views updated May 11 2018



A nail consists of a metal rod or shank, pointed at one end and usually having a formed head at the other, that can be hammered into pieces of wood or other materials to fasten them together. A nail is usually made of steel, although it can be made of aluminum, brass, or many other metals. The surface can be coated or plated to improve its corrosion resistance, gripping strength, or decorative appearance. The head, shank, and point may have several shapes based on the intended function of the nail. Of the nearly 300 types of nails made in the United States today, most are used in residential housing construction. The average wood frame house uses between 20,000 and 30,000 nails of various types and sizes.

Nails are divided into three broad categories based on their length. In general nails under 1 inch (2.5 cm) in length are called tacks or brads. Nails 1-4 inches (2.5-10.2 cm) in length are called nails, while those over 4 inches (10.2 cm) are some-times called spikes. These categories are roughly defined, and there is considerable crossover between them.

The length of a nail is measured in a unit called the penny. This term comes from the use of nails in England in the late 1700s when it referred to the price of one hundred nails of that size. For example, a "ten penny nail" would have cost ten pennies per hundred. The symbol for penny is "d," as in 10d. This designation is believed to go back to the time of the Roman Empire when a similar form of measurement for hand-forged nails involved a common Roman coin known as the denarius. Today the term penny only defines the length of a nail and has nothing to do with the price. The shortest nail is 2d which is 1 inch (2.5 cm) long. A 10d nail is 3 inches (7.6 cm) long, and a 16d nail is 3.5 inches (8.9 cm) long. Between 2d and 10d the nail length increases 0.25 inch (0.64 cm) for each penny designation. Beyond 10d there is no logical progression to the lengths and designations.

Nails may have been used in Mesopotamia as early as 3500 b.c. and were probably made of copper or bronze. Later, iron was used to make nails. Early nails were shaped, or forged, with hammers. They were usually made one at a time, and were consequently scarce and expensive. By the 1500s a machine was developed which produced long, flattened strips of iron, called nail rods. These strips could then be cut into lengths, pointed, and headed. Nails were so valuable in the early American settlements that in 1646 the Virginia legislature had to pass a measure to prevent colonists from burning down their old houses to reclaim the nails when they moved. Two early nail-making machines were patented by Ezekial Reed of the United States in 1786 and Thomas Clifford of England in 1790. These machines cut tapered pieces from flat iron sheet, then flattened the head. In rural areas, black-smiths continued to make nails from wrought iron right into the 20th century. The first machine to make nails from metal wire was introduced in the United States in about 1850, and this technique is now used to make most of the nails today.


Most of the 300 different types of nails produced in the United States today require no new design work. Once a nail has been designed, forming dies and processes are developed for its manufacture, and the nail is produced in quantity.

Most nails have a broad, circular head. Finishing nails have a narrow, tapered head which allows them to be countersunk below the surface of the material and covered over to produce a smooth finish. Upholstery nails have decorative heads. Double-headed nails are used to fasten wood forms used in concrete pouring. The nail is driven in up to the first head, leaving the second head protruding. The protruding head allows the nails to be easily removed and the forms quickly dismantled once the concrete has hardened.

The shank is usually designed to be round and smooth. Shanks with serrations, annular grooves, spiral flutes, or helical threads are used when a stronger, more permanent grip is required. Thermoplastic coatings may also be added to the shaft. These coatings heat up through friction while the nail is being driven, then quickly cool and set to lock the nail in place. The diameter of the shank is determined by the type of nail. Most nails, called common nails, have a relatively large diameter. Box nails, originally used to make thin-walled boxes, have a smaller diameter shank than common nails. Finishing nails have a very small diameter shank in order to make the smallest hole possible.

The most typical nail point is a four-sided tapered cut called a diamond point. Other nails may have a blunter point to prevent splitting certain woods. Chisel points, barbed points, needle points, and many others are sometimes used on specialty nails.

As new building materials become available, nail manufacturers work to develop new nails. There are special nails for tile roofing, hardwood flooring, shingles, rain gutters, wall board, sheet metal, and concrete. Some new nails are designed to be driven by air-powered nail guns rather than by a hammer. There have even been new nails designed for specific applications in the aerospace industry.

