Loyal Deere owners waited a long time for the company to come out with a rotary combine. When they finally did -- about a year and a half ago -- it was too late for at least one farmer who had already gone ahead and built his own Deere rotary.
It happened seven years ago but we only recently heard about the home-built Deere rotary put together by Nebraska farmer Alec Yeager. He took a conventional Deere 6600 and converted it to rotary by removing the straw walkers and installing his own home-built, hydraulically-powered rotary separator.
The rotor was designed to slide in or out of the back side of the combine. As the crop comes out of the cylinder, a metal shield diverts it to the rotor. Yeager made the rotor out of a 16-in. dia., 8-ft. length of oil field pipe, which he capped off at both ends. He made the cage around it out of a piece of 24-in. dia. high tensile gas line pipe. He installed auger flighting along the length of the rotor and welded beater bars on between the auger flighting. The beater bars throw crop material to the outside of the cage as the auger moves material to the back of the combine, where it drops onto the combine's original straw spreader.
Both the cage and rotor mount inside a steel frame made from 2 by 4 rectangular tubing. The cage bolts in place inside the combine. The shaft that originally drove the straw chopper is used to belt-drive a double hydraulic pump mounted at the back of the combine. One pump operates at 70 gpm and is used to power the rotor, while the other one runs at 20 gpm and rotates the cage. A flow control valve inside the cab allows Yeager to control speed and direction.
"I built the rotary separator in five months and used it to harvest about 2,000 acres of mostly wheat, with some milo, sunflowers, and corn," says Yeager, who has a custom combining business. "I built the rotor as a slide-in unit because I wasn't sure it would work, and I wanted to be able to put the straw walkers back in if necessary.
"My original reason for building it was because I was tired of watching Gleaner rotary combines outperform my 6600. If the straw was very dry and brittle, my machine's straw walkers couldn't separate the grain fast enough so I had to slow way down.
"I used the home-built machine for two years. It had so much capacity I didn't even have to rotate the cage -- just the rotor. It processed the crop much faster and cleaner than a conventional model. The big problem was that the hydraulics needed to operate the rotary separator used up about one third of the combine's horsepower. As a result I was able to go only 3 to 4 mph, which wasn't any faster than I had been going before the conversion. I'm sure that if I would have belt-driven the separator I could have greatly increased my ground speed.
"After a couple years I bought a Gleaner N7 rotary model. If the Gleaner rotary hadn't been available, I would've bought a Deere 8820 and put my home-built rotor into it. A belt-driven rotor inside an 8820 would've made a heck of a combine."