Fig. 30 shows how to line a countershaft as regards parallelism with the driving shaft when the countershaft's end-centers are availably situated for thus measuring. A is the countershaft, B the main shaft, C is a stick of proper length about 1½ inches in thickness and width, D a heavy nail—about 20-penny will do—driven into C far enough from its end E to allow of C's resting squarely upon the top of the shaft B.
Rest the measuring rod upon the main shaft, keeping the nail in touch with the shaft, so that when the F end is in contact with the end of the countershaft the stick shall be at right angles to the main shaft, and then mark the exact location a of the countershaft's end-center on the stick. Do the same at the other end of the countershaft. If both marks come at the same spot, your counter is parallel; if not, space between these two marks will show you how much and which way the counter is out.
It may only be necessary to shift one end in or out a little; and then, again, it may be that to get into line you will have to throw one end all the way in one direction and the other all or some in the opposite direction. But, whichever it be, do not rest content until you have verified the correctness of your adjustment by a re-measurement.
The nail should be well driven into C, so that its position will not readily change, and it should, preferably, be slant driven (as shown in Fig. 30), as it thus helps to keep the stick down in contact with the shaft.
Where an end-center is not available or where there is no clear space on the main shaft, opposite a center, the method shown in Fig. 31 can generally be used.
Rest C on top of both shafts and at right angles to the driving shaft B. With D pressed against B, place a square on stick C, as shown (stock in full contact with the top of the rod, and the tongue running down the side of it). Slide along C toward A until the side of the tongue touches the shaft the other side of A. Now mark a line on the stick down tongue. Do the same at the other end of your countershaft and the two resultant marks will be your parallel adjustment guides.
Fig. 31.
It often happens that a counter, or even line shaft, is end driven from the extreme end of the main or jack driving shaft with its other end running beyond the reach of the driving shaft, as shown in Fig. 32.
