r holding a
pipe or tube while turning the outside. The cone is adjusted to fit into
the hole of the pipe, by means of the tailstock spindle, and the
opposite end is usually held in a chuck.

[Illustration: Fig. 17. (A) Cone Arbor. (B) Nut Arbor. (C) Pipe Center]

Particular care should be taken to preserve the accuracy of the centers
of lathe arbors by keeping them clean and well-oiled while in use.

=Mandrel or Arbor Press.=--The best method of inserting an arbor of the
solid type in a hole is by using a press, Fig. 18, designed for that
purpose, but if such a press is not available and it is necessary to
drive the mandrel in, a "soft" hammer, made of copper, lead or other
soft material, should be used to protect the centered end of the arbor.
In either case, the arbor should not be forced in too tightly, for if it
fits properly, this will not be necessary in order to hold the work
securely. On the other hand, the work might easily be broken by
attempting to force the arbor in as far and as tightly as possible. In
using the arbor press, the work is placed on the base _B_ with the hole
in a vertical position, and the arbor (which should be oiled slightly)
is forced down into it by ram _R_, operated by lever _L_. Slots are
provided in the base, as shown, so that the end of the arbor can come
through at the bottom of the hole. The lever of this particular press is
counter-weighted so that it rises to a vertical position when released.
The ram can then be adjusted quickly to any required height by the
handwheel seen at the left.

[Illustration: Fig. 18. Press for Forcing Arbors into Work]

Some shops are equipped with power-driven mandrel or arbor presses.
This type is particularly desirable for large work, owing to the greater
pressure required for inserting mandrels that are comparatively large in
diameter. One well-known type of power press is driven by a belt, and
the downward pressure of the ram is controlled by a handwheel. The ram
is raised or lowered by turning this handwheel in one direction or the
other, and a gage shows how much pressure is being applied. This type of
press can also be used for other purposes, such as forcing bushings or
pins into or out of holes, bending or straightening parts, or for
similar work.

[Illustration: Fig. 19. Steadyrest and Follow-rest for Supporting
Flexible Parts]

=Steadyrest for Supporting Flexible Parts.=--Occasionally long slender
shafts, rods, etc., which have to b