Cut out the two rectangles so formed carefully, so as not to injure the lines. This can be done easily by first drilling a small hole, about an eighth of an inch in diameter, near one corner, and then putting a fretwork saw through it and fixing it in the frame, and sawing the metal away just inside the lines. The saw must be kept well moistened with water. The corners can be left circular, which will add to the finish of the plate, and make the cutting with the saw easier.
After the holes are cut they must be finished quite up to the lines, but without injuring them, with a fine-cut flat file. Through each corner of the plate a hole must be drilled an eighth of an inch in diameter, and about an eighth of an inch from the edges, as in [Fig. 1]. The top plate is now ready for mounting the cylinders on, which we will set about doing.
Fig. 2
Take the two steam-blocks ([Fig. 2]) and draw a pencil mark on each from the centre hole to the bottom, and at right angles to it ([Fig. 2]). Next place the two blocks back to back on the middle of the top plate, between the two large holes, so that the pencil marks coincide with the line C D, and so that the bottom edges of the faces coincide with the lines f-h and k-m. Be very careful in setting these blocks right. When in their places mark the top plate through the screw-holes in the projecting bases of each, and drill four holes straight down through the plate, making them a little smaller than the holes in the bases of the blocks. Now replace the blocks and fasten them there with two small screws each. These screws correspond with the size of the cylinders, and can be purchased by the dozen, together with taps, for each size, to make the thread in the holes with.
Next take the pivot-blocks and mark them with pencil, as the steam-blocks were marked, and put them on the line C D on the outer sides of the large holes, using the same care to get them properly centred along the line C D, and at right angles to it, and about an eighth of an inch from the lines e-g and l-n. Mark the screw-holes and drill them as before, and fasten the pillars in their places.
Now the cylinders can be hung. Unscrew the pivots about a quarter of an inch and place the cylinders in their places, with the spindles in the proper holes for them in the blocks. Now screw in the wire pivots till they catch in the indentations drilled for them in the sides of the cylinders. They will now swing freely between the blocks and pivots.
Fig. 3
Now to cut the bed-plate ([Fig. 3]). Take your second brass plate and divide it by the lines A B and C D as before. From the point O mark off each way along the line C D the distances five-eighths of an inch from O to x, and three-quarters of an inch from x to y. Through these points draw four lines two inches long, and projecting one inch on each side of the line C D, and parallel to the line A B. Join the lines in pairs as before, and cut out the rectangles so formed. Finish up the edges, and bore a hole in each corner, as in the top plate. On the line A B, and half an inch from each end, bore two holes an eighth of an inch in diameter, and countersink them at the top, as in the [figure].