PENCILING AND INKING Exemses for Practice in Using the T-Square, Triangles, and Scales 45. Plate 2 is to be laid out 10 inches by 14 inches, outside dimensions, with a border line 9 inches by 13 inches.
The paper used should be a good drawing paper, preferably a high-grade hot- or cold pressed paper. The 611 pencil, sharpened with a chisel edge, should be used for drawing the lines; and a 511 or 611 with round point, for marking divisions from the scale. There are to be six figures, as shown.
Figs. A and B are squares, each 3 inches on a side, and located on the paper as shown in the plate.
Fig. A is for practice with the T-square and triangles on horizontal and vertical lines. In this figure, the left-hand and upper sides of the square are divided into equal spaces. This is done by placing the scale on the line to be divided, taking a sharp, round-pointed pencil, and marking off the desired number Df spaces without moving the scale.
The lines are then drawn through the points of division—one set against the edge of the T-square, and the vertical lines against the edge of a triangle placed against the working edge of the T-square.
Fig. B is for practice with the 45-degree tri angle in two directions. The left-hand and lower sides of the square are divided into equal spaces, using the scale as in Fig. A. From these points of division, lines are drawn with the 45-degree triangle, upward and toward the right. After these lines are drawn, another set of lines are drawn from the points on the left hand side, and also from the points where the first set of lines cut the upper side of the square. If the work is accurately done, it will be found that the two sets of 45-degree lines cut each other at the bottom and right-hand sides exactly on the edges of the square.
In Fig. C, the 30-degree-60-degree triangle is the one used. The figure is not an exact square, being a little greater in width than height; so draw first the left-hand side, making it 3 inches long; then draw the top and bottom edges a little more than 3 inches, say inches.
The left-hand side of the figure is then divided with the scale into IA-inch spaces; and from these points, 30-degree lines are drawn, slanting upward and toward the right. Counting down from the top, take the point where the seventh 30-degree line cuts the upper edge; and from this point, draw a vertical line downward to form the right-hand side of the figure. Next, turn the triangle in the other direction; and from the points along the top edge, and also from the points on the left side, draw 30-degree lines, slanting downward and toward the right. From the points where these lines cut the bot tom edge, the rest of the lines of the first set may be drawn. Accurate work will be math fested by a series of intersections falling exactly on the right-hand edge of the figure.
The purpose of Fig. D is to illustrate the use of the 30-degree-GO-degree triangle, and inci dentally to show the construction of the sym metrical six-sided figure called the hexagon.
First draw with the T-square the base line inches long, : Y4 inch above the lower border, and place the left-hand end inches from the left border line. Next draw from the ends of this line 60-degree lines as shown, and measure very carefully on each the same length as the base, inches. Then, from these last-found points, draw two other 60-degree lines upward, and mark off again the same length. These two points should lie at the same distance above the base line, and may be joined by drawing a line with the T-square, thus forming the top of the figure.
Next draw the diagonal lines of the hexagon, connecting the opposite corners. Now divide one of these diagonals, as g-h, into six equal spaces, using the scale. (This diagonal should measure exactly twice the length of one of the sides—that is, inches.) Drawing from these points of division hori zontal lines and 60-degree lines to the next diagonals, and connecting the ends, there will be constructed two other hexagons like the first, but smaller.