hteen changes. The feeding
movement is transmitted to the spindle-head, spindle, platen or saddle,
as required, by the three distributing levers _T_, _U_ and _V_, which
control clutches connecting with the transmission shafts or feed screws.
When lever _T_ is turned to the left, the longitudinal power feed for
the spindle is engaged, whereas turning it to the right throws in the
vertical feed for the spindle-head. Lever _U_ engages the cross-feed for
platen _P_ and lever _V_, the longitudinal feed for saddle _E_. These
levers have a simple but ingenious interlocking device which makes it
impossible to engage more than one feed at a time. For example, if lever
_T_ is set for feeding the spindle, levers _U_ and _V_ are locked
against movement.

The feeds are started and stopped by lever _M_ which also engages the
rapid power traverse when thrown in the opposite direction. This rapid
traverse operates for whatever feed is engaged by the distributing
levers and, as before stated, in a reverse direction. For example, if
the reverse lever _O_ is set for feeding the spindle to the right, the
rapid traverse would be to the left, and _vice versa_. The cross-feed
for the platen can be automatically tripped at any point by setting an
adjustable stop in the proper position and the feed can also be tripped
by a hand lever at the side of the platen.

All the different feeding movements can be effected by hand as well as
by power. By means of handwheel _N_, the spindle can be moved in or out
slowly, for feeding a cutter by hand. When the friction clamp _Q_ is
loosened, the turnstile _W_ can be used for traversing the spindle, in
case a hand adjustment is desirable. The spindle-head can be adjusted
vertically by turning squared shaft _X_ with a crank, and the saddle can
be shifted along the bed by turning shaft _Y_. The hand adjustment of
the platen is effected by shaft _Z_. The spindle-head, platen and saddle
can also be adjusted from the end of the machine, when this is more
convenient. Shafts _X_, _Y_ and _Z_ are equipped with micrometer dials
which are graduated to show movements of one-thousandth inch. These
dials are used for accurately adjusting the spindle or work and for
boring holes or milling surfaces that must be an exact distance apart.

=Horizontal Boring Machine with Vertical Table Adjustment.=--Another
horizontal boring machine is partly shown in Fig. 2. This machine is of
the same type as that illustrated in Fig. 1,