Consequently, if we design a cylinder escape wheel tooth as previously
described, and setting one leg of our compasses at the point _e_ which
is situated at the center of the chord of the arc which defines the
impulse face of the tooth and through the points _d_ and _b_ we define
the inside of our cylinder. We next divide the chord _d b_ into eight
parts and set our dividers to five of these parts, and from _e_ as a
center sweep the circle _h_ and define the outside of our cylinder. From
_A_ as a center we draw the radial line _A e'_. At right angles to the
line _A e'_ and through the point _e_ we draw the line from _e_ as a
center, and with our dividers set to the radius of any of the convenient
arcs which we have divided into sixty degrees, we sweep the arc _i_.
Where this arc intersects the line _f_ we term the point _k_, and from
this point we lay off on the arc _i_ 220 degrees, and draw the line
_l e l'_, which we see coincides with the chord of the impulse face of the
tooth.
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