Now place the ends on cylinder and drill through them so as to screw them on to the flanges. The slide-valve case is a casting with separate lid ([Fig. 5]), and has to be faced up with a file, and four holes drilled through the lid and corners to screw on to the cylinder face. The boss on lid must now be drilled and tapped for steam-pipe to be screwed in.
The slide-valve itself is like [Fig. 6], has a hollow cast in its face, and a small projection on the back (B), which you must make a narrow groove in with a saw, and file the end of the valve-rod down to fit it, as shown at C, [Fig. 6].
The face of the cylinder and also of the slide-valve must now be made to work steam-tight by rubbing on a perfectly flat stone until true, and then putting some emery and oil on a board and working them up until they are quite true.
The eccentrics may now receive attention. They will require to be chucked twice, and the true centre marked. Do not drill it out yet, as the hole for the crank-shaft must not be in the centre, but half the travel of the slide valve from the centre. For instance, if the valve travelled one inch you would have to drill hole for shaft half an inch out of true centre of eccentric.
FIG 7
FIG 8
The straps ([Fig. 7]) have to be turned quite true to the size of the groove on eccentrics, then taken out of lathe and cut through line A B with a fine saw, and screwed together at C C. A hole has now to be drilled at D and tapped for the eccentric rods to be screwed into, one of which will have to be bent like [Fig. 8], so as to allow it to work on to the quadrant. It is the neatest way to key the eccentrics on to the shaft with a small steel wedge.
