passages from the exhaust. Their width is the distance between the
bent-down pieces CC of Fig. 60, and their bottom edges are shaped to the
curvature of the cylinder barrel. Finally, make the pieces bb (Fig. 61),
which form part of the top of the steam ways.

In the assembling of these parts a blowpipe spirit lamp or a little "Tinol"
soldering lamp will prove very helpful.

The following order should be observed:

(1.) Solder the piece shown in Fig. 60 to the cylinder barrel by the long
edges, and to the cylinder supports at the ends. This piece must, of
course, cover the steam ports in the cylinder.

(2.) Put pieces aa (Fig. 61) in position, with their tops quite flush with
the tops of BB (Fig. 62), and solder them to the cylinder barrel and sides
of the steam-way piece.

(3.) Solder the valve plate centrally to BB, and to the tops of aa, which
must lie between the central and outside ports. Take great care to make
steam-tight joints here, and to have the plate parallel to the standards in
one direction and to the cylinder in the other.

(4.) Solder in pieces bb. These should be a tight fit, as it is difficult
to hold them in place while soldering is done.

(5.) Bore a 5/16-inch hole in the lower side of the central division and
solder on the exhaust pipe.

Slide Valve.--The contact part of this is cut out of flat sheet brass
(Fig. 63), and to one side is soldered a cap made by turning down the edges
of a cross with very short arms. The little lugs aa are soldered to this,
and slotted with a jeweller's file to engage with notches cut in the valve
rod (see Figs. 58 and 62).

[Illustration: FIG. 63.-Parts of slide valve.]

The Crank and Crank Shaft.--The next thing to take in hand is the fixing
of the crank shaft. This is a piece of 3/8 or 1/2 inch steel rod 5 inches
long.

The bearings for this may be pieces of brass tubing, fitting the rod fairly
tight. By making them of good length--1 inch--the wear is reduced to almost
nothing if the lubricating can is used as often as it should be.

Each bearing is shown with two standards. The doubling increases rigidity,
and enables an oil cup to be fixed centrally.

The shape of the standards will be gathered from Fig. 53, their outline
being dotted in behind the crank.

Cut out and bend the standards--after drilling the holes for the foot
screws--before measuring off for the centres of the holes; in fact, follow
the course laid down with regard to the cylinder s