In Fig. 282, let C A B E be the side elevation of the article, of which F I K M is the plan at the base and G H L N the plan at the top. Let it be required to produce the pattern in one piece, the top included. Make H1 L1 N1 G1 in all respects equal to H L N G of the plan. Through the center of it likewise draw R P indefinitely, and through the center in the opposite direction draw O S indefinitely. From the lines H1 L1 and G1 N1 set off T O and W S respectively, each in length equal to the slant hight of the article, as shown by C A or E B of the elevation. Through O and S respectively draw I1 K1 and F1 M1, parallel to H1 L1 and G1 N1, and in length equal to the corresponding sides in the plan I K and F M, placing one-half that length each way from the points O and S. In like manner set off V P and U R, also equal to C A, and draw through R and P the lines F2 I2 and K2 M2, parallel to the ends of the pattern of the top part as already drawn, and in length equal to I F and K M of the plan. Draw I1 H1, K1 L1, K2 L1, M2 N1 M1N1 F1 G1 F2G1and V IT, thus completing the pattern sought. In the same general way the pattern may be described, including the bottom instead of the top, if it be required that way.
Considering this problem in the light of miter cutting proper, I H G F and F G N M may be regarded as the plan of two similar moldings of which A C is the profile, I H G F and N M being the miter lines. OT is the stretchout line, drawn at right angles to F M, while I1 K1and H1 L1are the measuring lines representing respectively the points C and A of the profile.
The points F and G are then dropped into their respective measuring lines, thus locating the points I1 and H1 at one end of the pattern, while points K1 and L1 are derived from M and N at the other end.
Fig. 282. - The Pattern, of a Rectangular Flaring Article.