g026935
Figure 15
1.
Front face
2.
Cutting face
The land area and relief angle of the reel blade are
pointed out in
. The land area is the part of
the reel blade that actually comes in contact with the
bedknife and cuts the grass in a scissors action. The
relief or back grind angle is ground into the reel blade
to provide clearance or relief behind the contacting
edges to reduce drag or friction. The recommended
relief angle is 15 degrees.
g026936
Figure 16
1.
Bed knife
3.
15 to 20 degree relief
angle
2.
Reel blade
4.
Land area established by
lapping
Note:
After a reel has run for an extended period of
time the blade contact point or land area will keep
getting wider and eventually will be the full blade
width. This is normal and does not mean that the reel
has to be reground to stay effective. A cutting unit can
cut effectively with full width blades if the adjustment
is checked frequently to maintain sharp cutting edges.
After the reel and bedknife have been ground, perform
the following adjustments:
1.
Set the height of cut.
2.
Adjust the bedknife to the reel.
Note:
As the reel blades continue to run against
the bedknife a slight burr will appear on the
front cutting edge surface the full length of the
bedknife. If a file is occasionally run across the
front edge to remove this burr, improved cutting
can be obtained.
If the reel blade edges and the bedknife edge
are slightly rounded and do not have severe
nicks, lapping only with a lapping compound
may restore the edges and match. Oftentimes
a cutting unit is deemed by users to need
grinding when the reel bearing adjustment,
bedknife adjustment and/or lapping is all that is
necessary.
Lapping the Cutting Unit
Prepare the cutting unit for lapping as follows:
1.
Remove the right wheel.
2.
Place the wheel under the gear case for support.
3.
Remove the reel pinion cover (
g026937
Figure 17
1.
Reel pinion cover
4.
Disengage the reel.
5.
Connect the lapping machine coupler to the nut
on the end of the reel shaft.
When lapping, use a good grade of commercial
lapping compound. A medium grit should be
for initial lapping and a fine grit for finishing. A
solution of 1 part liquid detergent and 2 parts
lapping compound is recommended. The liquid
detergent greatly eases washing away the
compound when finished. Water soluble oil may
also be used as a compound carrier.
12
