Page:Steamlocomotivec00ahrorich.djvu/98

84 bore of the cylinder, into which the wire is fastened. The cylinders can be raised or lowered on the jacks and adjusted slightly in a longitudinal and inclined direction until they are in their exact position according to the drawings. Two measurements are necessary to verify this. The circumference of the bore of each cylinder must be equidistant all round from the central wire throughout the full length of the bore. This measurement is tested with callipers. Finally the longitudinal distance of the face of the cylinders from the centre of the driving axle as shown on the straight-edge b, is measured on both sides of the engine with a rod of the exact length required. This fixes the longitudinal position of the cylinders.

Two longitudinal wires e are also stretched outside each of the frames. These are set with a long square applied to the straight-edge b, to which they must be at right angles, and they must also be parallel to the wires c representing the cylinder centre lines. The straightness and the parallelism of the frames are tested from these lines.

Finally the exact position of the motion plate f is located from the cylinder centre lines cc, since the slide bars are fixed to this plate, and it is necessary for the bore of the cylinder, the piston rod, and the slide bars to have the same centre line.

Permanent Fixing of Frame Attachments. So far the parts have only been bolted up temporarily.