Nails have been around for ages. The Romans forged them by hand. The same was the case in early America when nails had to be hammered out before they could be hammered in. An experienced craftsman could forge upward of two thousand wrought nails a day, according to Peter Ross, master blacksmith of Colonial Williamsburg.
After the American Revolution there were machines that cut nails from thick metal sheets, producing as many as a thousand an hour. Thomas Jefferson owned one, and convicts used the machines to make nails in prison.
Nails became cheaper in the 1850s, when new machines began making the kind we use today out of great spools of steel wire, both round and square. These machines can now size, cut and head up to 2,000 nails a minute.
Nails were not always made of metal. Some, called tree nails, were made of wood. Split into rough dowels, the tree nails were forced through undersized holes in the timbers they were to join. Their "farther ends" then were split and expanded with a wedge of wood. Tree nails often were used for early boat and house frame construction. Some of the early colonial "pegged" homes and barns are still standing. Our dad boasted that the home that he grew up in didn't have a single metal nail. Built in Princess Anne, Maryland in 1852, the home is a local landmark.
Although construction screws and adhesives have an increasing share of the market, nails are still the most frequently used means of fastening anything to wood. When a nail is driven through a piece of wood (not with the grain), it cuts through the fibers that form the grain and pushes them aside. When pressure is applied to pull the nail out, the fibers tend to jam against the sides of the nail and lock it in place. This is why wood has no holding power when a nail is driven into the end of the grain. Different woods have varying holding powers. Very hard woods do not hold nails well because the wood tends to split. When nailing woods such as oak and hickory, it is best to drill pilot holes for the nails, or not use nails at all, but screws instead.
Choosing the right nail for the job can make a big difference in hold power and appearance. Common practice calls for driving the nail through the thinner board into the thicker board. For maximum holding power, the length of the nail should be such that it passes almost, but not quite, through the thicker board. Thus, to fasten a 7/8-inch board to a 2 5/8-inch board, a 12-penny (12d) nail, that is 3 inches long, would be ideal.
When there is no need to conceal the nail head, or when maximum holding power is required, common nails are the best choice. They have flat, medium diameter heads. When the nail is temporary and will be pulled out again, as with form work, a double-headed or duplex nail is the best choice.
For finish work, when the nail head is to be recessed below the surface of the material and concealed with putty, a finish nail is the way to go. It has a small head that contains a dimple which readily accepts the point of a nailset.
A roofing nail has an oversize head to reduce "tear-through" of roofing felt and asphalt shingles. It also typically has a barbed shank for greater holding power and a galvanized finish to prevent rust.
Ordinary nails are make of steel, and thus will rust. To keep them from rusting, many types of nails are made with a zinc coating. This process is called galvanization. While zinc itself does not rust, zinc-coated nails sometimes do because the zinc often gets knocked off by the hammer, and the exposed iron thus can rust a bit. Consequently, a checkered head nail should be used. It holds extra zinc or paint so that hammering won't chip off the protective coating. An alternative is aluminum nails. They cost more, but don't rust.
