Harvest is well underway, but there's still time to consider the benefit of periodically checking chaffers, sieves and other combine components to maintain accuracy.
Lack of attention to chaffer calibrations and misalignment of a door on the straw chopper led to severe damage to the chaffer’s lou
“Sometimes guys tinker with adjusting their concave or rotor speed from the cab and temporarily put a lot of broken cobs through the combine and over the chaffer,” says Kelly Kravig, marketing manager, Case IH. “Those broken cobs get jammed in the chaffer louvers. Then, when they need to close their chaffer, the cobs hold open some of the louvers even though the cab display shows a tighter setting.”
Attempting to force a chaffer to close when cobs are creating a jam can spring the adjusting mechanism and cause inaccurate numbers to display on the cab console. A chaffer with an actuating mechanism that has been tweaked could show 14 on the cab display but produce a dirty grain sample because it’s actually open to 20 in the machine.
In addition to calibrating a concave’s clearance sensor, make sure the concave is level with the rotor, says AGCO’s Caleb Schleder.
“If the threshing surfaces and the surface of the concave aren’t parallel it can decrease threshing efficiency,” he explains. “Even if you start the season with the concave level, all it takes is one big slug of crop to knock the concave out of alignment.”
A combine’s grain loss monitors also require recalibration before and during harvest.
“Grain loss monitors will accurately sense and report even small changes in grain loss from the rotor or chaffer if they’re calibrated for crop and conditions,” Kravig explains. “But they aren’t preset from the factory, and they won’t automatically recalibrate when crops or conditions change.”
Checking for grain loss behind a combine is the key to calibrating grain loss monitors.Dropping the chopper puts all the losses in one spot and really tells you what the combine is doing. Once you’re happy with what you see in the windrow, then you can recalibrate the grain loss monitor and accurately keep track of what the combine is doing from the cab.