Welcome to Brainstuff from house stuff works dot com where smart happens. Hi am rc Brain with today's question, how do they get the lead in a wooden pencil? Take a look at the writing end of a brand new wooden pencil before sharpening it. It appears that the wood casing is one solid piece. This might lead you to believe that pencil makers bore a hole straight down the middle of the wood and then slide in a rod of lead. Although early pencils were constructed that way, it's
not how most wooden pencils are mass produced today. More than fourteen billion pencils are produced in the world every year, enough to circle the Earth sixty two times. Before discussing how the lead is put into the wood casing, let's clear up what the lead actually is. Pencil lead is not lead at all. It's a combedyation of finely ground graphite and clay, mixed with water and pressed together at
high temperatures into thin rods. We call it lead because the Englishman who first discovered graphite believed that they had found lad. According to the Cumberland Pencil Museum, in the mid sixteenth century, a violent storm knocked over several trees in England, uncovering a large deposit of a black substance that was first thought to be led. More than two hundred years later and English scientists discovered the substance was
not actually led, but a type of carbon instead. The substance was named graphite, after the Greek word meaning to write, since that's how people used the substance. Early pencils were crude versions of today's standard model. The first pencil was a chunk of graphite used by carpenters to make markings without denning their materials. This evolved into a graphite chunk wrapped in sheepskin, followed by a ring wrap graphite pencil,
the first pencil with a rod shaped graphite core. To use one of these pencils, the writer would have to unravel the string as the graphite wore down. The next major leap in design was hollowing out a stick of cedar and sticking a piece of graphite down the hole, an idea often credited to the Italians. The English embraced this idea but simplified the manufacturing process considerably. Instead of hollowing out a piece of wood, they simply cut a
groove in the wood. Inserted a piece of graphite and broke it off level with the top of the groove. Then they glued a small slat on top, encasing the graphite. Today, most wooden pencils are mass produced from large blocks of cedar cut into slats. A machine cuts eight grooves half as deep as the graphite clay rod is thick into slats and then places rods in each groove. Once the rods are in place, a second groove slat is glued
on top of the first. When the glue drives, the slats are fed through a cutting machine that cuts the wood into various shapes and divides the slats into eight separate pencils. The seams of the two slats are then sanded down and several coats of paint are applied to the pencil, giving it the appearance of a single solid structure. Do you have any ideas or suggestions for this podcast? If so, please send me an email at podcast at
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