The planer, also known as a thickness planer, is a woodworking machine used for creating a perfectly flat surface (a plane) on a piece of wood. To use the planer, it is turned on and a relatively flat wooden workpiece is passed through the machine. This will yield a perfectly flat plane at the specified depth of cut, which is especially good after you've joined multiple pieces of wood. The thickness planer can also be used to incrementally decrease the thickness of a board with relatively high precision, such as for fitting a joint. When using the planer, no more than 1/8-inch (0.125") should be taken off in each pass. Make sure that clothing, fingers, and everything else is kept clear of the planer, as it can be pulled into the machine. Use hearing protection (this is the loudest machine in the shop) and use a vacuum adapter or chip bag on the outlet of the planer, since sawdust from the planer can spray up to 10 feet.