High Quality Content by WIKIPEDIA articles! A mechanical pencil is a writing implement or art medium in which the solid marking core usually graphite based and called lead, but colored pigments and other solid substances are also used is not bonded to the outer casing, and is designed such that the core is to be extended as its point is worn away. Mechanical pencils are known by many alternative names, such as lead pencil, propelling pencil, automatic pencil, drafting pencil, technical pencil, clicky pencil, clutch pencil, leadholder, pushpoint pencil and pacer. Mechanical pencils are often designed and used to provide lines of constant thickness without requiring sharpening, making them well suited to applications like technical drawing and fine point, general writing. The first patent for a refillable pencil with lead-propelling mechanism was issued to Sampson Mordan and John Isaac Hawkins in Britain in 1822. After buying out Hawkins' patent rights, Mordan entered into a business partnership with Gabriel Riddle from 1823 to 1837. The earliest Mordan pencils are thus hallmarked SMGR.

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