Nails are essential to the construction of wood-framed buildings. This, however, was not always the case. Until the late 18th century, Americans built wooden buildings using heavy timber frames. At places where these massive timbers had to hold together, one end of a post or beam would be cut down to form a tongue ("tenon") and fitted into a hole ("mortise") cut in the adjoining beam. Additional strength could be added by driving wooden pegs through auger holes in the joined timbers. The skill and labor involved in such construction was considerable; carpenters had to be highly skilled individuals and, as such, commanded high prices in colonial America.

Until the end of the 18th century, nails were imported from England or made by local blacksmiths. The smithy, or often his apprentice, took a piece of bar iron maybe 5 feet long and 0.06-0.25 inch in diameter. Holding one end he heated the other, laid it on the anvil and, using the flat face of his hammer, tapered all four sides to about an inch from the end. He then used the peen, or sharpened end of his hammer, or a hardy, a wedge-shaped attachment to his anvil, to cut a notch in the rod. He thrust the sharpened end of the rod into a tapered hole in his anvil and snapped off the short nail. Then he flattened the end of the nail with four or five quick strikes of the hammer and popped it out of the anvil hole with a quick, upward strike at the point.

Between 1790 and 1830, several mechanical devices were developed in Europe and the United States to speed the production and lower the cost of nails. It is not entirely coincidental, therefore, that the balloon-framed house, which relied on two-by-fours held together by nails, was invented in the early 1830s in Chicago. The balloon-frame system required much less skill and labor in carpentry and made use of mass-produced nails.

William S. Pretzer

Raw Materials

Most nails are made of steel. Aluminum, copper, brass, bronze, stainless steel, nickel silver, monel, zinc, and iron are also used. Galvanized nails are coated with zinc to give them added corrosion resistance. Blued steel nails are subjected to a flame to give them a bluish oxide finish that provides a certain amount of corrosion resistance. So-called cement-coated nails are actually coated with a plastic resin to improve their grip. Some brads are given a colored enamel coating to blend in with the color of the material they are fastening.

The Manufacturing

Most nails are made from coils of metal wire. The wire is fed into a nail-making machine which can produce up to 700 nails per minute. The nails may then be further twisted or formed, cleaned, finished, and packaged.


  • 1 Wire is drawn from a coil and fed into the nail-making machine where it is gripped by a pair of gripper dies. The shape of the head of the nail has been machined into the end of the dies.
  • 2 While the dies clamp the wire in place, the free end of the wire is struck by a mechanical hammer. This deforms the end of the wire into the die cavity to form the head of the nail.
  • 3 With the wire still clamped in the dies, a set of shaped cutters strike the opposite end of the nail, forming the point and cutting the nail free from the rest of the wire coming off the coil.
  • 4 The dies open and an expelling mechanism knocks the nail into a collection pan below the machine. The free end of the wire is drawn from the coil and fed into the machine. The cycle then begins again.

Additional forming

  • 5 Nails with helical twists, serrations, or other surface configurations are fed into other machines that roll, twist, stamp, or cut the required forms. This may be a purely mechanical process or may require heating the material before forming.


  • 6 The nails are cleaned in a rotating barrel filled with hot caustic soda. This removes any oil from the forming machine and cleans up any small metal scraps, or nippings, that might be clinging to the nails.
  • 7 Many nails are given a final bright finish before being packaged. This is accomplished by placing the nails in a rotating drum of hot sawdust to lightly polish the surface of the nails. Other nails may be passed through an open flame in an oven to give them a blued finish. Galvanized nails are dipped into a tank of molten zinc in a process called hot-dip galvanizing. A zinc coating may also be applied by heating the nails to about 570°F (300°C) in a closed container filed with a powder composed of zinc dust and zinc oxide. Other coated nails are either dipped or sprayed to obtain their final finish.
  • 8 Depending on the tolerances desired, some specialty nails may also require an additional heat treating step.


