Correctly Measuring an O-Ring – How to Do It
Apr 26, 2020
If you have the correct tools available to use, the process of measuring an O-Ring is relatively simple. All you need to undertake the measurement process is a clean surface that is level, an O-Ring and a device that you can use to measure such as a calliper although other measuring tools can be used such as size charts, gauges and cones.
O-Ring Measurement Process
In order to correctly measure an O-ring, you need to follow the process below:
- Put the O-Ring on a surface that is flat and is free of any debris
- Identify the inside diameter (ID) of the O-ring as well as the outside diameter (OD).
- Now you will need to measure the width of the O-ring or the cross-section (CS) of it. This can prove a challenge, but it can be measured by gently pressing the calliper ends onto the O-Ring.
It is possible to use just two dimensions to determine an O-Ring size; for example, the inner diameter and the cross-section measurements. If you know two of the three dimensions, then you can use the following formulas to calculate the third.
OD = ID + (2 x CS)
ID = OD – (2 x CS)
CS = (OD – ID) / 2