Great Plains NTA3007 Operator Manual - Manual (Page 115)

Great Plains Manufacturing, Inc. Table of Contents Index Adjustments 111
2012-07-02 Table of Contents Index 166-371M
Row Unit Spring Adjustment
Row unit springs normally require no adjustment. Row
down-force is set and adjusted by the Lift system, using
hydraulic down-pressure (page 102). The factory setting
for the row unit springs is:
In some unusual conditions, rows in tire tracks may need
to be set heavier.
1. Make adjustments with the wings unfolded and the
rows lifted off the ground, so that the springs are at
full extension.
2. Loosen the jam nut . Rotate the adjuster nut .
Shorten spring to increase down-force; lengthen
spring to reduce down-force.
For each turn of the adjuster nut, the down force at
the opener disc changes by approximately:
1.7 kg/turn (3.7 pounds/turn)
3. Re-tighten jam nut after setting force.
Disc Blade Adjustments
Opener disc angle and stagger is not adjustable, but
disc-to-disc spacing is, and may need attention as discs
experience normal wear. Spacers will need to be reset
when blades are replaced.
Refer to Figure 112
The ideal spacing causes the blades to be in contact for
about one inch. If you insert two pieces of paper between
the blades, the gap between them should be
0 to 4.4 cm (0 to 1
3 ⁄
4
inch).
If the contact region is significantly larger or smaller (or
there is no contact at all), it needs to be adjusted by
moving one or more spacer washers. If the contact
region varies with blade rotation, one or both blades is
likely bent and in need of replacement.
Spring length 32.4 cm (12
3 ⁄
4
inch)
Assembly length 56.2 cm (22
1 ⁄
8
inch)
Machine Damage Risk:
Do not use spring lengths shorter than 29.8 cm (11
3 ⁄
4
inch).
It may contribute to premature parts failure which will not be
covered by warranty.
Figure 111
Row Unit Spring
29427
1
2
3 4
1
2
3 4
Figure 112
Checking Disc Contact
26451