Mechanical pencil
Overview
Pencil
A pencil is a writing implement or art medium usually constructed of a narrow, solid pigment core inside a protective casing. The case prevents the core from breaking, and also from marking the user’s hand during use....
with a replaceable and mechanically extendable solid pigment core called a lead (icon). It is designed such that the lead can be extended as its point is worn away. The lead is not bonded to the outer casing and is usually graphite
Graphite
The mineral graphite is one of the allotropes of carbon. It was named by Abraham Gottlob Werner in 1789 from the Ancient Greek γράφω , "to draw/write", for its use in pencils, where it is commonly called lead . Unlike diamond , graphite is an electrical conductor, a semimetal...
based, though colored pigments and other solid substances are also used.
Mechanical pencils are often designed and used to provide lines of constant thickness without requiring sharpening
Pencil sharpener
A pencil sharpener 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.-History:...
, making them well suited to applications like technical drawing
Technical drawing
Technical drawing, also known as drafting or draughting, is the act and discipline of composing plans that visually communicate how something functions or has to be constructed.Drafting is the language of industry....
and fine-point or general writing.
