Great Plains 2420 Operator Manual - Manual (Page 19)

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Section 3 Adjustments
5/15/06 2400, 2410 and 2420 Three-Point Drill 118-706M
Great Plains Mfg., Inc.
Frame Height
Drill operating height directly affects the working range of
the drill openers. Initially adjust frame height as explained
under Leveling Drill, Preparation and Setup, page 11.
You can make further adjustments to compensate for field
conditions.
When adjusting the gauge-wheel turnbuckles, remember:
• Lengthening turnbuckles raises drill and allows less
opener down float.
• Shortening turnbuckles lowers drill and allows less
opener up float.
After adjusting gauge-wheel turnbuckles, be sure to level
the drill with top hitch link.
NOTE: Lowering the drill increases the risk of opener
damage on rocks or obstructions.
Seeding Rate
Calibrating the seeding rate requires four steps:
• adjusting drive sprockets,
• setting seed-rate handle,
• positioning seed-cup doors, and
• checking seeding rate.
Refer to the seed-rate charts on page 19. These charts list
proper sprocket sizes and seed-rate-handle settings for
various seeds and seeding rates.
The seed-rate charts are based on cleaned, untreated
seed of average size and test weight. The charts are
based on 11L x 15, rib implement tires. Many factors will
affect seeding rates including foreign material, seed treat-
ment, seed size, seed weight, field conditions and tire
pressure. You likely will need to make minor adjustments.
Set and check the seeding rate, then readjust the rate as
necessary.
Before setting the seeding rate, rotate the gauge wheels.
Check that seed cups and drive are working properly and
free from foreign material.
Adjust Drive Sprockets
Use drive sprockets for the drive type for your desired
seeding rate. See Figure 3-8.
Figure 3-8
Drive Sprockets
For correct drive type, refer to seed-rate charts beginning
on page 19. The charts lists drive types as 1, 2, 3 or 4. Re-
fer to the following table for correct-sized sprocket for each
drive type.
Drive
Type
Driver Driven Speed
Type 1 15 Tooth 47 Tooth Slowest
Type 2 24 Tooth 36 Tooth Two Times Faster
Than Type 1
Type 3 24 Tooth 24 Tooth Three Times Faster
Than Type 1
Type 4 24 Tooth 15 Tooth Five Times Faster
Than Type 1
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