Then push them into either end of the boiler about an eighth of an inch from the edge, as in A (Fig. 11); they can now be soldered in place, and you will find your gas blow-pipe very useful here. The projecting flange should be hammered down all round, like B (Fig. 11), which can also be sweated afterwards with solder, and finished off with a half-round file.
When filing solder or lead, only use an old worn file, as the soft metal soon fills up and spoils a good one, and although it can be melted out by heat, it is not advisable to do so.
You will now require to drill a hole at A (Fig. 10) for the chimney, which should be three-quarters of an inch in diameter. Then cut a slot in the bottom of the boiler six inches long by an inch and a half wide, commencing a quarter of an inch from the forward end of the boiler.
Now take a sheet of copper and cut a piece about six inches and a quarter long by six inches broad, and bend it over a wooden roller to the shape shown at Fig. 12, keeping it an inch and a half apart between A B. Cut also two other pieces of copper to the shape of your bent sheet (Fig. 12), and make it long enough to reach to the dotted line. These form the two ends, which may be placed an eighth of an inch from the edges, as in Fig. 13, and soldered in place, and the projecting rims turned over and sweated with solder from the outside in the same manner as you did to the boiler-ends in Fig. 11. Then drill a three-quarter-inch hole at B (Fig. 13) for the bottom of chimney-tube to go into, and cut a piece of three-quarter-inch brass tubing of sufficient length to pass out at top of boiler about half an inch, as shown at A (Fig. 10). You can then hammer out a rim or flange on the bottom end of chimney-tube, and push it up through the hole in the copper box and solder it in place from the top, as at A (Fig. 14).
Now drill a couple of small holes at each end of the box B C (Fig. 14); these should be rather more than an eighth of an inch in diameter, to allow an eighth of an inch tube to pass through.
Get two twelve-inch lengths of hard-drawn steam-piping of an eighth of an inch in diameter, and with your screw-plate put a thread on each end of about half an inch in length, then drill some holes in any odd piece of brass plate, and with the screw-taps form eight nuts to fit the threads on the piping, and finish them up to shape with a file.