In woodworking and construction, a nail is a pin-shaped object ofmetal (or wood, called a treenail or “trunnel”) which is used as afastener, as a peg to hang something, or sometimes as a decoration.Generally nails have a sharp point on one end and a flattened head on the other, but headless nails are available. Nails are made in a great variety of forms for specialized purposes. The most common is a wire nail. Other types of nails include pins, tacks, brads, and spikes.
Nails are typically driven into the workpiece by a hammer, a pneumaticnail gun, or a small explosive charge or primer. A nail holds materials together by friction in the axial direction and shear strength laterally. The point of the nail is also sometimes bent over or clinched after driving to prevent pulling out.