A two-throw crank-shaft may be made also of one flat bar. The length of this bar is equal to the total length of the axle ; the width equals the total length of one lever or arm ; and the thickness equals the distance through the crank-gap when formed. When reduced to thickness, the work is carefully trimmed and flattened throughout one small side, usually termed one edge. The work is then ready for marking.

The bar being thus prepared, it is laid upon some convenient table, and the thickness of the intended axle is marked along the bar and at a proper distance from the flattened side, this distance being equal to the forged diameter of the axle. The middles of the two intended cranks are next marked by making two lines across the bar at right angles to the length of the axle. From these two centre lines the forged dimensions of the two cranks are marked, after which a chisel is driven in at each line.

When thus marked, the bar is ready to be formed into a two-crank axle, which is effected by either drilling or sawing. When sawing is adopted, two rows of holes must be drilled at the bottoms of the crank-gaps, each row being parallel to the length of the adjoining crank-pin part; the formation of the cranks is completed when the five superfluous pieces are cut out, at which time the two cranks are extended on the same side of the axle instead of at right angles to each other, as required.