" We should always bear in mind that _theory, if right, must
lead practice_.
CORRECT DRAWING REQUIRED.
If we delineate our entrance pallet to have a draw of twelve degrees
when in actual contact with the tooth, and then construct in exact
conformity with such drawings, we will find our lever to "hug the banks"
in every instance. It is inattention to such details which produces the
errors of makers complained of by Saunier in section 696 of his "Modern
Horology," and which he attempts to correct by drawing the locking face
at fifteen degrees draw.
We shall show that neither _C_ nor _C'_, Fig. 85, is the theoretically
correct position for the pallet center for a tangential locking.
We will now take up the consideration of a club-tooth lever escapement
with circular pallets and tangential lockings; but previous to making
the drawings we must decide several points, among which are the
thickness of the pallet arms, which establishes the angular motion of
the escape wheel utilized by such pallet arms, and also the angular
motion imparted to the pallets by the impulse faces of the teeth.
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