Gauge shoe
Steel runners are located under each disk. Right-hand and left-hand adjustable gauge shoes further protect the cutterbar.
The half-moon shaped disk protectors extend past the cutterbar module to protect the cutting disk.
The disk protectors are made of heat-treated boron steel, whose material characteristics are very similar to spring steel. Resistance to bending is nearly three times greater than molded ductile iron.
Knives rotate close to the disk protectors to give a good shearing action and help to keep the cutterbar clean.
Shearhub
Each cutting disk is attached to a driver (shearhub) on the splined pinion gear. The driver has part of its splines removed so it will shear if the cutting disk receives a severe impact.
The shear strength of the driver is designed to be just slightly less than that of the pinion gear.
Power to the disk is interrupted when the driver shears to protect the internal components of the cutterbar.
Damage is limited to exposed components and does not require disassembly of the cutting modules.
U-joint
Power is transmitted through a U-joint to the first cutting disk.
The U-joint attaches with four bolts to the driver on the first cutting disk. No special tools are required to remove the first cutting disk.
The torque for attaching bolts is the same as for attaching the disk to the driver (149.1 Nm [110 lb-ft] compared to the 339 Nm [250 lb-ft] required to attach the driver to the pinion gear).