18
File and file guiding (Fig. 34, 35 & 36)
–
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 291 (90PX): 4.5 mm
Chain blade 492 (91PX): 4.0 mm
Chain blade 25 (25AP): 4.0 mm
–
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 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 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 diam-
eter).
–
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 guide bar (Fig. 37)
Chips and sawdust will build up in the guide bar groove,
clogging it and impairing oil flow. Always clean out the
chips and sawdust when sharpening or replacing the saw
chain.
Cleaning the oil discharge hole (Fig. 38)
Small dust or particles may be built up in the oil
discharge hole during operation.
Small dust or particles built up in the oil discharge hole
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 oil discharge hole as follows.
Remove the battery cartridge from the tool.
Remove the sprocket cover and saw chain from the tool.
(Refer to the section titled “Installing or removing saw
chain”.)
Remove the small dust or particles using a slotted
screwdriver with a slender shaft or the like.
Insert the battery cartridge into the tool.
Pull the switch trigger to flow built-up dust or particles off
the oil discharge hole by discharging chain oil.
Remove the battery cartridge from the tool.
Reinstall the sprocket cover and saw chain on the tool.
Replacing the sprocket (Fig. 39 & 40)
Before fitting a new saw chain, check the condition of the
sprocket.
CAUTION:
• A worn sprocket will damage a new saw chain. Have
the sprocket replaced in this case. The sprocket needs
to be installed so that it always faces as shown in the
figure.
Always fit a new locking ring when replacing the
sprocket.
Replacing carbon brushes (Fig. 41 & 42)
Remove and check the carbon brushes regularly.
Replace when they wear down to the limit mark. Keep
the carbon brushes clean and free to slip in the holders.
Both carbon brushes should be replaced at the same
time. Use only identical carbon brushes.
Use a screwdriver to remove the brush holder caps. Take
out the worn carbon brushes, insert the new ones and
secure the brush holder caps.
Storing tool
Clean the tool before storing. Remove any chips and
sawdust from the tool after removing the sprocket cover.
After cleaning the tool, run it under no load to lubricate
the saw chain and guide bar.
Cover the guide bar with the guide bar cover.
Remove oil from the oil tank to empty it and place the
chain saw.
To maintain product SAFETY and RELIABILITY, repairs,
any other maintenance or adjustment should be per-
formed by DOLMAR Authorized Service Centers, always
using DOLMAR replacement parts.
