A pencil sharpener (also referred to as a parer or topper in Ireland, or pointer in Donegal, Ireland) is a device for sharpening a pencil's writing point by shaving away its worn surface. Pencil sharpeners may be operated manually or by an electric motor.
Before the development of dedicated pencil sharpeners, a pencil was sharpened by whittling it with a knife. Pencil sharpeners made this task much easier and gave a more uniform result. Some specialized types of pencils, such as carpenter's pencils are still usually sharpened with a knife, due to their flat shape, though recently a fixed-blade device with a rotatable collar has become available.
French mathematician Eiche Gardner applied for the first patent (French patent #2444) on pencil sharpeners in 1828, but it was not until 1847 that the pencil sharpener in its recognisable modern form was invented by fellow Frenchman Therry des Estwaux. The first American pencil sharpener was patented by Walter K. Foster of Bangor, Maine in 1855. Electric pencil sharpeners for offices have been made since at least 1917.
They now come in a wide array of colors and shapes. It is common for traditional sharpeners to have a case around them to collect the shavings. It can be removed for emptying the shavings into a compost bin.
In May 2011 tourism officials in Logan, Ohio put on display, in its regional welcome center, hundreds of pencil sharpeners which had been collected by Rev. Paul Johnson, an Ohio minister who died in 2010. Johnson, a World War II veteran, had kept his collection of more than 3,400 sharpeners in a small shed, outside his home in Carbon Hill in southeast Ohio. He had started collecting after his wife gave him a few pencil sharpeners as a gift in the late 1980s. He kept them organized into categories, including cats, Christmas and Disneyland. The oldest was 105 years old.
A larger, stationary mechanical sharpener can be mounted on a desk or wall and powered by a crank. Typically, the pencil is inserted into the sharpener with one hand and the crank turned with the other. This rotates a set of cylindrical cutters in the mechanism, set at an angle to each other. This quickly sharpens the pencil, with a more precise finish than the simpler blade device. Advanced models have a spring - driven holder for the pencil (the pencil advances inside the mechanism while being sharpened). Some versions also offer a regulator of the desired sharpness (it is not always optimal to make the graphite core needle-sharp). Such sharpeners may be very easy to use even by children but are much more expensive than prism sharpeners. Some such rotary sharpeners have only one burr cylinder. The casing of the sharpener is the repository for the pencil shavings; it needs to be emptied periodically. They are also called "planetary sharpeners", in reference to their use of planetary gears.
Artists may use a very sharp knife to sharpen pencils and other media by hand. The tip is cut into a triangle shape and then the edges of the triangle are trimmed down. This requires a total of 6 cuts and takes practice to master without breaking the lead.
Boston pencil sharpeners are made by the X-ACTO company, best known for making X-ACTO precision knives. X-ACTO is a division of Elmer's Products Inc., producer of glue products since the 1940s.