TECHNICAL // PREPARE A MAIZE DRILL
Get set for spring drilling
Above: All machines will benefit from a pre-season service and check-over to ensure your maize drill is ready to go when the conditions are right
With the soils slowly warming up, it’s time to pull equipment out from the back of the shed and turn attention to spring sowing. A thorough check-over, service and set-up now are cheap insurance that could help prevent an in-season breakdown WORDS MICK ROBERTS IMAGES GEOFF ASHCROFT
n common with most other machines, the pre-season service for a maize drill should ideally begin before it goes into winter storage, explains Phil Vickery, Kverneland’s south-west area manager. “Putting the machine away properly should be the first job in the pre-season service,” he says. “Clean the drill carefully with a pressure washer, removing all traces of seed and fertiliser dust. Allow it to dry properly before lubricating all the chains and bearings and applying a light coat of oil for protection. Slacken off chain tensioners and belts before storage. “Probably the worst thing you can do is not wash out the fertiliser metering units or, if you have washed them, not
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leave them to properly dry. Wet dust solidifies and will seize the mechanism up by the spring, and this has the potential to damage the gearbox when it’s started back up.” Here we are looking closely at a mechanical drive, 2013 Kverneland Optima 4.5m telescopic vacuum-controlled precision seeder, equipped with Suffolk seeding and fertiliser coulters. This model was superseded by the HD, which has twin discs that exert 129kg of pressure, with the option of increasing that to 229kg with assister springs. While mechanical models are still available, electric drive machines are now the most common. In 2015 the Optima V took over from the telescopic machine and remains the current model. The six-row
“The worst thing you can do is not wash out the fertiliser metering units”
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TECHNICAL // PRE-HARVEST PREPARATION
Left: The seeding disc hardly wears, thanks to being mounted on a plastic back plate. There is a wide range to suit different seeds, but the most common for maize has 40 x 5mmdiameter holes Right: The first key adjustment on the ‘seeding heart’ is to regulate the flow of seed with this three-position deflector plate. For maize it is usually placed in the middle position
Above: This pointer and scale control the singulation arm that knocks excess seed off the cell wheel. For maize it will usually work best set between 4 to 5 Above right inset: This pointer and scale control the singulation arm that knocks excess seed off the cell wheel. For maize it will usually work best set between 4 to 5
machine offers variable row widths from 45cm to 80cm in 5cm increments. There is a wide choice of seeding discs allowing the machine to work with a range of crops from broad beans, with a disc with 12 x 5mm holes, right down to oilseed rape using a disc with 96 x 1.2mm holes.
Heart of the machine Servicing and set-up are similar for all models. This is largely down to very few changes to the seeding ‘heart’. “This is literally the heart of the machine, in which the seeds are separated before passing to the coulter,” says Phil. “This was first introduced in 1989 and the only change was a switch from aluminium to a plastic heart housing, which is made in Kverneland’s own factory in Germany. The reason it is still used today is because it is incredibly reliable and, because the seeding disc is mounted on a back plate, it is not a wearing part.” Unsurprisingly, this key area is where Phil advises
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“Before starting, it’s a good idea to turn the metering units by hand with a spanner” starting the pre-season checks and set-up. “It is removed easily by undoing the black plastic nut at the rear and unclipping the chain clip that secures it to the frame. Then take off and clean the Perspex cover that, in work, allows you to see the seeds on the disc inside.” Removing the outer cover is then a simple matter of pulling the back out and rearwards from the seeding heart to reveal the seeding disc. “Because it is fixed to a back plate, it is very unlikely to be worn,” says Phil. In the centre is a red plastic disc with pegs around the outer edge. This provides agitation for the seed, but again seldom requires any attention. The disc fits into three cut-aways on the back plate and is removed by turning it anti-clockwise, which then allows it to lift out of the slots. A ‘40/50’ seeding disc is now supplied as standard for maize drilling. This has 40 x 5mm-diameter holes to hold the seed in place. This replaced the 32/5, which was used previously and permits faster working speeds.
