A folding machine (25) includes a first folding roll (90,95) with a series of the gripper assemblies (20) and a series of tucker assemblies (T) uniformly and alternately spaced to interact with a series of gripper and tucker assemblies of an adjacent second folding roll. The series of alternately spaced gripper (20) and tucker (T) assemblies interact to grip, carry, and release material in a manner so as to generate a folded stack of material, such as sheet material. Each of the gripper assemblies (20) generally includes a rotatable blade (116), a shaft (120) configured to rotate the blade, a spacer (135) disposed between the blade and the shaft, and a bolt (130) coupling the blade and the spacer to the shaft. A housing is configured with seals to retain lubricated bearings to provide rotation of the shaft of the gripper assembly and to prevent contamination of the bearings.