Which of the following materials is NOT commonly used for door hardware?

The correct answer is wood. In typical construction and carpentry practices, materials such as metal, plastic, and other composites are predominantly used for door hardware, including hinges, locks, and handles.

Wood is primarily utilized in the making of doors themselves rather than the hardware components. Conventional door hardware requires materials that provide strength and durability, which wood alone may not offer in this specific application. Metal and reinforced materials are often preferred for their wear resistance and structural integrity.

Cement, while not a typical material for hardware, may be used in broader applications such as structural components, but it is not associated with movable door hardware. Rubber might be utilized in gaskets or seals for doors to prevent drafts or noise. Slate is more commonly found in roofing or flooring rather than in door hardware.