTION:
• Always be sure that the tool is switched off and the
battery cartridge is removed before attempting to
perform inspection or maintenance.
• Always wear gloves when performing any inspection or
maintenance.
• Never use gasoline, benzine, thinner, alcohol or the
like. Discoloration, deformation or cracks may result.
Sharpening the saw chain (Fig. 31)
CAUTION:
• Always remove the battery cartridge and wear safety
gloves when performing work on the saw chain.
Sharpen the saw chain when:
– Mealy sawdust is produced when damp wood is cut;
– The chain penetrates the wood with difficulty, even
when heavy pressure is applied;
– The cutting edge is obviously damaged;
– The saw pulls to the left or right in the wood. The
reason for this behaviour is uneven sharpening of
the saw chain, or damage to one side only.
Sharpen the saw chain frequently, but remove only a
little material each time.
Two or three strokes with a file are usually sufficient for
routine resharpening. When the saw chain has been
resharpened several times, have it sharpened in a
DOLMAR specialist repair shop.
Sharpening criteria: (Fig. 32 & 33)
– All cutter length must be equal. Cutters of differing
length prevent the chain from running smoothly, and
may cause the chain to break.
– Do not sharpen the chain once a minimum cutter
length of 3 mm has been reached. A new chain must
then be fitted.
– The chip thickness is determined by the distance
between the depth gauge (round nose) and the cut-
ting edge.
– The best cutting results are obtained with following
distance between cutting edge and depth gauge.
Chain blade 291 (90PX): 0.5 mm
Chain blade 492 (91PX): 0.65 mm
Chain blade 25 (25AP): 0.65 mm
WARNING:
• An excessive distance increases the risk of kick-back.
– The sharpening angle of 30° must be the same on
all cutters. Differences in angle cause the chain to
run roughly and unevenly, accelerate wear, and lead
to chain breaks.
– The side plate angle of the cutter is determined by
the depth of penetration of the round file. If the spec-
ified file is used properly, the correct side plate angle
is produced automatically.
– Side plate angle for each saw chain are as follows:
Chain blade 291 (90PX): 75°
Chain blade 492 (91PX): 80°
Chain blade 25 (25AP): 85°
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