indicated by the arc _e_. It is well to put a
slight friction under the balance rim, in order that we can try the
freedom of the guard pin. As a rule, all the guard pin needs is to be
free and not touch the roller. The entire point, as far as setting the
fork and bankings is concerned, is to have the fork and roller action
sound. For all ordinary lever escapements the angular motion of the
lever banked in as just described should be _about_ ten degrees. As
explained in former examples, if the fork action is entirely sound and
the lever only vibrates through an arc of nine degrees, it is quite as
well to make the pallets conform to this arc as to make the jewel pin
carry the fork through full ten degrees. Again, if the lever vibrates
through eleven degrees, it is as well to make the pallets conform to
this arc.

The writer is well aware that many readers will cavil at this idea and
insist that the workman should bring all the parts right on the basis of
ten degrees fork and lever action. In reply we would say that no
escapement is perfect, and it is the duty of the workman to get the best
results he can for the money he gets for the job. In the instance given
above, of the escapement with nine degrees of lever action, when the
fork worked all right, if we undertook to give the fork the ten degrees
demanded by the stickler for accuracy we would have to set out the jewel
pin or lengthen the fork, and to do either would require more time than
it would to bring the pallets to conform to the fork and roller action.
It is just this knowing how and the decision to act that makes the
difference in the workman who is worth to his employer twelve or
twenty-five dollars per week.

We have described instruments for measuring the angle of fork and pallet
action, but after one has had experience he can judge pretty nearly and
then it is seldom necessary to measure the angle of fork action as long
as it is near the proper thing, and then bring the pallets to match the
escape wheel after the fork and roller action is as it should be--that
is, the jewel pin and fork work free, the guard pin has proper freedom,
and the fork vibrates through an arc of about ten degrees.

Usually the workman can manipulate the pallets to match the escape wheel
so that the teeth will have the proper lock and drop at the right
instant, and again have the correct lock on the next succeeding pallet.
The tooth should fall but a slight distance before the tooth