Essentials of woodworking

by Ira Samuel Griffith

Fig. 11.

Directions for ellipse, [Fig. 11]: An ellipse is a curve such that the sum of the distances from any point on it to two fixed points called the focii shall always be the same.

An easy way to construct such a curve is to place two thumb tacks at the focii, attach the ends of a string to them. With a pencil moving freely in the string but holding it taut draw the curve. By moving the tacks farther apart or closer together and by lengthening or shortening the string, the size and shape of the curve may be changed as desired.

Fig. 12.

Fig. 13.

6. Order of Procedure.

—Beginners should strive to know and to acquire good practice in drawing. Before beginning see that the pencil is properly sharpened.

(1) Determine the size and spacings of the views so that the parts of the drawings may be properly placed.