Flexible curves rules or rulers are useful drafting/drawing tools for miniaturists. The curves can be shaped to any type of curve you need, allowing you to make a smooth curve to trace onto your project. The most durable have a soft square metal body (often aluminum) encased in steel edges over-coated with plastic. They are used to copy or flip curves or lay out detailed curves for drawing cutting lines on paper, card, fabric, wood and other materials used by miniaturists.
Raised or 'inking' edges allow you to run the edge of a pen along the ruler to follow the exact shape of the curve without creating an ink smudge. Most flexible curves have one raised edge to use with ink, and one flat edge for pencil markings. The raised edges are useful if you use the curve to ink designs with gel or felt pens on acetate for miniature stained glass projects or other items which use slower drying pens.
Where to Find Flexible Curves
Flexible curve rules are usually found in the graphic arts or drafting section of an art or craft supply store. As the curve does not 'kink' at right angles it can easily be shaped into smooth curved shapes which can be drawn out or flipped to copy the shape in reverse.
If you purchase one of the heavier bodied flexible curve rulers usually used for drafting, the ruler can be shaped over a curve, then carefully moved to recreate the curve on another section of your project.
Some newer lightweight flexible curve rules are too lightweight to use this transfer technique without losing their shape.
Flexible curve rulers are Ideal for drawing out custom curved patterns or curved shapes on fabric as well as other materials. They can also be used to copy the shape of a curve, for example, the crotch line for sewing doll (or full size) patterns, or the hull line for a model boat.
Flexible curves are difficult to use with very tight curves, so a project like making a miniature scalloped valence for a dollhouse window using the flexible curve is not possible. Making arches for a custom door, miniature picket fence headboard or a headboard on an easy to make dollhouse bed is a task easily undertaken with a flexible curve, especially if you lay it out on a grid of graph or squared paper to make sure your curve is even, before transferring the lines to your project.
Flexible Curve Versus a French Curve
A flexible curve ruler is not the same as a "French" curve, which has permanently shaped curves. The flexible curve can be shaped to any curve within a range permitted by the material it is made from. Most flexible drafting curves will not curve to a diameter below 2 inches (5 cm).
What Size Flexible Curve You Need
The length of flexible curve ruler you use should be determined by the length and type of curves you need to repeat. A 12 inch (30cm) flexible curve can be laid out to make a roughly 5 1/2 inch (14 cm) tall arched door in dollhouse scale. For projects which need higher or wider curves, you would need a longer curve. 18 - 24 inches (45 - 60 cm) is a useful size for most modeling and craft projects.
Price and Availability
Flexible curves vary in price depending on their length and the style of markings. Most range in price from $6 to $20.