Craftsman S145 Original Instructions Manual page 23

SHARPENING THE SAW CHAIN
WARNING:
The saw chain is very sharp. Always wear
heavy-duty protective gloves when handling or performing
maintenance on the saw chain.
WARNING:
An improperly sharpened saw chain
increases the chance of kickback. Failure to replace or
properly maintain the saw chain can cause serious injury.
CAUTION:
A dull or improperly sharpened saw chain
can cause excessive engine speed during operation, which
can result in severe engine damage.
If the saw chain was damaged by contacting hard objects, such as
nails or stones, or was abraded by mud or sand on the wood, have
an authorized service dealer sharpen the saw chain.
When sharpening the saw chain, file all cutters to the specified
angles and measurements. Other angles or measurements can
cause excessive wear to the guide bar and saw chain, cause the
chain to dull quickly and increase the chance of kickback. Fast
cutting can be obtained only when all cutters are uniform.
1. Tighten the chain tension so that the saw chain is taut and does
not wobble. Refer to Adjusting the Chain Tension.
• Always file the saw chain at the midpoint of the guide bar.
2. Use a round file and file holder (tools not included) to sharpen
the top plate and side plate of each cutter.
• Use a 5/32 inch (4 mm) diameter file.
• Keep the file level with the top plate of the cutter (Fig. 33). Do
not let the file dip or rock. Use light, but firm pressure.
• File toward the front corner of the cutter (Fig. 34). Lift the file
away from the cutter at the end of the forward stroke. Only file
on the forward stroke.
• Apply a few firm strokes to each tooth. When filed correctly,
the top plate will be at a 30º angle and the side plate will be at
an 80º angle (Fig. 35). Using the correct file and file holder will
automatically produce the correct angles.
• File all the left-hand cutters in one direction (Fig. 34). Then
move to the other side of the saw chain and file all of the right-
hand cutters in the opposite direction (Fig. 34).
• Occasionally remove filings with a wire brush.
3. Use a depth gauge tool (not included) to measure the depth
gauge clearance (Fig. 36) of each cutter. The depth gauge
clearance must be maintained at 1/32 inch (0.6 mm). The depth
gauge clearance determines the depth at which the cutter enters
the wood during operation and the size of the wood chips
produced. Too much clearance increases the chance of
kickback. Too little clearance decreases the size of the wood
chips, thus deceasing the ability to cut.
• Use a 1/32 inch (0.6 mm) depth gauge jointer and a flat file
(tools not included) to lower the depth gauge to the correct
clearance (Fig. 36).
• After lowering the depth gauge, use the flat file to restore the
original rounded shape to the depth gauge (Fig. 37). Take care
not to damage the cutting edges or nearby links.
Depth Gauge Clearance
Top Plate
Filing Angle
Right-Hand
Cutters
Correct Filing Angles
Side Plate
Depth Gauge Jointer
23
1/32 inch (0.6 mm)
Side Plate
Fig. 33
Fig. 34
Top Plate
80º
30º
Fig. 35
Fig. 36
Depth Gauge
Left-Hand
Cutters
Flat File