Great Plains 1625AHL Material Rate User Manual
Page 73
Great Plains Manufacturing, Inc.
Sprocket Indexing (Stagger)
69
2014-03-17
411-020B
Indexing Fine Adjustment
If, after indexing, the twin-row side-to-side seed stagger
is substantially imbalanced, it is possible to make small
adjustments that may correct it. Imbalance can occur
over time as row unit chains wear and stretch.
The Indexing charts on pages 73 and 75 provide
columns for alternate rear row sprocket alignments.
These settings move the placement of the rear seed
drop. The amount of movement is given as a percentage
(
±20% or ±40%) of the in-row seed spacing.
Adjustments are made only to the rear row timing.
• Advancing the timing (dropping the seed sooner,
moves the seed position back).
• Retarding the timing moves the seed position forward.
If an adjustment is made, test it on one row pair before
adjusting the entire planter.
Indexing Adjustment Steps
1.
Make sure the current front sprocket index is 1, and
the current rear sprocket index number matches the
“Initial” number in the indexing chart for the
population being planted.
2.
Measure the actual stagger at the rear row seeds.
3.
Determine by how many inches (or cm) the rear
seed placement needs to move in order to be
centered between the front seed placements.
4.
Determine the percent of seed spacing, and whether
advance or retard, required to adjust the rear seed
drop to the desired spot.
5.
In the tables (thumbnail view of one shown at right),
find the new rear sprocket tooth setting for the
percent retard or advance desired.
Figure 16
40% Rear Timing Adjustments
29717
Example: 70 cm Twin Row
The front sprocket is at “1”. At a target population of
90000 seeds/ha, the rear sprocket is at tooth “2”.
At this population, spacing in a single row is:
15.9 cm
The rear row seeds would be ideally at:
8 cm
ahead or behind the front row seeds.
We find that the rear seeds are being placed:
5 cm behind the front seeds.
We need to move the rear seeds back another 3 cm.
A 20% advance is 3.2 cm at this seed spacing.
These Columns are for Fine Adjustment Only
Population Seeds/Hectare
Initial Rear
20% Rear Seed Drop Adjust
40% Rear Seed Drop Adjust
70.0 cm
75.0 cm
76.2 cm
91.4 cm
Tooth Number
Retard
Advance
Retard
Advance
84732
79083
77838
64865
17
14
1
4
18
86077
80339
79073
65895
17
14
2
11
18
87422
81594
80309
66924
5
14
2
8
18
88767
82849
81544
67954
5
18
5
8
14
90112
84104
82780
68983
2
18
17
15
14
91457
85360
84015
70013
1
18
17
12
14
92802
86615
85251
71043
1
3
9
12
14
94147
87870
86487
72072
6
3
9
19
10
95492
89126
87722
73102
6
3
13
19
10
96837
90381
88958
74131
10
7
13
16
10
98182
91636
90193
75161
10
7
13
4
6
99527
92891
91429
76191
10
7
9
4
6
100872
94147
92664
77220
14
11
17
4
1
102216
95402
93900
78250
14
11
17
8
2
103561
96657
95135
79279
14
11
5
8
2
104906
97913
96371
80309
18
11
2
8
5
106251
99168
97606
81339
18
15
2
12
17
107596
100423
98842
82368
18
15
1
12
17
108941
101679
100077
83398
3
15
1
12
9
110286
102934
101313
84427
3
19
6
16
9
111631
104189
102548
85457
3
19
6
16
13
112976
105444
103784
86487
7
19
10
16
13
114321
106700
105019
87516
7
4
10
16
13
115666
107955
106255
88546
7
4
10
16
9
117011
109210
107490
89575
11
4
14
16
17
118356
110466
108726
90605
11
8
14
16
17
119701
111721
109961
91635
11
8
14
16
5
121046
112976
111197
92664
15
8
18
16
2
122391
114231
112432
93694
15
12
18
16
2
36076L
Example:
Moving the rear sprocket from tooth 2 to tooth 17
provides a 20% advance.