What Is the Difference Between a Screw and Bolt?

difference-between-screw-bolt Credit: Ryouchin/Digital Vision/Getty Images

A screw is a fastener that has a ridge or thread encircling the entire length of the device, while a bolt has a smooth shaft and a threaded end. Screws have heads with a depression indicating the type of driver necessary for fastening. Bolt heads are manipulated with a wrench and often have hexagonal designs.

Screws and bolts are fasteners used for various types of construction and repair. They have different heads and body designs that make each of them uniquely appropriate for certain projects. The specification allows for ease of assembly and greater durability of final products.

A screw is an externally threaded post that bears ridges all the way down the length of the shaft. This threading helps dig into the surface of the pieces being screwed together, making it difficult to pull the materials apart and providing greater support in solid objects. Screws are perfect for drywall and wood.

A bolt is a smooth length of metal with a substantial head and a threaded tip. It is paired with a nut on the end that is fastened to the threading and provides reinforcement while also permitting materials to expand and contract without creating as much friction. Bolts are ideal for metal structures.