A pulley on one of the motors at a certain plant had been giving some trouble by becoming loose and working its way along the shaft toward the motor bearing. Each time the pulley became loose, the set-screw was loosened, the pulley put back in position, the set-screw made tight and the motor started. After a few trials it was found that this would not prevent the pulley from working its way along the shaft. In order to overcome this difficulty the pulley was placed in its proper position, a line was drawn around the shaft close to the hub and, after the line was scribed, the pulley was removed and the shaft was burred upon the line as shown at B, Fig. 56. The pulley was then put back and driven close up to the burred line, the set-screw made tight and the pulley is now running without any apparent tendency to travel from its proper position. It will be seen that the position of the set-screw as indicated by the line at A is a poor one and calculated to give plenty of trouble at the most inopportune time.

Not long ago a cast-iron pulley had to move along a countershaft in order to make room for a pulley of another diameter. The pulley had not been on the shaft long, so it was thought that little work would be required to move it. A heavy bar was placed against the hub and a sledge hammer was used to strike the bar. After an hour and a half of heavy work the pulley was not moved over 1 inch (it had to be moved 16 inches), so it was suggested that a Bunsen burner be attached to a gas pipe by means of a hose and placed beneath the hub. The plan was immediately adopted. The burner was placed beneath the hub, the gas lit and allowed to heat the hub. After about twenty-five minutes it was found that a blow from the bar was sufficient to move the pulley. The pulley was moved the 16 inches inside of twenty minutes.

A very handy arrangement for moving pulleys is a bolt and nut. Fig. 57 shows the bolt and nut with a piece of pipe attached. A piece of pipe can be cut to suit the distance between the nut and hub of one pulley while the bolt head is against the other hub. The nut is screwed back upon the bolt as far as possible. A washer is then placed against the nut, and a piece of pipe cut to suit. Of course, the pipe must be large enough in diameter to fit over the bolt. If we screw back upon the nut, a powerful strain can be brought to bear between the hubs and in all probability the pulley will move.

In taking down solid pulleys from main or counter shafting it sometimes happens that a hanger must be removed to permit the pulley to be taken off. A first-rate plan is to make a couple of long bolts hooked at the end as shown in Fig 58; pass the hook around the shaft and the threaded end through a hole in the stringer. By screwing up the nut as shown, the shaft and remaining pulleys can be kept in position, obviating the use of tackle, not to mention the labor required to hoist back the shaft into position. The application of this contrivance is especially valuable where heavy cone pulleys are required to be lowered or changed. It will be seen that if we employ a pipe thread we will be enabled to suit almost any condition of length that may arise between the shaft and stringer.

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