There are many different kinds of woodworking machines. Most of them work on more or less the same principle: a spinning knife, blade or bit either removes wood from the surface of a piece of wood, or cuts through a piece of wood leaving two pieces. From these basic principles come tools as varied as jointers, planers, routers, shapers, table saws and band saws.
A jointer consists of a movable infeed table, a spinning head with knives in it and an outfeed table. The height of the infeed table determines how much wood will be removed from the bottom of a board when it is passed over the spinning knives onto the outfeed table. There are two main uses for a jointer: to flatten the bottom of a board so that it will pass accurately through a planer, and to straighten and flatten the edge of a board (in order to glue it to something) or in preparation for passing the board through a table saw.
Planers flatten the tops of boards and dimension boards to specific thicknesses. Planers can be used on rough lumber or on panels that have been glued up from narrow boards. Planers range from small, portable models, with a capacity of 10 or 12 inches, to massive, 3-phase industrial monsters that can plane boards and panels 36 inches wide.
Shapers work on the same principle as jointers and planers but are designed to cut profiles and shapes into wood rather than to flatten it. A shaper has a head that spins on a vertical shaft that has one of many differently shaped cutters affixed to it. Shapers are used for making crown moldings, baseboards, millwork and accents for furniture.
Table saws are the basic and most frequently used tool in a wood shop. The basic elements of a table saw are a flat table, an arbor holding a motor (with adjustable height and angle) that sits inside the body of the saw, the blade attached to the arbor and the fence on top that is used to stabilize wood as it is pushed through the blade. The two most common functions of a table saw are ripping, in which a board is cut along the grain by being run through the blade with one side against the fence, and crosscutting, in which a board is cut across the grain by being pushed through the blade with a T-square or a crosscut sled, both of which fit into grooves in the saw table’s top for stability.