If
we should make a drawing of an escape-wheel tooth shaped exactly as the
one shown at Fig. 132 and the point of the tooth resting at _x_, we
would show the position of a tooth encountering the cylinder after a
tooth which has been engaged in the inside of the shell has passed out.
By following the instructions now given, we can delineate a tooth in any
of its relations with the cylinder shell.
DELINEATING AN ESCAPE-WHEEL TOOTH WHILE IN ACTION.
We will now go through the operation of delineating an escape-wheel
tooth while in action. The position we shall assume is the one in which
the cylinder and escape-wheel tooth are in the relation of the passage
of half the impulse face of the tooth into the cylinder. To do this is
simple enough: We first produce the arcs _a b c_, Fig. 133, as directed,
and then proceed to delineate a tooth as in previous instances. To
delineate our cylinder in the position we have assumed above, we take
the space between the points _e d_ in our dividers and setting one leg
at _d_ establish the point _g_, to represent the center of our cylinder.
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