ade with
$V$ slides on top, and placed at right angles to each other. Upon each
of the bed-plates is fitted a vertical arm B 1 and B 2, each of which
carries two saddles, C 1 and C 2, these being each adjustable vertically
on its respective arm by means of rack and pinion and hand wheels D 1
and D 2. The saddles are balanced so that the least possible exertion is
sufficient to adjust them. The vertical arms, B 1 and B 2, are cast each
with a round foot by which the arms are attached to the square boxes E 1
and E 2, which are fitted to the $V$ slides on the horizontal beds A 1
and A 2, and are adjustable thereon by means of screw and ratchet motion
F 1 and F 2. Each of the square boxes has cast on it a small arm G 1 and
G 2, carrying studs upon which run pinions gearing into the circular
racks at the foot of the vertical arms. The square boxes have each a
circular groove turned in the top to receive the bolts by which the
vertical arms are connected to them, and thus the vertical arms, and
with them the drill spindles N 1 and N 2, are adjustable radially with
the boiler--the adjustment being effected by means of the pinions and
circular racks. The pinions are arranged so that they can be worked with
the same screw key that is used for the bolts in the circular grooves.

The shell to be drilled is placed upon the circular table H, which is
carried by suitable framework adjustable by means of screw on a $V$
slide I, placed at an angle of 45 deg. with the horizontal bed-plates. By
this arrangement, when the table is moved along I, it will approach to
or recede from all the drills equally. J 1 and J 2 are girders forming
additional bearings for the framework of the table. The bed-plates and
slides for the table are bolted and braced together, making the whole
machine very firm and rigid. Power is applied to the machine through the
cones K 1 and K 2, working the horizontal and vertical shafts L 1 and L
2, etc. On the vertical shafts are fitted coarse pitch worms sliding on
feather keys, and carried with the saddles C 1 and C 2, etc. The worms
gearing with the worm wheels M 1 and M 2 are fitted on the sleeves of
the steel spindles N 1 and N 2. The spindles are fitted with self-acting
motions O 1 and O 2, which are easily thrown in and out of gear.

The machine is also used for turning the edge of the flanges which some
makers prefer to have on the end plates of marine boilers. The plates
are very readily fixed to the circular