the, outer surfaces of the standard, and the
nicks of the barrel in line with the standard nicks. Then screw the other
standard to the base. Solder must be run well into the joints, as these
will have to stand all the longitudinal working strain.

The next step is the fitting of the cylinder covers. If you can obtain two
stout brass discs 2-1/8 inches in diameter, some trouble will be saved;
otherwise you must cut them out of 3/32-inch plate. The centre of each
should be marked, and four lines 45 degrees apart be scratched through it
from side to side. A circle of 15/16-inch radius is now drawn to cut the
lines, and punch marks are made at the eight points of intersection. Solder
the covers lightly to the foot side of their standards, marked sides
outwards, and drill 1/8-inch holes through cover and standard at the punch
marks. Make matching marks on the edges. Unsolder the covers, enlarge the
holes in them to take 5/32-inch screws; and tap the holes in the standards.
This method will ensure the holes being in line, besides avoiding the
trouble of marking off the standards separately.

Bore a 1/4-inch hole in the centre of one cover--be sure that it is the
right one--for the piston rod.

You can now proceed to the making of the piston-rod gland (Fig. 54, G1).
Fig. 57 shows how this is built up of pieces of tubing and brass lugs for
the screws. If possible, get the tubular parts trued in a lathe.

[Illustration: FIG. 57.--Vertical section of cylinder.]

Before the gland is soldered to the cover, the cover should be put in
place, the piston rod attached to the piston, and the parts of the gland
assembled. Push the piston rod through the cover until the piston is hard
up against the back of the cover. Slip the gland over the rod, turn it so
that the screws are parallel to the foot of the standard, and make the
solder joint. This is the best way of getting the gland exactly concentric
with the cylinder so that the piston rod shall move without undue friction.
But you must be careful not to unsolder the cylinder from its standard or
the parts of the gland. Blacken the piston rod in a candle flame to prevent
solder adhering.

Steam Chest.--The walls of the steam chest are best made in one piece out
of 1/2-inch brass by cutting out to the dimension given in Fig. 58. A sharp
fret saw will remove the inside rectangle. Get both inside and outside
surfaces as square as possible in all directions, and rub down the two
contact