Make a manikin, that is a little jointed figure of a man as shown at A in Fig. 32. The figure can be made to any scale but 1 inch to the foot which is ⅙ full size is a good ratio to make it but it must of course be made to the same scale as the machine you are drawing.
To get the right proportions rule a sheet of paper a couple of inches wide and about 8 inches long so that the divisions will be ¹/₁₂ inch square and draw on this the different parts of the manikin as shown at B in Fig. 32. Now since every ¹/₁₂ inch on the paper is equal to 1 inch for a man 6 feet tall your manikin will be 6 inches high when it is jointed and complete.
Fig. 32b. THE PROPORTIONS OF A MANIKIN DRAWN ON CROSS-SECTION PAPER
The figure can be made of cardboard if it is to be used only a few times but thin wood, celluloid or hard rubber, or sheet tin, brass or copper will make a much more substantial one. Whatever the material that is used the edges of each part should be filed smooth; and when you rivet the parts together to make the joints the latter should work smooth and yet stiff enough so that the parts will stay in whatever position you place them.
Fig. 32c. A TRIAL POSITION OF THE MANIKIN
When you lay the manikin on your drawing you can see whether or not the levers are in the right places as shown at C and D in Fig. 32.
