Nails are the carpenter’s most useful fastener. Many nail types and sizes are available to meet the demands of the industry. On any kind of construction work, an important consideration is the type and size of nails to use.

An important factor in selecting nails is size. Long, thin nails will break at the joints of the lumber. Short, thick nails will work loose quickly. The kind of wood is a big factor in determining the size of nail to use.

Wood screws are often used in carpentry because of their advantage over nails in strength. They are used in installing various types of building hardware because of their great resistance to pulling out and because they are more or less readily removed in case of repairs or alterations.

There are generally three standard types of screw heads: the ?at countersunk head, the round head, and the oval head. All of these can be obtained in crossed slot, single straight slot, or Phillips slot.

Lag screws or lag bolts are heavy-duty wood screws that are provided with a square or hexagonal head so that they are installed with a wrench. These are large, heavy screws that are used where great strength is needed, such as when working with heavy timber and beam installations. Holes are generally bored into the wood because the diameter of lag screws is large.

A bolt is generally regarded as a rod having a head at one end and a threaded portion on the other to receive a nut. The nut is usually considered as forming a part of the bolt. Bolts are used to connect two or more pieces of material when a very strong connection is required.

Various forms of bolts aremanufactured tomeet the demands and requirements of the building trade. The common machine bolt has a square or hexagonal head. The carriage bolt has a round head; the stove bolt has a round or countersunk head with a single slot. Lock washers are used to prevent nuts from loosening. Other fasteners are the toggle, Molly, and expansion bolt.