Woodworking planes are tools, usually hand-held, used for smoothing and shaping wood by shaving very thin strips from a workpiece. Built in many sizes and configurations to accomplish different purposes, hand-held woodworking planes require a good amount of practice and experience to use proficiently. The advent of power woodworking planes has reduced the amount of time normally taken when planing wood, but many woodworkers prefer the hand tool for the amount of control they can exert over it, as well as for the quality of the finished work.
Although modern woodworking planes can seem quite complex in their construction, a serviceable plane consists basically of three elements: a sharp, sturdy blade, called an “iron,” a block of wood or metal to guide the iron across the surface to be planed, and something to secure the iron, often a small wedge. The block's bottom, called the “sole,” is perfectly flat and smooth, and has a slot, or “mortise,” cut into it to accommodate the iron, which is rarely wider than two inches (5.08 cm) and often narrower, and generally no longer than six inches (15.24 cm). The iron is inserted into the slot and the cutting edge extended just barely past the sole. Once the iron is placed perfectly to the woodworker's satisfaction, the wedge is tapped into place and work is commenced. These are the elements of woodworking planes found in the ruins of ancient Egypt and Pompeii, and they're the same elements of the planes many woodworking students are assigned to build for themselves in woodworking schools.
The iron is the only part of a woodworking plane that absolutely must be made of metal, and modern irons are made of steel. Modern planes are built of wood or of metal, and some are built of blocks of wood enclosed by metal bands. The many different types of woodworking planes are designed to perform many different tasks. Some planes, called block planes, are designed to be held and worked by a single hand, and are used for tasks like removing small amounts of stock, especially from the ends of boards. There's a wide variety of one-handed planes, some no larger than the woodworker's finger, built for specific fine tasks like cleaning out the inside edges of a mortise. Longer planes, generally six inches (15.24 cm) and longer, require two hands to control and operate properly. These planes have a knob toward the front for the woodworker's forward hand, and a handle near the rear for the other.
Planes with longer soles — from 14 inches (35.56 cm) and up — are called jack planes or smoothing planes. Because of their length, and the absolute flatness of their soles, they ride on the “high spots” of the workpiece. The blade, just barely extended beyond the sole, shaves off those high spots until the work surface is flat and smooth enough for final finishing and polishing.
One of the hardest parts of planing to master is avoiding a phenomenon called “tear-out,” which occurs when the plane is forced against the grain of the wood and small pieces are lifted by the iron and literally ripped out, leaving a jagged finish. This happens because the direction of woodgrain varies, so that even a single stroke of the plane along a workpiece could follow the grain in some areas, and go against it in others. Some ways to avoid tear-out are to make certain that the blade is as sharp as possible, and to reduce the iron's extension past the sole.
Most plane irons have either straight or slightly convex cutting edges, to facilitate removal of stock, smoothing and flattening. Some planes, though, are made to form molding, and the blades made for them form the shapes of common moldings, such as quarter-round, ogee and cavetto. Molding planes also look nothing at all like other woodworking planes; instead, they're either simple, flat blocks of wood with the molding profile at the end, or complicated-looking metal contraptions. In either case, they incorporate the same three elements of a traditional plane: a sharp blade in the shape of the molding to be formed, a device to hold the blade while it's cutting, and a way of securing the blade in the device.
An interesting variation on the use of woodworking planes exists in the Japanese woodworking tradition, which has evolved over the centuries independently of any western tradition. While the planes of both traditions are similar in design and function, the technique employed is different: in the Western tradition, the blade faces away from the woodworker and the cut is made when the plane is pushed away. Japanese woodworkers, however, draw the plane toward themselves, cutting on the pull.