Penciling and Inking

Thus far, if the work is accurate, all of the lines are either T-square lines or 60-degree lines. Now, with the scale, find the middle point of each side of the outside hexagon, and connect these points. The lines joining these points should be either 30-degree lines or verticals. Do the same thing for the two inner hexagons, testing in the same way the inclined lines to see if they are at 30 degrees.

Fig. E is for an exercise in drawing parallels and perpendiculars by means of the triangles, without the aid of the T-square.

First fix the position of the point x, inches from the left border line, and inches above the lower border; and locate point z on the same T-square line as the base of Fig. D, and 1 inch to the right of x; and join x and z. Starting at point z, mark off on line zx, without moving the scale, the following distances in order: inch, inch, inch, 1/4 inch, inch, and 1/2 inch. Then draw as a base line a T-square line through z, and set off in the same way the distances 1/4 inch, 1/2 inch, 1/4 inch, inch, inch, inch, inch, 1/2 inch, and inch; and through this last point, draw a line parallel to zx, as shown in Fig. 21. This line will be the right-hand boundary of the figure; and a line drawn through x at right angles to line xz, by the method of Fig. 22, will be the upper boundary of the figure. Now, by sliding one triangle along another, draw lines parallel to the upper boundary of the figure from the points on line xz, and also from the points on the base line. Draw also parallel to xz another set of lines from the points on the base line.

For Fig. F, locate the point c as shown, and make the base line cd inches long, making the short dashes each about inch long. Then, from c and d, draw 45-degree lines upward, and make each one the same length, inches, drawing them full lines. Next draw the dotted verticals; then the second pair of 45-degree lines; then the horizontal at the top of the figure. This produces the regular eight-sided figure cdefghij, or regular octagon. Draw the verticals ch and dg, and the T-square lines fi and ej, making them dash lines. The intersec tions of these lines give the four corners of a square kmoq.

Next, using the 45-degree triangle, draw eh, di, gj, and fc, making the parts solid and dotted as shown in the figure. These lines will inter sect in the corners of a second square lnpr. Now connect the points k, 1, m, etc., forming a regular octagon. Finally join 1 with q and o, m with r and p, n with k and q, o with r, and p with k, thus completing an eight-pointed star.

Inking. The sheet is to be inked—Fig. A, with lines of medium thickness; B with heavy lines; and C with fine lines; while D, E, and F are to be drawn with medium-weight lines. In Fig. F the dotted pencil lines are to be erased, not appearing at all on the finished ink draw ing. Make as nearly as possible the same dif ference in weight of line between A and B as between B and C. For this first sheet, ink one figure at a time. Remember that ink lines must not be rubbed with the triangle or T-square until they are perfectly dry.