Royal Way AS568 O-Ring Technical Reference

Royal Way AS568 O-Ring Technical Reference is a selection guide for identifying common AS568 size series, checking the installation gland and preparing a technically complete inquiry. It is intended for engineering and procurement use; final suitability must be confirmed against the actual drawing, compound, operating medium and service conditions.

1. AS568 Size-Series Reference

An AS568 dash number identifies a standardized nominal O-ring size. The dash number is not a complete sealing specification: it does not decide the compound, hardness, gland geometry, pressure capability, chemical resistance or service life.

Dash-number series	Nominal cross-section	Royal Way selection note
0xx	0.070 in / 1.78 mm	Use the exact dash number or measured gland dimensions to confirm inside diameter.
1xx	0.103 in / 2.62 mm	Confirm static or dynamic application before selecting material and hardness.
2xx	0.139 in / 3.53 mm	Review clearance and extrusion risk when pressure increases.
3xx	0.210 in / 5.33 mm	Check gland fill, installation lead-in and compression requirements.
4xx	0.275 in / 6.99 mm	Confirm actual groove width, depth and assembly method before quotation.

These are nominal series cross-sections for fast identification. Always provide the specific dash number, or the measured inside diameter and cross-section, for the final size review.

2. Royal Way Gland Verification Checklist

• Seal function: static axial, static radial, reciprocating or rotary.
• Groove diameter, width, depth and stated tolerances.
• Mating diameter, surface condition, lead-in chamfer and corner radii.
• Maximum extrusion gap at operating pressure and temperature.
• Required squeeze, stretch and gland-fill target for the actual configuration.
• Installation method and any risk of twisting, cutting or over-stretching.
• Whether a backup ring or alternative seal profile is required.

3. Material Selection Inputs

AS568 controls size designation, not material selection. For oilfield and industrial sealing inquiries, state the intended polymer family only as a starting point and include the duty conditions required for review.

Material family	Typical selection starting point	Information still required
NBR / Buna-N	General petroleum-oil and grease service.	Actual fluid, temperature, pressure and required hardness.
HNBR / HSN	Applications needing improved heat, ozone or mechanical resistance compared with standard NBR.	Exact medium, gas exposure, decompression conditions and acceptance requirement.
FKM	Elevated-temperature oil, fuel or hydrocarbon service screening.	Actual chemical mixture, low-temperature requirement and exposure duration.

Material family alone is not a final compatibility approval. Compound formulation, hardness, geometry, pressure, temperature and exposure time must all be reviewed together.

4. Measurement Guidance for Used O-Rings

Use the equipment drawing or parts list where available. A used O-ring may have changed size because of compression set, swelling, wear, stretch or handling damage. When the original dash number is unknown, record the measured inside diameter, cross-section, groove dimensions and equipment reference rather than relying on the removed seal alone.

5. Information Needed for a Royal Way AS568 Inquiry

• AS568 dash number, or measured inside diameter and cross-section.
• Drawing, gland dimensions, photo or equipment part reference.
• Medium or gas composition; continuous and peak temperature.
• Operating pressure, motion type, extrusion-gap information and any decompression condition.
• Requested material, hardness, quantity, packaging and destination.
• Customer specification, inspection requirement or documentation requirement where applicable.

Related Products and Technical Support

Browse AS568 O-Rings & Sealing Rings for standard size options. For non-standard dimensions or application-specific geometry, see Custom Rubber Parts. Submit the size and application data through Request a Quote for a Royal Way technical review.

Using this reference for an inquiry

This reference is prepared to help with product selection and inquiry preparation. It does not replace the current governing standard, an approved equipment drawing, a customer specification or project-specific validation.