French Curve

french curve [¦french ′kərv]

(graphic arts)

A guide, usually made of clear plastic, used for making regular, irregular, and reverse curves in mechanical drawings and illustrations.

---

French Curve 

(also template; see [2] below). (1) A drawing instrument for drawing or checking curved lines in drafting or design work; they may have fixed or variable curvature. French curves with fixed curvature are wooden, plastic, or less frequently metal plates with a curved edge. A curve with variable curvature is usually a steel guide bar with an arrangement for varying its configuration (curvature).

(2) Template, a scaleless measuring instrument or layout device (pattern) for checking or outlining curved contours of shaped parts. It is used in machine building and shipbuilding. It is a steel plate with a working edge that describes the inverse (complementary) profile of an object. Measurements are usually made by estimating the width of the gap between the template and the object with a clearance gauge.