By the process of cementation just described, the exterior only of the bars is carbonised. To produce steel of uniform quality throughout its mass, bars of blister steel are cut into short lengths; these are piled into bundles or faggots, sprinkled with sand and borax, placed at a welding heat under a tilt hammer, which by rapid blows removes the blisters, closes the seams, beats and amalgamates the faggots into a bar of single shear steel.
In order still further to improve the quality of the metal, this bar is doubled or faggoted, and again subjected to the processes of hammering and rolling, the result being a bar of double shear steel.
The oftener the processes of faggoting and hammering are repeated, the more uniform is the resulting steel, but at the same time it loses carbon during these operations, and therefore becomes softer.
The processes to which the steel has been subjected restore its fibrous character. It is still weldable, is more malleable, and tougher, is close grained, and capable of receiving a finer edge and higher polish than blister steel.
Shear steel can be forged into such tools as are required to be tough without extreme hardness, such as large knives, scythes, plane irons, shears, etc., and it is useful for such instruments as are composed of iron and steel.