6 Pointers to Maintain, Adjust Corn Heads to Minimize Harvest Losses

By: Dave Mowitz
Previously published by Successful Farming

Corn head checkpoints.

Closer attention to combine settings and improvements in threshing and separation technology has worked wonders in minimizing grain losses in the combine. Dennis Bollig warns that corn heads contribute enormously to grain losses, however, citing an Iowa State University study that estimates 60% of all losses happen now at the corn head.

“The need for speed has farmers driving faster, pushing a corn head to its limits. That leads to more grain losses,” Bollig says. “Combine that with the fact that genetics has created shanks that are stronger and ears that dry down rapidly, and it sets up a situation where the impact of an ear hitting deck plates can lead to more butt shelling.”

Consider that if you run at 5 mph, a head is pulling down 12 to 15 plants per second per row. “That is pulling ears into the head at 15 to 18 mph,” Bollig estimates. “Now consider the challenges a head faces if it has to operate in down corn, which is more common these days.”

Bollig offers six pointers to maintaining and adjusting corn heads to minimize harvest losses.


Designed to pull the stalk into the head, chain tension is crucial to properly presenting the stalk so its ears can be stripped off. “Besides checking tension, examine the chain for wear. When tension adjustment is maxed out, then it’s time for new chains,” Bollig says.

Anticipate how many acres existing chains must harvest in the coming season. “If they are approaching the end of their useful life, don’t think you can squeak through another harvest on older chains,” he says.

During your inspection, look at sprockets for cupping in their valleys. “Pay close attention to lower idler sprockets (that operate near dirt) for wear. Take the chain off and spin sprockets to listen for noise coming from the bearing,” he says.


Whether deck plates are bolted on or are hydraulically or automatically adjusted, make sure they’re free to move since they can rust to their frames. “Remove the plates not only to clean them but also to remove corrosion and foreign objects. Hydraulic plates can rust at their pivots points and then they will not move,” he says.

Adjust plates to stalk size (if not automatically adjustable). “You want the gap between plates to be as tight as possible to avoid butt shelling. Check to see that all deck plates are set the same distance,” Bollig says.

Deck plates should be operating so they are positioned next to the stalk. “Set too wide, they will cause increased butt losses. Set too narrow, the plates will break off stalks feeding more MOG (material other than grain) into the combine slowing down threshing,” he says.

Check for plate wear, particularly at the lower end of the plates.


Rollers are the muscles of a head pulling plants at a furious pace. “If you have 35,000 plants per acre and you are harvesting 1,000 acres, you have 35 million plants going through those rollers. Stalks are tougher than in the past, which causes extra wear on the rollers,” he says. Rollers do wear, particularly at the bottom end of the component. “A worn roller will not pull the plant down at the right speed to properly strip off the head. It can also lead to more head plugging by breaking off stalks,” he says.

  1. AUGER

Little can go wrong with a head’s auger. Still, you need to inspect its flighting to see if it’s bent.


Often overlooked, the feederhouse has a huge impact on how the crop is presented to the thresher. “Check chain tension so that it is pushing ears gently up the feederhouse. Loosely operating chains can result in slugs of crop going into the combine,” he says.


A corn head, particularly one with chopping components, consumes a lot of power from the combine. “Inspect all drive components (particularly belts or gear drives) that transfer power wear,” he says.


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