Echo 72928 Owners Manual v.5 - Manual (Page 24)

9 INCH CHIPPER 22
SERVICE & MAINTENANCE
4.3 SharPening chiPPer bladeS
Warning
The rotor assembly has a lock mechanism. When work-
ing on the rotor assembly, use the lock mechanism at
all times. Remove plastic bearing cover by the chip-
per chute. There is a hole in the rotor jack shaft and
a matching hole in the bracket mounted to the rotor
bearing front side. Install a punch through the rotor
shaft and bracket to lock the rotor in place.
Before inspecting or servicing any part of the machine,
shut off engine and make sure all moving parts have
come to a complete stop. The chipping blades are
sharp! Use care when working on machine to avoid
injury.
Warning
The chipper blades will eventually become dull, making
chipping difficult. It is recommended that the chipper blades
are sharpened every 5-15 hours of chipper operation. To
remove the chipping blades for sharpening:
1. Remove the two retaining bolts holding access cover
to main frame assembly.
2. Tilt access cover over to allow rotor access. Rotate
the rotor so that the bolts holding a chipping blade are
most accessible.
3. Remove the two nuts holding the blade itself. Repeat
for all four blades. The four chipping blades have two
edges per blade and can be reversed one time each
before sharpening. If both sides have not been used,
remove and reverse the chipping blades. Reinstall
chipping blades and proceed with chipping.
To grind the angled edge of the chipping blade to 45
degrees (Figure 4.1): grind the blades on a slow-speed
wet grinder if possible, or have them sharpened by a
professional. If you use a bench grinder, be careful when
grinding so that the blade material does not get too hot
and change color. This will remove the blade's special heat
treated properties. Use short grinding times and cool with
water. Try to remove an equal amount from each blade to
maintain balance. Replace the chipping blades and tighten
bolts to 120 ft-lbs. Close cover and replace bolts.
chiPPing blade SharPening TiPS
Poor chipping performance is usually a result of dull
chipping blades. If your chipper's performance has
decreased, check for the following symptoms:
• Severe vibration when feeding material into the chip-
per.
• Small diameter branches do not self-feed.
• Chips discharge unevenly or have stringy tails–espe-
cially when chipping green branches.
Before you sharpen the chipping blades, check for
permanent damage. Replace the blade if:
• The blade is cracked (especially around the bolt holes)
or the edges are too deeply chipped to be ground
smooth.
• The base of the cutting edge is worn or has been re-
sharpened so that it is too close to the rotor chipping
slot.
MOUNTING SURFACE
DO NOT GRIND
MOUNTING SURFACE
DO NOT GRIND
SHARPENED
SURFACE
SHARPENED
SURFACE
45°
.38
Figure 4.1, Sharpening the chipper blades
4.4 SeTTing blade clearance
The four-edged chipping anvil located directly behind the
chipper chute (Figure 4.2) should clear the chipping blades
by 1/16" to 3/16" inch. The chipping anvil is adjustable
and reversible.
To adjust:
1. lift rotor access cover and expose rotor. loosen
the three 1/2" bolts that hold the chipper anvil to the
frame.
2. Measure the amount of clearance between chipping
blade and chipping anvil from inside of housing.
3. Adjust inward or outward to desired measurement.
4. Tighten bolts on chipping anvil to 75 ft-lbs. Make sure
all blades clear the anvil by 1/16" to 3/16".