Page:Lowell Hydraulic Experiments, 4th edition.djvu/32

 crowns, the latter are then drawn together, by means of a number of screws applied to different parts of the circumference, and when the edges of the buckets are drawn into the bottom of the grooves, the tenons are riveted on the opposite sides. This construction gives great stability to the buckets, and permits the use of very thin iron.

30. d d The vertical shaft. This is of wrought iron, and is accurately turned in every part.

The diameters are as follows: —

By reference to plate I., it will be seen that the shaft does not run upon a step at the bottom, but upon a series of collars, resting upon corresponding projections in the suspension box e. The part of the shaft on which the collars are placed, is made separate from the main shaft, and is joined to it at f, by means of a socket in the top of the main shaft, which receives a corresponding part of the collar piece. The collars are made of cast steel; they are separately screwed on, and keyed to a wrought iron spindle.

31. e The suspension box. This is made in two parts, to admit of its being taken off, and put on the shaft; it is lined with babbit metal, a soft composition consisting principally of tin. It is found that bearings thus lined will carry from fifty to a hundred pounds to the square inch, with every appearance of durability.

32. f f, The upper and lower hearings. These are of cast-iron, lined with babbit metal; they are retained in position, horizontally, by means of adjusting screws; vertically, their weight is sufficient. The parts of the shaft inside the hubs of the wheel and the bevel gear, are made slightly tapering, about $7 1⁄4$ of an inch in diameter in the length of the hubs; the hubs are bored out with the same taper, but a very little smaller in diameter; they are then drawn on by a powerful screw purchase, and in this manner are made to fit very tight. To prevent danger of bursting the hubs, they are before being drawn on or bored out, strongly hooped with wrought iron hoops, driven on hot.

33. The suspension box e (art. 31,) rests upon the gimbal g, plates I. and II. The gimbal itself is supported on the frame h h, by adjusting screws, which give the means