Cotter Pin & Split Pin Manufacturer | Custom Fasteners

Cotter Pins and Split Pins are among the most trusted retention fasteners in mechanical engineering. A Cotter Pin, also commonly called a Split Pin, is a half-round wire fastener folded back on itself to form two legs. Once inserted through a hole in a shaft, bolt, or castle nut, the legs are separated and bent to lock the assembly in place. This simple yet effective design prevents loosening under vibration, making Cotter Pins essential in automotive steering systems, aircraft controls, agricultural equipment, and industrial machinery. The terminology varies across markets: in North America, the term Cotter Pin typically refers to the split, two-legged fastener, while in the United Kingdom and many Commonwealth countries, the same component is called a Split Pin. In some regions, a Cotter Pin may refer to a tapered pin, so clear specification is critical when sourcing internationally. We help global buyers avoid confusion by confirming dimensions, material grades, and performance requirements before production. Material selection directly affects performance. Stainless steel Split Pins resist corrosion in marine and chemical environments, zinc-plated carbon steel Cotter Pins suit general industrial use, and brass Split Pins serve electrical and decorative applications. Our production process combines forging, cold heading, CNC machining, and stamping, allowing us to control leg spread, chamfer quality, and surface finish precisely. With 8 forging machines including 630T and 300T models, 10 multi-station cold heading forming machines, over 100 CNC lathes, 50 CNC machining centers, 20 turning-milling composite machines, and 10 centering machines, we match the right process to each Cotter Pin and Split Pin order.