Cotter Pins

Cotter pins are a widely used simple fastener that help to secure a nut or bolt in place and prevent it from loosening. Cromwell provide a range of lengths and diameter to suit your needs from suppliers Kennedy and Qualfast.

What are cotter pins?

Cotter pins, also known as split pins or cotter keys are a simple metal fixing fastener that have two parallel prongs with a U shape eyelet bend, which is inserted into nuts and bent to firmly hold and lock them into position. They are usually made from metal that are both strong enough to hold in place but also can be easily bent into shape such as brass, stainless steel and aluminium.

When are cotter pins used?

Cotter pins are used almost everywhere to either hold firmly in place or ensure alignment in machinery. Split pins can be used as part of a combination with other types of fixings or independently.

Considerations when choosing a cotter pin

Nom. Hole Diameter  -    There are a range of hole diameter sizes available, to ensure correct fit consideration to the diameter of the hole size should be considered.

Material  -    Cotter pins are available in different materials, some are less supple than others, this will be a vital consideration at selection.

Length  -    It is crucial to ensure the length of the cotter pin is suitable for your purpose.

System of Measurement  -    Cotter pins are produced in different measurement units that include metric and imperial, to ensure correct installation compatibility should be considered at selection.

Cotter pins jargon buster

DIN  -    Approval from the German institute for standardisation.


Can I reuse a cotter pin?

It is advised that cotter pins should not be reused as once used they become weak and not able to hold in place.