A strap hinge is a type of basic hinge hardware, technically a type of bearing, consisting of two long narrow pieces, usually of metal, connected by a metal rod called a pin. The pin passes through metal loops at the end of the hinge sections that are designed to line up and interlock with each other, forming a pivot. The straps themselves are attached to objects, such as a trunk body and lid, and serve to connect the two objects as well as to allow rotational movement at the pivot point, such as when raising the lid on the trunk. The long narrow pieces, which can resemble straps, give this type of hinge its name. A typical strap hinge has holes for accepting screws. Strap hinges are a very common type of hinge, particularly on doors, steamer trunks and gates and can be functional as well as decorative.
One of the earlier types of hinges, a strap hinge is a very basic and simple hinge that was, in earlier times, usually made from cast or wrought iron. This history is reflected in many decorative strap hinge designs that are made to resemble these older styles, often with motifs depicting arrows, spears, or fleur-de-lis type designs. Sometimes these rustic looking strap hinges are made from wrought or cast iron, although they are commonly made from another metal and painted with a flat black finish to resemble the older iron styles.
Depending on the application, a strap hinge may have matching or similar long metal pieces, such as those found on steamer trunks, or one long piece paired with a short, square, rectangular, or decorative piece. This type of strap hinge is common on doors. The long strap is attached to the door and the small base piece is attached to the frame which is too narrow, or otherwise unable, to accept a second strap like section. In some cases, again using a trunk as an example, the strap hinges may be curved to fit the shape of an object as necessary.
As a basic type of hinge, strap hinges can be found in a wide array of sizes, designs, materials and finishes. Stainless steel, brass, and galvanized steel are some of the more common materials for these hinges. Strap hinges, depending on size, may have a varying number of holes for screws, and these holes can vary in size depending on the intended application and type of screw. Some strap hinges are merely stylistic elements and do not actually serve the function of a hinge at all. These are called dummy hinges and and are often used on doors or gates as decoration, while more traditional hinges, which are hidden from view, are the true pivot point.