A BRIEF HISTORY OF NAILS

The use of nails goes back thousands of years. Bronze nails, found in Egypt, have been dated to 3400 B.C., but the Romans are generally credited with the first use of iron. The earliest nails were hand-forged, usually square in shape with all four sides tapering to a point, and resembled spikes, suited for the building materials commonly in use. Over time, as building materials evolved and new products were introduced, customized nails were developed to keep pace with the changing industry

Prior to the American Revolution, England was the largest manufacturer of nails in the world. However, nails were virtually impossible to obtain in the American Colonies, where it was not unusual for families to have a small nail manufacturing process in their homes by the hearth. Entire families made nails not only for their own use but also for barter. Even Thomas Jefferson had his own nail producing facilities at Monticello, and he took great pride in them.

The first major innovation in nail production occurred in the late 1700s, with the introduction of cut nails. Cut or "square" nails are not actually "cut", but are sheared from steel plate that is the thickness of the nail shank. The invention of water-powered "slitting mills" made this new technology possible, and rapidly put the United States at the forefront of nail manufacturing. Hot iron was hammered or later, rolled, into sheets, which were then slit into long, square-sectioned bars by shear-like rollers. Two sides of the cut nail shank are parallel as they represent the thickness of the plate from which they were sheared. The cutting machine tapers the other two sides of the shank, while a second machine forms the nail head.

Cut nails could be produced much more quickly and somewhat less expensively than hand-forged nails, and starting in the mid-1800s, began to dominate the industry. A machine that produced stamped nails with a simple head was also introduced at this time with limited success. Still, nails continued to be expensive to produce and used sparingly. It was not uncommon for a building to be burned down and the ashes combed for the nails for reuse.

"Modern" nail manufacturing may have started in the U.S. as early as the 1850s with the importation of French wire nail machinery. These nails were not intended for construction but for other light-duty applications such as bookbindery. The early 1900s is generally accepted as the turning point for wire nail production, from which point on they have dominated the industry. Wire nails have a round shank, and produced by steel wire fed into a machine that grips the wire, cuts it, makes the head, and chisels the point, all in one operation. The process is totally mechanized, can produce thousands of nails per minute, and provides a significantly less expensive nail than previous methods.

The relatively low-cost wire nails have all but replaced cut nails. However, the cut nail has a holding power of approximately four times a wire nail. It is because of this impressive holding power and the hardness of the nail that cut nails are still used today for projects such as masonry and flooring.

WHAT DOES PENNY MEAN?

The term "penny", as it refers to nails, is thought to have originated in medieval England to describe the price of 100 nails. For example, 100 3-1/2" nails would cost 16 pence, whereas 100 2-1/2" nails could be purchased for 6 pence. This system of classifying nails by size according to price was in place by 1477 A.D. The letter "d" used to represent "penny", stands for the Latin name given to Roman Coins, denarius. Traditionally, nails used for wood-to-wood applications (decking, wood siding, framing, etc.) are referred to in penny sizes, while nails for non-wood applications (roofing, siding, etc.) are referred to in inches.

Nails usually start at 2d (1" long), and range up to 60d (6" long). From 2d to 16d the penny length increases by quarter inches. Above 16d, the size increases by half inches. Nails longer than 60d or shorter than 2d are described in inches or fractions thereof. A very thick nail or one longer than 6" is considered a spike. A nail less than 1" long are called wire nails if they have a head, and brads if they have a very small head or none at all.

COMMON NAIL HEADS

Flat head - Most common nail head. Provides large surface area for greater holding power.

Large flat head - Larger than standard head, usually more than 3 to 3-½ times shank diameter. Provides greatest surface area for ultimate holding power. For applications such as sheathing and insulation.

Checkered flat head - Helps to stop slippage of the hammer on the head with applications such as framing, where excessive hammering may take place.

Countersunk head - Conically shaped bearing surface, which compresses the surface of the material under it as it is driven. Aids in concealment of the fastener head.

Deep countersunk head - Reduced holding power, but increased concealment of the fastener head. Using primarily on casing nails.

Brad head - Deep, circular, barrel-shaped head. Reduced holding power, but increased concealment of the fastener head. Used primarily with finish and trim work.

Duplex head - For temporary nailing jobs, such as scaffolding and concrete framing.

Cupped head - Concave or recessed top surface to accommodate material to aid with concealment. Used primarily with drywall fasteners.

Oval head - Used in certain geographic areas primarily with siding to avoid contact between the hammer and the siding.

COMMON NAIL POINTS

Diamond point - Most common nail point. To avoid splitting wood, best for medium to soft wood.

Long diamond point - For use with drywall. Eases driving into harder materials.

Blunt point - Reduces splitting, but not as easy to drive as a diamond point.

COMMON NAIL SHANKS

Smooth - Most common for everyday projects, provides the least amount of holding power.

Barbed - Horizontal or herring-bone indentations in the shank. Relatively better hold than smooth shank, but far less than a comparable threaded nail.

Screw/spiral/ardox - Designed to drive into hard woods and dense materials. Nail actually turns when driven, much like wood screws. Very good holding power.

Ring/annular thread - A series of closely spaced concentric rings around shank. Nail does not turn when driven; instead, the wood fibers are forced over the ring shoulders into their annular grooves like wedges. Gives greatest holding power in soft or medium woods.

Fluted - Vertical thread for driving into cinder block, mortar joints, or other relatively soft masonry to minimize cracking and provide high holding power.