Great Plains 800 Operator Manual - Manual (Page 34)

30 800 Table of Contents Index Great Plains Manufacturing, Inc.
175-057M Table of Contents Index 2011-10-25
Opener Height
The depth to which the opener disc blades penetrate the
soil is controlled in front by the tool bar and pivot (opener
height), and in the back by the press wheel height.
If the actual ground level is lower for some rows, such as
those in tire tracks, you can lower that row unit by
lowering the pivot point.
Refer to Figure 21
1.
Raise the drill just enough to relieve tension in the
down-pressure spring.
2. Remove the bolt from the upper hole .
3. Re-position the arm at the lower hole , and secure
with bolt.
Note: No spring tension or position adjustment is
required. The pivot holes are designed for neutral
effect on spring tension (the bolt at the top end of
the spring uses a hole
that depends on spring
length, and not opener height.)
Row Unit Down Pressure (Spring)
For planting in tire tracks, and no-till conditions, you can
increase spring pressure on individual or on all openers.
Adjust the spring in conjunction with the subframe down-
force, and opener height, to keep the top of the row unit
parallel to the ground.
Adjusting pressure at the springs for all rows is not
recommended. Use the opener frame pivot pin
(page 28).
Refer to Figure 22 and Figure 23
To increase spring pressure:
1. Loosen jam nut at lower end of opener spring.
2. Tighten flange against spring tension.
Note: Each
1 ⁄
4
inch adjustment adds about 13 pounds of
force at opener disc (approximately 9 kg per cm).
Do not tighten nut more than one inch (2.5 cm).
3. After adjusting, lock flange nut in place with jam nut.
The length of the spring is factory-set to:
13
5 ⁄
16
in. (33.8 cm).
The reference points for this length are the
center of the upper/front clevis pin
and
the base of the lower/rear spring stop cup .
The factory preset length is recommended for
conventional till and min-till conditions. Shorten it for
rows in tire tracks or more difficult min-till conditions. The
minimum recommended length is:
12
5 ⁄
16
in. (31.3 cm).
Figure 21
Pivot Point Bolt Holes
26382
2
1
3
1
2
3
Figure 22
Row Unit Spring Tension
17158
1
1
Figure 23
00 Series Spring Length
26454
3
2 4 2
3
4