As a concave begins to wear, the edges become dull and rounded, reducing the friction on your crop as it is threshed. With the loss in friction the crop slides by and the heads simply are not held in place long enough to allow for proper threshing.
A loss in the threshing performance of the concave results in white caps which leads to more material being returned and an increase in grain loss over the shoe or rotor.
To reduce the white caps that have been caused by the worn concave, many operators increase the speed of the cylinder or rotor. This may help reduce white caps but it will also increase kernel damage and do very little to reduce the loss over the shoe in the form of unthreshed heads.
Increasing rotor or cylinder speed is a poor solution to the real problem of a worn concave.
Combines are just too expensive and harvesting season too important to take your concave for granted.
Every year, long before you go to the field, the concave should be removed and the entire threshing area carefully inspected. You have to take the concave out to inspect it properly. You know that all parts do wear and will have to be replaced at some point in time. It is just a lot easier to do it at your leisure rather than the middle of the harvesting season.
If the concave is bent and twisted or the edges are rounded off, it is time to either replace it or have it rebuilt by a reputable concave rebuilding firm. Unlike rub bars most concaves are not hardened or chromed and as a result they don’t last as long as rub bars.
All concaves should be inspected once a year and they will probably require some serious attention after 400 hours if you pick up a swath or 600 – 700 hours if you straight cut. Because rotary combines are capable of processing more bushels per hour they do wear faster and should be inspected more often.
HARVEST Concaves are manufactured with more bar over the wires to give you a longer lasting concave. With more bar over the wires your HARVEST Concave can usually be re-bored once. After the edges become rounded you don’t have to buy a new concave. By re-boring you get new concave performance for a fraction of the replacement cost.
HARVEST Concaves have square edges which retard the crop to allow for the proper threshing and separation of all your different crops.
By adding or removing the Filler Plates on HARVEST Concaves for conventional combines or the Cover Plates for concaves on rotary combines you can easily fine tune the concave to achieve the proper balance between threshing and separating to keep returns at acceptable levels and maximize the performance of your combine.
With a more aggressive concave the cylinder or rotor speed can be lowered to reduce kernel damage. The improved threshing and separating ability of HARVEST Concaves increases your combines’ capacity, thereby lowering your operating costs.