Pencil is the most widely used writing and drawing instrument in the world. People use pencils to write words, numbers, music, and poetry, and to draw pictures, plans, maps, and diagrams. There are pencils that write underwater, and pencils used by physicians to mark their patients’ skin before surgery. Astronauts have also taken pencils into space because the writing ability of pencils is unaffected by gravity, pressure, or conditions in the atmosphere. More than 10 billion pencils are produced annually throughout the world. The United States manufactures almost 2 billion pencils yearly—more than any other country.
Pencils consist of a writing core made mostly of graphite set within a case of wood, metal, or plastic. There are three main types of pencils: (1) cased pencils, (2) colored pencils, and (3) mechanical pencils.
Cased pencils,
in most instances, consist of a wood case and a black writing core. The core is composed of graphite and fine clay, sometimes combined with other chemicals. When graphite was first used in pencils, people mistakenly thought it contained lead. The graphite mixture is still called lead and the pencils, which contain no lead, are often called lead pencils.
Graphite for pencils is formed into spaghettilike strings, cut to precise measurements, and dried in ovens. Manufacturers vary the proportions of graphite and clay in the mixture to produce pencils with harder and softer writing cores. The Number 2 pencil is the standard and most common pencil used today. Pencils with numbers less than 2 have softer leads and contain less clay and more graphite. Soft pencils make a dark, heavy line. Harder pencils make a finer, lighter line.
Most cased pencils are made from incense-cedar. This wood sharpens easily and smoothly and does not warp or lose its shape. Cedar logs that are used to make pencils are sawed into narrow strips called slats. The slats are about 71/4 inches (18.4 centimeters) long, 1/4 inch (6.4 millimeters) thick, and 23/4 inches (7 centimeters) wide. They are stained, waxed, and dried before shipment to the pencil factory. At the factory, parallel grooves are cut into one side of the slats and half of the slats are then coated with a fine layer of glue. Next the graphite is laid in the grooves of the glued slats, and pencil “sandwiches” are made. Pencil sandwiches are produced by pressing the empty slats onto the slats that already have graphite inserted in them. The sandwiches then go into a shaper, which forms the slats into individual hexagonal (six-sided) or round pencils. Most pencils are made into a hexagonal shape. The flat sides of such pencils prevent the pencils from rolling off surfaces.
After the individual pencils have been cut, they are painted. Yellow is the color most often used for pencils. Erasers are then attached to the pencils. Each eraser is surrounded by a round, metal case called a ferrule, which is held in place either by glue or by small metal prongs. Most ferrules are made of aluminum or steel.
Colored pencils
are made in more than 70 colors. They are produced in much the same way as black-writing pencils, but their cores contain such coloring materials as dyes and pigments instead of graphite.
Mechanical pencils
have a metal or plastic case. They use leads similar to those used in cased pencils. Mechanical pencils require no sharpening. The lead is forced out of the pointed end by twisting the cap, or by some other mechanical method. The lead rests inside a spiral (round coil) within the case and is held in place by a rod that has a stud (piece of metal) fastened to it. When the cap is twisted, the rod and stud move downward in the spiral, forcing the lead toward the point.
History.
The earliest pencils date back to the ancient Greeks and Romans, who used flat cakes of lead to mark faint black lines on papyrus (an early form of paper) to guide writers. In the Middle Ages, people used thin rods of lead or silver for drawing. The marking ability of graphite was discovered in the 1500’s, and the first modern pencil—that is, a pencil consisting of a wood case glued around a stick of graphite—was made in the late 1700’s.
In 1795, Nicholas Jacques Conte, a French chemist, developed a pencil of powdered graphite and clay. His mixture proved to be as smooth and hard as pure graphite. Conte also discovered that a harder or softer writing core could be produced by varying the proportions of clay and graphite.
In the mid-1800’s, William Monroe, a Massachusetts cabinetmaker, invented a machine that cut and grooved wood slats precisely enough to make pencils. About the same time, the American inventor Joseph Dixon developed a machine that smoothed the surfaces of the pencils after the slats were cut apart. In 1861, the first pencil factory in the United States was built in New York City by Eberhard Faber, an American manufacturer. The Eagle Pencil Company patented the first mechanical pencil in 1879.
