What is a cotter pin?

A cotter pin, also known as a split pin or cotter key, is a metal fastener typically used to secure two components together in a manner that allows for easy disassembly. It is a simple and effective fastening device that consists of a pin with one end split and bent back to form two prongs that can be inserted through a hole to hold the components in place.

Cotter pins are commonly used in various applications such as securing clevis pins, castle nuts, and other fasteners in machinery, automotive, and construction equipment. They are often made of stainless steel, brass, or other corrosion-resistant materials to ensure durability and longevity.

Cotter pins come in various sizes and configurations to accommodate different types of fastening requirements. They are easy to install and remove, making them a versatile and essential tool for many mechanical and engineering applications.