Ryobi RY40505 Operator's Manual page 23

NOTE: Inspect the drive sprocket for wear or damage when
replacing the chain. If signs of wear or damage are present
in the areas indicated, have the drive sprocket replaced by
a RYOBI Service dealer.
HOW TO SHARPEN THE CUTTERS
See Figures 38 - 39.
Be careful to file all cutters to the specified angles and to
the same length, as fast cutting can be obtained only when
all cutters are uniform.
WARNING:
The saw chain is very sharp, always wear protective
gloves when performing maintenance to the chain to
prevent serious personal injury.
Properly tension the chain prior to sharpening. Refer to
Chain Tension section earlier in this manual. Do all of
your filing at the mid-point of the bar.
Use a 5/32 in. diameter round file and holder.
Keep the file level with the top plate of the tooth. Do not
let the file dip or rock.
Using light but firm pressure, stroke towards the front
corner of the tooth.
Lift file away from the steel on each return stroke.
Put a few firm strokes on every tooth. File all left hand
cutters in one direction. Then move to the other side and
file the right hand cutters in the opposite direction. Oc-
casionally remove filings from the file with a wire brush.
WARNING:
Improper chain sharpening increases the potential of
kickback, which can result in serious personal injury.
WARNING:
Failure to replace or repair damaged chain can cause
serious injury.
NOTICE:
A dull or improperly sharpened chain can cause excessive
motor speed during cutting which may result in severe
motor damage.
MAINTENANCE
TOP PLATE FILING ANGLE
See Figure 40.
CORRECT 30° – File holders are marked with guide marks
to align file properly to produce correct top plate angle.
LESS THAN 30° – For Cross Cutting.
MORE THAN 30° – Feathered Edge Dulls Quickly.
SIDE PLATE ANGLE
See Figure 41.
CORRECT – 80° Produced automatically if correct diam-
eter file is used in file holder.
HOOK – "Grabs" and dulls quickly. Increases potential
of KICKBACK.
Results from using a file with diameter too small, or file
held too low.
BACKWARD SLOPE – Needs too much feed pressure,
causes excessive wear to bar and chain.
Results from using a file with diameter too large, or file
held too high.
DEPTH GAUGE CLEARANCE
See Figures 42 - 43.
The depth gauge should be maintained at a clearance of
.025 in. Use a depth gauge tool for checking the depth
gauge clearances.
Every time the chain is filed, check the depth gauge
clearance.
Use a flat file and a depth gauge jointer to lower all gauges
uniformly. Depth gauge jointers are available in .020 in. to
.035 in. Use a .025 in. depth gauge jointer. After lowering
each depth gauge, restore original shape by rounding the
front. Be careful not to damage adjoining drive links with
the edge of the file.
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 cutter face with flat file when adjust-
ing depth gauges.
MAINTAINING THE GUIDE BAR
See Figure 44.
CAUTION:
Remove the battery pack from the chain saw and make
sure the chain has stopped before you do any work on
the saw. Failure to do so may result in accidental starting
and possible serious injury.
17 - English