Compasses are often used for scribing a line parallel to another line or surface, whether regular or irregular, in places where the gauge cannot be used. Suppose, for instance, you wish to cut the edge of a board to fit the undulating surface shown in Fig. 667. Run the compasses along with one point on the surface and the other making a mark on the board, and the line on the board will be parallel with the surface.
Another example is that of making a table, bench, chair, horse, or any four-legged object stand evenly. If it stands on three legs, which is a common fault and likely to occur in your first attempts, do not hastily saw one leg shorter by guess, and, making it too short, saw another and so on until it stands firmly, when the top will probably be all out of level. If there is any true surface on which you can stand the article (right side up), you can level the top by wedging under the legs until the corners of the top are equally distant from the surface on which the object stands.
Then setting the compasses at a distance equal to that at which the end of the shortest leg is raised (Fig. 668), scribe around the other legs, which can then be cut off.1 See also Winding-Sticks and Marking.