TRUING UP LINE SHAFTING

It is assumed, for the purposes of this description, that the modern style of shafting, increasing in diameter by the ½ inch, is used, and that all pulleys and belts are in place. We will take a line composed of sizes ranging between 3 15/16 and 2 7/16 inches. This gives us four sizes, 3 15/16, 3 7/16, 2 15/16 and 2 7/16 inches in the line.

We will first consider the plumb-bob. The accompanying sketch, Fig. 47, illustrates a good one.

The ball is 1½ inches diameter, and the large end of the tapered stem ½ inch in diameter, turned parallel for a short distance at the lower end. The two thin sheet-steel disks, 1 and 2 inches in diameter, are drilled to fit snugly when pushed on to the ½-inch part of the stem, and stay there until pulled off. These disks are turned true. This arrangement of plumb-bob and disks enables us to deal with five sizes on one line, and there are not many lines that contain more.

Now having our plumb-bob ready, we will stretch the line. The stretchers should be set horizontally by nailing a strip of wood, say 1 × 1½ × 12 inches, with a piece at each end to form a space between it and the wall, or place of location in line with the edge of the shaft, as in Fig. 48. The top of this stretcher should be low enough to clear the largest pulley, and high enough to clear the hat of your tallest man. You would perhaps find it convenient to go between the spokes of a large pulley.

Fig. 47.

Now having located your stretcher, find approximately the position of your line, and drive a nail a foot or more below it in a vertical line, and another nail anywhere for convenient winding. The advantage of this plan is that the line can be easily adjusted as it merely passes over the stretcher, and is free to respond to movement either way; then when the final adjustment is made, and is ready for its final stretch, it is only necessary to pinch the line to the nail with one hand, while the other is at liberty to unwind, stretch and rewind the line without fear of its shifting.

Fig. 48.