Nikola Tesla Books
164 HIGH FREQUENCY APPARATUS are pinned to the shaft and to the disc, thus insuring the permanency of the construction. The final operation is to take a finishing cut off the periphery of each disc with the shaft held between centers in the lathe. The details of the bearings are given in the enlarged drawings, Fig. 18. The reader will note that the bearing proper is a journal of brass tubing reamed to fit the shaft nicely. The bearing support is a casting with a hole cored through it to take the journal. Slots in the feet of the bearings permit the distance between the discs to be varied. When the various parts have been finished, the bearings are located on the framework as shown in the plan drawing and the journals slipped over the shafts. A piece of cardboard is then forced over each end of each journal after the latter has been propped up inside the bearing with bits of wood. Melted lead is then poured into the opening at the top of the bearing and when cold it will hold the journals in perfect alignment with the shaft. The bearings may then be removed and a small hole drilled down through the lead and brass to afford a passage for oil to the shaft. The addition of an oil cup stuffed with a wick completes the bearings, which may be replaced on the frame. The shafts are belted together with rubber belting crossed to make the discs turn in opposite directions. The driving is accomplished by means of an electric motor belted to a pulley on one shaft. The current is conducted to the discs through wire or gauze brushes bearing upon the smooth bosses, as shown in the plan view in Fig. 17. The details of the brush holder are to be seen in Fig. 18. The discs should rotate freely and quietly when the motor is started. If the oil cups are properly fitted, the gap should be capable of an all-day run without trouble
