A new jewel (or indicating instruments

IT has been almost universal practice to use highly polished sapphire jewel bearings, cut approximately in the form shown by Figure la, in electric indicating instruments. Such a jewel is commonly known as a “Vee.” The other member of the bearing is a cone-shaped piece of hardened steel or other hard metal also accurately cut and highly polished. Figures 2 and 3 show both the common proportions of these parts and the clearances involved. Figure 2 shows an instrument which has the moving shaft vertical, and Figure 3 an instrument with the moving shaft horizontal. Figure 4a shows typical moving systems and jewel settings.