  • 9 Magnetic elevators convey the finished nails to weighing machines which drop them into open cardboard boxes. As they are dropped in, a magnetic field aligns them so they stack in neat rows. After they are packaged, the nails are demagnetized. Nails are usually sold in boxes of 1, 5, 10, 25, and 50 pounds. Smaller nails, such as brads, are sold in 2-ounce or 4-ounce boxes and are packaged without being magnetically aligned.

Quality Control

Raw materials must meet certain standards for chemical composition, yield strength, hardness, corrosion resistance and other properties. These are usually certified by the company supplying the wire, and may be independently checked by the nail manufacturer.

During manufacture, nails must also meet certain specifications regarding dimensions and properties. These are achieved using a method known as statistical process control, which periodically samples the dimensions and properties of the nails being produced and evaluates any changes through statistical analysis techniques.

The Future

The demand for mass-produced commodity nails is dependent on the fluctuations in the housing market, which varies with the economy. Demand for these nails is also subject to competition from foreign manufacturers, further reducing profits.

The demand for specialty nails, on the other hand, is expected to continue to grow and be profitable. New building materials, such as composite wood-fiber and cement-based siding and roofing, require new specialty nails. New corrosion-resistant coatings for nails are also being developed.

One unique new nail market is the result of the increase in building restoration and preservation efforts throughout the country. One nail factory in Massachusetts makes old-fashioned cut nails. They estimate that 20% of their work is in producing a variety of these nails for use in authentic building restoration projects.

Where To Learn More


Loveday Jr., Amos J. The Rise and Decline of the American Cut Nail Industry. Greenwood Press, 1993.

Vila, Bob. This Old House Guide to Building and Remodeling Materials. Warner Books, 1986.


Johnson, Duane. "Nails Get a Better Grip." The Family Handyman, September 1994, p. 16.

Whorf, Amy. "A Thumbnail History of Nails." Country Living, June 1993, p. 72.

Laurel M. Sheppard


views updated May 17 2018

nail / nāl/ • n. 1. a small metal spike with a broadened flat head, driven typically into wood with a hammer to join things together or to serve as a peg or hook.2. a horny covering on the upper surface of the tip of the finger and toe in humans and other primates. ∎  an animal's claw. ∎  a hard growth on the upper mandible of some soft-billed birds.3. hist. a medieval unit of measurement: ∎  a measure of length for cloth, equal to 21/4 inches. ∎  a measure of wool, beef, or other commodity, roughly equal to 7 or 8 pounds.• v. [tr.] 1. [tr.] fasten to a surface or to something else with a nail or nails: nail the edge framing to the wall | the teacher was nailing up the lists.2. inf. expose (someone) as deceitful or criminal; catch or arrest: have you nailed the killer? ∎  expose (a lie or other instance of deception).3. inf. Football tackle the quarterback or ballcarrier, esp. at or behind the line of scrimmage. ∎  Baseball (of a fielder) put (a runner) out by throwing to a base: he dropped a perfect throw home that should have nailed Joe by yards. ∎  (of a player) defeat or outwit (an opponent): Navratilova tried to nail her on the backhand side. ∎  (of a player) secure (esp. a victory) conclusively: there's no doubt I had chances to nail it in the last set.4. vulgar slang (of a man) have sexual intercourse with (someone).PHRASES: fight tooth and nailsee tooth.hard as nails (of a person) very tough; completely callous or unfeeling.a nail in the coffin an action or event regarded as likely to have a detrimental or destructive effect on a situation, enterprise, or person: this was going to put the final nail in the coffin of his career.PHRASAL VERBS: nail someone down elicit a firm promise or commitment from someone: I can't nail her down to a specific date.nail something down1. fasten something securely with nails.2. identify something precisely: something seems unexpected—I can't nail it down, but it makes me uneasy.3. secure something, esp. an agreement: the company has finally nailed down the agreement with its distributors.DERIVATIVES: nailed adj. [in comb.] dirty-nailed fingers. nail·less adj.

