But if we should extend the width of the passing hollow to
twenty-four degrees it would do no harm, as the jewel pin would be well
inside the horn of the fork before the guard pin could enter the passing
hollow.
[Illustration: Fig. 63]
We show in Fig. 61 the fork as separated from the roller, but in Fig.
62, which is a side view, we show the fork and jewel pin as engaged.
When drawing a fork and roller action it is safe to show the guard pin
as if in actual contact with the roller. Then in actual construction, if
the parts are made to measure and agree with the drawing in the gray,
that is, before polishing, the process of polishing will reduce the
convex edge of the roller enough to free it.
It is evident if thought is given to the matter, that if the guard pin
is entirely free and does not touch the roller in any position, a
condition and relation of parts exist which is all we can desire. We are
aware that it is usual to give a considerable latitude in this respect
even by makers, and allow a good bit of side shake to the lever, but our
judgment would condemn the practice, especially in high-grade watches.
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