Combine Concaves

combine harvester with concaves

You would think that buying any type of concave for your combine would help you in threshing or filtering any type of crop you have on your farm (corn, soybean, wheat, canola, etc), but it is much more elaborate than that. In this article we will explain what concaves are, and all the different types there are for all of the crops that we have in Canada and the United States.

What are Combine Concaves?

Combine concaves are essential parts of combine harvesters and the quality of your crops will depend crucially on the type of concave you are going to use.

Combine concaves perform two of the three main purposes of the machine. One is that they separate the grain and the small straws and two is that together with the threshing cylinder (called Rotor) they thresh the crops.

In other words, combine concaves are the most important parts for harvesting purposes, since they dictate the efficiency, speed, and quality to your harvest grain treatment.

At Thunderstruck Ag, we deal Copperhead Concaves. They are designed to get the job done faster, safer and more efficient and they do it better than the competition in any crop.

Crops are made up of 3 parts, the grain, the chaff and the stalk; as only the grain is needed, the chaff and the stalk must be removed., This is what the process of crop harvesting is for, to only leave the grain and separate it from the chaff and the stalk. This is achieved through threshing and separation.

With the help of combine concaves the processes of threshing and separating can be done easily and efficiently. Combine concaves work together with the rotor to automatically thresh and separate the crops. At the end of these processes, the grain is ready for storage.

combine concaves

Types of Combine Concaves

Farmers and manufacturers have developed concaves through years of testing and they have based their production and types of combine concaves in two concepts: Clearance and Design.


Clearance means the distance between the rotor and the concave. This setup is significant in the threshing process, and it can be modified to best fit the crop type that is being harvested. It also controls the grain flow, so the clearance setup must be very accurate to not have a lot of grains unseparated (that is not threshed properly), or to not have grain damaged because the clearance was too tight.


Combine concaves have bar and/or wire designs. This characteristic is also a very important aspect when choosing a concave. Each design handles a different crop type and the shape of the bars and wires will determine which one will be the best for the type of crop you have. You can find the following types:

Small-Wire Concaves

These are usually recommended for wheat, barley, and other cereal crops. They give maximum grain quality and productivity when harvesting small grains.

Large-Wire Concaves

Large-wire concaves are used for corn and small-grain combines. They are used for rice, sorghum, soybeans, and corn. They have a very good threshing performance in rice soybean harvest.

Round-Bar Concaves

They are highly recommended for corn and soybeans. They give high grain quality and productivity when harvesting corn or soybeans.

Cover Plates of Combine Concaves

There are some farmers who install cover plates to increase threshing productivity. The cover plates are set to circle the concave, making sure the grains spend more time in the clearance.

At Thunderstruck Ag, we have John Deere and Case IH Concave Cover Plates.  They have an adaptable segment that slides partially open or can be fully closed in order to control the amount of flow of material out of the concave.

Choosing the Right Combine Concaves

Understanding your field and the crop types you have on your farm, will ensure you have the ideal concave setup for your combine harvester and that you can turn out greater efficiencies in your harvest. Knowing how to perform the two out of three harvesting functions we mentioned (threshing and winnowing) in an optimal way and tuning the clearance and selecting the most accurate combine concave design will help you get more productivity out of your harvest.

Thunderstruck™Ag Equipment distributes quality Ag equipment (especially The Copperhead Concaves. These concaves are designed as an all crop concave and feature a filler plate design like others on the market) designed by farmers for farmers, we provide plant, storage and harvest solutions throughout Canada and the United States. View our complete line of innovative ag products and more clicking here.