Abstract: A chuck tool usable to apply or remove threaded fasteners provided with an eye formation includes an elongated retainer sleeve having a cylindrical body presenting a forward cut-out adjacent a slotted base plate. During use of the chuck, the enlarged eye formation of a fastener is disposed within the sleeve cut-out with the fastener shank disposed through the base plate slot. In this position, the longitudinal axis of the fastener is aligned with the central axis of the sleeve as laterally spaced points on the fastener eye nest within two recesses communicating with the sleeve cut-out. Rotary displacement of the fastener is accomplished following the insertion of a bifurcated drive insert into the rear of the sleeve whereupon two forward fingers on the insert straddle a significant portion of the fastener eye, between the two points engaged within the sleeve recesses.