A thickness planer or planer machine is a tool that flattens and/or thins the long side of boards. If you need to obtain an even surface with no bumps, a shop planer should be your go-to. The process starts by placing the board in the power planer on one end; it passes through where it is pulled by the feeding roller, it is then cut to size with a trimming head. It then goes under blades for further trimming before being pulled out by another set of rollers creating a smooth even surface.