Instead of setting the dead centre of the lathe over, the bar may be set over, as in [Fig. 1145], in which the boring tool is carried in the sliding head at t, and is fed by a screw having a star feed on its end. At b is a block sliding in the end of the bar and capable of movement along the same, to adjust the degree of taper by means of the screw shown in the end view, [Fig. 1146]. n is a nut to secure b in its adjusted position.
Fig. 1146.
In this case the work must be bolted to the lathe carriage, and the tool feeds to the cut, and the largest end of the hole bored will be at the live spindle end of the lathe.
Fig. 1147.
But we may turn the bar around, as in [Fig. 1147], driving the work in a chuck, and holding the dead centre end of the bar stationary, feeding the sliding head to the cut by the feed screw f.