How Does A Combine Harvester Work?


A combine harvester is a tractor-like machine that combines different parts of a wheat harvesting process. It has a header, which cuts the grain off at ground level and drops it into a strainer. The strainer separates the wheat from chaff, straw, and rocks. Then the grain is blown into storage bins for transport to market. In this article, you will find everything you wanted to know about how a combine harvester work.

How Does A Combine Harvester Work?

Combine harvesters combine the functions of a tractor, threshing machine, reaper, and winnowing machine in one machine. They harvest crops such as wheat, barley, oats, and rye.

Combine harvesters work by cutting the plants close to the ground with rotating reapers or chainsaws. The cut stalks of grain are then blown into a large hopper at the rear of the machine with disks that hold back larger dirt clods or stones from entering with them. Then these cut stalks tumble inside an auger which feeds them onto moving conveyor belts that carry them through four stages: cleaning, separation from the chaff, separation from stones, and finally, threshing (breaking). 

Finally, it is spread out through another system of rotating fans which blow away any remaining material like dust or light chaff, so only pure grain remains on top. At the same time, heavier dirt falls below this layer – allowing you to collect just high-quality kernels after each stage completes its cycle before starting again!

Combine Header

The combine header is the part of the combine harvester that cuts and threshes your crop. It consists of a series of parallel knives, with the cutting edge facing downwards.

The combine header is mounted on top of a frame known as the combine header frame or knife bar. The frame has slots where individual knives can be inserted or removed.

This part also includes a pin to secure the entire structure together, allowing you to attach it to your harvester and remove it when not in use.

Strand Feederhouse

The strand feederhouse is the part of the combine harvester that collects and feeds the crop into the combine header. The conveyor moves material from the ground to the combine header.

Variable Stream Rotor

The rotor comprises a series of discs, typically made of metal or plastic that are spaced to allow the grain to pass through them but not the straw. As each disc rotates in one direction at an increasing speed, it also turns in its opposite direction at a slower pace. This causes both sets of gaps between discs (and hence spaces between individual grains) to increase. At the same time, they pass each other until they are so wide that only air can enter them and not any more grain.

The discs have ridges around their perimeter which help them grip onto the wheat stalks during harvesting and prevent them from being swept away by centrifugal force as they spin.

Threshing & Separation

The combine harvester separates grain from the chaff, straw, and other materials through threshing. A rotating drum achieves the separation with a series of fluted rollers. The rollers are set at different angles, which causes the grain to fall through them. At the same time, the unwanted debris stays on top of the drum until it is removed manually or automatically.

Tailings Return

The tailings return, or conveyor belt, can be set to different speeds and heights.

The speed of the combine harvester is usually set at 2 meters per second (4.4 miles per hour). This allows for easy harvesting of crops such as wheat and barley.

When setting up your harvest, consider that certain crops may need higher speeds to prevent them from being blown away by the wind or caught on other obstacles during a stormy day.

You will also want to ensure your tailings return is set at a height that matches the crop you are harvesting. Otherwise, it will overlap with your combine harvester’s grain tank when they meet up with each other during operation.

It is worth mentioning that the traditional (axial) harvesters do not have such versatility of operating speed as the hybrid ones (such as these Massey Ferguson combine harvesters).

Grain Tank

The grain tank is where the harvested crop is stored. The grain tank is located in the cab of the combine and is made of metal. It stores harvested grain until it is removed from the combine.

Grain Auger

The grain auger, a rotating cylinder that conveys the grain, is a combined harvester’s primary transport mechanism.

You can adjust the auger speed by varying its hydraulic motor’s speed.

A high-speed setting will help you to pick up more cuttings and deposit them in your trailer. In contrast, a lower one will help you avoid damaging crops on or below your field.

Rear Discharge

There are three main ways in which combines discharge the grain:

Side discharge 

This is where the grain is discharged from the combine through a chute on either side of it. The discharging mechanism for this type of machine can be powered by hydraulics, meaning you may have to pump up your combine before using it.

Rear discharge

In this case, all your harvested crops will leave via an auger at the rear of your machine. This type of system requires no extra work as there’s no need for you to pump anything up!

Semi-propelled / self-propelled combines 

This is another method by which combines discharge their crop into storage bins or onto trucks or trailers behind them.


A combine harvester is a mechanical device used to harvest crops. It combines a tractor with a harvesting head, which is attached to the machine’s front end and consists of three main components: cutting unit, threshing section, and grain tank.