Abstract: A cylinder of electrically insulating material provided with a plurality of stationary contacts has a shaft rotatably disposed therein about an axis of the cylinder and is formed with movable contact members engageable with the contacts, and a bearing assembly in which the shaft is journaled on the cylinder at least at one end thereof, the bearing assembly including at least two tubes of electrically insulating material traversing the wall of the cylinder at opposite sides thereof so that opposite ends of the tubes project beyond the cylinder, the projecting ends of the tubes having slits formed therein, and a bearing member of electrically insulating material supported centrally and nonrotatably by the tubes and supporting the shaft for relative rotation of the shaft and the bearing member, and respective wedges received in the slits for spreading the split ends of the tubes to anchor the tubes at the wall of the cylinder.