The points _f e_, Fig. 6, are, of course, just
sixty degrees apart and represent the extent of two and one-half teeth
of the escape wheel. There are two systems on which pallets for lever
escapements are made, viz., equidistant lockings and circular pallets.
The advantages claimed for each system will be discussed subsequently.
For the first and present illustration we will assume we are to employ
circular pallets and one of the teeth of the escape wheel resting on the
pallet at the point _f_; and the escape wheel turning in the direction
of the arrow _j_. If we imagine a tooth as indicated at the dotted
outline at _D_, Fig. 6, pressing against a surface which coincides with
the radial line _p f_, the action would be in the direction of the line
_f h_ and at right angles to _p f_. If we reason on the action of the
tooth _D_, as it presses against a pallet placed at _f_, we see the
action is neutral.
[Illustration: Fig. 6]
ESTABLISHING THE CENTER OF PALLET STAFF.
[Illustration: Fig.
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