GREAT PLAINS 1007NT, Operator'S Manual, Page: 35 / 86

Great Plains Manufacturing, Inc.
Adjustments 31
03/18/2019 150-290M
Coulter Spring Length
Coulter springs are preset at 10in (25.4cm), 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 com-
press 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 19
1. Raise the drill and install transport locks. See “ Drill
Lift/Lower ” on page 18.
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 wheels), resulting in low seeding rates
and uneven seed depth. If high forces are required,
frame weights are probably required.
Resetting coulter-spring length shorter than 9
3

4
in may cause
premature failure of parts, and voids the warranty. No 1007NT
configurations have enough weight to compress all springs
shorter than 9
3

4
in.
Figure 19
Coulter Spring
27139
Spring Length
Force at Blade
10.50 in (26.7 cm) 175 lbs (79 kg)
10.25 in (26.0 cm) 300 lbs (136 kg)
10.00 in (25.4 cm) 400 lbs (181 kg)
9.75 in (24.8 cm) 525 lbs (238 kg)
1
1
3 2
1
2
3