In Fig. 5 the tail-stock is shown in two sections. It has a long bearing on the ways, and an extension that serves for a tool-shelf. The front bearing is split for binding the spindle.
To overcome the difficulty of moving it against the sliding-friction of the ways, wheels R are placed as shown, one at each side over the Ks. These wheels are so mounted as to be free to more vertically a short distance, and are loaded 1w adjustable springs. When the tail-stock is loosened the springs tend to assume the load, thus transferring, the weight to the wheels, and transposing the hard sliding to an easy rolling motion. The arrangement for clamping the tail-stock to the ways is shown at. B. It consists of it binding-holt and nut, the face of the mit being cam-shaped, to correspond with the cam-shaped washer underneath it. In tighten ing, the somewhat abrupt faces of the cams take up the slack motion by a slight movement of the handle, when the nut and Ihread bind the tail-stock rigidly. Similarly, in loosening the the abrupt angle of the cams gives the necessary freedom with the same small amount of 'notion. The back-rest has a lever-handle lock-nut.
Fig,. 6 is a perspective view of a 14-in. swing-lathe of this type.
Cur- Whael Luthe.—Pig. 7 illustrates a car-wheel lathe built by the Niles Tool Works, of 0,, especially designed for turning steel-tired car and truck wheels on their axles. The problem presented in this case is to grip the axles by their journals, keep them in line with each other, and revolve them about their common centers, whether these should be true with the original centers of the axle or not. This is accomplished in the following manner : The lathe is arranged with two face-plates revolving on hubs projecting from each head turned true and placed in exact alignment. Within these face-plates and revolving with them are placed two very strong, self-centering chucks, with four swivel jaws. They are operated by gearing mounted on each head-block. These grip the axle firmly about the centers of the journals, and with the face-plates revolve them in exact line. The two face plates are geared together in the same manner as on driving-wheel lathes, by a heavy forged steel shaft. The chucks above mentioned are used only to center the work and insure the wheels being turned true with the journals. The wheels are revolved by two drivers on each face-plate, which engage with the heads of the bolts used to secure the tire to the wheel center. These drivers are adjustable both lengthwise and radially to suit any wheel. Each head is arranged with a sliding spindle, with centers, which are capped to prevent end-motion of the axle when used for turning truck-wheels with inside journals. These naps can be
removed and the spindles run out beyond the face-plates, when the work may be carried on the centers. The right-hand head is movable on the bed by rack and pinion. As the chucks have swivel-jaws, they will accommodate themselves to the work as it is put into the lathe, The feeds are operated from the driving-shaft by means of a rock-shaft placed in front of the machine, and work through the means of a racthet-lever in the Caine manner as on driving wheel lathes.
8 shows a forming-la-the made by the Meriden Machine-Tool Co., Meriden, Conn. This machine is turning large numbers of pieces to certain shapes, such as handles. cocks, packing-nuts, glands, bonnets, caps. nipples, etc. The turning is done by a single motion of one lever. The first part of the motion of the lever tightens the chuck, and a further movement brings the forming tool forward under the work and turns it to shape, after which the tool drops sufficiently to clear the work during the reverse motion of the lever, which motion loosens the chuck and raises the tool at the proper time and in position for another cut. All operations are performed without stopping the lathe.
Richards' Anglo-American Lathe.—Figs. 9 to 11 illustrate a lathe made by George Rich ards & Co., Limited, of Broadheath. near 3Ianchester, England, and exhibited by them at the Paris Exhibition of 1889. It is called an Anglo-American lathe, and is intended to combine the best features of American and English practices. Figs. 9 and 10 show the machine in elevation and plan, while Fig. 11 is a detail section of the fast head-stock. This, it will be seen, has an arrangement of back-gearing giving an extra set of speeds by equal pinions on the spindle and back-shaft. The spindle has parallel necks, hardened and ground true, in which run taper bushes as shown, and wear can thus be compensated for. The thrust is taken up at the back end of the spindle, which is surrounded by a metal cap intended to be filled with oil, and thus the thrust-bearing is efficiently lubricated. The feed is taken from the spindle by the sliding-pinion shown below it, and the rate of feed can be changed by causing this pinion to gear either with that on the spindle or that on the cone. The tool carriage is moved by a rack and pinion in ordinary work, and by a screw in screw-cutting. All the feed-motions of the carriage can be reversed. The guiding surfaces, both back and front, are square. The sliding head-stock is arranged to set over slightly, and thus allow long tapers to be turned.