Fig. 2533.
It may here be remarked that if the bore of the crank-pin brasses of the connecting rod is not at right angles to the centre line of the rod itself, the end e, [Fig. 2529], might fall either inside or outside, laterally, of the cross-head bearing, but in this case the error will show more at one end of the stroke than at the other, for reasons which are explained with reference to [Fig. 2530]; hence it follows that the connecting-rod brasses should be properly fitted to their journals, and made to lead true before using the rod to line the engine by. In some cases it is more convenient to connect the rod at the cross-head end, and try the other end with the crank-pin journal, as shown in [Fig. 2531]. In this case, however, the connecting rod will (whenever the axial line of the crank shaft is out of square, forming an acute angle with the centre line a a, as in [Figs. 2529] and [2530]), fall laterally inside the crank-pin journal when on one dead centre, as in [Fig. 2531], and outside when on the other dead centre, as in [Fig. 2532], the respective amounts of error being in this case equal for the two positions. The reason for this is that the plane of revolution of the crank pin falls outside of the centre line in one case, and inside for the other, as shown in [Fig. 2530] at d c.
Fig. 2534.
Fig. 2535.