The Complete Handbook of Chains

Chapter 1: Understanding Chains

A chain is a series of links connected by pins or rivets, designed to transmit force—usually pulling force—from one point to another. That simple description covers everything from the roller chain on a motorcycle sprocket to the massive Grade 100 alloy chain holding a ship's anchor. But to understand why chains matter and how to use them correctly, you need to know more than the definition. You need to know what chains actually do, where they appear, why they fail, and what makes one chain fundamentally different from another.

What Chains Actually Are

At the most basic level, a chain is a load-bearing mechanism made of metal links joined so that they can bend and flex while staying connected. The two primary components are the links (the ring-shaped pieces) and the pins or rivets (the pieces that hold the links together). The specific geometry of those links and the spacing between pins is called the pitch. Pitch matters because it determines whether a chain will mesh with a sprocket, whether it can support certain loads, and how it will behave under stress.

The key to understanding chains is that they transmit force through a series of small contact points. Unlike a rope, which distributes load somewhat evenly across its entire cross-section, or a steel rod, which is a solid piece, a chain concentrates the load at each pin and link junction. This means that the strength of a chain depends not just on the material used