What Are Bolts?

Bolts are fasteners that attach one piece of metal or other material to another. They come with a nut that fits over the bolt shank to create a secure connection. These components can be used in a wide variety of materials and applications, from structural and automotive to manufacturing and electronics. The selection of the right type of bolt depends on several critical considerations, such as load bearing capacity, strength, and material compatibility.

While screws have their place in certain applications, bolts are the preferred choice for high-load and structural applications. They have a higher load-bearing capacity, provide significant clamping force, and distribute stress more evenly to prevent stress concentrations. In addition, they can be used in a wide range of materials and are compatible with most other types of fasteners.

The primary bolt dimensions that determine strength are diameter, length and thread pitch. Diameter is the width of the bolt shank; length is its total length from the underside of the head to the tip of the bolt. The thread pitch is the distance between the apexes of the bolt’s threads per unit of its length.

In general, bolts are made from a combination of copper alloys, aluminium, brass and steel. The alloys make bolts hard, strong, lightweight and corrosion resistant. Steel bolts are available in standard and stainless steel grades. The latter are highly valued for their ability to function well in a wide range of temperatures and conditions, including the presence of salt water and acidic chemicals. Stainless bolts also don’t release toxic substances when heated, making them an environmentally friendly choice for many applications. Other finish options for bolts include black oxide, hot dip galvanizing and chrome plating. These finishes add durability, prevent corrosion, and improve the aesthetic appearance of bolts.