The Locomotive Of Today

The Engine : Crossheads. 75 may be used for these, but case-ha Mened wrought iron is most common. It is usual to fit these guides up to the cross- head and piston, and have liners, of grmmetal, between them and the lugs on the cylinders and motion plate, so as to enable the distance between them to be adjusted when wear takes place. This, of course, can only be done when two or four bars are used; with single bars the crosshead has to be either white metalled or let together when slack, so as to fit the slide bar. At A, Fisf. 15, one form of crosshead, suitable for single bar engines, is shown in elevation. It is of cast Steel, but a somewhat similar design may be frequently met with in cast or wrought iron. The socket for the reception of the piston rod end is on the left, the rod being ground in and held by the cotter shown. The taper of the rod end is generally 1 in 16, and of the cotter 1 in 32 ; the latter is of steel -|-in. thick, rounded on both edges and kept from slacking back by means of a split pin or cotter passed through the end just below the crosshead ; it is set at an angle so as to be more accessible when it is found neces- sary to remove it with the crosshead in position. The cover and bottom wearing plates are of cast iron, well supplied with oil grooves, and often having white metal let into holes on their surfaces. At the sides, pieces of gunmetal are inserted for wearing strips, which are easily replaced when worn. Cheeks are carried down on either side to take the ends of the gudgeon pin, on which the small end works. Ihe shape ot this pin can be best seen in the cross section at B. It is coned where it passes through the cheeks so as to be always tight, and it is held in place by means of a nut on the thread at the smaller end, a split pin preventing this from slacking ; the centre where the small end works is parallel. 1 his pin is usually of wrought iron, case-hardened, and is lubricated from a cup fixed to the side of the crosshead. The small end is usually of the “ solid eye ” type for this form of crosshead. Ät C and D another design is shown, benig one suitable for engines fitted with two slide bars. The centre portion is of steel, having four lugs upon it, and a tapered hole through which the end of the piston rod passes ; this part can be entirely finished in the lathe. The piston rod end is tapered and secured by means of a nut, check nut, and split pin. The top and bottom lugs are for the attachment of the slide blocks or slippers, which are of cast iron, and have holes recessed in them for the lugs, no further means of securing them being adopted. The side lugs are for taking the small end of the connecting rod, which is of the “forked type. Caps of gun-