Wiley mill

A Wiley Mill, Model 1

A Wiley Mill is a laboratory-scale machine for grinding materials to a powder and belongs to the family of cutting mills. The term "Wiley" refers to a specific group of grinding mills manufactured by Thomas Scientific and is their registered trademark. These mills prepare materials for analysis with minimal moisture loss. Well-dried samples are preferred. In the grinding mill, the material is loaded cut into crude pieces or lumps and loaded into a hopper. From the hopper, the material drops by gravity into the path of a set of revolving hard tool steel blades driven by an electric motor. The revolving knives work against stationary knives and the resulting powder is forced through a steel screen. The powdered material then drops into a waiting collection vessel underneath.

The Wiley mill is commonly used in agriculture and soil science laboratories. The Wiley mill was originally designed for grinding fertilizer materials, animal hair, hoofs etc. The hard, tool steel cutting edges on the knives allow milling of a wide range of materials, including plastics.