ICFR – Chainsaw Safety and Operating Handbook
45
All cutters must be the same length after sharpening.
Owing to the rearward slope of the top plate, the
cutter heights will be uneven if the cutter lengths are
different. If the cutters are not the same height the
chain will cut roughly and may break.
After the chain has been resharpened, the filings can
be removed from the bar groove by running the engine
briefly off load at full throttle.
14.1.9.3 c
utter
sharpening
terminoLogy
To sharpen a saw chain the operator must understand
the following:
•
The
side plate angle
is the angle between the side
plate cutting edge and the horizontal line formed
by the cutter toe and heel. This angle varies on
individual chain types.
Figure 59: Side plate angle
•
The
top plate filing angle
is the angle measured
from the top plate cutting edge at a right angle to
the guide bar.
Figure 60: Top plate filing angle
The filing angle differs on individual chains.
The standard filing angle for normal applications
is 25°- 30° as specified by the manufacturer.
Wider filing angles increase cutting performance
in softwood. Narrower filing angles ensure a
smoother running chain and less vibration in
hardwood.
The side plate angle and top plate filing angle have a
significant influence on the chain’s ability to cut wood
and therefore it is essential to maintain the specified
values.
•
The
depth gauge
is the small projection in front of
the cutting edge. The difference in height between
the top of the depth gauge and the leading edge of
the top plate is known as the
depth gauge setting
.
It determines the height at which the cutter enters
the wood (chip thickness) and therefore has an
influence on chain cutting capacity.
Figure 61: Depth gauge setting
14.1.9.4 f
iLing
the
chain
Use the correct tools according to the manufacturer’s
specifications. The following is needed to file the
chain:
•
Round file for cutters.
•
File holder or file gauge for cutters.
•
Flat file for the depth gauges.
•
Depth gauge tool (It could be incorporated into
the file gauge).
Figure 62: (a) Round file and file holder, (b) File
handle, (c) Round file, (d) Flat file, (e) File gauge
incorporating depth gauge tool