Fig. 3007.
Fig. 3008.
[Fig. 3005] represents the bar in position in the furnace, the aperture through which it was admitted having been closed up by bricks luted with clay, one brick only being left loose, so that it may be removed to examine the heat of the bar. The end of the bar is flattened somewhat, and a slab is laid upon it as in [Fig. 3006], the appearance after the first weld being shown in [Fig. 3007]. It is then turned upside down, and blooms are piled upon it as in [Fig. 3008]. After these are welded the end is shaped up round and to size. The extreme end is again flattened, or “broken down,” as it is termed, and first a slab, and after reheating, blooms are added, as already explained; when these are welded and forged enough to consolidate the mass the mass is rounded up again, thus increasing the length of finished shaft. The end is again broken down and a slab added, and so on, the shaft thus being forged continuously from one end, and being composed of alternating slabs and blooms.
To forge this shaft 118,000 lbs. of blooms, 185 tons of coal, and 360 days of labor were required, the time occupied being 34 working days.
The slabs are simply forged pieces of larger dimensions than the blooms, and more thoroughly worked, the difference between slabs and blooms being that there is more waste with the blooms than with slabs, because the blooms heat quicker than the forged part of the crank.