Sharpening The Blades; Wear Limits Of The Blades - Stihl GHE 420 Manual De Instrucciones

11.8 Sharpening the blades

We recommend that all blades are
sharpened only by a specialist
dealer, as the function (drawing in
of shredding material, durability of
the cutting edges etc.) of the
garden shredder may deteriorate if
blades are ground incorrectly
(wrong sharpening angle,
imbalanced due to unevenly ground
blades etc.).
Always wear safety glasses when
sharpening. Make sure that others
are kept out of the danger area.
● Removing the blade discs. (
● Remove the blade. ( 11.7)
Sharpening angle:
The sharpening angle for all the blades is
30°.
Instructions for sharpening the blades:
The following points must be observed
when re-sharpening the blades:
● Cool the blades when sharpening,
e.g. with water. The blade must not be
allowed to display blue colouring, as
this would reduce its cutting quality.
● Sharpen the blade evenly to prevent
vibrations due to imbalance.
● Check blades for damage before
installing: The blades must be replaced
if notches or cracks are visible or if the
blades have reached the wear limits.
● Re-sharpen the cutting edges to the
specified sharpening angle.
● Sharpen the blades against the cutting
edge.
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● After sharpening, remove any
sharpening burr at the cutting edge
using fine sandpaper.

11.9 Wear limits of the blades

The blades must be reversed or
replaced before reaching the
specified wear limits (A, B, C, D).
STIHL recommends STIHL
specialist dealers.
The specified values should be
measured at several points (two or
three recommended) along the
cutting edge on all the blades.
11.3)
Use the smallest value for a blade.
We recommend that you always
reverse or replace all the blades at
the same time.
1 Blade overview
2 wing blades (1)
6 blades (2)
1 blades (3)
1 counter-blade (4)
Soft material blade disc:
The soft material blade disc is fitted with
four blades.
Hard material blade disc:
The hard material blade disc is fitted with
two blades and one chipping blade.
● Removing the blade discs. (
2 wear limit of wing blades (1):
The measurement procedure and
the value specified are the same for
both wing blades.
Asymmetrical wear may occur at
the two wing blades due to uneven
use of the cutting edges.
Minimum blade width (A) of the two wing
blades (1):
A = 39 mm
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3 Wear limit of blades (2):
The blades (2) are reversible
blades. After reaching the specified
wear limit (B), the blade can be re-
sharpened and reversed until the
wear limit is reached, before
needing to be replaced.
● Measure the distance (B) shown in the
illustration from the large diameter of
the bore to the cutting edge (X).
● Repeat this procedure at the second
bore on the blade.
Minimum distance (B) on the blades (2):
B = 6 mm
The particular blade (2) must be
reversed or replaced if one of the
two distances measured is less
than the minimum distance (B).
4 Wear limit of blade (3):
The blade (3) is a reversible blade.
On reaching the specified wear
limit (C), the blade (3) can be re-
sharpened and reversed until the
wear limit is reached, before
needing to be replaced.
● Measure the distance (C) at a right
angle to the cutting edge.
11.3)
Minimum distance (C) on the blade (3):
C = 7 mm
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