TECH TIPS FOR DRILLS

 :: Drill Design Comparisons

The concepts for drills are really no different from planters. Some drill designs cannot adequately perform Steps 1 - 4 described above because they are holdovers from the tillage era. In North America, one design that fulfills Steps 1, 2, 3, & 4 is the John Deere 750-type single-disc opener, including the 60- and 90-series*. Some comments to help them function:

Use adequate down-pressure for the conditions. This often results in the rockshaft being tilted down in back (See photo) to gain enough compression on the big coil spring (up to 2 inches of compression is sometimes necessary). Additional ballast on the frame is often required. Increasing hydraulic down-pressure without adequate ballast can result in the opener 'rolling under' or over-rotating, which actually decreases effective depth. Faster ground speeds will require more down-pressure and ballast.

The gauge wheel should be firmly on the soil surface during seeding, which holds the sidewall together while the blade exits the soil. Also for this reason, reduced inner diameter tires (RID / CIH indented gauge tire) are strongly discouraged. Assessing whether the gauge wheel is remaining firmly on the surface requires examining a length of furrow to see that: 1) the furrow is being cut to a consistent depth, and 2) the sidewall is not blowing apart prematurely.

Opener blades should be replaced when the bevel is gone (~ 17.12 - 17.25" diameter) for optimum performance. Dull blades require more down-pressure to cut residue and slice the soil. Because the outside edge of the boot hangs out past the blade (wider than the furrow being cut), it is very difficult to push the boot into the soil. The lower edge of the boot generally should be at or slightly below the soil surface. If attempting to continue running worn blades, move the seed boot to the upper mounting hole (return it to the middle hole when installing new blades).

Seed boots should be inspected and maintained—the wear is not obvious from casual inspection. Compare a worn-out seed boot with a new one. When the bottom outside edge of the boot is no longer straight across, performance is compromised (the photo shows severe wear, performance was being affected much earlier). For improved wear life, upgrade to the chrome-alloy boots for 60- and 90-series drills, or tungsten-carbide boots for 50-series drills. Another option is to have the soft cast boots hard-surfaced (before they wear through).

The 60-series drills had a poorly designed seed boot. The boot was 0.75-inch farther forward and had an internal channel that directed seed toward the blade, which then flung the seeds out of the furrow. The 60-series drills should be upgraded to the 90-series boot, which corrects the problem (geometry and location are then the same as the 50-series). When installing, note that the leaf spring must be installed before the bolt, unlike the earlier designs.

Maintain leaf springs to keep the boot against the blade. These weaken with age, and eventually break.

Use a narrower seed-firming wheel, such as CNH’s SDX flexible firming wheel (part number N306145A1 ). (The new JD firming wheel, introduced in late ’06, isn’t narrow enough yet.) Another option is the Fin from JD Skiles (ph 785-626-9338), which is a large poly sliding firmer that bolts onto the JD firming arm instead of the wheel. The Fin also has provision for liquid fertilizer routing. The Fin’s seed firming capability appears good, although we hear occasional reports of residue dragging. Yet another option is the new narrow rigid wheel from Needham Ag (ph 270-785-0999), which has a high quality bearing and thin periphery. However, the SDX wheel is still the best choice (in our view) because of its ability to flex laterally up to 0.75 inch while remaining fully functional (See photo; if you are on perfectly flat fields and running sub-inch guidance and auto-steer, perhaps it’s not an issue – for everyone else, it is.) You cannot afford to compromise on the seed-firming function – it is too crucial. Narrow firming devices are vastly superior for reaching the bottom of the 'v,' which is critical to their function, and also shed mud better. Run maximum pressure on them for most conditions.

Strive to gently close the furrow, consistently breaking the sidewall and filling the furrow with loose material. Loose soil over the seed will slow the drying of the seed zone more than packed soil over the seed.

On air drills, beware too much velocity on the seed caused by excessive air pressure. To assess your air velocity, take one of the secondary lines off of an opener and aim it straight up in the air with some wire or tape.  Run at normal speed, pushing a normal amount of product (seed +  fertilizer).  The product should be blowing about 18 – 24 inches out of the line.  If it is blowing 5 ft up in the air, you have far too much air pressure.  If you still have problems, take a look at our D-Cup Diffusers. (Even with Diffusers, it is highly advisable to set the fan speed using the guideline set forth here, especially with Deere 1900-series carts.)

On the 1850 only, beware that these drills had the frame/rockshaft too high for the openers to function properly (can't get much down-pressure, opener runs on its 'heel'), which required a 'drop-kit' to remedy. If you are unsure whether your 1850 drill has the drop-kit already installed, look at the position of the rockshaft in relation to the frame and compare to 60- and 90-series air drills (See photo).

On the 90-series (or 60-series drills with 90-series boots) only, the firming wheel runs 0.75" closer to the back of the seed boot, due to the redesigns previously discussed. When drilling over terraces or other uneven terrain where some openers momentarily come out of the soil, the firming wheel brakes on the boot, causing wear on both items and some instances of breakage of the rear edge of chrome-alloy boots. The solution is to drill a new hole in the firming wheel arm, between the existing hole and the end of the strap (or replace the strap entirely with one 0.75 inch longer and holes 0.75 inch farther apart).

*No, we’re not John Deere fanatics – but these drills do perform reasonably well over a range of soil conditions and crops. We’d love to see something better come onto the market.