Abstract: Devices and processes are disclosed for controlling and measuring precisely the many variables associated with fiber wear and transfer among materials. Specifically, one embodiment of the invention involves a slide and track arrangement for translating rotary motion of a crank shaft into reciprocal or, if desired, orbital motion of a second pad holding a sample or abrasive material against a first pad holding a sample material. The translation apparatus is such that even when orbital motion is selected, a constant angular relationship between the pattern of the materials held on the first pad and second pad is maintained.