A graphite pencil is a steel-cased pencil with a flat top. It was invented by Henry Gomberg, an American engineer who discovered graphite in 1786 and developed a variety of pencils over the next few decades. Today, a graphite pencil has an intrinsic strength of about 3,300 psi, compared to the tensile strength of about 10,000 psi. A sharpened graphite pencil can achieve about 3,600 psi, which is strong enough to slice steel. Graphite pencils that are too sharp may harm the pencil during sharpening.
Graphite is a very rare element that has little value in modern construction. When it becomes available as a new element, some countries use graphite metal in new construction.
To use graphite in a pencil, the metal must be shaped to produce the desired curvature, or “shape,” of the pencil. This may seem complex, but in fact this is a very simple process using a special manufacturing process. First, a large piece of graphite is cut into a rectangular shape. Next, a set of small holes is drilled in the center. These holes are filled with a mixture of graphite and a solvent. As the hole expands, the liquid flow expands, creating a sheet of graphite, which eventually forms the shape of the pencil. The material that is produced in this process is actually called “graphite metal.” In these pencils, there is no sharp point, since it should be impossible to achieve this with a sharpened pencil.
When the graphite is shaped, it must be heated, and this requires a flame or similar device to produce heat. This may appear very strange to you, but graphite works with heat and can be made to do just that. In fact, graphite is so heat sensitive that it can be created in certain thermally unstable conditions using chemicals. A thermoplastic like graphite has the right properties to produce heat in a pencil, as well as providing an incredibly resilient finish, and therefore a strong quality. Using graphite in a pencil involves using very small amounts of the material that is produced, which does require some skill! The graphite in a graphite pencil can be broken down, cleaned, refilled, and re-used with little or no loss in hardness or even appearance.
A few common pencils may be made using graphite pencils. The most common of these are the “lead-lined” ball pens, pencils with steel nibs and tips