Stair machines, also known as stair stringer machines, are used in the woodworking industry to produce staircases. These machines are specifically designed to cut the stringers, or the structural supports of the staircase, to precise dimensions and angles. They can be manual or automated, and can be equipped with various tools such as routers, saws, and drills to create different types of staircases. With a stair machine, woodworkers can produce high-quality, custom-made staircases efficiently and accurately.