Makita UC4020A - Manual (Page 14)

14
MAINTENANCE
CAUTION:
• Always be sure that the tool is switched off and
unplugged before attempting to perform inspection or
maintenance.
• Always wear gloves when performing any inspection or
maintenance.
Carry out the maintenance work described below at regu-
lar intervals. Warranty claims will be accepted only if
these operations have been performed regularly and
properly.
Only maintenance work described in this instruction man-
ual may be performed by the user. Any other work must
be carried out by a MAKITA specialist repair shop.
Cleaning the chain saw
Clean the saw regularly with a clean rag. The handles, in
particular, must be kept free of oil.
Checking the plastic housing
Carry out regular visual inspections of all parts of the
housing. Should any parts be damaged, have them
repaired immediately and properly in a MAKITA specialist
repair shop.
Sharpening the saw chain
CAUTION:
• Always withdraw the mains plug and wear safety
gloves when performing work on the saw chain.
(Fig. 29)
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 rea-
son 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 MAKITA specialist repair shop.
Sharpening criteria:
- All cutters must be of equal length (dimension a). Cut-
ters 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 cutting
edge. The best cutting results are obtained with a dis-
tance of 0.5 mm between cutting edge and depth
gauge. (Fig. 30)
WARNING:
• An excessive distance increases the risk of kick-back.
- The sharpening angle of 30 ° distance 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 of 80 ° 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. (Fig. 31)
File and file guiding (Fig. 32 - 34)
- Use a special round file (optional accessory) for saw
chains, with a diameter of 4.5 mm, to sharpen the
chain. Normal round files are not suitable.
- The file should only engage the material on the forward
stroke. Lift the file off the material on the return stroke.
- Sharpen the shortest cutter first. The length of this cut-
ter is then the gauge dimension for all other cutters on
the saw chain.
- Guide the file as shown in the figure. The file can be
guided more easily if a file holder (optional accessory)
is employed. The file holder has markings for the cor-
rect sharpening angle of 30 ° (align the markings paral-
lel 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.
Cleaning the guide bar and lubricating the
return sprocket
CAUTION:
• Always wear safety gloves for this task. Burrs present a
risk of injury. (Fig. 35)
Check the running surfaces of the bar regularly for dam-
age. Clean using a suitable tool, and remove burrs if nec-
essary.
If the chain saw receives frequent use, lubricate the return
sprocket bearing at least once a week. Before adding new
fresh grease, carefully clean the 2 mm hole on the tip of
the guide bar, then force a small quantity of multi-purpose
grease (optional accessory) into the hole.
Cleaning the oil guide (Fig. 36)
- Clean the oil guide groove and the oil feed hole in the
bar at regular intervals.
Cleaning the oil filter at the oil discharge
hole
Small dust or particles may be built up in the oil filter at the
oil discharge hole during operation.
Small dust or particles built up in the oil filter may impair
the oil discharge flow and cause an insufficient lubrication
on the whole saw chain.
When a poor chain oil delivery occurs at the top of guide
bar, clean the filter as follows.
Unplug the tool from the mains.