These harvesters include a pivoting “ball joint” connection at the rear of the conveyor, which allows the cutting head to rise and fall with undulations in the direction of motion of the harvester. A “track rod” connects the cutting head or conveyor to the tractor with pivoting ball joints and holds the cutting head parallel to the direction of motion. These pivot joints also allow the conveyor and cutting head frame to rock from side to side to follow undulations perpendicular to the direction of motion of the harvester. The axis about which the conveyor and cutter assembly rotates is defined by the location of the centres of the rear pivot point and the track rod connection to the cutting head or conveyor. Since this axis is not horizontal, the cutting knives turn away from being exactly perpendicular to the direction of travel when the head pivots, resulting in damage to the edges of the sod strip.