The Lofting Equal Height Ordinates for Arches to Ellipses calculator will return the lofting ordinates to plot the ellipse for arches.

Arch Width

Enter the width of the arch opening.

Arch Rise

Enter the rise-height of the arch opening.

Ellipse Width

Enter the width/length of the ellipse to calculate the ordinates for.

Lofting Spacing

Enter the spacing of the ordinates. The default is 6". Using 1" for the ordinate spacing produces better results.

- Length/Dimensions Input Menu Mode
- Imperial/English Inch base 12 —— default.. use American standard pitches over 12.
- Metric 300mm base —— 300mm is 11.81102 inches, similar usage to the American framing squares printed in inches.
- Decimal Inch base 10 —— use this option when working with tangents or using the Chappell Master Framing Square multiply the tangent of the angle by 10

The output mode selection can be completely different from the input mode.

- Length/Dimensions Output Menu Mode
- Imperial/English Inch base 12 —— default.. use American standard pitches over 12.
- Metric 300mm base —— 300mm is 11.81102 inches, similar usage to the American framing squares.
- Decimal Inch base 10 —— use this option when working with tangents or using the Chappell Master Framing Square