Two-crank-axles made of straight bars, or made by any other mode, may be twisted also by a method which obviates the use of levers and all their necessary attachments.

This plan is applicable to an axle of one inch diameter, or to another of twenty inches, and is accomplished by supporting one crank in a gap-block or pedestal, while the other crank is on an anvil and beneath a hammer of any size to suit the dimensions of the work. The gap-block may consist of any desired number of tons of metal, and be of the needful dimensions for the usual work. In the upper part of the block, and in the vertical position, is the gap or opening for containing the cranks; and across the gap, at the top of the block, is a cap-plate to prevent the work being much shaken with hammering. The precise width of the gap is of no consequence, but it is necessary to make the opening a few inches wider than the thickness of the thickest crank to be put within, in order to allow the crank to be inclined about ten or fifteen degrees while adjusting it for twisting. When a small crank is in the gap, any required number of packing-plates can be inserted to fill the openings that remain.

After a great length of the axle is heated, the work is put upon the anvil and into the gap, and, while suspended with the crane, the shaft is adjusted until the crank-pin part is beneath the hammer, at which time the fixing-cap is tightened and the hammering for twisting commenced.

When a sufficient length of axle is heated at the first heat, the entire twisting can be performed at one heat; but if only a short length is heated, the process of reheating should be adopted. A two-crank axle supported by a gap-block is shown in Fig. 201.

After the cranks are thus put nearly at right angles to each other by some of the methods described, and the outsides of the cranks tapered, or sometimes smoothed, by being hammered into moulds, the work is cut to length and adjusted.