TECHNICAL // PREPARE A MAIZE DRILL
Above: These damaged rollers will need changing. This is done fairly simply by undoing the securing plates, withdrawing the square shaft and replacing the rollers
Above: Tyre pressure on mechanical drive machines is critical. Anything above or below the recommended inflation pressure will change its rolling radius, confuse the monitor and affect the seed rate
Below: After removing the seeding disc use a toothbrush and soapy water to clean the sensor (top left) and the vacuum interrupter (bottom left)
Below: Furrow closers should be set to 5in (125mm) apart. Moving them closer together can lead to excessive soil dragging, which can adversely impact on seed spacing and sowing depth
Back plate checks There is little to check and set on the back plate. The metal strip, which extends from the centre, holds the vacuum interrupter. Its job is to shut off the vacuum, allowing the seed to fall off the disc ahead of the coulter outlet. This can become clogged with dust, reducing its effectiveness to release seed at the correct moment. Use a toothbrush to clean the interrupter, and to clean the optical eye, above, which counts seeds. After inserting the disc and replacing the cover, it’s time to check the settings for the crop – which in this case will be maize. To the right of the cover, at the top, is a three-position deflector plate that regulates the flow of seed into the heart. “Most maize seeds will run through best when this is on the middle setting. This allows a steady flow to the heart, without it over-filling or running short. Some larger seeds may need the top setting, but that’s unusual,” he explains.
Below this is a pointer and scale. This controls the singulation arm that knocks excess seed off the cell wheel. This has settings from ‘off’ at the bottom to 9 then Max at the top. “For maize it will usually work best set at between 4 to 5. Set it at this and then make fine adjustments when the machine is running – if necessary,” advises Phil. The butterfly nut holding a pointer in place, in the middle of the outer case, is the secondary singulator. Its job is to knock off any second seeds and ensure the one remaining is aligned in the centre of the vacuum hole.
Turn over by hand With the heart set we can now turn attention to other areas. “Before starting, it’s a good idea to turn the metering units by hand with a spanner – just in case they have seized up over winter. Cleaning and lubricating before storage should prevent this happening – but it’s still worth checking,” advises Phil. At the same time, remove the cover and inspect the
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TECHNICAL // PREPARE A MAIZE DRILL
Right inset: Lubricate the chain, check tensioner idlers move freely and the rollers turn. Torque the nuts at the front and rear of the parallel linkage to the correct setting and tighten the lock nuts
Above: JF Watkins & Sons at Vicarage Farm, East Chaldon, Dorset, has recently traded up to the latest six-row Optima V model. This offers row adjustment between 45cm and 80cm in 5cm steps. Electric drive allows individual row shut-off
“There really isn’t much to go wrong on the drills but they will last longer and work better if they are correctly serviced”
metering rollers’ condition. On the example in the picture one roller is badly damaged – possibly by a rogue stone or bolt in the hopper. It can be replaced by disconnecting the drive shaft, sliding it out and putting a new one in its place. Square shafts drive the units, and these are connected by simple plates held in place by nuts and bolts. Check and lubricate all the drive chains and tensioners, and ensure the idler rollers move freely before resetting to the correct tension. At the same time follow the grease chart in the manual and lubricate the whole machine. Kverneland helpfully provides the facility to download the operator manual from its website - https://ien.kverne landgroup.com/Parts-and-Service/Download-manuals Or search for ‘Kverneland operator manuals’ and on Google it will be at the top of the listings.
Feel the pressure Finish off by checking the tyre pressure on mechanical versions, which ensures it has the correct rolling radius
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to maintain an accurate seed rate. Also inspect the furrow closers for wear or damage and ensure there is a 5in (125mm) gap between them. Some operators move these closer together, which will adversely affect the sowing depth and consolidation. “Another reasonably common mistake is to over-tighten the nuts on the bolts that suspend the seeding units on the parallelogram frames,” says Phil. These are fitted to the front and rear and should be tightened to the correct toque setting and secured by the lock nuts. The torque is shown on the yellow sticker on the arms. “There really isn’t much to go wrong on the drills. But they will last longer and work better if they are correctly serviced, set and maintained. And the best start is to clean, lubricate and store them carefully after use,” he adds.
ACKNOWLEDGEMENTS Thanks to JF Watkins & Sons at Vicarage Farm, East Chaldon, Dorset, for the use of their six-row Optima for this feature. The farm has since replaced this machine with an Optima V model.