NAILS (National Automated Immigration Lookout System)

views updated Jun 11 2018

NAILS (National Automated Immigration Lookout System)

NAILS (National Automated Immigration Lookout System) is a centralized database and computing system used by entry inspectors to identify aliens not eligible for admission. NAILS (and the updated version, NAILS II) allows inspectors to quickly retrieve and review biographical or historical case data and was designed to facilitate evaluation of entrant status.

The primary source of data for the NAILS database is gleaned directly from data supplied by potential immigrants on entry and immigration documents. This base of data provides a framework for the addition of information obtained from other federal, state, and foreign agencies.

Following the September 11, 2001, terrorist attacks on the United States, the NAILS system drew criticism because it is essentially a name-based system that can be thwarted by the use of a false name or falsified supporting documents. By relying on names rather than biometrics, NAILS provided gaps through which determined terrorists could slip into the United States.

NAILS is a secure database with access restricted on a "need to know" basis that was, prior to March 2003, operated by the Immigration and Naturalization Service (INS). On March 1, the newly created United States Department of Homeland Security (DHS) absorbed the former Immigration and Naturalization Service (INS). All INS border patrol agents and investigatorsalong with agents from the U.S. Customs Service and Transportation Security Administrationwere placed under the direction of the DHS Directorate of Border and Transportation Security (BTS). Responsibility for U.S. border security and the enforcement of immigration laws was transferred to BTS.

BTS is scheduled to incorporate the United States Customs Service (previously part of the Department of Treasury), and the enforcement division of the Immigration and Naturalization Service (previously part of the Department of Justice). Former INS immigration service functions are scheduled to be placed under the direction of the DHS Bureau of Citizenship and Immigration Services. Under the reorganization the INS formally ceases to exist on the date the last of its functions are transferred.

Although the description of the technologies involved in the NAILS entry security program remain the same as when operated by the INS, in an effort to facilitate border security, BTS envisions higher levels of coordination between formerly separate agencies and databases. As of April 2003, the specific coordination and future of the NAILS program was uncertain with regard to name changes, program administration, and policy changes.

Although the NAILS system is limited as an isolated system, even prior to DHS integration, data contained in the NAILS system, along with data from the Consular Lookout and Support System (CLASS), and the Treasury Enforcement Communications System (TECS II), was available to inspectors through the Interagency Border Inspection System (IBIS) maintained by U.S. Customs Service.

One reason for separate database systems is that it allows easier compartmentalization of data, keeping classified information secure while allowing access to data that may be requested under the Freedom of Information Act (FOIA).



Department of Homeland Security. April 2, 2003. <> (April 11, 2003).

Department of Homeland Security, Bureau of Citizenship and Immigration Services. Law Enforcement: The National Border Patrol Strategy. <> (April 12, 2003).


APIS (Advance Passenger Information System)
IBIS (Interagency Border Inspection System)
IDENT (Automated Biometric Identification System)
INSPASS (Immigration and Naturalization Service Passenger Accelerated Service System)
PORTPASS (Port Passenger Accelerated Service System)
SENTRI (Secure Electronic Network for Travelers' Rapid Inspection)


views updated May 21 2018

nails The replacement of sharp claws with flattened nails in primates is considered part of the evolutionary development of a hand able to grasp objects. The nails start to develop in the fetus by the end of the third month, and are formed from the same epidermal tissue as the skin. They reach the ends of the fingers and toes about a month before birth.

The mature nail is a plate of the protein keratin which is also present in hair and skin. The pale ‘half-moon’ at the base — often exposed above the nail-fold only on the thumbs and big toes — marks the area of the bed of the nail where its substance is formed and from which it grows — the germinal matrix. The rest of the nail bed provides a surface for the growing nail to slide over as it advances at the rate of about 0.1 mm/day. The germinal cells continually divide to replace those which generate, and disappear into the non-cellular substance of the nail. This proliferation can be interrupted by injuries or acute illnesses, leaving grooves across the nails which gradually grow out.

