![\"Cotter](\"https:\/\/blog.monroeaerospace.com\/wp-content\/uploads\/2026\/09\/a1519__43041-300x59.webp\")
<\/figure>\nIf you\u2019re planning to use a cotter pin, you\u2019ll need to choose the right type. Also known as a split pin, it offers a simple solution to prevent parts from coming loose. Cotter pins are inserted through predrilled holes in shafts or bolts, after which they are deformed. Deforming a cotter pin will prevent it from falling out of the hole, thereby holding the parts together. There are different types of cotter pins, however. Here are five important things to consider when choosing one.<\/p>\n
#1) Material<\/h2>\n
You should consider the material when choosing a cotter pin. Common materials in which they are made include stainless steel and carbon steel. Stainless steel cotter pins offer a superior level of protection against rust and corrosion. They feature a higher chromium content, which acts as a protective barrier to prevent oxidative damage that could otherwise cause rust and corrosion. Carbon steel cotter pins, on the other hand, offer a superior level of strength. They feature a higher carbon content, which increases their strength.<\/p>\n
#2) Diameter<\/h2>\n
Some cotter pins are thicker than others. Cotter pins, of course, need to fit through the hole in which they are inserted. If a cotter pin is too thick, it won\u2019t fit. Conversely, if it\u2019s too thin, it may fit loosely while subsequently failing to secure the fastened parts. You can avoid problems such as these by choosing a cotter pin in the right diameter.<\/p>\n
#3) Length<\/h2>\n
Equally important when choosing a cotter pin is the length. Cotter pins need to extend all the way through the hole so that the legs can be bent. If a cotter pin just barely extends past the hole, you may not be able to bend the legs, in which case the pin won\u2019t hold the parts together. If a cotter pin is too long, though, it may be difficult to install and access, especially in spaces where access is limited.<\/p>\n
#4) Extended vs Standard Prong<\/h2>\n
Something else to consider is whether you want a cotter pin with a standard or extended prong style. The legs of a cotter pin are the prongs. All cotter pins have two legs or prongs. Standard prongs are of equal length. Extended prongs mean that one of the legs or prongs is longer than the other. This typically makes installation easier. You can grab and bend the longer prong without the shorter prong getting in your way.<\/p>\n
#5) End Type<\/h2>\n
Don\u2019t forget to consider the end type when choosing a cotter pin. Whether standard or extended prong style, cotter pins can have different end types. Some of them have mitred ends where the prongs are angled or pointed at the ends. Other cotter pins have \u201chammer lock\u201d ends that allow for quick and easy deformation with a hammer.<\/p>\n