AS568 inch O-rings
Source by SAE AS568 dash number for inch-based designs, ports and replacement requirements.
Send dash number, compound, hardness and quantity.Review requirements →Standard, metric and custom sealing
O-Ring Manufacturer and Supplier for Industrial Applications
Source O-rings by AS568 dash number, ISO 3601 metric size, inside diameter × cross-section, or drawing. We review the compound, hardness, dimensions and service conditions together.
- AS568 inch sizes
- ISO 3601 metric sizes
- Custom requirements
- Drawing or sample review
Find the O-ring you need
Start with a standard size, drawing or existing seal
A reliable specification combines size, elastomer compound, hardness and operating conditions—not color or nominal diameter alone.
ISO 3601 and metric O-rings
Specify by standard designation or inside diameter × cross-section in millimetres.
State the tolerance class or drawing requirement.Review requirements →Custom O-rings
Non-standard dimensions, compounds and tolerances reviewed from a controlled drawing.
Include annual volume and validation requirements.Review requirements →Replacement and MRO O-rings
Identify an obsolete or unmarked seal from dimensions, groove data, equipment details or a sample.
Do not identify material from color alone.Review requirements →Dimensions and quality
O-ring standards and size identification
A size standard identifies dimensions. It does not by itself define the compound, hardness, operating limit or regulatory status.
| Reference | What it addresses | What to send with an RFQ |
|---|---|---|
| SAE AS568 | Inch O-ring inside diameters, cross-sections, tolerances and dash numbers. | Dash number, compound, hardness and quantity |
| ISO 3601-1 | O-ring dimensions, tolerances and designation codes. | Size/designation, tolerance class, compound and hardness |
| ISO 3601-2 | Housing dimensions for general applications. | Application type, hardware, pressure direction and duty |
| ISO 3601-3 | Quality acceptance criteria for O-rings. | Required grade and inspection documentation |
| ASTM D1418 | Standard nomenclature for rubber families. | Polymer designation, such as NBR, EPDM, FKM or VMQ |
| ASTM D2000 / SAE J200 | Classification framework for vulcanized-rubber properties. | Complete material callout and suffix requirements |
| ASTM D2240 | Durometer hardness test method. | Shore A hardness, tolerance and report requirement |
AS568 inch sizes
Common nominal cross-section groups include 0-series at 0.070 in / 1.78 mm, 100-series at 0.103 in / 2.62 mm, 200-series at 0.139 in / 3.53 mm and 300-series at 0.210 in / 5.33 mm. Always use the exact dash-number dimensions and tolerances.
Metric sizes
Specify inside diameter × cross-section in millimetres and cite the applicable ISO 3601 designation or drawing tolerance. Confirm the quality acceptance requirement separately.
Compound selection
Compare O-ring materials
Polymer family is only a shortlist. Fillers, cure systems and formulation changes affect chemical resistance, temperature capability and compression set.
| Material | Reasons to consider | Important limitations to check | Common industrial use |
|---|---|---|---|
| NBR / Buna-N | Petroleum oils, lubricants and general hydraulic or pneumatic service. | Ozone, weather, polar solvents, brake fluid and temperature limits. | Fittings, pumps and general machinery |
| HNBR | Improved heat, oxidation and mechanical performance over many conventional NBR compounds. | Exact refrigerant, lubricant and chemical compatibility. | Mobile equipment, compressors and refrigeration |
| FKM | Heat, fuels, oils and many chemical environments. | Ketones, some amines, steam, hot water and low-temperature flexibility. | Fuel systems and high-temperature equipment |
| EPDM | Water, weather, ozone, many polar fluids and selected steam duties. | Petroleum oils, hydrocarbon fuels and greases. | Water systems and outdoor equipment |
| VMQ / silicone | Broad temperature flexibility and clean static-sealing applications. | Tear strength, dynamic wear, oils, fuels and steam conditions. | Static process, appliance and low-temperature service |
| FVMQ | Low-temperature flexibility with improved fuel and oil resistance over conventional silicone. | Steam, wear and high-pressure dynamic service. | Specialized fuel and low-temperature static seals |
| FFKM | Severe chemical and high-temperature environments requiring a qualified grade. | Cost, low-temperature grade limits and supply lead time. | Chemical-processing and semiconductor equipment |
| CR / chloroprene | Weather, ozone and selected refrigerant environments. | Strong oxidizers, aromatics and exact chemical exposure. | Refrigeration and outdoor service |
Hardness changes sealing, assembly and extrusion behavior
O-ring hardness is commonly specified on the Shore A scale. Around 70 Shore A is a frequent starting point for general industrial elastomer O-rings, but it is not automatically correct for a particular gland or compound.
