The following is a simple method for testing the alinement and level of a line of shafting that is already up.
Fig. 29.
As in Fig. 29, stretch a line C so that it is exactly opposite the shafting. Set it equidistant from the shaft end centers G and F and free from all contact along its entire length except at its retaining ends A and B. Now, it is self-evident, as line C is straight and set equidistant from the shaft end centers G and F, that if you set the entire center line of the shafting at the same distance from line C, as G and F, you are bound to get your shafting into perfect alinement.
In leveling a line of shafting that is already up, you can, by the use of a level and perseverance, get it right.
Placing the level at A, you are just as likely to raise the first hanger as to lower the middle one. Look before you jump, even if compelled to climb to the top of the fence to do so. When you find a length of shafting out of level, try the two adjacent lengths before acting, and your action will be the more intelligent for it.
On exceptionally long lines of shafting the following method, in which the level and a line constitute a check upon and a guide for each other, can be used to great advantage. Stretch a line so that it is exactly above, or, if more convenient, below the shafting to be leveled. With the level find a length of shafting that is level and adjust your line exactly parallel with this length. Your line now, free of contact except at its retaining ends, and level owing to its parallelism to the level shaft length, constitutes a safe hight level guide while the level itself can serve to verify the accuracy of the finished job.
In lining, whether for level or alinement, unless the shafting line consists of the same diameter of shafting throughout its entire length, though of necessity measuring from the shaft circumference to the line, always base your calculations on the shaft centers. The figures in Fig. 29 will make this point clear.
The manner of securing the ends of the line under different circumstances must be left to individual ingenuity. Only be sure that the line is so placed that the shafting adjustment shall not affect its original position with reference to the end shaft centers.
Coupling clutches, i.e., those joining two lengths of shafting into one at option, will fail, utterly or partially, if the respective shafts which bear them are out of line or level with each other. Such a condition should not be tolerated on account of the danger entailed by the inability to shut off the power in cases of emergency.