Craftsman 247.77638 Operator's Manual page 17

removingthe hexbolts.
5. Rotateimpellerassemblyby handuntil youlocateone of two
chipperbladesin thechipperchuteopening.
6. Removetheblade by removingthe internalhex screws,lock
washers,and hex nutswhich secureit to the impeller.Retainthe
/
/
Figure15
hardware.See Figure15.
NOTE:Use a 3/16" hexkey (Allen)wrenchon theoutside of the blade
and a 1/2" box(or socket)wrenchon the insideof the impeller.Hold
the Allenwrenchstationaryand rotatethe box(or socket)wrenchto
loosenthenut.
7. Installa replacementblade(Part No. 742-0544) with the hardware
removedearlieror sharpenand replaceexistingblade.
IMPORTANT: W hensharpeningthe blade,protecthandsby using
gloves.Followthe originalangleof grind and make sureto removean
equalamountfrom eachblade.
8. To replacetheother blade,rotatethe impellerto exposethe
secondbladeand repeatthe stepsabove.
NOTE: Makecertain bladesare reassembled with the sharpedge
facingthe samedirectionas when removed.Torquehardwareto 250
- 300 in. Ibs.
The impeller'schipperbladesand shredderbladeare sharp.Wear
leatherwork glovesto protectyour hands.
SHARPENING OR REPLACING THE
SHREDDER BLADE
1. Stopthe engineand makecertain that all movingparts have
cometo a completestop.
2. Disconnectthe spark plugwire and groundagainsttheengine.
3. Lowerthehopperassembly and placea blockunder theflailhousing.
4. Removethesix hexlock nuts and flat washersfrom the weld
studson the flail housing.Retainthe hardware.
17
5. Carefullyseparatethe hopperassemblyfrom the impelleras-
semblyand removethe shredderplate.The shredderplatecan be
identifiedby referringto item29 in theparts list on page 20 & 21.
NOTE:Whenreassemblingtheshredderplate, makecertainthe
embossedtab facesinwardtowardsthe impeller.
6. Removethe two wingknobs that securethe chuteddlector and
raisethe chute.
7. Inserta 1/2"or 3/4" diameterpipethroughtheshredderscreen
intothe impellerto keepit from turningor removetheflail screen
and inserta pieceof woodintothe chute opening.
8. A. Removethe two internalhexscrews,lock washers,and hex
lock nutswhich securethe shredderbladeto the impeller.
B. Removethe hex bolt, lockwasher,and flat washerto
completelyfree shredderblade.See Figure16.
f
Weld
Flail Housing
Figure16
9. Installa replacement b lade (PartNo. 742-0544) with thehardware
removed earlier or sharpenand replaceexistingblade.
IMPORTANT: When reassembling the shredderblade,tightencenter
boltto between550 and 700 in.-Ibs,and the two outsidebolts to
between250 and 350 in.-Ibs.
NOTE:Usea 3/16"hex key (Allen)wrenchon the outsideof the
shredderblade and a 1/2" box(or socket)wrenchon the insideof the
shredderblade.Holdthe Allen wrenchstationaryand rotatethe box
(or socket)wrenchto loosenthe nut. Usecautionwhen removing the
bladeto avoidcontactingthe weldstudson housing.
IMPORTANT:Whensharpeningthe blade,follow theoriginalangle
of grind as a guide.It is extremelyimportantthat eachcuttingedge
receivesan equalamountof grindingto preventan unbalancedblade.
An unbalancedbladewill causeexcessivevibrationwhen rotatingat
high speedsand may causedamageto the unit. The bladecan be
testedby balancingit on a screwdriveror nail. Removemetal fromthe
heavysideuntil it is balancedevenly.