Measure off two inches on either side of the vertical center line and draw light pencil lines through these points parallel to the vertical center line. These lines will form the sides A D and B C of Fig. 2 and Fig. 5. Parallel to these lines and at a distance of 1/2 inch draw similar lines to form the sides B C of Fig. 1 and Fig. 4 and A D of Fig. 3 and Fig. 6. The vertical sides A D of Fig. 1 and Fig. 4 and B C of Fig. 3 and Fig. 6 are formed by drawing lines perpendicular to the horizontal center line at a distance of 6 1/2 inches from the center.
Complete the figures by laying off lines 1/2 inch and 4 1/2 inches above and below the horizontal center line respectively, thus forming six 4-inch squares.
In drawing Fig. 1, divide A D and A B into 4 equal parts, then draw horizontal lines through Et F, and G and vertical lines through L, M, and N. Draw lines from A and B to the intersection O of lines E and M, and from A and D to the intersection P of lines F and L. Similarly draw D J, J C, C I, and I B. Also connect the points O, P, J, and I, thus forming a square. The four diamond-shaped areas are formed by drawing lines from the middle points of A D, AB, BC, and D C to the middle points of lines AP, AO, OB, IB, etc., as shown in Fig. 1.
Fig. 2 is an exercise of straight lines. Divide AD and A B into four equal parts and draw horizontal and vertical lines as in Fig. 1. Now divide these dimensions, A L, M N, etc., and E F, G B, etc., into four equal parts - each 1/4 inch - and draw light pencil hnes with the T-square and triangle as shown.
In Fig. 3, divide A D and A B into eight equal parts, and through the points 0, P, Q, H, I, J, etc., draw horizontal and vertical lines. Now draw lines connecting 0 and H, P and I, Q and J, etc. As these lines form an angle of 45 degrees with the horizontal, a 45-degree triangle may be used. Similarly from each one of the given points on A B and A D, draw lines at an angle of 45 degrees to B C and D C respectively.
Fig. 4 is drawn with the compasses. Draw the diagonals A C and D B, and with the T-square draw the line E H. Now mark off on E H distances of 1/4 inch, and with H as a center describe, by means of the compasses, circles having radii respectively 2 inches. 1 1/2 inches, 1 inch, 3/4 inch, 1/2 inch, and 1/4 inch. Similarly with H as a center and a radius of 1 3/4 inches and l 1/4 inches respectively draw the arcs F G and J J and K L and M N, being careful to end the arcs in the diagonals.
Fig. 5 is an exercise with the line pen and compasses. Draw the diagonals A C and D B, the horizontal line L M and the vertical line E F passing through the center Q. Mark off distances of 1/2 inch on L M and E F and complete the squares N R R' N', etc. With the bow pencil adjusted so that the distance between the pencil point and the needle point is \ inch, draw arcs having centers at the corners of the inner squares. The arc whose center is N will be tangent to the lines A L and A E and the arc whose center is O will be tangent to N N' and N R. Since the smallest square has 1 inch sides, the 1/2-inch arcs drawn with Q as a center will form a circle.
In Fig. 6, draw the center lines E F and L M, and find the centers of the four squares thus formed. Through the center I draw the construction lines HIT and RIP forming angles of 30 degrees with EF. Now adjust the compasses to draw circles having a radius of one inch, and with I as a center, draw the circle H P T R. With the same radius draw the arcs with centers at A, B, C, and D, and also draw the semicircles with centers at L, F, M, and E. Now draw the arcs as shown having centers at the centers of the four squares. To locate the centers of the six small circles within the circle H P T R, draw a circle with a radius of 11/16 inch and having the center in I. The small circles each have a radius of 5/16 inch.
In Plate II ink in only the lines shown full in the specimen plate. First ink the star and then the square and diamonds. As this is an exercise for practice, the cross-hatching should be done without measuring the distance between the lines and without the aid of any cross-hatching device. The lines should be about 1/16 inch apart. After inking in the plate all construction lines should be erased.
In inking Fig. 2 first ink the principal horizontal and vertical lines and then very carefully ink in the short lines. Make these lines all of the same width.
Fig. 3 is drawn entirely with the 45-degree triangle. In inking the oblique lines make P I, R K, T M, etc., of the usual width, while the alternate lines 0 H, Q J, S L, etc., should be somewhat heavier. All of the lines which slope in the opposite direction are light. Now ink in the border lines and erase all other horizontal and vertical lines.
In inking Fig. 4 use only the compasses, adjusting the legs so that the pen will always be perpendicular to the paper. In inking the arcs, see that the pen stops exactly at the diagonals. The inner circle and the next but one should be dotted as shown in the specimen plate. After inking the circles and arcs erase the construction lines that are without the outer circles, leaving in pencil the diagonals inside the circles.
In Fig. 5 draw all arcs first and then the straight lines meeting these arcs, as it is much easier to make a straight line meet an arc or tangent to it, than the reverse. Leave all construction lines in pencil. This exercise is difficult, and as in all mechanical and machine drawing, arcs and tangents are frequently used, the beginner is advised to draw this exercise several times.
Fig. 6 is an exercise with compasses. If the laying out has been accurately done in pencil, the inked arcs will be tangent to each other and the finished exercise will have a good appearance. If, however, the distances were not accurately measured and the lines carefully drawn, the inked arcs will not be tangent. The arcs whose centers are L, F, M, and E, and A, B, C, and D should be heavier than the rest. The small circles may be drawn with the bow pen. After inking the arcs all construction lines should be erased.
Finally ink in the figure numbers, the border lines of the plate, name, address, and plate number as in Plate I.