The Comprehensive Guide To O-Ring Size Chart Parker Finding the Perfect Fit

O-Ring Size Chart Parker

O-rings are humble yet indispensable components that play a vital role in sealing applications across a myriad of industries. From aerospace and automotive to pharmaceuticals and plumbing, these small circular wonders prevent leaks, contamination, and fluid escape. With numerous manufacturers in the market, Parker Hannifin Corporation stands out as a leading expert in motion and control technologies, including O-rings.

In this comprehensive guide, we will delve into the world of O-Ring Size Chart Parker, exploring the diverse types, materials, and sizing options available. Whether you’re a seasoned engineer, a DIY enthusiast, or simply someone seeking the right O-ring for a household project.

What are O-Rings?

O-rings are circular sealing elements typically made from elastomers like nitrile rubber, silicone, fluorocarbon (Viton), or EPDM. Their simple, doughnut-shaped design allows them to fit securely between two mating surfaces, creating a reliable seal that prevents fluid or gas leakage.

How do O-Rings Work?

When placed in a groove between two components, O-rings are compressed, which causes them to exert an outward force against the surfaces they seal. This deformation creates a tight, leak-proof seal that can withstand a range of pressures and temperatures.

Founded in 1917, Parker Hannifin Corporation has established itself as a global leader in motion and control technologies. With over a century of experience, the company has become synonymous with reliability, innovation, and exceptional engineering.

Why Choose Parker O-Rings?

Parker’s O-rings are known for their high-quality materials, precision manufacturing, and superior performance in critical applications. The company offers a vast selection of O-ring sizes, making it easier for customers to find the perfect match for their sealing needs.

Types of O-Rings Offered by Parker:

Parker provides an extensive range of O-ring types, each catering to specific applications and industries. Some of the most common types include:

  • Standard O-Rings

Standard O-rings are the most commonly used type, designed for general sealing purposes across a wide range of industries. They come in various materials, sizes, and cross-sections to accommodate different applications.

  • X-Rings

X-rings, also known as quad rings or four-lip seals, are an alternative to traditional O-rings. Their unique four-lobed design offers improved sealing efficiency and reduced friction in reciprocating applications.

  • Square-Rings

Square rings, as the name suggests, have a square-shaped cross-section. They provide a higher sealing capacity than standard O-rings and are often used in applications with higher pressures.

  • Backup Rings

Backup rings are used in conjunction with O-rings to prevent extrusion and improve overall sealing performance in high-pressure applications.

  • Encapsulated O-Rings

Encapsulated O-rings are O-rings with a coating or jacket made from materials like FEP or PTFE. This additional layer provides enhanced chemical resistance and prevents the O-ring from being damaged or contaminated.

Understanding O-Ring Sizes A Deep Dive:

Selecting the right O-ring size is crucial for achieving an effective seal. Fortunately, Parker offers an O-ring size chart that simplifies the process of finding the perfect fit.

  • Decoding the Parker O-Ring Size Chart

Parker’s O-ring size chart follows industry-standard sizing conventions, making it compatible with most applications. The chart includes two essential dimensions: the inside diameter (ID) and the cross-sectional diameter (CS). The CS determines the O-ring’s thickness when viewed in a radial cross-section, while the ID represents the inner diameter of the ring when it is in a relaxed state.

  • Metric and Imperial Measurements

Parker’s O-ring size chart caters to both metric and imperial measurements, ensuring compatibility with various systems of measurement used worldwide. The chart typically lists sizes in millimeters for metric and inches for imperial measurements.

  • AS568 Standard Sizes

The American Society of Mechanical Engineers (ASME) developed the AS568 standard, which assigns unique dash numbers to O-ring sizes. These dash numbers correspond to specific ID and CS measurements, providing a standardized labeling system for O-rings in the USA.

  • Global O-Ring Sizing Standards

While AS568 is commonly used in the USA, there are other global sizing standards for O-rings, such as the Japanese Industrial Standard (JIS) and the International Organization for Standardization (ISO) metric sizes. Parker’s O-ring size chart includes these global standards, allowing customers worldwide to find the right O-ring with ease.

Factors Affecting O-Ring Size Selection:

Choosing the correct O-ring size involves considering several factors that can influence the seal’s effectiveness and longevity.

  • Groove Dimensions

The groove where the O-ring will sit must be precisely measure to ensure a proper fit. The groove width and depth are crucial in preventing over-compression or extrusion of the O-ring.

  • Temperature and Pressure

The operating temperature and pressure of the application significantly impact the O-ring’s material selection and size. Extreme temperatures or pressures may require specialized O-rings to maintain optimal performance.

  • Chemical Compatibility

Different O-ring materials have varying resistance to chemicals and fluids. It is essential to choose a material that is compatible with the specific media it will come into contact with.

  • Cross-Sectional Diameter (CS)

The cross-sectional diameter of the O-ring must be appropriate for the width of the groove. A larger CS may lead to over-compression, while a smaller CS may not provide an adequate seal.

  • Inside Diameter (ID)

The inside diameter should match the shaft or piston diameter precisely to ensure a proper seal. An O-ring with an incorrect ID may lead to leaks or premature failure.


O-rings play a crucial role in sealing applications across diverse industries, and Parker Hannifin Corporation offers an extensive selection of O-rings to meet the needs of various applications. Understanding the O Parker Ring Size Chart provides is essential for selecting the perfect fit, and factors such as groove dimensions, temperature, pressure, and chemical compatibility should be consider to ensure an effective and durable seal.

Next time you embark on a project that requires O-rings, you can confidently navigate Parker’s O-ring size chart and make an informed choice. Remember, these small yet mighty components are the unsung heroes that keep the world running smoothly, one perfect seal at a time.

David Wilson
Author: David Wilson

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