Abstract: Contact overtravel adjustment apparatus for a vacuum contactor. Two nuts, each having a plurality of radially spaced teeth about their periphery, are threaded onto the mounting stud or shaft of the moveable contact of each vacuum interrupter in the contactor. The first nut is positioned on the shaft to establish the contact overtravel gap. The second nut is used to lock the position of the first nut. A blade of a screwdriver is inserted between adjacent teeth in both nuts. Rotation of the screwdriver in one direction locks the two nuts while the rotation thereof in the opposite direction loosens the two nuts. The teeth allow the torque used for tightening to be applied to the nut with zero net torque being applied to the shaft of the moveable contact of the vacuum interrupter. The toothed nuts also provide for a more accurate setting of the overtravel gap adjustment.