TOP-PLATE SHARPENING
ANGLES (FIG. 19)
CORRECT 30°- This optimal angle can be
obtained only when the specified files and
proper setting are used. File holders are
marked with guide marks to align the file
properly to produce the correct top plate
angle.
LESS THAN 30°- The tooth is too dull for
cutting.
MORE THAN 30°- The edge of the cutting
tooth is feathered and dulls quickly.
SIDE-PLATE ANGLE (FIG. 20)
CORRECT 55°- The optimal angle can be
produced automatically if the correct diameter
file is used in the file holder.
HOOK- "Grabs" and dulls quickly. Results
from using a file with a diameter that is too
small, or a file held too low.
BACKWARD SLOPE- Needs too much feed
pressure, causes excessive wear to guide bar
and saw chain. This is the result of using a file
with a diameter that is too large, or a file that
was held too high.
DEPTH-GAUGE CLEARANCE
(FIG. 21, 22)
The depth gauge should be maintained at a
clearance of 0.025 in. (0.6 mm), as shown
in Fig. 35. Use a depth gauge tool (available
separately) to check the depth gauge
clearances.
Check the depth gauge clearance every time
the chain is filed.
Use a flat file and a depth-gauge jointer (both
available separately) to lower all gauges
uniformly. Depth-gauge jointers are available
in 0.020 in. to 0.035 in. (0.5 mm to 0.9 mm).
Use a 0.025 in. (0.6 mm) depth-gauge jointer.
Depth gauges must be adjusted with the flat
file in the same direction the adjoining cutter
was filed with the round file. Use care not to
contact the cutter face with the flat file when
adjusting depth gauges.
22
Fig. 19
Top Plate Sharpening Angles
Less Than 30°
30°
Correct
Incorrect
Fig. 20
Side Plate Angle
55°
Correct
Incorrect
Fig. 21
Depth Gauge Clearance
Fig. 22
Depth Gauge
Jointer
More Than 30°
Incorrect
Hook
Backward Slope
Incorrect
0.025" (0.6mm)
Flat File