Overum VF – EX5975H five-furrow reversible plough
The Overum VF – EX5975H five-furrow reversible plough is a sturdy, well-designed and built plough with plenty of specs to make adjustment and routine ploughing a breeze
- Fast plough reversal reducing headland time
- Hydraulic stone release system allowing up to 50mm of upward travel
- Solid construction
- Easy to adjust
- No need for a lot of tools
The Danish built Overum VF – EX5975H five-furrow, reversible plough comes with hydraulic vari-width, hydraulic reset and spring loaded disc coulters which sit in the middle of the four to six-furrow line-up.
The Vari Flex EX range is the heaviest duty, fully-mounted reversible plough that Overum builds. This is perfect for those New Zealand regions that prove a challenge for most tillage implements, with abrasive sandy soils, volcanic rocks, hard timber and contours.
The test was carried out in a sprayed pasture being planted for maize, in south Taranaki.
Build quality and performance
Ploughs are among those machines in many contractors’ arsenals that don’t get used for large portions of the year, but when they’re pulled out of the shed it is hammer and tongs for a month or two at a time. This not only makes build quality and reliability important, but it must be able to chew up the hectares.
"Mucro" is the name of the heat-treated steel Overum uses in its wearing parts. The raw material is heat-treated where the correct carbon content in the steel profile determines the properties of parts. The tips, skimmers and mouldboard are processed for 24 hours in an oven with a carbon-rich environment and high temperature. Carbon penetrates into the surface layer of the steel, providing hardness, wear resistance, toughness and impact strength.
The EX series is equipped with a double cylinder ram with a common piston rod. One half of the cylinder manages the automatic alignment while the other half controls the width adjustment. When you have come to the headland and lift the plough out of the ground and flip it over, the furrow width is automatically sucked into the minimum position.
As the plough flips, the furrow width returns to the pre-set value. This process compacts the plough to produce a smoother reverse action, and also reduces a heap of weight swinging out the back of the tractor. The heavy duty headstock (with a 180mm pivot shaft with needle roller bearings) also helps spread the forces on a large surface, reducing both stress on the plough and tractor.
During flipping the rear depth wheel also needs to move 90º and a shock absorber gives the wheel a gentle turn. A rear-mounted wheel works better than mid-mounted, especially for the larger 260/70-16 version on the test plough, as this offers the best depth control and weight transfer during transport while also offering low rolling resistance.
The only negative about the wheel is every now and then a piece of sod gets caught in the stopper which stops the wheel from dropping down, although you could see this happening and only became an issue at night when visibility is poor.
The plough overall was very well built, though the spring disc coulters seem to be a weak spot. Where you tighten the shank in the locking collar, a setscrew in the hinge casting holds the coulter for maximum swivel. The problem is when you hit wood with the coulter – it doesn’t always trip the stone release system.
The wood pushes the coulter past the stopper which snaps the bolt and becomes jammed. This makes it out of line, and to prevent bending the shank it must be removed. Depending on the conditions, this happened often with one or two of the 10 coulters missing. Like the rear wheel, this was more of an issue at night when visibility to the back furrows is limited.
Stone release system
When working in tough ploughing conditions the wood often does more damage than the stones to the plough (as with the coulters), which is why the lifting height of the plough body when releasing over a large stone or log is very important.
The hydraulic release system is obviously dearer at purchase time but in the long run much cheaper R & M-wise over shearbolts, and much more user-friendly. The hydraulic reset allows the share point to move well over 50cm vertically from the working position, which allows the rocks to pass underneath and helps extend the plough life, preventing overloading of material and welding seams.
Weight and transport
The plough’s spec sheet estimates the weight of the machine at 2200kg, but specifies that a minimum lift capacity of six-tonne is available. A negative factor of any five-furrow plough is that although it doesn’t weigh a great deal, the weight is a long way out the back of the tractor. Even though I had 1200kg of weight on the front and water in the tyres, the tractor would still wheel stand. This becomes a particular issue if your headlands are on a hill as the flipping of the plough from one side to the other can be a character-building exercise if you are not careful.
The manufacturer recommends that the plough is transported in the "butterfly position" to relieve pressure on the tractor. This is where the plough is flipped half way so the mouldboards are on top and the depth wheel is placed in the transport lock position and the top link is removed. That leaves the plough on the two linkage arms and the rear wheel which keeps the front of the tractor on the ground (a good thing).
The test machine was equipped with an optional check valve which is easy to adjust with the tractor hydraulic outlet on the go. So changing from lower pressure in light soils to higher pressure in heavy soils can all be done without leaving the tractor seat.
The plough alignment is set with a turnbuckle. Front furrow adjustment can be done either with a spindle or by a hydraulic cylinder. Ploughing depth is easily set without a need for tools, but a large spanner comes with the machine that fits every nut and bolt on the plough. You don’t have to carry an extensive array of tools for breakdowns. It attaches easily and securely to the main beam so you won’t lose it during reversals.
The geometrical design of the furrow width settings allows them to be hydraulically adjusted from in the cab. You can select widths from 35-55cm depending on the conditions.
The Overum is a sturdy, well-designed and built plough with plenty of specs to make adjustment and routine ploughing a breeze. The coulter design is a let down, although this may not be an issue in other parts of the country. Driving out the gate there was no sod visible on the plough, which means the power harrow will transform the paddock into a perfect seedbed for whatever crop is planted.
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