Abstract: A document shredder comprises a pair of cutter assemblies, each having a shaft on which there are cutter disks with interspersed spacers. The disks overlap to form a nip. On the one shaft, additionally, there are rings mounted in the spacers, and that permits the shaft to be axially compressed tighter than the shaft without rings. This provides for relative flexibility and axial movement between the shafts such that foreign objects can more easily be removed. A 20 inch cutter assembly driven by a single phase motor through a planetary gear system is provided.