Measuring an O-Ring is quite simple when you have the right tools at your disposal. All that is required is a clean, level surface; an o-ring; and a measuring device such as a caliper or other measuring tools such as cones, gauges, and size charts.
Directions to Measure an O-Ring
To measure an O-Ring, following the directions below:
- Place your o-ring on a flat surface clean of debris.
- Determine the inside diameter (ID) and outside diameter (OD) of the o-ring. The o-ring dimensions chart below illustrates where on the o-ring each dimension is measured.
- Measuring the width, or cross-section (CS), can be tricky and is measured by lightly pressing the caliper ends onto O-ring as shown in section A-A.
For more information on O-ring sizes click to see the JIS B 2401 Standard O-Ring Size Tables.
Dimensionally specifying an o-ring can typically be done with just two dimensions, the inner diameter (ID) and the cross-section (CS). Occasionally, an O-ring may be speciﬁed with an outer diameter (OD) and cross-section or an inner diameter and outer diameter. If two of the three dimensions are known, the third can be calculated using the formulas shown below.
O-Ring Dimension Calculations
The original article can be found on Dichtomatik’s website. Gallagher Fluid Seals is a distributor of Dichtomatik, a brand of Freudenberg.
For more information about measuring o-rings or determining the best o-ring to use, please contact Gallagher’s engineering department.
Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.
Original content can be found on Parker’s Blog.
O-Ring Selection Made Easy with the Parker O-Ring Selector
Two things are equally important for the reliable performance of an O-Ring seal: the right size and the right material. Parker’s new O-Ring Selector is an engineering tool that enables users to make the right material and size selections easily, quickly and reliably – in a single application. The accuracy of the results ensures the desired performance of the O-Ring in the subsequent application. This is primarily based on the fact that both functionalities – the material selection and the O-Ring size calculation – are closely interlinked. This achieves a new quality in calculating the total sealing system.
Overview of the O-Ring Selector
The Parker O-Ring Selector is divided into three main sections:
- Service Conditions & Material Selector
- Size Selector
The Service Conditions & Material Selector section is focused on mapping the material-related application conditions. Entering the operating temperature range, the desired polymer family and/or material hardness will take the user to the suitable material selection. The Advanced Material Selector enables experienced users to specify the operating conditions in even greater detail. Here the medium to be sealed can be selected from a database containing 2,500 media. In addition, a search for required approvals and conformities can be run.
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