How Pencils are made?
Pencil is a writing instrument that has a solid core made of clay and graphite, and wooden casing. We started using pencils when a vast deposit of graphite
was found in England in 16th century. Graphite got its name from Greek word "graphein" which means "to write". At first, graphite was used cut in blocks
and coated in sheep’s leather. Pencils were still made of graphite but were encased in wood which made them easier to use because graphite would not break.
In time, due to various circumstances, pure graphite was harder to obtain and a substitute had to be invented. Solution came in mixture of powdered
graphite and clay which is still used today. This method allowed manufacturing of pencils that had different hardness and different shades of black. Next
step was a method of mass producing of pencils which brought its price down and allowed more people to come in possession of one. Eraser was added to the
end of the pencil in 19th century and made it more practical. Although we have other tools for writing we still use pencils today, war writing and for
drawing. Pencils evolved into mechanical pencils, colored pencils, grease pencils, those used by carpenters and other.
First step in making a pencil is mixing of graphite powder with clay. The more graphite mixture has, the pencil will be softer and mark that it leaves on
the surface like paper will be darker. Then a mixture is formed in long string-like forms and that can be done in two ways. First one is extrusion where
mixture is forced through a hole of a precise diameter to make a string of a predetermined length and then baked to become hard and brittle. Second method
uses a machine called a “billet press”. Mixture is poured into a mold that is plugged from the above a metal piston ascends from the bellow and presses the
mixture until we get a hard, solid cylinder called a "billet." Cylinder also goes through an extrusion machine and a hole that makes it a desired diameter.
Wood casing is usually made of cedar wood and it starts as narrow strips called "slats" which are already dried, stained, and waxed, to prevent warping.
They are planed to give them a flat surface. They are passed through a cutter head which makes parallel semicircular grooves into them. These grooves are
as deep as half of diameter of a graphite core and are placed on one side of the slat. Half of these slats are covered in glue on the side where they have
grooves and earlier prepared graphite strings are placed in their grooves. Other half of slats are left without glue and turned around by a machine so
their grooves are bellow. They are placed over slats with glue and graphite. Each of these “sandwiches” is placed in a vise where it stays until glue
dries. After drying, ends of slats are cut to remove excess glue.
Pencils are then shape. Each sandwich goes through a machine that has two sets of cutters, one above and one below the sandwich. Each cutter cuts between
graphite sticks a channel in triangular shape, shaping individual pencils that are hexagonal in the end. This shape prevents them from rolling from the
desk when used. Pencils are then smoothed by sanders, painted and left to dry. This is repeated as many times as needed. When the final layer of color is
done and dried, pencil is varnished. Excess varnish is removed by a machine which all so cuts pencils to the same size. Last step is attaching of a metal
ring called “ferule” which hold the eraser and a logo of company is pressed.