Great Plains NTA3007HD Operator Manual - Manual (Page 86)

82 NTA907HD or NTA3007HD
166-207M 04/04/2011
2. Move drill to a hard surface area, so that openers do
not lower below ground level.
Contact Spring Force
It may be necessary to loosen and move the jam nuts
for this adjustment. Re-check jam nut adjustment in any
case, as force adjustment changes up-limit.
3. Raise openers, to fully compress springs .
4. Measure the length of the springs between any
two convenient points that encompasses all turns of
the spring windings, such as from the centerline of
the lower cross-bolt to the top of the casting.
5. Lower openers to ground.
6. Re-measure spring length. Adjust bolt until spring
length when lowered is 2.5cm (1in) longer than when
fully compressed (as measured at step 4).
7. If reducing force, make sure that at least 7 turns of
bolt threads are in spring casting. Check exposed
length of bolt
between bottom of spring anchor
and top of casting (not to top of jam nuts). The maxi-
mum length of exposed thread is 91mm (3.6in).
Contact Shaft Up-Limit
8. With openers raised, at each ground drive, rotate the
shaft
and check the gap between the shaft and
the top of the slot . There must be at least 10mm
(0.4in) clearance.
9. To adjust the shaft up-limit, loosen all four jam
nuts
in the spring assembly. Rotate the upper jam
nut to set the upper limit of shaft travel. Adjust for
12mm (0.47in) or more slot clearance, and equal
clearance on both sides of each ground drive arm
assembly. Secure upper jam nut with lower.
Null4:
Note: With openers lowered in the field, spring extension
will be more than 2.5cm. The setup procedure
accounts for this.
Figure 87
Contact Drive and Slot
29379
6
5
4
8
9
6
1
7
8
8 9
4
5
6