Single and double column planers are machines used to plane wood and other materials. Single column planers have only one table and one planing shaft. Double column planers have a table on each side of the planer shaft. Some of these machines also have a milling head, which allows the material to be milled in addition to being planed. Equipped with a milling head, these machines are also called combination machines. Single and double column planers can be used in a wide range of industries, such as woodworking, furniture making, joinery and window and door frame manufacturing. They are used to smooth the surfaces of workpieces and reduce their dimensions.