Abstract: A quick-change adapter for rotary devices such as power drills comprises a shaft that can be inserted in a chuck of the powered rotary tool. The shaft is coupled to and is coaxial with a tool holder that inlcudes means for retaining a tool and means for driving the tool. The retaining means typically involve one or more spring-loaded balls that engage a groove or detent in the tool. The driving means include a shape that is not circular, to engage a corresponding shape on the tool to apply torque, and a surface having a component that is substantially perpendicular to the axis of the adapter to enable the application of force in an axial direction. Tools such as drills, screw drivers, and the like are rendered usable with the adapter by receiving a shaft to fit the adapter and couple torque from the adapter, a groove or detent to fit the retaining means, and a shoulder or the like to apply axial thrust.