The simplest sort of lever mould is that which will form only one of the lever's bosses, so that two moulds are required to shape one lever, each mould having a recess of proper size to form the particular boss which is to be put into the mould. A mould of this class, having one boss cavity, is denoted in Fig. 256. At the further side of the mould is a sort of groove, indicated by H, which is to receive the superfluous metal that will be squeezed from the boss during hammering. This portion becomes a handle or holder, and is useful to the smith, and sometimes also for fixing purposes during turning or other shaping; the holder is therefore allowed to remain after the forging is complete, if necessary.

A very useful class of levers is that in which the boss is formed in the mid-part of the lever, so that the boss is between two arms of equal dimensions. To shape a lever boss of this sort, the mould shown by Fig. 257 is suitable. Levers having arms on both sides of the boss are forged by reducing a thick bar to form two arms with a thick part between; this part is next heated to welding and put into the mould, and the boss with both the short arms are shaped at one or two heats.

An ordinary crank-lever having both its bosses projecting from one side of the lever is easily forged of a straight bar and two piles; the bar being intended for the lever, and the two piles for the two bosses. Each boss-pile may consist of only one piece of metal, if a small boss is required; or for a large boss, the pile may consist of three or four pieces. After the bosses are roughly welded to the lever, and in their proper places, both bosses may be heated to welding at one heating, at which time the entire lever may be put into a mould resembling Fig. 258, and partly shaped. Another heat is next given to the work, and the superfluous metal squeezed into the two openings for the handles, shown by H and H ; and, if necessary, the superabundant material is cut off during the making.

Moulds of this character (Fig. 258) will also shape levers made by any other mode, whether of one piece drawn down in the middle, or of one bar which is doubled or trebled at each end, or whether the lever is made of two pieces and joined at the middle of the arm.