Sharpening The Saw Chain - Makita GCU05 Instruction Manual

Sharpening 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.
(caused by uneven sharpening of the saw chain or
damage to one side only)
Sharpen the saw chain frequently but a little 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 our
authorized service center.
Sharpening criteria:
WARNING:
An excessive distance between
the cutting edge and depth gauge increases the
risk of kickback.
2
1
3
Fig.35
► 1. Cutter length 2. Distance between cutting edge
and depth gauge 3. Minimum cutter length (3 mm)
— All cutter length must be equal. Different cutter
lengths prevent the saw chain from running
smoothly and may cause the saw chain to break.
— Do not sharpen the chain when the cutter length
has reached 3 mm or shorter. The chain must be
replaced with new one.
— The chip thickness is determined by the distance between
the depth gauge (round nose) and the cutting edge.
— The best cutting results are obtained with following
distance between cutting edge and depth gauge.
• Chain blade 91PX : 0.65 mm (0.025")
Chain blade 80TXL : 0.65 mm (0.025")
30
55
Fig.36
2
1
1
30
55
— The sharpening angle of 30° must be the same on
all cutters. Different cutter angles cause the chain
to run roughly and unevenly, accelerate wear, and
lead to chain breaks.
— Use a suitable round file so that the proper sharp-
ening angle is kept against the teeth.
• Chain blade 91PX : 55°
Chain blade 80TXL : 55°
File and file guiding
— Use a special round file (optional accessory) for
saw chains to sharpen the chain. Normal round
files are not suitable.
— Diameter of the round file for each saw chain is as
follows:
• Chain blade 91PX : 4.0 mm (5/32")
Chain blade 80TXL : 4.0 mm (5/32")
— The file should only engage the cutter on the for-
ward stroke. Lift the file off the cutter on the return
stroke.
— Sharpen the shortest cutter first. Then the length
of this shortest cutter becomes the standard for all
other cutters on the saw chain.
— Guide the file as shown in the figure.
1
2
Fig.37
► 1. File 2. Saw chain
— The file can be guided more easily if a file holder
(optional accessory) is employed. The file holder
has markings for the correct sharpening angle of
30° (align the markings parallel to the saw chain)
and limits the depth of penetration (to 4/5 of the
file diameter).
30
Fig.38
► 1. File holder
17 ENGLISH
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