Nail is the most widely used fastener for attaching one piece of wood to another. Nails also join wood and such materials as cloth, sheet metal, and wire. Special nails hold wood and other materials to brick and concrete.
Most nails are made of steel, but some are made of aluminum, brass, copper, or stainless steel. Steel nails may be coated with zinc or plated with aluminum, copper, or nickel to resist rust. Some nails have a coating of resin, an adhesive substance that makes them hold more tightly.
Carpenters generally use a claw hammer to drive nails. This kind of hammer has a claw for removing nails. Many carpenters who build or remodel houses use power tools to drive nails.
The parts of a nail.
A nail has three main parts: (1) the point; (2) the shank, or body; and (3) the head. The point acts as a wedge that separates the fibers of wood as the nail is driven. After the nail is in place, the fibers grip the shank and keep the nail from loosening. The head covers the hole made by the nail and prevents the wood from springing back.
The most common type of nail point is the diamond point, a sharp point that works well in most kinds of wood. A blunt point works better in some hardwoods, such as maple and oak. This point breaks off some of the wood fibers and helps keep the wood from splitting.
Most nails have a smooth, round shank. Nails with a twisted, threaded, or ringed shank hold better but cost more. A narrow, flat, or barbed shank helps prevent hardwood from splitting. Nails with a square shank are used to attach wood flooring to concrete.
Most kinds of nails have a broad, flat head. A nail with a narrow head can be hidden in the wood by driving it completely below the surface with a punchlike tool called a nailset. The hole left by the nail can be filled with putty and then painted. Roofers use a nail with an extra wide head to install shingles. Upholsterers use tacks with decorative heads if the tacks can be seen.
Sizes of nails.
Most countries use the metric system to identify nails, describing both their length and shank diameter in millimeters. In the United States, nails are usually measured in units called pennies, designated by the letter d. Nails measured in this way range in size from 2-penny nails that are 1 inch (2.5 centimeters) long to 60-penny nails 6 inches (15 centimeters) long. Nails that are shorter or longer than those are measured in inches or centimeters. The system of measuring nails in pennies began in England and originally referred to the price for a hundred nails.
How nails are made.
The earliest nails were made about 5,000 years ago in Mesopotamia. Artists used them to fasten sheets of copper to wooden frames to make statues. In the early 1700’s, American colonists hammered nails by hand from a bar of hot iron. About 1775, Jeremiah Wilkinson, an inventor in Cumberland, Rhode Island, developed a process for cutting nails from a sheet of cold iron. About 1851, William Hassall (or Hersel), a machinist in New York City, invented the first machine for making nails from wire.
Today, almost all nails are made from wire fed into a machine that can produce hundreds per minute. A set of cutters trims off a length of wire and forms the point of the nail at one end. At the same time, a hammer shapes the head at the other end. The nails are then polished, plated, or coated.
