O-Ring Groove Information - AS568


An O-Ring groove refers to a specifically designed groove or channel in a mating surface or component that accommodates an O-Ring. The purpose of the O-ring groove is to securely position and retain the O-Ring in place, allowing it to effectively seal a joint or connection.

The O-Ring groove is typically a circular or rectangular indentation in the surface of the component. It is designed to match the shape and dimensions of the O-Ring, ensuring a proper fit and seal. The groove geometry and dimensions are crucial in providing optimal sealing performance and preventing leakage.

The groove dimensions include the width, depth, and sometimes the diameter, which are specific to the O-Ring size and cross-section diameter. The dimensions of the groove are calculated based on factors such as the O-Ring's cross-section diameter, desired compression percentage, and clearance requirements.

The O-Ring is placed within the groove, and when the mating surfaces come together, the O-Ring is compressed between them, forming a seal. The compression of the O-Ring creates a deformation that fills any gaps and provides a tight seal against fluid or gas pressure.

It's important to note that O-Ring groove design also takes into account factors such as surface finish, corner radii, and chamfers to ensure proper O-Ring installation and performance. The groove design should follow industry standards or guidelines provided by O-Ring manufacturers to achieve effective sealing in different applications.

AS568 Static O-Ring Axial Face Seal Glands
(Link to: Metric O-Ring Groove Information)

Static seals exist where there is no relative motion between the mating surfaces being sealed.
CS Cross Section | DC Diametral Clearance | BR Backup Rings Measurements in inches.

  GlandSqueezeGroove WidthGroove
AS568BCSDepthInches%LiquidsGasesRadius

-004 to
-050

.070

.050 to
.054		.013 to
.023		19 to
32		.101 to
.107		.084 to
.089		.005 to
.015

-102 to
-178

.103

.074 to
.080		.020 to
.032		20 to
30		.136 to
.142		.120 to
.125		.005 to
.015

-201 to
-284

.139

.101 to
.107		.028 to
.042		20 to
30		.177 to
.187		.158 to
.164		.010 to
.025

-309 to
-395

.210

.152 to
.162		.043 to
.063		21 to
30		.270 to
.290		.239 to
.244		.020 to
.035

-425 to
-475

.275

.201 to
.211		.058 to
.080		21 to
29		.342 to
.362		.309 to
.314		.020 to
.035

AS568 Static O-Ring Radial Glands

Static seals exist where there is no relative motion between the mating surfaces being sealed.
CS Cross Section | DC Diametral Clearance | BR Backup Rings Measurements in inches.

  GlandSqueeze Groove WidthGroove
AS568BCSDepthInches%DC0 BR1 BR2 BRRadius
-004 to
-050		.070.050 to
.052		.015 to
.023		22 to
32		.002 to
.005		.093 to
.098		.138 to
.143		.205 to
.210		.005 to
.015
-102 to
-178		.103.081 to
.083		.017 to
.025		17 to
24		.002 to
.005		.140 to
.145		.171 to
.176		.238 to
.243		.005 to
.015
-201 to
-284		.139.111 to
.113		.022 to
.032		16 to
23		.003 to
.006		.187 to
.192		.208 to
.213		.275 to
.280		.010 to
.025
-309 to
-395		.210.170 to
.173		.032 to
.045		15 to
21		.003 to
.006		.281 to
.286		.311 to
.316		.410 to
.415		.020 to
.035
-425 to
-475		.275.226 to
.229		.040 to
.055		15 to
20		.004 to
.007		.375 to
.380		.408 to
.413		.538 to
.543		.020 to
.035

AS568 Dynamic O-Ring Reciprocating Glands

Dynamic seals exist where there is relative motion between the mating surfaces being sealed.
CS Cross Section | DC Diametral Clearance | BR Backup Rings Measurements in inches.

  GlandSqueeze Groove WidthGroove
AS568BCSDepthInches%DC0 BR1 BR2 BRRadius
-004 to
-050		.070.055 to
.057		.010 to
.018		15 to
25		.002 to
.005		.093 to
.098		.138 to
.143		.205 to
.210		.005 to
.015
-102 to
-178		.103.088 to
.090		.010 to
.018		10 to
17		.002 to
.005		.140 to
.145		.171 to
.176		.238 to
.243		.005 to
.015
-201 to
-284		.139.121 to
.123		.012 to
.022		9 to
16		.003 to
.006		.187 to
.192		.208 to
.213		.275 to
.280		.010 to
.025
-309 to
-395		.210.185 to
.188		.017 to
.030		8 to
14		.003 to
.006		.281 to
.286		.311 to
.316		.410 to
.415		.020 to
.035
-425 to
-475		.275.237 to
.240		.029 to
.044		11 to
16		.004 to
.007		.375 to
.380		.408 to
.413		.538 to
.543		.020 to
.035

 

 

O-Ring Groove Sizing – General Formula Guide

This guide outlines the standard formulas used to calculate O-Ring groove dimensions. These are general guidelines – always verify final specs with application-specific requirements or O-Ring manufacturer recommendations.

1. Cross-Section Diameter (CS)

Formula:

CS OD - ID) / 2

Where:

  • CS = Cross-section diameter of the O-Ring
  • OD = Outside diameter of the O-Ring
  • ID = Inside diameter of the O-Ring

2. Squeeze Percentage (%Squeeze)

Formula:

%Squeeze = [(OD - ID) / OD] * 100

Purpose: Determines how much the O-Ring is compressed when installed – critical for sealing effectiveness.

3. Groove Width (GW)

Formula:

GW = CS + (2 * Compression)

Where:

  • GW = Groove width
  • Compression = Amount the O-Ring is compressed (typically 4–8%, depending on application or manufacturer guidance)

4. Groove Depth (GD)

Formula:

GD = CS + (2 * Gap)

Where:

  • GD = Groove depth
  • Gap = Space between the groove’s top surface and the mating surface

Application Considerations

These formulas are general starting points. Always consider:

  • O-Ring material (hardness, thermal expansion)
  • Application pressure and temperature
  • Dynamic vs. static use
  • Environmental exposure (chemicals, UV, etc.)

We recommend consulting industry standards (e.g., AS568, ISO 3601) or your O-Ring supplier for precise tolerances and material-specific advice.

Groove Width Calculation Example

Given:

  • Inside Diameter (ID) = 0.424 inches
  • Cross-Section (CS) = 0.103 inches
  • Assumed Compression = 0.04 inches (approximately 4%)

Formula:

GW = 0.103 + (2 * 0.04) = 0.103 + 0.08 = 0.183 inches (approx.)

Result:

For an O-Ring with ID = 0.424" and CS = 0.103", and assuming 4% compression, the groove width (GW) should be approximately:

0.183 inches

If you're unsure about your values or tolerances, contact The O-Ring Store. Our team is here to help you size it correctly the first time – we make getting O-Rings easy.