23
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. The reason for this behavior 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
MAKITA authorized service center.
Sharpening criteria:
- All cutter length
(A)
must be equal. Cutters of different length prevent the
chain from running smoothly, and may cause the chain to break.
- The chip thickness is determined by the distance between the depth gauge
(round nose) and the cutting edge
(B)
.
- The best cutting results are obtained with following distance between cutting
edge and depth gauge.
Chain blade 91VXL: 0.64 mm (0.025”)
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 specified file is used properly, the correct side plate angle
is produced automatically.
- Proper angle for each saw chain are as follows:
Chain blade 91VXL: 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 91VXL: 4.0 mm (5/32”)
-
The file should only engage the cutter on the forward 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.
-
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).
- After sharpening the chain, check the height of the depth gauge using the
chain gauge tool (optional accessory).
-
Remove any projecting material, however small, with a special flat file
(optional accessory).
- Round off the front of the depth gauge again.
B
A
55°
30°
90°
30
4/5
