The goal of using a jointer plane (jointer for short) is to create boards with greater width by joining them together. In order to do that, the jointer creates flat edges on each board, where the flattened edges are later assembled together to produce the wider board.
Jointer planes are used globally for woodworking. The scope of these hand plane instruments' operation is cross functional over many applications (wherever a flattened surface is needed over the length of a wooden board). The produced boards are later assembled together via the flattened surfaces to create more width on assembled boards.
The table top assembly consists of a pair of solid wood or metal tables that form the work surface of the jointer. The tables are fixed together in parallel. The end of the table where the work is placed is called the in-feed. The other end of the table is termed the out-feed. Along the side of the table is a shield or guide fence. Opposite the shield/ guide is a circular machine saw. A wheel knob is turned to secure the shield/ guide along the length of the work surface. The machine saw is either belt driven from an assembly line or run by its own electric powered motor. Supporting the top assembly is a metal frame supported on two wood boards. The metal frame is bolted into the wood boards. The motor or belt assembly is fixed near the jointer (often on the ground level).
A wood board is laid on the workspace, and carefully fed through the in-feed to the circular machine saw. The blade of the saw cuts through the board as the board is pushed over the workspace. The saw rotates against the wood (spinning toward the in-feed and away from the out-feed of the workspace). The in-feed side of the workspace is lowered (the amount depending on the desired depth of the cut) by turning a knob on the side of the jointer. This action sets the board lower than the out-feed. The width of the cut is adjusted from as low as 4 inches to as high as 16 inches.
A wood board is picked up by the operator and held face toward the shield/ guard. The edge of the wood rests on the in-feed side of the workspace. The operator moves the board across the circular machine saw blades (two or more blades per saw head). The board is passed through the saw until it reaches the out-feed side of the workspace. A complete pass through the circular machine saw will produce a flattened edge along the length of the board. However, to make the face of the board flat, the operator removes the shield/ guard from the table top assembly portion of the jointer unit. The operator passes the board through the circular machine saw with the board positioned to flatten the board's face.