26". Again,
suppose the diameter of the escape wheel in the large drawing is 10" and
the distance between the centers _A B_ is 5.78"; to obtain the actual
distance for the watch with the escape wheel .26" diameter, we make a
statement in proportion, thus: 10 : 5.78 :: .26 to the actual distance
between the pivot holes of the watch. By computation we find the
distance to be .15". These proportions will hold good in every part of
actual construction.
All parts--thickness of the pallet stones, length of pallet arms,
etc.--bear the same ratio of proportion. We measure the thickness of the
entrance pallet stone on the large drawing and find it to be .47"; we
make a similar statement to the one above, thus: 10 : .47 :: .26 to the
actual thickness of the real pallet stone. By computation we find it to
be .0122". All angular relations are alike, whether in the large drawing
or the small pallets to match the actual escape wheel .26" in diameter.
Thus, in the pallet _D_, Fig. 93, the impulse face, as reckoned from _B_
as a center, would occupy four degrees.
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