Whats The Difference Between A Bolt And A Screw?

It’s a question we hear surprisingly often. Since they are commonly used interchangeably, you might think they are the same. However, there are distinct differences that make a bolt and screw different.

Bolts Vs. Screws

Bolts:

A bolt is a fastener with threads and a head that is intended and designed to be used (installed) with a nut. Bolts are not intended to hold themselves into a material and rely on that nut to provide the holding tension needed. A bolt must protrude from the other side of a material in order to be fastened. Bolts are more commonly used with washers than screws.

Screws:

Screws are also a threaded faster, but can either have a head or lack one entirely, (ex. set screw). Screws are designed to be installed in a pre-drilled hole, or they are engineered to tap their own hole with the threading while being installed. They do not use a nut and secure themselves by being tightened into their hole. Screws are not meant to appear on the opposite side of the material they are being drilled into, even though you will often see screws poking through roofs and wood. While they are less often used with washers, it is common to see finishing cup washers used to make a clean finished look for flat head and oval head screws.

“That’s Not What Your Site Says”

Although we go over the differences here, you will notice Albany County Fasteners uses “bolt” and “screw” somewhat interchangeably on the website. We do this because sometimes a product is better known by a different name that may not be  it’s “formal” name, but we speak your language and we want to help you find it. For example, a Lag Screw is sometimes referred to as a Lag Bolt; this is for customer convenience as it is more commonly, informally called a lag bolt than a lag screw.