A planer/thicknesser, also known as a jointer/planer or combination machine, is a versatile woodworking tool used for surfacing and dimensioning rough lumber or boards. It combines the functions of both a planer and a thicknesser in a single machine, making it an efficient and space-saving solution for woodworking shops.

The planer function is used to flatten one face of a board, creating a smooth and even surface. The board is passed over rotating blades that remove material from the top surface until it becomes flat and level.

The thicknesser function is used to reduce the thickness of a board to the desired dimension. The board is fed through the machine between rollers and against a set of blades, which remove material from the bottom surface until the board reaches the desired thickness.

Some planer/thicknesser machines also come with additional features, such as a fence for edge jointing, allowing users to straighten and square the board's edges.

Planer/thicknesser machines are commonly used in woodworking shops for preparing rough lumber for various projects, such as furniture making and cabinetry. They help ensure uniform thickness and smooth surfaces, which are crucial for achieving precise and accurate woodworking results.