18
6. Blade engagement
Check that the engine is at rest before making adjustment.
Grind and adjust the blade reel cylinder and bottom blade entirely so that a
newspaper will be cut sharply.
[IMPORTANT] Lapping
Conduct lapping after mowing operation (before adjusting the engagement).
1) Check the entire portion of the blade reel cylinder to check which portion is dull. (If a
newspaper cannot be cut in any portion, put in two sheets of paper to carefully check
which portion is dull.)
2) Connect the lapping machine (RM20B) or lapping bolt (option) to the lapping shaft of
the mower.
3) Rotate the blade reel cylinder in the direction opposite to the mowing direction, and
apply abrasive with a brush only to the portion where a newspaper was sharply cut.
The portion where a newspaper was not cut is worn away. Do not apply abrasive to
such portions.
* The right side (when viewed from the front of the blade reel cylinder) of the blade
reel cylinder will be worn away 3-4 times earlier than the left side. When applying
abrasive to the blade reel cylinder, be sure to move the brush from left to right.
(See right sketch)When the abrasive is a mixture of powder (#200~#400) and oil,
mix them at the rate of 1:3 to 4. The gel compound (option) can be used as it is.
4) Keep rotating the blade reel cylinder, and stop rotation when the contact sound
disappears. Put in a newspaper again to check the blade reel cylinder entirely for
the sharpness of each portion.
5) Repeat operations (3) and (4). When the blade reel cylinder and bottom blade are in
contact with each other uniformly, apply abrasive to the blade reel cylinder entirely
for final lapping.
6) After lapping, remove the abrasive with steam, etc.
Both blade reel cylinder and bottom blade are edged. Handle them
carefully.
Be careful of the fingers, which turn the blade reel cylinder, when
cutting a newspaper to check sharpness. Uniformly lap the right and
left sides of the bottom blade in contact with the blade reel cylinder,
and the life of the blade will be maximized.
6-1
[IMPORTANT] Engagement
1) Lightly engage the blade reel cylinder and bottom blade uniformly on both sides.
2) Uniformly adjust the bottom blade on the right and left sides.
Turn the blade adjusting nut clockwise for slight engagement, and turn it
counterclockwise for firm engagement.
3) Lightly engage both sides to the extent that a newspaper will be cut sharply.
When the blade reel cylinder is worn and the spring pressure decreases, adjust the
spring pressure by the spring adjusting screw and 14 nut. (Make adjustment so that
the spring will be 50 mm long.)
[IMPORTANT] Cam adjustment
Turn the cam bush on both sides of the bottom blade, and the blade will be raised and
lowered within a maximum range of 0.3 mm. The above method is used when the
edges of the blade reel cylinder and bottom blade are not in parallel.
1) When there is a gap between the blade reel cylinder and the left frame side of the
bottom blade loosen the lock nut, and turn the left cam bush clockwise as much as
the gap. Turn it clockwise by 30°to raise the bottom blade by 0.1 mm. After
adjustment, firmly fasten the lock nut.
2) When there is a gap on the right frame side, loosen the lock nut, and turn the right
cam bush counterclockwise as much as the gap.
6-2
6-3
CAUTION
Move the brush
from left to right
Spring length
50mm Blade adjusting nut
