Oval Tube development
What it is
The oval, or obround, tube has a section made of two semicircles joined by two straight runs. It is the easiest shape to form after the circle, because there are only two radii and they are equal.
Where it is used
Flattened ventilation ducting, under-floor runs, light structural sections, handrails and guards.
Measurements the calculation needs
- X Width of the section (larger measure)
- Y Height of the section (diameter of the semicircles)
- H Length of the tube
- DV Divisions
- THK Plate thickness
Worked example
The values the form comes pre-filled with, run through the tool itself:
| Width of the section (larger measure) | 600 mm |
|---|---|
| Height of the section (diameter of the semicircles) | 200 mm |
| Length of the tube | 300 mm |
| Divisions | 16 |
| Plate thickness | 3 mm |
| The flat pattern fits a plate of | 1419 × 300 mm |
Result of the example
| Plate | 1419 × 300 mm |
|---|
Guides about this part
Frequently asked questions
- Why can X and Y not be equal?
- If they were, the straight runs would vanish and the part would become a cylinder — which has its own, more direct calculation.
- Is the plate length the section perimeter?
- Yes, taken on the neutral axis: the two semicircles add up to one full circumference, plus twice the straight run.
