Farmer invents own hammer mill


By Digital team | 7 January 2017
hammer mill
Mr. Werner Nell with a bushbuck ewe on his farm.

The herd of bushbuck of Mr. Werner Nel of Brits never go hungry. As he says: Their stomachs should be full, 24 hours a day. But in the summer sowing areas, winter grass isn’t worth much when it comes to nutrition and then licks or additional feed needs to be provided. And that’s when a farmer needs a hammer mill.

Werner, in the North-West province of South Africa, has been farming on a small scale with bushbuck since he retired seven years ago. Although it’s ‘only’ a hobby, he takes it very seriously. He built his own electrical hammer mill as it didn’t make sense to spend money on an expensive mill.

The ration

Initially, Werner paid about R6 000 (ZMK 4600) per bushbuck ram and ewe, and a R1 000 (ZMK 767) for the darting, catch and delivery. Today this small game can easily cost you about R16 000 (ZMK 12 200). His herd has since multiplied to about 20, therefore he also rents grazing when necessary.

It’s a big problem for him to ensure that there is always a good supply of feed. The game graze on natural pastures throughout the year (typical sourveld with parts sweetveld and thorn trees). But Werner supplies extra feed throughout the year and 24 hours a day. His ration consists of a mix that was compiled professionally for game: feed lime, lucerne (alfalfa), minerals, maize bran, full fat soybean flour and molasses flour. He buys and mixes all these ingredients himself.

The bushbuck is a ‘fine’ feeder, which is why Werner separates all the leaves from the lucern stems before he grinds it.

“If you put it through the mill as is, the leaves turn to a fine powder. I grind the stems into pieces of 25 mm to 35 mm so the bushbuck get enough roughage in the right size and can ruminate. Their digestive systems can’t go without it.”

The leaves are then mixed with the ground stems and other ingredients and placed in self-feeders, which Werner built from scrap material (Picture 1).

Picture 1
Picture 1

Old wheelbarrow

Werner built the hammer mill years ago and refined the design over time.

“Initially I had a small scale cattle farm and it was especially in winter that I had to supplement the cattle’s feed, so I had to regularly grind lucerne for them. In the 1970s I used a neighbour’s tractor and hammer mill, which often caused frustration when the mill got blocked or when the medium-sized tractor over heated.”

For his own hammer mill, he used an old wheelbarrow as base (Picture 2).

Picture 2
Picture 2

The power source is an old 1967 model electric motor of 1,5 kW (Picture 3), which used to be on the first borehole on the farm.

Picture 3
Picture 3

Werner bought an old hot water system that was mounted on a wood stove for next to nothing from a neighbour. A part of it was collapsed and mounted on the wheelbarrow base. Another part was reinvented to form the milling bin.

Loose parts, like the sieves and steel for the milling action, was bought from a co-op and was, with the welding rods, the only other expense. An employer of back in the day agreed to cut the axle of the milling bin.

This first model served its purpose for nearly forty years, but the milling speed was just about 40 kg per hour. Whenever Werner tried to speed up the milling, the mill got blocked and he had to stop everything to clean the mill by hand.

After his retirement, a friend – Mr Jan Lambrecht of Sentrum in Limpopo province – recommended he start a game farm on small scale as a hobby. He followed his advice and started with nyalas, but now only has bushbuck. In the meantime he started milling lucerne for other farmers too and the slow hammer mill started testing his patience.

He not only needed to up the milling speed, but he also needed a solution for the mill’s tendency to get blocked so that he could improve the mill’s performance without letting go of his trusty motor. He also had to keep in mind that the lucerne could not be milled to an ultra fine product, as it would unnecessarily speed up the ruminators’ digestive system and valuable nutrients would go to waste in this manner.

In most ways, his hammer mill was similar to most other hammer mills, but the amount of hammers that beat the feed to pieces before it’s blown through the sieve, was limited to four (Picture 4) because of the small motor of only 1,5 kW.

Brits, Noordwes
Brits, Noordwes

The hammer head was originally designed for eight hammers. An old fuel tank was cut up and transformed to serve as feeding gutter (Picture 5).

Picture 5
Picture 5

At the end of 2014, early 2015,Werner started making adjustments to the design to up the milling speed and prevent blockages. Now the mill is much faster and it gets blocked much less often. Conservative estimates put the speed at about 250 kg per hour (Picture 6).

Picture 6
Picture 6

When Werner demonstrated the hammer mill, he milled two bales of lucerne (about 35 kg) in only seven minutes. The old motor still works well and was recently opened up and serviced by professionals without needing any repairs.

Features

Werner summarises the features as follows:
– It’s equipped with an electric motor of only 1,5 kW which doesn’t overheat during a shift of five hours.
– The hammer head takes only four hammers and disproved the original expectation that it would be completely inefficient.
– Whole maize pips and lucerne are put through the same maize chop sieve.
– The baler has the ability to process lucern bales at about 250 kg per hour.
– The simple inside design is powered by cost-efficient smaller power sources, which is a huge saving on fuel and electricity.

Werner says with enough time and continuous adjustments, the 40 year old hammer mill has finally come into its own.

Enquiries: Mr Werner Nel, email: bosbokr514@gmail.com.