Black Max BM5020 Operator's Manual page 29

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 an authorized
service center.
NOTE: If you do not fully understand the correct
procedure for sharpening the chain after reading the
instructions that follow, have the saw chain sharp-
ened by an authorized service center or replace with
a recommended low-kickback chain.
SHARPENING THE CUTTERS
See Figures 47 - 50.
Be careful to file all cutters to the specified angles
and to the same length, as fast cutting can only be
obtained when all cutters are uniform.
WARNING:
The saw chain is very sharp. Always wear protec-
tive gloves when performing maintenance to the
chain to prevent serious personal injury.
 Tension the chain prior to sharpening. Refer to
Adjusting The Chain Tension.
 Use a 3/16 in. diameter round file and holder. Do
all of your filing at the midpoint of the bar.
 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 the 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.
 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 a damaged chain can
cause serious injury.
MAINTENANCE
TOP PLATE
RIVET HOLE
RIGHT HAND
NOTICE:
A dull or improperly sharpened chain can cause
excessive engine speed during cutting, which may
result in severe engine damage.
Page 29 — English
CUTTING
CORNER
HEEL
GULLET
LEFT HAND
CUTTERS
CUTTERS
SIDE PLATE
DEPTH GAUGE
TOE
Fig. 47
Fig. 48
Fig. 49
Fig. 50