and the three positions for _B_ are
indicated, by slots in the disk shown. The number of table revolutions
per minute for different positions of pilot-wheel _A_ and lever _B_ are
shown by figures seen through whichever slot is at _C_. There are five
rows of figures corresponding to the five spokes of the pilot-wheel and
three figures in a row, and the speed is shown by arrows on the sides of
the slots. The segment disk containing these figures also serves as an
interlocking device which prevents moving more than one speed
controlling lever at a time, in order to avoid damaging the driving
mechanism.

[Illustration: Fig. 16. Bullard Vertical Turret Lathe]

The feeding movement for each head is independent. Lever _D_ controls
the engagement or disengagement of the vertical or cross feeds for the
head on the cross-rail. The feed for the side-head is controlled by
lever _E_. When this lever is pushed inward, the entire head feeds
vertically, but when it is pulled out, the tool-bar feeds horizontally.
These two feeds can be disengaged by placing the lever in a neutral
position. The direction of the feeding movement for either head can be
reversed by lever _R_. The amount of feed is varied by feed-wheel _F_
and clutch-rod _G_. When lever _E_ is in the neutral position, the
side-head or tool-bar can be adjusted by the hand-cranks _H_ and _I_,
respectively. The cross-rail head and its turret slide have rapid power
traverse movements for making quick adjustments. This rapid traverse is
controlled by the key-handles _J_.

The feed-screws for the vertical head have micrometer dials _K_ for
making accurate adjustments. There are also large dials at _L_ which
indicate vertical movements of the side head and horizontal movements of
the tool slide. All of these dials have small adjustable clips _c_ which
are numbered to correspond to numbers on the faces of the respective
turrets. These clips or "observation stops" are used in the production
of duplicate parts. For example, suppose a tool in face No. 1 for the
main turret is set for a given diameter and height of shoulder on a part
which is to be duplicated. To obtain the same setting of the tools for
the next piece, clips No. 1, on both the vertical feed rod and screw
dials, are placed opposite the graduations which are intersected by
stationary pointers secured to the cross-rail. The clips are set in this
way after the first part has been machined to the required size and
before