Craftsman 247.889980 Operator's Manual page 22

CUTTING bLAdES
WARNING
Shut the engine off and remove ignition key before removing the
cutting blade(s) for sharpening or replacement. Protect your hands by
using heavy gloves when grasping the blade.
WARNING
Periodically inspect the blade and/or spindle for cracks or damage,
especially after you've struck a foreign object. Do not operate the
machine until damaged components are replaced.
To remove the blades, proceed as follows.
1. Remove the deck from beneath the mower, (refer to Cutting Deck
Removal earlier in this section) then gently flip the deck over to
expose its underside.
2. Place a block of wood between the center deck housing baffle
and the cutting blade to act as a stabilizer. See Figure 27.
3. Remove the hex flange nut that secures the blade to the spindle
assembly. See Figure 27.
SERVICE AND MAINTENANCE
Figure 27
4. To properly sharpen the cutting blades, remove equal amounts
of metal from both ends of the blades along the cutting edges,
parallel to the trailing edge, at a 25°- to 30° angle. Always grind
each cutting blade edge equally to maintain proper blade balance.
See Figure 28.
If the cutting edge of the blade has previously been sharpened, or if
any metal separation is present, replace the blades with new ones.
A poorly balanced blade will cause excessive vibration, may damage
to the mower and/or result in personal injury.
5. Test the blade's balance using a blade balancer. Grind metal from
the heavy end until the blade balances evenly.
NOTE: When replacing the blade, be sure to install the blade with the
side of the blade marked ''Bottom'' (or with a part number stamped in
it) facing the ground when the mower is in the operating position.
Use a torque wrench to tighten the blade spindle hex flange nut to
between 70 lbs-ft and 90 lbs-ft.
The cutting blades
must
the blades cannot be installed perpendicular to each other, the blade
timing belt must be reset. See your Sears or other qualified service
dealer to have the deck timing belt reset.
22
CAUTION
WARNING
Figure 28
CAUTION
CAUTION
be installed perpendicular to each other. If