Figures from [3063] to [3066] represent a locomotive driving wheel ready to have its hub welded by hydraulic pressure. The spokes having been forged are held together by a band or hoop, as shown. The thickness of the hub or boss is made up by the rings or washers shown in the sectional view. The dies under which the welding is done are shown in [Figs. 3064] and [3066].
Fig. 3067.
Thin forgings are often made by compression between two rollers, the form of the surface of the rollers, or projections or depressions upon the same, pressing the forging to shape.
Thus, in [Fig. 3068] are shown a pair of rolls a b, p representing a piece of work, and c d two cam pieces fast upon the roll surfaces; s is a fixed stop.
Suppose the work to be pushed through the rolls and to rest against the stop s, then when the cams c d meet it they will pull it through and reduce its thickness by compression towards the workman. The rollers are obviously rotated by gear wheels; but they are sometimes provided with a certain amount of give or elasticity at their bearings, so that the reduction of work diameter may be obtained by several passages of the work through the rolls.
Fig. 3068.