The decoration of both toenails and fingernails for aesthetic purposes dates back at least as far as Ancient Egypt, where henna and other products were applied to colour the feet and hands as well as the nails. Growing long fingernails has also been practised in Chinese and Hindu cultures, in part as a sign of leisure and status, since many forms of manual labour are difficult or impossible with long fingernails. Well-groomed nails have been a sign of cultivation and cleanliness for both men and women in American and European cultures as well. As a 1952 etiquette guide pronounces, ‘A fastidious man … keeps his nails clean and short with the cuticle pushed back. If he has his nails professionally manicured, they may be buffed but should never have any coloured or even colourless polish applied’. Coloured and clear nail enamel, or ‘polish’, became popular for women in the early twentieth century, and often replaced the literal polishing of nails with a buffer. False and elaborately painted nails are also now popular among some cultural groups.

In folk beliefs, the nails are often said to continue to grow after death. For instance, long fingernails, or sometimes no nails at all, are characteristic of vampires, revenants, and other beings of ‘undead’ status. In fact, in decomposition the tissues of the body dehydrate and contract, giving the appearance that the nails, hair, and teeth have ‘grown’. Sometimes the nails are sloughed off with the outer layer of skin, leaving exposed what appears to be new skin or nails, another sign of preternatural ‘life’ in a corpse. This same phenomenon is also the explanation for stories of dead bodies supposedly having come to life in the coffin and having either chewed off their nails in anxiety, or having scraped them off trying to escape. To keep the nails in place, Ancient Egyptian embalmers sometimes either tied the nails to the fingers and toes, or covered them with metal thimbles.

Sarah Goodfellow


views updated May 18 2018

nail in devotion or meditation, nails, as used for the crucifixion of Jesus, are taken as symbolizing the Passion.

Nails are the emblem of St Joseph of Arimathea, St Louis, and St William of Norwich.

Livy records the belief in ancient Rome that a plague could be checked by the dictator driving a nail into the Capitol.
nail in the coffin an action or event regarded as likely to have a detrimental or destructive effect on a situation, enterprise, or person.
nail jelly to the wall the type of an impossible task. The image was used by US President Theodore Roosevelt (1858–1919) at the time of the Panama Revolution in 1903, ‘You can no more make an agreement with those leaders of Colombia than you can nail currant jelly to the wall. And the failure…is not due to the nail. It's due to the currant jelly.’
nail one's colours to the mast refuse to admit defeat; declare openly which side one favours. The allusion is to a sea-battle in which the colours nailed to the mast cannot be lowered in defeat.
on the nail immediately, at once (usually referring to the payment of money). The explanations associating this phrase with certain pillars of the Exchange at Limerick or Bristol are too late to be of any authority in deciding the question.

See also bed of nails, when all you have is a hammer, everything looks like a nail, one nail drives out another, fight tooth and nail, for want of a nail.


views updated May 23 2018

nail hard terminal covering of finger and toe; small spike of metal OE.; the applications (XV) to measures of weight and length are of uncert. orig. OE. næġ(e)l = OS., OHG. nagal (Du., G. nagel), ON. nagl :- Gmc. *naʒlaz, f. an IE. base *nogh- repr. also by Lith. nāgas nail, claw, OSl. nogŭtĭ nail, noga foot. Gr. ónux, Skr. nakhá-, rel. further to L. unguis, Olr. ingen.
Hence nail vb. OE. næg̣lan.


views updated Jun 11 2018

Nails ★½ 1992 (R)

Harry “Nails” Niles (Hopper) is a tough, experienced cop whose partner has been killed by drug dealers. Harry doesn't take this well and decides to go on a violent search for revenge. Archer is wasted as Harry's estranged wife and Hopper can sleepwalk through this type of cliched wildman role. 96m/C VHS . Dennis Hopper, Anne Archer, Tomas Milian, Cliff DeYoung; D: John Flynn. CABLE


views updated May 14 2018

nail (nayl) n. a horny structure, composed of keratin, formed from the epidermis on the dorsal surface of each finger and toe. Growth of the nail occurs at the end of the nail root, behind the exposed nail, by division of the germinative layer of the underlying epidermis. Anatomical name: unguis.


views updated May 09 2018

nail In anatomy, tough keratin (fibrous protein) outgrowth from the fingers and toes of primates.