Great Plains CALIBRATION CRANK Assembly Instructions - Manual (Page 6)

152-302M 10/4/2005
Great Plains Mfg., Inc.
Calibration Crank Kit 6
Calibrate
Refer to Figure 4
1. To adjust seeding rate, decide which drive
type (gearbox) setting you need from the
seeding charts. Set the gearbox.
2. Record weight of an empty container large
enough to hold seed metered for one acre.
3. Place several pounds of seed over three seed
cups on an outside end of drill box. Pull seed
tubes off of these three openers.
4. Attach calibration crank to upper jackshaft
and secure with retaining pin. Rotate crank a
few turns to confirm gearbox has engaged.
5. Rotate calibration crank to see that feed cups
and drive are working properly and are free
from foreign matter.
6. Turn crank several times to fill seed cups with
seed. Rotate crank until seed falls to the
ground from each cup.
7. For this shaft location, turn crank 913 rota-
tions. This will equal the amount of revolutions
in one acre.
8. Check that the three seed cups have plenty of
seed coming into them.
9. Weigh metered seed. Subtract initial weight of
container. Divide by three. Multiply by the
number of openers on your drill to determine
total pounds seeded per acre. If this figure is
different than desired, set your seed rate ad-
justment handle accordingly.
NOTE: You may want to repeat the calibration pro-
cedure if your results vary greatly from seed rate
chart.
Equations for calibrating seed rate:
measured seed - empty container
3 (number of seed cups measured)
= pounds per seed cup
pounds per seed cup x number of openers = pounds per acre
23392
Figure 4
Calibrate