A device designed to apply shear to a grease. The full-scale grease worker consists of a metal cup of standard dimensions, and a cover fitted with a handle and shaft attached to a metal plate drilled with 61.x ¼-inch holes. The plate is designed to be pushed through the grease sample to be worked. The device can be manually or mechanically driven. For ½-scale and ¼-scale penetrations, the equipment is progressively smaller. The equipment details can be found in ASTM D217 (full-scale) and ASTM D1403 (small-scale).