on Vertical
Turret Lathe--First Position]

=Examples of Vertical Turret Lathe Work.=--In order to illustrate how a
vertical turret lathe is used, one or two examples of work will be
referred to in detail. These examples also indicate, in a general way,
the class of work for which this type of machine is adapted. Fig. 17
shows how a cast-iron gear blank is machined. The work is gripped on the
inside of the rim by three chuck jaws, and all of the tools required for
the various operations are mounted in the main and side turrets. The
illustration shows the first operation which is that of rough turning
the hub, the top side of the blank and its periphery. The tools _A_ for
facing the hub and upper surface are both held in one tool-block on the
main turret, and tool _A_{1}_ for roughing the periphery is in the side
turret. With this arrangement, the three surfaces can be turned
simultaneously.

[Illustration: Fig. 19. Turning Gasoline Engine Flywheel--Second
Position]

[Illustration: Fig. 20. Diagrams showing How Successive Operations are
Performed by Different Tools in the Turret]

The main turret is next indexed one-sixth of a revolution which brings
the broad finishing tools _B_ into position, and the side turret is also
turned to locate finishing tool _B_{1}_ at the front. (The indexing of
the main turret on this particular machine is effected by loosening
binder lever n and raising the turret lock-pin by means of lever _p_.)
The hub, side and periphery of the blank are then finished. When tools
_B_ are clamped in the tool-blocks, they are, of course, set for
turning the hub to the required height. The third operation is performed
by the tools at _C_, one of which "breaks" or chamfers the corner of the
cored hole in the hub, to provide a starting surface for drill _D_, and
the other turns the outside of the hub, after the chamfering tool is
removed. The four-lipped shell-drill _D_ is next used to drill the cored
hole and then this hole is bored close to the finished size and
concentric with the circumference of the blank by boring tool _E_, which
is followed by the finishing reamer _F_. When the drill, boring tool and
reamer are being used, the turret is set over the center or axis of the
table, by means of a positive center stop on the left-side of the turret
saddle. If it is necessary to move the turret beyond the central
position, this stop can be swung out of the way.

Figs. 18 and 19 illustrate the turning o