How to lay out a perfect ellipse

You can't beat an ellipse [Drawing 1], shown above, when you want a graceful curved-edge tabletop, frame, or opening. Most computer drawing or design programs generate ellipses, but coming up with a full-size pattern can be a problem if you want an ellipse larger than a sheet of printer paper.

For best results, lay out your ellipse right on the workpiece. (Or, lay it out on hardboard, plywood, or MDF to make a template.) A simple scrapwood trammel [Drawing 2] makes drawing any size ellipse, shown below, a straightforward task.

Decide on the size

First, determine the length (major axis) and width (minor axis) for your ellipse [Drawing 1]. A minor axis that measures about half to two-thirds the length of the major axis produces a pleasing form.

Draw the axes on your workpiece [photo below, perpendicular to and bisecting each other. (We drew the axes on masking tape applied to our panel to prevent marring the face.)

Make the trammel
Start with hardboard or other material ¹⁄₈ " thick, 1" wide, and about three-fourths the length of your ellipse. Drill a hole for a pencil point near one end [Drawing 2]. Measuring from the pencil hole to the far end of the trammel, mark a point at a distance equal to one-half the width of the ellipse (dimension a on the drawing) and another at a point equal to one-half the length (dimension b).

Drive a brad or small finish nail through the trammel at each mark, allowing the points to barely protrude on the back.

Draw the ellipse

Adhere your framing square to the workpiece with double-faced tape on the back, aligning the square as shown below.

Place the trammel on the square with the brad points riding against the edges as shown. Insert a pencil point through the hole and move the trammel and pencil so the brad points remain in contact with the framing square.

After drawing the first quarter of the ellipse, move the square to the other quadrants to complete the shape.

When you cut out your ellipse, saw slightly off the line on the waste side and sand to it for a smooth edge.

Quick Tip! Draw small ellipses quickly with ellipse templates available from art supply stores. They come in many varieties, usually with several sizes on a single template. You'll find templates for ellipses with major axes from ¹⁄₁₆ " up to about 7".

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