Cotter Pin Types: Uses, Size Chart


The cotter pin is used to fix different parts with special arrangements. Cotter pin types:

  • Split type cotter
  • Spring cotter pin
  • Tapered pin
  • Barrel type cotter pin
  • Dipped cotter
  • R type pin
  • Straight cotter
  • Split cotter pins

A cotter pin is a simple pin used to join two-part. It is passed through the holes between two-part to join or fix them. It is also known as a split pin in some countries.

cotter pin types
Split pin Credit Wikipedia

The cotter pins are available in various sizes and shapes. It is designed according to the applications and the load.

cotter pin types
Split pin Credit Wikipedia

Generally, these pins are manufactured from semi-circular wire with good hardness. The tapered pins are used to prevent the motion of the shaft in an axial direction.

R clip Credit Wikipedia

The tapered type of pin will face compression force in working conditions. This compressive force generates frictional force due to the tightness of the pin. Due to this friction force, the motion of the shaft is prevented.

Cotter pin size

The dimension of the cotter pin is decided based on the applications.

The length of the cotter pin is the distance from the eye portion to the short side of the pin. The diameter of the pin is to be measured more than the hole.

The eye of the pin is bigger than the diameter of the hole. The pin should fit properly through the hole based on the dimension.

Pin sizes Credit Wikipedia

In actuality, the length of the pin is not fixed for every pin. It is manufactured based on the connections. The pin is measured from the connection of the pen and hole to the large end of the pin.

The size of the cotter pin starts from 1/32. There are two main dimensions of the cotter pin. One should know the length of the pin and the diameter of the pin.

The usage of the prongs is securing the connections properly. The hammer is used to increase the prong size. The prongs are used in some applications to better lock a pin in the hole. It does not allow the pin to escape from the hole.

Some precautions

  • The use of cotter pins is only once, Don’t reuse the pin.
  • The cotter pin should have a larger dimension than the hole.
  • The safety wire is the necessary part of the cotter pin. It is inserted properly through the pin.

Split pin vs. cotter pin

A cotter pin and split pin are locking devices used in various applications.

The material used to manufacture cotter pins and split pins is different. For the cotter pin, The material is mild steel (MS). The split pin is manufactured from grade steel.

The general use of a cotter pin is to lock the nut with the bolt. The cotter pin is kept in a hole provided in the bolt so that the nut cannot go out from the bolt. The cotter pin is bent to prevent the nut’s movement on the bolt.

Cotter pin uses

There are large applications of the cotter pin in various types of machinery.

A cotter pin prevents nut’s falling out due to vibrations. It is used in various types of machinery where the nut and bolt are present. It is a device that can easily fix locking problems.

The Replacement of the cotter pin is easy than another locking device. It can be easily removed from the machinery without interfering with other components.

There are many other locking nuts and devices available in equipment. A cotter pin only fails if the shear force is extreme. Its performance is far better than another locking device. For a while, any locking device fails due to continuous vibrations.

A cotter pin prevents the loosening of the nut. The cotter pin is only possible if the hole is provided in the bolt. There are some bolts available without a hole in them. If we want to fix a nut tightly in any equipment, we must have a bolt with the drilled hole.

The bolt is specially designed to use the cotter pin. There are two prongs in the construction of the cotter pin. The prongs are twisted in the opposite direction of each other to improve safety. It is recommended in all cases to twist the ends of the cotter pin. It is a low-cost fastener but saves huge machinery to get fail.

It prevents the nuts to get fall out in any vibration conditions.

What is cotter pin?

There is requirement of locking the nut with bolt in proper manner.

Vibration is a crucial issue in any machinery. It is critical to prevent all the bolts and nuts from vibrating conditions. A cotter pin is a device used to solve this problem in machinery.

It is famous in any place to lock the nut and bolt. It is a rode shape pin manufactured from mild steel. The construction of the pin is simple with the low cost of manufacturing. The eye is provided in a cotter pin larger than the hole diameter.

It is easy to replace the cotter pin in any machinery. The cost of the cotter pin is more nominal than other locking devices. Sometimes, a simple wire is used to lock nuts in emergency conditions.

Deepakkumar Jani

I am Deepak Kumar Jani, Pursuing PhD in Mechanical- Renewable energy. I have five years of teaching and two-year research experience. My subject area of interest are thermal engineering, automobile engineering, Mechanical measurement, Engineering Drawing, Fluid mechanics etc. I have filed a patent on "Hybridization of green energy for power production". I have published 17 research papers and two books. I am glad to be part of Lambdageeks and would like to present some of my expertise in a simplistic way with the readers. Apart from academics and research, I like wandering in nature, capturing nature and creating awareness about nature among people. Let's connect through LinkedIn - https://www.linkedin.com/in/jani-deepak-b0558748/. Also refer my You-tube Channel regarding “Invitation from Nature”

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