(See Fig. 26.)
For standards use a couple of the small angle irons used for supporting
shelves, and sold at about a penny each. These are screwed on to the board
2 inches from what may be considered to be the rear edge, and are so spaced
as to leave room for a washer on each spindle between the roller and the
standards, to diminish friction.
[Illustration: FIG. 26.-Side elevation of disappearing target apparatus.]
Remove one standard, and drive into the roller a piece of stout wire with
its end bent to form an eye. The inclination of the arm to the roller is
shown in Fig. 26.
To the front of the board now nail a rectangle of stout sheet iron, long
and deep enough to just protect the standards and roller. Place the roller
in position, insert a target, and revolve the roller to bring the target
vertical. A small wire stop should now be fixed into the baseboard to
prevent the arm coming farther forward, and a hole for the operating string
be drilled in the protection plate at the elevation of the eye on the
arm. The edges of this hole need careful smoothing off to prevent fraying
of the string.
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