Cleaning The Guide Bar - Makita DUA251 Instruction Manual

— 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 90PX : 55°
• Chain blade 91PX : 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 90PX : 4.5 mm (3/16")
• Chain blade 91PX : 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.50
► 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.51
► 1. File holder
1
1/5
— After sharpening the chain, check the height of the
depth gauge using the chain gauge tool (optional
accessory).
Fig.52
— 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

Chips and sawdust will build up in the guide bar groove.
They may clog the bar groove and impair the oil flow.
Clean out the chips and sawdust every time when you
sharpen or replace the saw chain.
Fig.53
Cleaning the sprocket cover
Chips and saw dust will accumulate inside of the
sprocket cover. Remove the sprocket cover and saw
chain from the tool then clean the chips and saw dust.
Fig.54
21 ENGLISH