Like nails, screws come in a dizzying array of styles and materials that make them useful around the house. Flathead screws are used when the screw will be hidden, whether it's a drywall screw, which will be covered with plaster, or the type of screw that holds a door hinge in place. Screws with rounded heads have a dressier look. These are used when the screw is visible, such as on exposed hinges on cabinets or on doorknobs and window latches.

Screws get their holding power from the little grooves they form in wood or plaster, which act like wedges to hold them in place. Because of this, they can't be pulled out by force without ripping apart the wood or plaster as well. Whatever kind of screw you use, always predrill a hole for a stronger connection. Screwing into undrilled wood compresses the wood fibers and diminishes the screw's advantage.