What are split pins?

Split pins, also called cotter pins or split cotter pins, are a basic type of metal fastener. Split pins are normally constructed from a piece of wire or metal that is folded in half. Split pins have two tines (or prongs) with an eyelet at the bend.

What are split pins made from?

Split pins need to be strong enough to hold components in place, but flexible enough to be bent to secure the fastening. Split pins are typically made from aluminium, brass or stainless steel. Some pins feature zinc plating or have been galvanised. This offers protection against corrosion.

How do I use a split pin?

Split pins are typically used to fasten a shaft or similar component in place. Split pins can also be used to keep machinery aligned.

The pin is placed through a hole and the prongs (or tines) of the pin can then be bent to hold the pin in place. You may need a set of pliers or additional tools to help you bend the tines. The tines can also be cut down to size before installation. This can prevent any snagging injuries from occurring in future.

Split pins are similar to staples in that they are a temporary, light duty fastening. Split pins can be used as a fastener in their own right or combined with other types of fastenings such as clevis pins.

Can I reuse a split pin?

It is not recommended to reuse split pins. After the initial installation, the tines will have been bent. Trying to reshape the prongs of the split pin again can damage the integrity of the pin and cause weakness on the tines. If used again, the pin and fastening may fail.