What is AS568?
AS568 is the Aerospace Standard for O-ring sizes, established by the Society of Automotive Engineers (SAE). It defines standard dimensions for O-rings used in aerospace and industrial applications, ensuring interchangeability and reliability.
AS568 Size Naming Convention
AS568 O-rings are identified by a dash number (e.g., AS568-123):
- AS568- indicates compliance with the standard
- Number identifies the specific size
Common AS568 Sizes
| Size | ID (inch) | CS (inch) | ID (mm) | CS (mm) |
|---|---|---|---|---|
| AS568-001 | 0.029 | 0.040 | 0.74 | 1.02 |
| AS568-010 | 0.089 | 0.070 | 2.26 | 1.78 |
| AS568-020 | 0.149 | 0.070 | 3.78 | 1.78 |
| AS568-110 | 0.736 | 0.103 | 18.69 | 2.62 |
| AS568-120 | 0.984 | 0.139 | 25.00 | 3.53 |
| AS568-214 | 1.984 | 0.139 | 50.39 | 3.53 |
| AS568-325 | 3.734 | 0.210 | 94.84 | 5.33 |
How to Measure an O-Ring
To identify your O-ring size, measure:
- Inner Diameter (ID): Measure the inside opening
- Cross Section (CS): Measure the thickness/diameter of the ring itself
Then compare to the AS568 chart to find the matching standard size.
Why Standard Sizes Matter
- Interchangeability: Easy replacement across suppliers
- Availability: Standard sizes are always in stock
- Cost-effective: No custom tooling required
- Proven performance: Sizes are engineered for optimal sealing
Conclusion
AS568 standard sizes make O-ring selection simple. Browse our complete catalog of AS568 O-rings in NBR, FKM, EPDM, and Silicone materials.
Can't find your size? Contact us for custom O-ring solutions.
