It is best to go over the whole line first, before disturbing anything; so starting at the first hanger at the 2-7/16-inch end, throw your plumb line over the shaft, and record on the floor in chalk beneath it whether it is O. K. or wants to go either way, and how much; then go to the next hanger, and so on to the end. A short study of the conditions enables one to correct the faults, with a knowledge of the requirements, and consequently in the least time and with the least trouble.
Now suppose we start at the 2-7/16-inch end to inspect the line, we use the center point of the bob on the line so long as we are testing 2-7/16 inches.
When we get to the 2-15/16-inch part, which is 1/2 inch larger, we use the half diameter of the stem, the edge of which should just touch the line.
When we come to the 3-7/16-inch part, 1 inch larger than 2-7/16, we use the 1-inch disk, slip it on to the stem, and when it just touches the line with its edge it is O. K.
The 3-15/16-inch, being 1-1/2 inches larger than the 2-7/16-inch, will be right when the ball of the bob is in light contact with the line.
The 2-inch disk would be suitable for the next size, and other disks or modifications of the bob proper might be made to suit circumstances.
Now having straightened the line, the next process is to level it. As in some cases your pulleys will be too close to place your level where you want, make a light iron frame as per Fig. 49, making the suspending members of sufficient length to admit of your reading the level conveniently when standing on the floor. Hang your frame on the shaft, and put your level on the straight-edge below; in this way travel along the shaft, placing your frame where convenient. Be sure that one end of your frame does not rest on a shaft of different diameter, a key, keyseat, or anything to distort the reading.
Never be content with trying your level, especially an adjusting level, one way; always reverse it and try again; for if it is out of truth at the start, you might want to go through the roof or down cellar at the finish. Get into a habit of reversing your level, and so prove your work as you proceed.
APPARATUS FOR LEVELING AND LINING SHAFTING
THE first apparatus explained in this chapter was designed by the late Chas. A. Bauer, and is a highly perfected instrument.