The switches shown in Figure 96 are capable of carrying heavier currents than those just described, and more nearly approach the type used on lighting and power switchboards.
The base may be made of wood, but preferably should be made of some insulating substance such as fiber or slate.
Fig. 96.—Knife Switches.
The patterns for the metal parts are shown in Figure 97. These are cut from heavy sheet-brass or sheet-copper, and then bent into shape with a pair of flat-nosed pliers.
The handle of the single-pole switch is driven on over the metal tongue.
The double-pole switch is almost a duplicate of the single-pole type, but has two sets of levers and contacts, actuated by the handle, in place of one.
Fig. 97.—Metal Parts for the Knife Switches.
The ends of the blades to which the handle is connected are turned over at right angles and a hard-wood cross-bar fastened between the ends. The handle is fastened to the center of the cross-bar.