fact that it utilizes a greater arc of
impulse of the escape wheel; (_b_) the impulse being divided between the
tooth and the pallet, permits greater power to be utilized at the close
of the impulse. This feature we have already explained. It is no doubt
true that it is more difficult to match a set of pallets with an escape
wheel of the club-tooth order than with a ratchet tooth; still the
writer thinks that this objection is of but little consequence where a
workman knows exactly what to do and how to do it; in other words, is
sure he is right, and can then go ahead intelligently.

It is claimed by some that all American escape wheels of a given grade
are exact duplicates; but, as we have previously stated, this is not
exactly the case, as they vary a trifle. So do the pallet jewels vary a
little in thickness and in the angles. Suppose we put in a new escape
wheel and find we have on the entrance pallet too much drop, that is,
the tooth which engaged this pallet made a decided movement forward
before the tooth which engaged the exit pallet encountered the locking
face of said pallet. If we thoroughly understand the lever escapement we
can see in an instant if putting in a thicker pallet stone for entrance
pallet will remedy the defect. Here again we can study the effects of a
change in our large model better than in an escapement no larger than is
in an ordinary watch.

HOW TO SET PALLET STONES.

There have been many devices brought forward to aid the workman in
adjusting the pallet stones to lever watches. Before going into the
details of any such device we should thoroughly understand exactly what
we desire to accomplish. In setting pallet stones we must take into
consideration the relation of the roller and fork action. As has already
been explained, the first thing to do is to set the roller and fork
action as it should be, without regard in a great degree to pallet
action.

[Illustration: Fig. 107]

To explain, suppose we have a pallet stone to set in a full-plate
movement. The first thing to do is to close the bankings so that the
jewel pin will not pass out of the slot in the fork on either side; then
gradually open the bankings until the jewel pin will pass out. This will
be understood by inspecting Fig. 107, where _A A'_ shows a lever fork as
if in contact with both banks, and the jewel pin, represented at _B
B''_, just passes the angle _a c'_ of the fork. The circle described by
the jewel pin _B_ is