Machinery Repairman

turn the spindle. The nose of the spindle holds the
driving plate, the faceplate, or a chuck. The spindle is
hollow throughout its length so that bars or rods can
be passed through it from the left and held in a chuck
at the nose. The chuck end of the spindle is bored to a
Morse taper to receive the live center. The hollow
spindle also permits the use of the draw-in collet
chuck, which is discussed later in this chapter. At the
other end of the spindle is the gear by which the
spindle drives the feed and screw-cutting mechanism
through a gear train located on the left end of the
lathe.
TAILSTOCK
The tailstock (fig. 6-6) may be used to hold the
dead or ball bearing center or it can be used to hold
tapered shank drills, reamers, and drill chucks. The
tailstock moves on the ways along the length of the
bed to accommodate work of varying lengths. It can
Figure 6-6.—Cross section of a tailstock.
6-5
be clamped in the desired position by the tailstock
clamping nut (13).
The dead center (11) is held in a tapered hole
(bored to a Morse taper) in the tailstock spindle (6).
To move the spindle back and forth in the tailstock
barrel for longitudinal adjustment, turn the handwheel
(9) that turns the spindle-adjusting screw (7) in a
tapped hole in the spindle at (8). The spindle is kept
from revolving by a key (4) that fits a spline, or
keyway (5), cut along the bottom of the spindle as
shown. After making the final adjustment, use the
binding clamp (10) to lock the spindle in place.
The tailstock body is made in two parts. The
bottom, or base (1), is fitted to the ways; the top (2)
can move laterally on its base. The lateral movement
can be closely adjusted by setscrews. Zero marks
inscribed on the base and top indicate the center
position and provide a way to measure setover for
taper turning. Setover of the tailstock for taper
turning is described in a later chapter.