Split pins (cotter pins) are a reliable, one-time-use locking device for castellated nuts, clevis pins, and castle-nut assemblies — providing a positive, visible safeguard against nut rotation. Part number CA280. Champion split pins are available in metric and imperial sizes, in zinc-plated steel and stainless steel. Where this tool is used Locking castellated and castle nuts on vehicle wheel bearings, steering components, and brake systems. securing clevis pins and linkage pins in agricultural and industrial machinery. General maintenance and workshop applications. Selecting the right option Select the split pin diameter to pass through the castle nut slot and clevis pin hole with minimal clearance. Replace split pins on every re-assembly — never re-use a bent or removed split pin.