One must now make the bridge pieces (Fig. 61, a, a) to separate the inlet 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.]