9, as
a center, we draw the line _j_ at an angle of twelve degrees to _b b''_.
In doing this we employ the same method of establishing the angle as we
made use of in drawing the lines _e g_ and _e h_, Fig. 10. The line _j_
establishes the locking face of the pallet _B_. Setting the locking face
of the pallet at twelve degrees has been found in practice to give a
safe "draw" to the pallet and keep the lever secure against the bank. It
will be remembered the face of the escape-wheel tooth was drawn at
twenty-four degrees to a radial line of the escape wheel, which, in this
instance, is the line _b b'_, Fig. 9. It will now be seen that the angle
of the pallet just halves this angle, and consequently the tooth _A_
only rests with its point on the locking face of the pallet. We do not
show the outlines of the pallet _B_, because we have not so far pointed
out the correct method of delineating it.
METHODS OF MAKING GOOD DRAWING INSTRUMENTS.
Perhaps we cannot do our readers a greater favor than to digress from
the study of the detached lever escapement long enough to say a few
words about drawing instruments and tablets or surfaces on which to
delineate, with due precision, mechanical designs or drawings.
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