nail - A slender piece of metal commonly pointed and having a flattened head, driven with a hammer, and commonly used to hold pieces of wood together, or as a peg or a hook from which to hang things. Also to use a nail.
As symbols, nails often refer in Christian iconography to Christ's passion, and are usually three in number (here shown with a crown of thorns). According to a medieval legend, St. Helena discovered both the true cross and the nails that were used in it. Nails are attributes associated with Helena, as well as with Joseph of Aramathea, St. Bernard, and St. Louis.
There are many different types of nails. The conventional system for grading nail sizes can be confusing, and the many different types of shanks (surface textures and coatings) and the various styles of heads to go with them can further increase confusion. Beyond the kinds of nails noted below, there are many types not described here.
Nails are graded (measured) in a system that refers to their size. The unit is called a "penny." The larger the number, the larger the nail. A 3-penny (3 d) nail is much smaller than a 16-penny nail. See links to diagrams of nail sizes for each of several types of nails below.
This system originated in 15th century England, when the "penny" size determined what one paid a blacksmith to forge a hundred nails of that size of nail (one paid three pennies to get a hundred nails of the size called the "3-penny" nail). This price became obsolete before 1500, but has continued to be so entrenched in convention, that its use persists to this day. Now we use it primarily as a measure of length (approximate, at least). We abbreviate the "penny" with the symbol "d", which came from the "denarius", an early Roman coin.
Types of nails most frequently used:
Common and box nails have heads that are clearly visible after the nail has been driven. Common nails are used for general construction purposes -- framing buildings and situations where appearance is not important. Click here to see a diagram of sizes of common nails, listing for each size its length, the diameter of its shank and its head, and the number of nails per pound.
Box nails -- intended for lighter construction -- are the same length per penny size as common nails, but their shafts and heads are slightly narrower.
Finishing nails have much smaller heads that can be concealed after the nail has been driven. These nails are used for applying trim and other areas where appearance is important. Click here to see a diagram of sizes of finishing nails, listing each size's length, the diameter of its shank and its head, and the number of nails per pound.
Roofing nails have a large heads that are intended to hold shingles and are usually galvanized.
Drywall nails look the same as roofing nails but are not galvanized.
Nails are generally either coated or non-coated. The different coatings are:
Galvanized nails and are recommended for exterior applications as they are made of steel and coated with zinc to resist rusting. They are available in common, finishing and roofing types.
Adhesive coated nails usually have a dark coating that is intended to make them stay where they are driven.
Spiral nails have helical shanks -- twisted like screws. These nails are excellent for exterior applications that are subjected to repeated stress. Staircases and decks are examples. Some of these nails are coated with an adhesive.
Masonry nails are "hardened" and will endure the stress of being driven into a mortar joint. Their texture helps them to grip the material they're driven into.
Cut nails are rectangular in cross-section. They are used in masonry and are also found in older buildings. Horseshoe nails may also be cut nails.
Aluminum nails are used for plaster lathe and other specialty applications.
Examples of art in which nails are especially important:
Austrian, Augsburg, mid-17th century, Reliquary with a Nail from the Cross, gold, silver-gilt, partially enamelled and painted, painted brass, gemstones, rock crystal, pearls, glass, height 79.6 cm, Kunsthistoriches Museum, Vienna. See reliquary.
Africa, Zaïre, Yombe or Woyo, Fetish, wood, nails, metal fragments, small chain, traces of polychrome, 97.5 x 47 x 28 cm, Georges Pompidou Center, Paris. See African art and fetish.
James Rosenquist (American, 1933-), Pulling out, 1972, color lithograph, 26/39, 65 cm x 76.5 cm, Tehran Museum of Contemporary Art, Iran. Rosenquist pictures a claw hammer pulling nails that he's rendered in the primary colors. See Pop Art.
Also see brad, construction, diameter, hammers, join, point, and staples.