Demystifying Oil Seals: Types, Materials, and Selection

It is crucial to utilise oil seals to prevent the accidental leakage of lubricant and potential damage to sensitive internal components. Also known as rotary shaft seals, oil seals play a vital role in this process but, because they are available in a variety of types, sizes, and materials, it can be challenging to select the right ones for each industrial application.

In this article, we’ll demystify these essential components, focusing on their types and materials, and discussing how to select the right one for your precision engineering machinery.


Oil Seal Types 

When it comes to types of rotary shaft oil seals, there's a variety from which to choose, with the Trusted Containment (TC) seal being one of the most common.

Often referred to as the R23, TC oil seals feature a distinctive double-lip design that is equipped with a self-tightening spring. This innovative design ensures effective containment and sealing of lubricants, making them a preferred choice in various applications. The double-lip of TC seals offers enhanced sealing capabilities, especially in environments in which preventing contamination is critical.

Oil Seal Sizes 

Oil seals are sized based on three critical dimensions:

  • Inside Diameter (ID)
  • Outside Diameter (OD)
  • Width (W)

Typically, standard sizes are marked directly on the seal which simplifies the process of identifying and ordering the correct seal for your specific application. However, if you are unsure which size seal you require, it’s advisable to seek professional advice from the experts at BTL UK.


Oil seals are manufactured from a variety of materials, each of which is suited to specific operational needs, so it is important to select the most appropriate one for your application. NBR/Nitrile and FKM/Viton are popular due to their compatibility with a variety of operating conditions.

  • NBR/Nitrile: Known for its excellent heat resistance and durability, NBR/Nitrile is a versatile material suitable for a range of applications.
  • FKM/Viton: As well as excelling in high-temperature environments, FKM/Viton is renowned for its strong resistance to chemicals and heat.

Find Out More 

At BTL-UK, we are a trusted oil seal supplier who will ensure that your precision engineering equipment is protected against lubrication leaks, excessive friction, and overheating. To find out more, please call us on 01233 542267 to speak to an expert.

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