A standard laboratory-scale device used to apply shear to a grease. The grease worker consists of a metal cup of standard dimensions, a cover fitted with a handle, and a shaft attached to a metal plate drilled with 61 x ¼-inch holes. The cup is filled with grease, the cover is closed, and the plate is pushed through the grease sample. 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) and ISO 2137.