Echo 74520 Owners Manual v.2 - Manual (Page 23)

Page 19 5" Chipper W/Hyd. Feed Owners Manual
5.2 SHARPENING CHIPPER BLADES 5.3 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:
1. Severe vibration when feeding material into the
chipper.
2. Small diameter branches do not self-feed.
3. Chips discharge unevenly or have stringy tails–
especially when chipping green branches.
Before you sharpen the chipping blades, check for
permanent damage. Replace the blade if:
1. The blade is cracked (especially around the bolt
holes) or the edges are too deeply chipped to be
ground smooth.
2. The base of the cutting edge is worn or has been re-
sharpened so that it is too close to the rotor chipping
slot.
Service and Maintenance
Before inspecting or servicing any part of the machine,
shut off the 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
Never sharpen the back side of the chipper blade. This
will cause the edge to roll and the chipping blade will
be damaged, causing poor chipping and feeding of
material. Small imperfections, nicks, burrs, etc. on the
flat side of the blade will not affect performance.
WARNING
The chipper blades will eventually dull, making chipping
difficult. It is recommended to sharpen chipper blades every
5-15 hours of chipper operation.
To remove the chipping blades for sharpening:
1. Remove the one 3/8 inch retaining bolt 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 hex head bolts holding the chipper
blade. Repeat for all four chipper blades. The four
chipping blades have two edges per blade and can be
reversed one time each before sharpening. Remove
and reverse the chipping blades if both sides have not
been used. Reinstall chipping blades and proceed
with chipping.
4. If blades need sharpening, grind the angled edge of the
chipping blade to 45 degrees. Grind the blades on a
slow-speed wet grinder if possible, or have them sharp-
ened 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 grind-
ing times and cool with water. Try to remove an equal
amount off each blade to maintain balance. Reinstall.
Fig. #10, blade sharpening
.25
45°
SHARPEN TO
A 45° ANGLE
IMPORTANT
NEVER SHARPEN OR
BACK GRIND THIS SIDE
POOR FEEDING AND
CHIPPING WILL RESULT