A harder compound can better resist deformation into a clearance gap, but may increase assembly force and be less forgiving of imperfect hardware. A softer compound can conform at lower closure force, but may be more vulnerable to extrusion and handling damage.
Where O-rings work
Industrial O-ring applications
State the hardware and duty rather than the industry name alone; the same machine can contain very different sealing environments.
Static face and flange seals
Covers, housings, manifolds and flanges. State whether pressure acts from inside or outside.
Static radial seals
Plugs, ports, fittings and fixed cylindrical interfaces. Provide bore, shaft, groove and clearance.
Hydraulic and pneumatic equipment
Ports, valves, pumps and cylinders. Fluid, pressure cycling, temperature and extrusion gap are key.
Pumps, valves and compressors
List every process and cleaning medium, pressure or vacuum range, and decompression rate.
Food, water and process equipment
Name the exact regulatory or third-party requirement; suitability belongs to a documented compound, not a polymer family.
OEM production and service kits
Define inspection, traceability, packaging and change-control needs with prototype and annual quantities.
How to select an O-ring
- Define the seal typeStatic face, static radial, reciprocating, rotary, vacuum or another duty.
- Identify every mediumInclude process fluids, gases, lubricants, additives and cleaning agents.
- State the real temperature rangeInclude startup, shutdown, cleaning, storage and short peaks.
- Give pressure and motionInclude vacuum, working and peak pressure, cycling, speed and frequency.
- Confirm size and glandSupply a dash number, ID × cross-section, or a complete hardware drawing.
- Set quality requirementsSpecify compound, hardness, tolerance, acceptance criteria and documents.
- Validate in the applicationTest the selected seal in representative hardware and service before release.
Built for technical sourcing
One specification path for every buyer
The quotation should make the product, evidence and commercial requirements clear before samples or production begin.
OEM engineers and buyers
Submit a drawing, validation stage, annual volume and required inspection, traceability or change-control documents.
Seal distributors
Send multi-line requirements with dash numbers, metric sizes, compounds, hardness, packaging and annual demand.
MRO and repair teams
Use dimensions, groove data, equipment reference or a sample to review recurring, obsolete or urgent requirements.
O-ring FAQ
Questions buyers and engineers ask
What information is needed to quote an O-ring?
Send quantity, size or drawing, material or compound, hardness, operating media, temperature and pressure. For dynamic service, also include speed, lubrication, surface finish and cycle frequency.
What is an AS568 O-ring dash number?
It is a standardized size code tied to specified inside diameter, cross-section and tolerances. It does not define the compound, hardness or application suitability.
How are metric O-rings specified?
They are commonly described by inside diameter × cross-section in millimetres, together with the applicable ISO 3601 designation or class when required.
How do I measure an existing O-ring?
Measure inside diameter and cross-section without stretching the ring. Because an aged seal may be deformed, cross-check it against groove and mating-hardware dimensions.
Which O-ring material is best for oil?
NBR is often considered for petroleum oils, while HNBR or FKM may be evaluated for additional heat or media demands. Identify the exact fluid, additives and temperature before selecting a compound.
Can EPDM O-rings be used with petroleum oil?
EPDM is generally not selected for petroleum oils or hydrocarbon fuels. Confirm the actual compound against the exact medium and operating conditions.
What O-ring hardness should I choose?
Around 70 Shore A is a common industrial starting point. The correct hardness depends on compound, pressure, clearance, assembly force, hardware and the need to resist extrusion.
Do high-pressure O-rings need back-up rings?
They may when pressure and clearance create extrusion risk. Review pressure, temperature, compound, clearance gap, pressure direction and cycling together.
Can Auter review a custom or replacement O-ring?
Send a controlled drawing, groove dimensions, equipment information or an available sample. Feasibility, tooling, tolerance, compound, quantity and timing are confirmed in the quotation.
Are regulated or certified O-ring compounds available?
State the exact FDA, NSF, WRAS, KTW, REACH, RoHS or other requirement and intended conditions. Availability and documentation must be confirmed for the exact compound and supplied product.
Technical O-ring inquiry
Send the size, drawing or service conditions.
The fastest review starts with dimensions, material, media, temperature, pressure and quantity. If a value is unknown, tell us what still needs to be identified.
- Standard size, ID × cross-section or drawing
- Compound and Shore A hardness if known
- Static or dynamic duty and complete media
- Quality, compliance, packaging and delivery needs
Final suitability depends on the exact compound, hardware, tolerances, operating conditions, installation and application validation.