A Keen Spreader

Brent Lilley headed south to Raikaia in Canterbury to put the Keenan Orbital spreader through its paces. The results were pleasing…


The test took place on a dairy farm not far from Rakaia on a brilliant, sunny Canterbury day. And with plenty of material to test the machine on, it was a good day for it.

The machine design

The Keenan Orbital spreader is a unique and simple design. The material to be spread is contained in a semi-cylindrical open tank with a 10m3 capacity. A pushing door with a heavy-duty seal contains the load in the tank, while twin hydraulic rams under the rear of the machine and a large, well-built folding arm push the load to the front of the machine to be spread. This sets the Keenan apart from other spreaders because, when the load is brought forward, it transfers weight off the wheels of the spreader thereby lowering compaction and maintaining the weight on the tractor drawbar for traction.

At the front of the load tank a sealed slurry door keeps the load sealed in the tank and away from the flywheel to allow for easier start-up of the machine. The large 1.8m solid steel flywheel at the front of the machine is extremely robust, with six bolt-on plates that are hardened and reversible to break-up material before propelling it out of the machine. In the centre of the flywheel is a counter-rotating spinner with three fins to further shred the material. The flywheel spins at approximately 170rpm to propel the material evenly though the side door in an arc over 20m out the left-hand side of the machine.

The drive comes from the tractor though a heavy-duty wide angle PTO shaft, with an overrun clutch and shear bolt protection. The drive is transferred to the flywheel and centre spinner via a vertical drive chain, which runs through an oil bath for longer chain life. The drive mechanism and bearings on the machine are located outside of the load tank, keeping repairs and maintenance costs low. With around 30 grease points (some quite high up the pushing arm on the back of the machine), I believe it would benefit from some grease banks and lines to make maintenance easier. 

The hydraulics run though a sequence valve block located under the machine which is set-up to control how the pushing, slurry and side door open and close. The spreader also comes standard with hydraulic brakes and a hydraulic jack. The machine is standard on 550/60 R 22.5 floatation tyres but, as with most equipment, a range of rims and tyres is available.


The spreader I tested was set-up on the 6520 John Deere that was provided. The tractor was easily hitched up to draw bar with a hydraulic jack on the machine, although the draw bar need to be adjusted slightly to accommodate the plastic guards on the PTO shaft. The John Deere had three sets of hydraulic valves; when the jack was retracted out of the way, the hose was unconnected and put back in the holder on the machine. There are three other sets of hydraulic hoses for the machine. These were fine on the test tractor, although Keenan suggests the machine could be run on a tractor with only one or two sets of hydraulic vales by setting the position of the breaker bars and the top deflector plate first before uncoupling the hoses needed for their adjustment. But in my mind, a tractor with three sets of hydraulic valves is required to get the full benefits of the machine.

The electronic boost button in the cab is wired in though the nine-pin plug for the lights, which means the tractor needs to have the lights on when working to power the boost button. This, I believe, would be made simpler by having a 12-volt plug, common in most tractors. 


The machine was relatively simple to operate. Once at the start of the run to be spread, the PTO is engaged and runs at 1000rpm, the hydraulics are set to constant flow which starts the sequence of opening the side door, the slurry door and then the pushing door starts moving, bringing the load forward from the rear of the machine into to the flywheel to begin spreading. The speed that the pushing door moves the load to the front is adjustable to 12 settings on a hydraulic value block at the front of the machine.

At start of the load, the electronic boost button in the cab is a great idea: when the button is held down, the speed of the pushing door is increased temporarily until the button is released to compact the load against the flywheel and begin spreading sooner.

As the load is spread, the breaker bars on the side of the machine can be adjusted into path of the material, leaving the machine to further break-up any lumps leaving the machine. The deflector plate at the top of the machine can also be adjusted to narrow the spreading width and concentrate the material leaving the machine.  

Once the pushing door has moved to the front of the machine and the load has been spread, the hydraulics are simply set to pump in the opposite direction. This reverses the sequence, returning the pushing door the back of the load bed, closing the slurry door and the side door, leaving the load bed clean and ready for the next load.

A potential problem is that, if something shouldn’t be in the material being spread, the flywheel will jam and break the shear bolt. There is then no way of reversing the flywheel or moving the material back away from it.

The test drive

I was lucky that there was a variation of material available to test the spreader with including scrapings off the race, manure and some old silage. The spreader was being loaded with a digger, although with a loading height only a little over two metres, it could easily be loaded with tractor and loader.

The first few loads were made up of dairy race scrapings; a mixture of crushed lime rock, manure and some fairly large stones. The machine handled this material well, given some of the stones were much larger than I would have like to have seen going through a spreader, and the lime rock was quite fine.

Next, we put some of the old grass silage in the spreader to see how well the adjustable breaker bars and the centre spinning disc broke the material up. The machine also handled this well, breaking the clumps of old silage up nicely and spreading it in an even coverage to approximately 20m.

A few more loads – with a mix of the silage, race scrapings and dairy manure – proved that this machine really is capable of handling a variety of material and is very well built. The John Deere had adequate power to drive the spreader on the flat ground, but I would think a bigger tractor would be required for work on hills with denser materials. The manufacturers claim that the flywheel has been designed and built in order not to gather plastic, twine, net wrap and other materials that can cause problems in some machines.

I have to admit I didn’t stay around to help clean-up the machine after the test, but was told that it is a relatively easy machine to clean – with the slurry and side doors open, the load tank and flywheel can be hosed out.

Due to the load tank being sealed, one of the most impressive features of the Keenan, I’m told, is its ability to spread liquids and slurry. This would certainly be possible without leaving a trail of liquid all the way to the spreading area.

Unfortunately, we were unable to test this on the day to see what the spread pattern was like and whether the whole load would empty in the first few metres once the slurry door is opened. But the Keenan reps from Rakaia Engineering informed me that they have several customers using the spreaders for a variety of liquids, including whey and slurry, who are pleased with the results.


The Keenan Orbital handled spreading the available materials well. It achieved a very wide and even spread pattern with all materials, which will cut down on the number of runs required to cover a paddock.

Prior to testing the Orbital, I thought the operation may be complicated, but in fact it was really easy to use, with the spreading sequence operating the doors on the spreader, so the only thing to do when spreading was to drive in the correct line.

Having some experience in the past with rear discharge spreaders that had flood chains and vertical beaters, I can see huge benefits in the Keenan system, one of which is its ability to keep the drive system out of the load bed.

Overall, I was very impressed with the Keenan Orbital spreader: it is a very innovative machine, built to the same high quality of other Keenan products on the market.

Photography: Brent Lilley

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