The rotary cutterbar is designed and built by John Deere. Large oval disks with free-swinging knives are used to cut the crop.
All cutting disks are the same and are computer-designed for improved wear and cutting performance.
Cutting disks are made of high-strength, austempered steel to ensure the steel is thoroughly and evenly tempered for good wear characteristics.
The disks rotate to give a knife-tip speed of 307 km/h (191 mph) for clean cutting.
The knives are free-swinging to reduce damage if a solid object is struck, and they are reversible to double the useful life.
The knives are removed at the front of the cutterbar for convenience.
Made of austempered, heat-treated, ductile steel for excellent wear characteristics, wear caps are installed on each end of the cutting disks (except on the end disks where crop accelerators are used) to increase the wear life of the cutting disks and knife-bolt nuts.
Wear caps are open on the end to prevent debris from packing in close to the nut, making hardware and knives easier to change.