Nails are mechanical fasteners that are driven into materials, such as wood, concrete, or plastics, with a hammer or nail gun. Nails are the most common fastener in use today by volume. They are made of metal or plastic materials and they differ in terms of head style, length, diameter, and application.
Nails are usually the steel wire type. A wire nail, or sometimes called a French nail after the country where it was invented, is cut off from a spool of steel wire, then stamped into the shape of the nail. Wire nails all have round shafts. Before wire nails became the standard, nails came in a rectangular wedge shape. These types are still available for restoration work.
Most nails are made of simple steel, so they are subject to rusting. Galvanized steel nails are more rust resistant. Aluminum nails are used to tack aluminum siding to a house’s side. Using steel nails with aluminum would cause detrimental electro-chemical reactions between the two dissimilar metals. Copper nails are used to secure copper pipe straps to the joists and frames of a house for the same reasons. Brass nails are used more for their clean finish look and hardness, as well as for their corrosion resistance.
Nails differ in terms of features and materials of construction. Common nails have larger nail shank diameters than other nails. Wire nails are divided into five main classes which are:
Common types of nails include common nails, brad nails, cap nails, double-headed nails, finishing nails, masonry nails, and roofing nails.
- The most common nail today is the common, or the framing, nail. According to one large retail outlet, the 6 penny, or 6d, common framing nail is the most popular nail.
- A cap nail is driven with a hammer and has a strong outer rim for increased rupture values.
- A brad nail is a nail with a head on one side and is usually galvanized. It is used for finish work because it is very thin and has little holding power.
- A double-headed, or a duplex, nail has a collar that is located away from the head. A double-headed nail is easy to remove and suitable for scaffolding or other temporary work because its top head is above the wood so it is easy to get a nail puller under it.
- A finishing nail is designed for applications where the nail head must be hidden from view. Finishing nails are small in diameter and have a barrel-shaped head with a dimple on top.
- A masonry nail has a single head and is usually made of hardened steel. Masonry nails have knurling on its shaft to increase its holding power in concrete.
- A roofing nail has a larger head but is only an inch long and is coated to resist weathering. The large head of the roofing nail also helps cover and seal the hole the nail made in the shingle and the roof board.
- A tack nail is a short nail, around half an inch long, with a large head used for tacking upholstery to wood such as in furniture use. They can have decorative heads. Nails with other head styles are also available.
In most countries that use the metric system, nails are sized similar to bolts and screws by using the length, minus its head, in millimeters by the nail’s diameter in millimeters. An example of that is 50 x 2.2, which means a nail 50 mm long by 2.2 mm wide.
In the United States and the United Kingdom along with some other countries, nails are sold by penny sizes. This is based on the old days when nails were made at home and used as an informal currency. Ironically, instead of the “¢” sign, nail penny sizes are denoted by a “d.” The “d” is used because in England “d” was short for the Roman denarius coin, which was a near equivalent of an English penny. So an 8d nail meant that you could buy 100 of them for 8¢. 2d nails are an inch long. But from there on, every additional 2d or 2 penny in size is another half inch of length; so a 4d nail is 1.5 in. long and an 8d nail is 2.5 in. long.
For most people, a hammer or a similar tool like a tack driver is the tool they’d use to drive a nail. But in construction or in other industrial situations, a nail gun is used. These guns are usually powered by compressed air. Some nail guns use a .22 caliber shell to push the nail into the wood. For these applications, the nails come in premade strips or clips of 100 nails, held together usually by adhesive tape, or just glue, that are loaded in the gun’s magazine.