Lubricators.—­These are short pieces of tubing hollowed at one end by a round file of the same diameter as the bearings.  A little “Tinol” is smeared over the surfaces to be joined, and the lubricators are placed in position and heated with the blow-lamp until the solder runs.  To prevent the oil flowing too freely, the lubricators should be provided with airtight wooden plugs.

Escape Pipes.—­The pipe for the exhaust steam is now soldered into disc E, and a small water escape into the ring at its lowest point.  This pipe should be connected with a closed chamber or with the exhaust at a point lower than the base of the turbine case.

Stirrup.—­Fig. 69 shows a stirrup carrying a screw which presses against the pulley end of the spindle.  This attachment makes it easy to adjust the distance between the rotor and the steam ports, and also concentrates all end thrust on to a point, thereby minimizing friction.  The stirrup can be fashioned in a few minutes out of brass strip.  Drill the holes for the holding-on screws; drill and tap a hole for the adjusting screw; insert the screw and centre it correctly on the spindle point.  Then mark the position of the two screw holes in E; drill and tap them.

Feet are made of sheet brass, drilled to take the three (or two) lowermost bolts, and bent to shape.  Note.—­A side and foot may be cut out of one piece of metal.  The difficulty is that the bending may distort the side, and prevent a tight joint between side and ring.

Assembling.—­Cut out two rings of stout brown paper a quarter of an inch wide and slightly larger in diameter than the casing ring.  In assembling the turbine finally, these, after being soaked in oil, should be inserted between the ring and the discs.  Put in four screws only at first, and get the ring properly centred and the bearings exactly in line, which will be shown by the spindle revolving easily.  Then tighten up the nuts and insert the other bolts, the three lowest of which are passed through the feet.  Affix the pulley and stirrup, and adjust the spindle longitudinally until the rotor just does not rub the casing.  The soldering on of the cap of A completes operations.

To get efficiency, heavy gearing down is needed, and this can be managed easily enough with the help of a clockwork train, decreasing the speed five or more times for driving a dynamo, and much more still for slow work, such as pumping.

A More Elaborate Turbine.

[Illustration:  Fig. 70.—­Vertical section of steam turbine with formed blades (left); outside view of turbine, gear side (right).]