HISTORY:
The first attempt to manufacture graphite sticks from powdered graphite was in Nuremberg, Germany, in 1662. It used a mixture of graphite, sulphur, and antimony.Residual graphite from a pencil stick is not poisonous, and graphite is harmless if consumed.
Writing cores - made from a mixture of graphite and clay - are placed into the grooves. Coloring pencils may use wax-based cores while many other formulations are used in cosmetic pencils. A second grooved slat is glued onto the first - making a "sandwich" - by a machine called a "lead layer". The sandwiches are then"clamped" and held together tightly while the glue dries.
Writing cores - made from a mixture of graphite and clay - are placed into the grooves. Coloring pencils may use wax-based cores while many other formulations are used in cosmetic pencils. A second grooved slat is glued onto the first - making a "sandwich" - by a machine called a "lead layer". The sandwiches are then "clamped" and held together tightly while the glue dries. Individual pencils cut from the sandwich are ready for further processing. Any pencils with defects, such as uncentered leads or chipped wood, are discarded at this point.
Next, each pencil is painted in a machine receiving from 4-10 coats of lacquer, depending on the desired quality of the finish and the color depth. A recess is cut to accept the ferrule.After painting, some pencils are wrapped in decorative film or foils with fancy designs; although, most pencils are imprinted with the brand name by stamping the foil into the surface of the pencil. On a "tipping" machine, an eraser and a ferrule (the metal ring that holds the eraser to the pencil) are crimped into place on each pencil.
Some time before 1565 (some sources say as early as 1500), an enormous deposit of graphite was discovered on the approach to Grey Knottsfrom the hamlet of Seathwaite in Borrowdale parish, Cumbria, England The locals found that it was very useful for marking sheep. This particular deposit of graphite was extremely pure and solid, and it could easily be sawn into sticks. This remains the only large scale deposit of graphite ever found in this solid form.Chemistry was in its infancy and the substance was thought to be a form of lead. Consequently, it was called plumbago (Latin for "lead ore").The black core of pencils is still referred to as lead, even though it never contained the element lead. The words for pencil in German (Bleistift) and in Irish (Peann Luaidhe) both literally mean lead pen.
MANUFACTURE:
At the Slat factory, pencil stock is cut into "Pencil Blocks"
a bit longer than the normal length of a pencil. The small amount of extra length is called "trim allowance" that bears importance later on in the process. Pencil Blocks are cut into "Pencil Slats" using specially designed circular saws. These saws are very thin in order to reduce the amount of "waste" in the form of "sawdust". Due to the natural grain and defect characteristics of the wood, slats are sorted by width and grade for further processing. Slats without defects are called "full ply". Some slats are cut to smaller widths (called "narrow ply") or shorter lengths (called "memos") in order to eliminate the defects and to produce a variety of usable grades and plies of pencil slats. 
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Writing cores - made from a mixture of graphite and clay - are placed into the grooves. Coloring pencils may use wax-based cores while many other formulations are used in cosmetic pencils. A second grooved slat is glued onto the first - making a "sandwich" - by a machine called a "lead layer". The sandwiches are then"clamped" and held together tightly while the glue dries.
Writing cores - made from a mixture of graphite and clay - are placed into the grooves. Coloring pencils may use wax-based cores while many other formulations are used in cosmetic pencils. A second grooved slat is glued onto the first - making a "sandwich" - by a machine called a "lead layer". The sandwiches are then "clamped" and held together tightly while the glue dries. Individual pencils cut from the sandwich are ready for further processing. Any pencils with defects, such as uncentered leads or chipped wood, are discarded at this point.
Next, each pencil is painted in a machine receiving from 4-10 coats of lacquer, depending on the desired quality of the finish and the color depth. A recess is cut to accept the ferrule.After painting, some pencils are wrapped in decorative film or foils with fancy designs; although, most pencils are imprinted with the brand name by stamping the foil into the surface of the pencil. On a "tipping" machine, an eraser and a ferrule (the metal ring that holds the eraser to the pencil) are crimped into place on each pencil.
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