Design
Rounded Rectangle O-Ring Groove Calculator
Model a non-circular face-seal path and calculate the custom ring length, corner conditions, squeeze and gland fill.
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Calculator guidance and result interpretation
What this calculator solves
Non-circular grooves need path-length and corner checks in addition to ordinary face-seal compression. This tool models straight runs and corner radii as one continuous seal path.
When to use it
- •Inspection covers and rectangular plates
- •Battery, electronics and enclosure seals
- •Custom moulded or spliced O-rings
Input parameters
- Plan geometry
- Overall length, width, corner radius and groove path definition.
- Cross-section geometry
- O-ring cord, groove width and depth with tolerances.
- Ring construction
- Moulded, cord-spliced or selected ring length and allowable stretch.
How to read the results
- Use calculated path length to specify the free ring length or equivalent ID.
- Review corner stretch and minimum bend radius for local strain.
- Check squeeze and fill across straight and corner-controlled conditions.
Engineering considerations
- Tight corner radii can twist or thin the ring even when total length is correct.
- Splice quality can become the controlling leak path.
- Large covers may need flange-deflection analysis beyond this groove model.
Related tools and engineering resources
Frequently asked questions
How is rounded-rectangle O-ring length calculated?
The seal path combines four straight segments with four quarter-circle corner arcs at the groove centreline, then applies the intended installation stretch.
Can a standard circular O-ring be used in a rectangular groove?
Sometimes, if the length and corner strain are acceptable, but custom moulded or spliced rings are often more predictable for large non-circular paths.