What is a Pencil?
A pencil is an instrument, containing graphite, that is used for writing and drawing. The most common type of pencil consists of a thin cylinder of graphite and clay contained in a sheath of wood. Another kind of pencil is the mechanical pencil, which dispenses inserts of graphite, called leads.
In the manufacture of pencils the wood sheath and the graphite compound are made separately and then joined together. The graphite is ground into a very fine powder and is then blended with clay to form a soft mixture. The mixture is forced through dies that shape it into stringy leads of various sizes. After these leads are tempered by baking in kilns at a temperature of 1950° F., they are dipped into wax to give them smoothness for writing.
The hardness of a lead is determined by the proportions of clay and graphite in the lead compound. The more graphite that is used, the blacker and softer the lead. Other elements, such as tallow and wax, may also be added to leads. Colored pencils have leads that are made by mixing coloring materials with clay, chalk, or wax. They contain no graphite and are not baked. Cedar is the wood most commonly used for making pencil sheaths.
History of the Pencil
The manufacture of wooden pencils began in Nurnberg, Bavaria, in 1662.
Working independently, between 1790 and 1795 Nicolas Jacques Conte, a French scientist and mechanical genius, and Josef Hardtmuth, of Vienna, Austria, evolved a method of refining graphite by grinding and mixing it with clay. Their method is still employed in making graphite sufficiently smooth for use in pencils.
The first pencils made in the United States were manufactured by William Monroe, a cabinetmaker of Concord, Mass., in 1812, when the war with England cut off imports from abroad. Since then the United States has grown to be the world's leading pencil manufacturer and user, some 15 factories making a total of 10,000,000 straight grain and is soft enough to be sharpened without splintering. This present-day substitute, despite its name, is not as aromatic as red cedar, and manufacturers have attempted without success to heighten the cedar aroma. They continue to dye the wood to give it the color of old-fashioned pencils.
There are 125 different steps in the production of the modern pencil. First clay and graphite are ground together and mixed with water, the amount of clay governing the hardness of the lead. There are usually 17 degrees of texture— from 6B, the softest, to 9H, the hardest, with two intermediate gradations, HB and F, which are about midway on the scale. Some United States makers number their business pencils instead of designating the hardness in letters, a No. 2 being the equivalent of an HB, a No. 2V3 gross in 1959 of a world total of 25,000,000 gross. Germany ranked second, Japan third, and Russia fourth. Almost every country makes pencils, some only a few gross per year. Materials come from all over the world: the best clay from Bavaria; graphite from Ceylon, Madagascar, and Mexico; flints for grinding the mixture from Denmark, Belgium, and France; wood now from California, but earlier from Florida, Tennessee, and other states in the southern United States; pumice for erasers from Burma and Italy; rubber from Malaya and Sumatra; wax from Brazil, Czechoslovakia, and Japan; gum from Iran and Iraq; metals from Bolivia, Chile, China, Cuba, Great Britain, India, Indonesia, and South Africa; and color pigments from Switzerland and West Germany. Red cedar, growing in the southern United States, was long the best wood for encasing pencils. When the forests were depleted, pencil makers bought up log cabins and fence posts to obtain the material, and when there were no more of these to be had they turned to incense cedar growing in the high Sierra Nevada Mountains in California. Like red cedar, this wood also has a of an F, and a No. 3 of an H.
Mixed clay and graphite of the proportion required are kneaded into a doughy substance, placed in cylinders having a small hole in one end, and extruded through the hole by pressure. The string is clipped into seven-inch lengths, dried and kiln-fired, and then impregnated with a smooth, waxy mixture. Meanwhile, grooved slats, the thickness of half a pencil, the width of four to seven, and a little longer than a finished pencil, are prepared and coated with glue. Leads are placed in the grooves, covered with a second slat, and dried under hydraulic pressure. The resulting blocks are then passed through a machine that divides and shapes the pencils. The individual pencils are next sanded, lacquered, polished, stamped, and, if they are to have erasers, tipped with brass ferrules and pumice-and-rubber inserts. These steps, once done by hand, are now accomplished by automatic machines.