The Secret To Choosing The Perfect Nail
Today we’re going to hit the nail on the head, get right to the point. Sometimes we’ll be painfully blunt. Occasionally we may bend the issue or split hairs. In any case we hope that you will find this discussion about nails galvanizing.
Okay, enough humor. Nails are serious stuff. And they’ve been around for ages. The Romans forged them by hand. The same was true in early America where nails had to be hammered out before they could be hammered in. An experienced craftsman could forge upwards of two thousand “wrought nails” a day, says Peter Ross, master blacksmith of Colonial Williamsburg.
After the American Revolution came machines that cut nails from thick metal sheets, producing as many as on thousand an hour. Thomas Jefferson owned one, and convicts used the machines to make nails in prison. Cheap and plentiful in a land thick with timber, nails helped build the frontier towns as Americans pushed westward.
Nails became even cheaper in the 1850’s, when new machines began making the kind we use today out of great spools of steel wire, both round and square. Theses machines can now size, cut and head up to two thousand nails a minute! They have to work fast: Each year in the United States, we hammer on the heads of more than half a million tons of nails.
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 were then split and expanded with a wedge of wood. Tree nails were often used for early boat and house frame construction. Some of the early colonial “pegged” homes and barns are still standing. In fact our Dad would frequently boast 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 continue to generate 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 (and not with the grain), the nail 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 different 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 to use nails at all, but screws instead.
Choosing the right nail for the job can make all the difference in the world 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 twelve penny (written 12d) nail, which is 3 ¼ inches long, would be just right. Penny designations originated in 15th century England. The abbreviation “d” – from Rome’s penny, the denarius-meant penny or pence.
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 which 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. They also typically have a barbed shank for greater holding power and a galvanized finish to prevent rust.
Ordinary nails are make of steel. Unfortunately, steel will rust. Therefore, as a method of avoiding rust, 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 usually rusts a bit. Consequently, a checkered head nail should be used. It holds extra zinc or paint so hammering won’t chip off the protective coating. An alternative would be aluminum nails. They cost more, but they don’t rust.