The Boy's Own Book of Indoor Games and Recreations / A Popular Encyclopædia for Boys

by C. Stansfeld Hicks; John Nevil Maskelyne; Gordon Stables

Fig. 21

Cut the brass away at the ends of the block, leaving a flange at the bottom, at each end, a quarter of an inch long and one-sixteenth of an inch thick, as in [Fig. 21]. In each flange bore two small holes, to screw it to the top plate by. Drill four holes, one through each side of the block one-eighth of an inch in diameter, right into the centre hole and at right angles to each other, as in [Fig. 21]. Wipe the plug and hole quite clean from the oil and emery, and replace the plug. Put a needle-point into one of the side holes, and lying on the bottom of it and pressing against the plug. Turn the plug round in the socket. Now move the needle-point to the top of the hole and turn the plug round again.

Fig. 22

Take out the plug, and there will be two lines one-eighth of an inch apart scratched all round it, as in [Fig. 22]. With a small round file cut two grooves opposite each other in the plug, by filing between the scratched lines, leaving the brass between them one-sixteenth of an inch or less thick, as seen in [Fig. 22]. Drill a hole one-eighth of an inch in diameter and a quarter of an inch deep down the top end of the plug, and another up the lower end, to fit one of your small screws. Be careful that neither of these holes enters the grooves.

Cut a small circular plate of copper seven-sixteenths of an inch in diameter, and drill a small hole in the middle of it. Give this plate two or three taps with a small hammer in the middle to hollow it a little. Put the plug in its place in the block, and turn it over and place the circular plate on the bottom, with the concave side to the plug, and fix it there with a screw. This will keep the plug from coming out of the block. Solder an iron wire one-eighth of an inch thick and six inches long into the hole in the top of the plug. Fasten the block on to the square projecting piece of the top plate, first cutting out of it a circular hole half an inch in diameter, to let the circular plate at the bottom of the plug drop into. The valve must now be connected with the steam-blocks. Take two pieces of steam-pipe three-sixteenths of an inch in diameter and an inch and a quarter long, and bend them the shape of [Fig. 23], so that the distance apart of the ends is the same as from one hole in the top of one block to the corresponding hole in the other.

Fig. 23

Cut a hole in one side of the bent piece, as in [Fig. 23], large enough for the end of another piece of the pipe to fit into when tapered a little. This piece is to be about three and a quarter inches long, and bent so as to pass from the steam-blocks round the cylinder to the hole in that side of the reversing-valve block. Fit the end of this pipe into the hole in the bent tube and braze it in the following way. Rub a small lump of borax on a moistened tile and rub the joint to be brazed with the mixture of borax and water. Cut a small piece of silver off a threepenny-piece about the size of a large pin-head, and put it on the joint. Now hold the end of the tube in the left hand, covered with a cloth, and with a blow-pipe direct the flame of a spirit-lamp or gas-jet on to the joint till it is red-hot, when the silver will melt and flow round the joint and fix it. If you cannot do this yourself a jeweller or watchmaker will do it for you. Make two of these bent tubes with double ends, and solder them in their places, connecting the steam-blocks with the reversing-valve. You must enlarge the holes, to let the ends of the pipe in before soldering.

Bend a piece of steam-pipe, a quarter of an inch in diameter and eight inches long, so that about two inches of one end stands at right angles to the other part. The bend must be circular, or it will compress the pipe. Solder this end firmly into the front hole in the reversing-valve. Bend another piece of the pipe about the same length so as to go into the after hole of the valve and be parallel with the other pipe. On the top of the boiler solder a piece of pipe about six inches long; one end is to be bent up about one inch and inserted through a hole in the bottom of the funnel, and directed upwards inside, the other end is to project about one inch from the end of the boiler.