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June 13, 2022

How Does a Combine Harvester Work?

Few pieces of machinery provide the versatility and power of a combine harvester, making it no wonder that it’s become a staple of modern agriculture. But you might experience some sticker shock when browsing brand-new machines. Luckily, you can find thousands of high-quality used combines for sale at

In this blog, we’re climbing down from the cab for a brief discussion of this impressive and exceptionally-useful piece of equipment. Once you understand the fundamentals, you can be an informed shopper, and find the right piece of equipment, at the right price—whatever your specific needs may be.

What Is a Combine Harvester Used For?

A combine harvester is an essential piece of equipment for a wide variety of farmers as well as large-scale agricultural operations. So, “What is a combine harvester and how does it work?” Let’s dig in.

First things first: Why is it called a combine harvester? Simple: a combine harvester is a piece of equipment that combines different harvesting processes—reaping, threshing, and winnowing. While there are a few different types of combine harvester, they’re all more than capable of performing these functions:

  • Reaping: Cutting grain crops for harvest.
  • Threshing: Loosening of the edible grain from husks and straw.
  • Winnowing: Separating edible grain from discardable chaff.

If you’re wondering whether you need a combine harvester for these functions, you technically don’t. The amount of manpower required to match the performance of even an entry-level combine harvester, however, is gigantic. Modern combines can cut a 40-foot wide swath of grain in a single pass…can you?

What Is the Working Principle of Combine Harvester?

Next, we’ll introduce you to the basics of how to operate a combine harvester, which should further illustrate the sheer power of the machinery—as well as the time and energy savings (vs. manual harvesting methods). In many ways, you could argue that the step by step procedure in using a harvester has more in common with driving a big rig than it does with manual farming and harvesting methods. 
Here are the basics an operator needs to know:

  • Get to know your machinery. While it may not be an exciting read, the machinery’s owner’s manual is a great place to start. Even if you’re experienced and already know the basics, there’s always more to learn. Plus, combine harvesters are not identical to each other, so focus on getting to know your specific equipment. If you’re buying used equipment, you may or may not receive a user’s manual. You can usually find manuals online in that case, by searching the web for the specific make/model; you might also be able to find it via the manufacturer’s website.
  • Make sure everything’s in working order. When you learned to drive a car, you were likely taught to check your vehicle before each time you drive (to ensure that brake lights are working, etc.)—this is the same idea. Here, though, it’s arguably more important, since a combine harvester can cost as much as half a million dollars.
  • Start it up! Hey, now we’re getting somewhere! Most of the time, a combine harvester’s startup procedure is simple: pump the fuel pedal, then turn on the ignition.
  • Make adjustments in preparation for the task at hand. Depending on a number of factors—whether the weather is wet or dry, for example—you’ll want to adjust the combine harvester’s header position. This is typically a matter of raising or lowering the header.
  • Operate the combine harvester. Finally…it’s time to farm! This is where you’ll operate the specific controls needed for effective reaping, threshing, and winnowing. Since the mechanism that actually detaches the usable grain from the unwanted plant material (husks, etc.) needs to be running at high speed before the crop is drawn into the machine, begin by pushing forward the thresher control. Then, move the header lever forward. 
  • Make sure you know how to brake. Whenever you go to press the drive lever forward, be sure to release the brake first. Operating in the correct gear (for the crop being harvested, as well as the weather and crop conditions) will prolong the life of the brakes.
  • Shut it down. To shut down the machine, apply the brake and make sure the controls are left in neutral. Here, you’ll reverse the basic order of operations in the “operate the combine harvester” step above, dealing with the header lever first, followed by the thresher control

What Can Go Wrong with a Combine Harvester?

While in-depth knowledge of how, exactly, your farming equipment works isn’t a requirement for its purchase and use, the more you understand about the most important parts of a combine harvester and their functions, the better-positioned you’ll be to zero in on the right repairs. 

This informative piece from Successful Farming magazine outlines 9 things that cause a combine to break down, providing an excellent starting point for understanding how a combine harvester should function so you can better-identify when it’s not functioning properly.

We’ll spare you the exhaustive list of what all could go wrong, and instead point you to a few resources that can help you understand what exactly is going on with your harvester—and how to repair it. Whether you’re experiencing issues with feeding, threshing, separating, or cleaning functions, this website provides suggestions to troubleshoot and diagnose what might be going wrong. You can also search online for combine harvester operator training, which may be offered in your area or in a virtual setting.

Are Used Combines Reliable?

For many farmers, the price tag on a brand new combine harvester can be a bit of a shock, leading them to explore the secondary market. With so much at stake, though, can you count on a used combine harvester to get the job done? With the help of Machinery Pete, the answer is a resounding YES. 

We have thousands of used combine harvesters for sale, making us the fastest growing marketplace for buyers and sellers of used farm equipment. We make it easy to be an informed and empowered shopper, offering full-color photos, in-depth lists of features and specifications, and one-click communication with sellers, as well as financing options and Extended Service Plans. You can also view price histories, compare similar machines, and more. We’re your one-stop-shop for high-quality, new-to-you farm equipment. Start browsing now, or reach out with any questions you have.