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New combine grate reduces grain loss

New combine grate reduces grain loss

Back in 1995, Don Estes of CM Welding invented the Disrupter, a set of steel lugs installed inside the rotor separator section of Case IH and John Deere rotary combines to cut up corn shucks, green stem soybeans, and wheat straw, which can otherwise lead to rotor loss. This year, Estes has come out with a second product to reduce grain loss in rotors, this time caused by an overloaded separator.

“The two main reasons for grain loss in rotors are crop residue and an overloaded rotor,” Estes says. “If you want to stop rotor overload, you must start removing grain in the concave section before it gets to the separator section.” 

Estes says in Case IH combines, there are wires you can remove in the concave to open up the area prior to separation to allow more grain to flow into the tank. The John Deere STS, by comparison, uses round bars in the concave with 5/8-in. openings that are not removable.

“The grate used in the concave of John Deere STS combines, in my opinion, is not large enough or open enough to get eight rows, let alone 12 rows, through the combine without sacrificing ground speed,” he says. “Try pouring either 29% or even 13% of the corn through the 5/8-in. slot with two round openings.” 

To fix the problem, Estes has designed a replacement grate for the concave in John Deere STS combines. The grate is made up of ½-in. square rods that have a 1 1/4-in. space between the rods to allow for more grain to pass through before reaching the separator. He says the new grate, installed in the rear section of the concave, will allow for 68% greater crop flow.

“The more crop volume you can get out of the concave section, the less that has to be separated in the separator section,” Estes says.

List price is $749.00  You can also buy an entire kit that includes the grate along with a set of STS Disrupter lugs for $1,098.

For more information, contact CM Welding Inc., Dept. FIN, 4496 N. Co. Rd. O E-W, Frankfort, IN 46041, 765/258-4024 or 765/891-1722, or visit

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