Internal vs. External Retaining Rings: Choosing the Right One

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Retaining rings, also known as snap rings or circlips, are essential components in various mechanical and industrial applications. They serve the critical function of holding components in place on a shaft or within a bore, preventing axial movement, and ensuring the integrity of the machinery. However, when it comes to selecting the appropriate anillo de retención for a specific application, there is an important decision to be made: internal or external.

In this comprehensive guide, we will delve into the world of internal and external retaining-rings, exploring their differences, applications, and factors to consider when choosing one over the other.

Understanding Internal and External Retaining Rings

Before we can make an informed choice between internal and external retaining-rings, it’s crucial to understand the fundamental differences between these two types.

Internal Retaining Rings

Internal retaining-rings are designed to be installed inside a bore or a housing. They consist of a circular or semicircular piece of metal with small gaps or discontinuities in their circumference. These gaps allow the ring to be expanded or contracted for easy installation and secure retention. Internal retaining-rings are ideal for applications where components need to be held within a cylindrical bore, preventing them from moving outward.

External Retaining Rings

External retaining-rings, on the other hand, are intended to be installed on the outside of a shaft. Like their internal counterparts, they also have gaps or discontinuities around their circumference, enabling them to expand or contract. External retaining rings are used when it is necessary to keep components from moving off the end of a shaft.

Factors to Consider

When deciding between internal and external retaining-rings, several factors come into play, including the application’s requirements, diseño constraints, and other considerations.

  1. Application Type

Consider the specific application and the role of the retaining ring. If you need to retain components within a bore, internal retaining-rings are the logical choice. Conversely, if the goal is to secure components on a shaft, external retaining-rings are the way to go.

  1. Space Constraints

The space available for installation can significantly influence your choice. Internal retaining-rings occupy space within a bore, while external retaining rings do not intrude into the bore or housing, which can be beneficial when space is limited.

  1. Shaft Diameter and Tolerance

The size and tolerance of the shaft or bore are critical. Internal retaining-rings must fit snugly within the bore, while external rings must fit securely around the shaft. Ensure that you measure the dimensions accurately and select the appropriate retaining ring size.

  1. Axial Load and Thrust

Consider the forces acting on the retained components. If the application involves substantial axial loads or thrust forces, make sure that the retaining-ring you choose is capable of withstanding these forces without deformation or failure.

  1. Operating Environment

Environmental factors such as temperature, moisture, and exposure to chemicals can affect the choice of retaining ring material. It’s essential to select a material that can withstand the conditions in which the machinery will operate.

  1. Installation and Removal

Ease of installation and potential future removal should be considered. Internal and external retaining-rings require different methods and tools for installation and removal. Choose the type that aligns with your maintenance and repair procedures.

  1. Cost Considerations

Cost is always a consideration in engineering and manufacturing. While internal and external retaining rings may have similar functionality, there can be variations in cost depending on factors such as size, material, and quantity.

Anillo de retención en espiral personalizado


Both internal and external retaining rings find applications across various industries and machinery. Here are some common uses for each type:

Internal Retaining Rings:

  • Automotive Industry: Internal retaining-rings are often used in transmission systems to secure gears and bearings within housings.
  • Aerospace: They can be found in aircraft engines to retain components within cylindrical bores.
  • General Machinery: Internal rings are widely used in industrial machinery, such as pumps, to secure impellers and bearings.

External Retaining Rings:

  • Automotive Industry: External retaining-rings are employed in wheel hubs to prevent wheels from sliding off the axles.
  • Agriculture: They can be found in farm machinery to secure various components on rotating shafts.
  • General Manufacturing: External rings are used in assembly applications for holding components in place on rotating shafts.

Installation and Removal

Proper installation and removal techniques are essential for the effectiveness and serviceability of retaining rings. Here’s an overview of the procedures for each type:

Installing Internal Retaining-Rings:

  • Insert the internal retaining-ring into the bore, ensuring it is properly positioned.
  • Use specialized internal retaining-ring pliers to expand the ring and secure it in the groove.
  • Ensure the ring is fully seated and properly engaged.

Removing Internal Retaining Rings:

  • Use internal retaining-ring pliers to compress the ring and remove it from the bore.
  • Exercise caution to avoid damaging the ring or the bore during removal.

Installing External Retaining Rings:

  • Slide the external retaining-ring over the shaft, ensuring it is properly positioned in the groove.
  • Use external retaining-ring pliers or other appropriate tools to expand the ring and secure it in place.
  • Verify that the ring is fully engaged and holding components securely.

Removing External Retaining Rings:

  • Use external retaining-ring pliers or specialized tools to compress the ring and carefully slide it off the shaft.
  • Handle the ring with care to avoid deformation or damage during removal.


The choice between internal and external retaining rings is a critical one that directly affects the functionality and reliability of machinery and components. By considering the application requirements, space constraints, forces involved, environmental conditions, and other factors, you can make an informed decision to select the right type of retaining-ring.

Ultimately, the proper selection and installation of retaining-rings ensure the safety, longevity, and performance of machinery in a wide range of industries. It’s a decision that engineers, designers, and maintenance professionals must make with care and precision to meet the demands of their specific applications.

In summary, whether you opt for internal or external retaining rings, choosing the right one is about maintaining the integrity and functionality of your machinery. Make your selection wisely, and your equipment will continue to perform reliably for years to come.