A mill is a machine that utilizes a rotary device to cut wood. The term can also refer to a business that converts wood into usable lumber. The primary function of a mill is to saw timber into lumber or other wood materials that can be used for various purposes. Traditional mills were powered by water, while modern mills run on electricity and can be easily transported. Mills offer carpenters the ability to cut timber into manageable, usable pieces. They specialize in cutting lumber, molding, doors, pallets and other wood products. Mills also produce byproducts such as MDF, particleboard, and posts which can be fashioned into marketable materials. Some carpenters prefer to cut and mill their own timber, which provides them with more flexibility, while others rely on mills for consistency and convenience in meeting their lumber needs.