Several classes of nuts require to be frequently fixed and unfixed, involving much wear and tear. All such are forged, either of steel, or of iron sufficiently solid and welded to allow the nuts to be hardened after being screwed, turned, and shaped.

A soft steel nut is the most durable and efficient of all varieties with which we are acquainted. Several obstacles, which have prevented the free use of such nuts, are now removed by the manufacture of Bessemer steel. Soft Bessemer steel, being only half the price of charcoal-steel, is preferable for nuts, because Bessemer nuts are about as durable as those made of the costly variety. The screwing or tapping and the turning and shaping processes are troublesome and lengthy with the superior sorts of charcoal steel; consequently, the soft Bessemer steel is eminently useful and applicable to nut-making. Such nuts are, in all cases, thoroughly softened, and all slag or scale thoroughly cleaned off by chisels and old files previous to being screwed, to avoid injury to the taps, and also to facilitate the whole of the shaping processes to which all nuts are subjected.

Disconnecting Levers

Such levers are used to lift the excentric-rod from the gap-pin; by this disconnexion, motion of the slide-valve and engine is immediately arrested. The forging of one, which is shown by Fig. 19, is performed with a straight bar of soft steel that is drawn to its width and thickness, and then partly curved by bending, and partly by a trimming chisel. By careful trimming, the precise dimensions of the gothic arch, and the necessary distance between the two intended joint-pin-holes, can be easily attained, - these holes being, in all cases, bored by careful drilling.