#1 What is the O-ring inner diameter?
The diameter indicates the furthest distance between two points on a circular line. The line connecting the points runs through the center of the circle.
A distinction between inner and outer diameters is necessary in order to clearly describe a geometric body with a specific wall thickness. This includes rings and hollow cylinders whose outer diameter is calculated from the inner diameter and twice the wall thickness. The inside diameter is also referred to as the nominal diameter.
In technology, the specification of the internal diameter is used for many standard elements:
- Pipes, hoses and connectors
- Sealing rings
- Hollow shafts
#2 Definition inner diameter
The inside diameter is used to describe rotationally symmetrical bodies such as rings and hollow cylinders. They have a passage, the size of which is determined by the inside diameter. The outer diameter is calculated from the inner diameter and wall thickness.
Sealing rings are usually installed in circular grooves, so the diameter is crucial for the correct fit of the components.
For O-rings, it is therefore common to specify the inner diameter and cross-section (cord thickness).