rod, and with it be centred on the paper and held in position while the
parts are soldered together.

OTHER DETAILS.

Adjusting the Guides.--Put the connecting rod in place on its pins, and
revolve the crank until the guides have taken up that position which allows
the crosshead to move freely. Then mark off the holes for the guide
holding-down screws, and drill and tap them.

Packings.--The glands and piston should be packed with asbestos string.
Don't be afraid of packing too tightly, as the tendency is for packing to
get slacker in use. The rear end of the cylinder should be bevelled off
slightly inside, to allow the packed piston to enter easily.

Joints.--The cylinder head and valve chest joints should be made with
stout brown paper soaked in oil or smeared with red lead. All screw holes
should be cut cleanly through the paper, and give plenty of room for the
screws.

[Illustration: FIG. 66.-Vertical section of force pump driven by engine.]

When making a joint, tighten up the screws in rotation, a little at a time
so as not to put undue strain on any screw. Wait an hour or two, and go
round with the screw-driver again.

Lubrication.--When the engine is first put under steam, lubrication
should be very liberal, to assure the parts "settling down" without undue
wear.

The Pump.--Fig. 65 shows in section the pump, which will be found a
useful addition to the engine. (For other details, see Figs. 53 and 54.)
Its stroke is only that of the eccentric, and as the water passages and
valves are of good size, it will work efficiently at high speed. The method
of making it will be obvious from the diagrams, and space will therefore
not be devoted to a detailed description. The valve balls should, of
course, be of gun-metal or brass, and the seatings must be prepared for
them by hammering in a steel ball of the same size.

In practice it is advisable to keep the pump always working, and to
regulate the delivery to the boiler by means of a by-pass tap on the feed
pipe, through which all or some of the water may be returned direct to the
tank.

The tank, which should be of zinc, may conveniently be placed under the
engine. If the exhaust steam pipe be made to traverse the tank along or
near the bottom, a good deal of what would otherwise be wasted heat will be
saved by warming the feed water.

Making a Governor.

[Illustration: FIG. 66.--Elevation of governor for horizontal engine.
Above is plan of valve