Great Plains 3P806NT Operator Manual - Manual (Page 37)

Great Plains Manufacturing, Inc. Table of Contents Index Adjustments 33
2011-12-20 Table of Contents Index 151-143M
Coulter Down Pressure
The maximum down force at the coulters depends on:
• empty drill weight (page 26),
• extra weights added (page 34),
• down-force consumed by the opener discs (this can
range from 50-150 pounds), and;
• the current material loading (which declines to zero
during planting).
3P806NT configurations typically are too light to reach
the factory down-force of 400 lbs at all rows. The table at
right shows typical forces available. Do not increase
coulter spring forces drill-wide unless weight is available.
Coulter Spring Length
Coulter springs are preset at 10 in. (25.4 cm), giving
coulters an initial operating force of 400 pounds before
the spring compresses. This setting is adequate for
many difficult no-till conditions.
In normal operation at target running depth, springs are
at full extension or only slightly compressed. They
compress briefly at obstructions and in denser soil.
• In heavy no-till conditions, you may observe the
springs in compression most of the time. This means
that the blades are not reaching the desired coulter
depth. If adequate drill weight is available, you can
increase the spring down-force to compensate.
• In light but rocky conditions, the factory setting may be
higher than needed. Extend blade life by reducing the
force at which the blades ride up over obstructions.
To adjust the coulter spring:
Refer to Figure 23
1.
Raise the drill and install transport locks. See “Drill
Lift/Lower (s/n A1057V+)” on page 20.
2. Determine the new spring length desired. See the
table at right.
3. Measure the current length of the spring(s) to be
changed. If already shorter than 9
3 ⁄
4
in., or longer
than 10
1 ⁄
4
in., do not further adjust them.
4. Loosen the jam nut .
5. Rotate the adjuster nut until the spring is at the
new length. Tighten the jam nut.
Note: If all springs are continuously in compression, the
coulters can lift the drill off the ground (at the
ground drive wheel), resulting in low seeding rates
and uneven seed depth. If high forces are required,
frame weights are probably required.
Standard Drill 161 lbs (73 kg) 250 lbs (114 kg)
Drill w/Fertilizer 178 lbs (81 kg) 267 lbs (121 kg)
Drill w/Native Grass 187 lbs (85 kg) 276 lbs (125 kg)
Drill w/Small Seed 170 lbs (77 kg) 259 lbs (118 kg)
183 lbs (83 kg) 273 lbs (124 kg)
NG & Small Seed 196 lbs (89 kg) 285 lbs (129 kg)
32337B
Drill
Configuration
Empty
Drill
Drill with Full
Weight Kit
Fert. & Small Seed
Available Coulter Force Per Row
Machine Damage Risk:
Resetting coulter-spring length shorter than 9
3 ⁄
4
in. may cause
premature failure of parts, and voids the warranty. No
3P806NT configurations have enough weight to compress all
springs shorter than 9
3 ⁄
4
in.
Figure 23
Coulter Spring
27139
Spring Length Force at Blade
10
1 ⁄
2
in. (26.7 cm) 175 lbs. (79 kg)
10
1 ⁄
4
in. (26.0 cm) 300 lbs. (136 kg)
10 in. (25.4 cm) 400 lbs. (181 kg)
9
3 ⁄
4
in. (24.8 cm) 525 lbs. (238 kg)
1
2
3
1
1
2
3