_B_, Fig. 22, is
brought into position and fed to the proper depth, as determined by
another cross-stop. The turret is also locked in position for this
operation. The finishing cuts for the bore and the outside are next
taken by a box-tool which is shown near the end of its cut in Fig. 26.
This box-tool is similar to the one used for roughing, but it is
equipped with differently shaped cutters to obtain the required finish.
The outside turning tool has a straight cutting edge set tangent to the
cylindrical surface and at an angle, while the boring tool has a cutting
edge of large radius. An end view of this box-tool is shown in Fig. 27.
A reduced feed is employed for the finishing cut, and the speed is
increased to 130 feet per minute, which is the same as that used for
roughing.
[Illustration: Fig. 27. Fifth Operation--Rounding Ends, Scoring Large
End, and Cutting Off]
During the next and final operation, the turret, after being indexed to
the position shown in Fig. 27, is first located by a stop of the "A"
group so that the cutting-off tool _R_ in front can be used for rounding
the corner _b_, Fig. 22. The stop lever _L_ is then shifted and the
turret is moved to a second stop of the "B" group. The corner _c_ is
then rounded and the shell is scored at _d_ by two inverted tools _S_
and _T_ at the rear, after which the finished work is severed by the
cut-off tool at the front. The cross-movement of these three tools is
controlled by positive stops on the cross-slide, and the latter is moved
to and fro by hand lever _O_. After the shell is cut off, the stop _M_,
mounted on the turret, Fig. 26, is swung into position, and the tube is
automatically fed forward to the swinging stop by the roll feed, as soon
as the chuck is released by operating lever _Q_. This completes the
cycle of operations. A copious supply of lubricant is, of course,
furnished to the tools during these operations, and the two boring-tool
shanks are hollow so that lubricant can be forced through them and be
made to play directly upon the cutters.
=Chuck Work in Flat Turret Lathe.=--Two examples of chuck work on the
Acme combination flat turret lathe are shown in Figs. 28 and 29. Fig. 28
shows the tool equipment for turning a cylindrical part _A_ which is
held in a three-jaw universal chuck. The front flange is first
rough-turned by a bent turning tool _B_. The diameter is regulated by
one of the cross-stops at _D_ which has been previously set and
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