A tool, such as a pneumatic tool, includes a casing, tool-holder spindle extending along an axis, and a drive mechanism for the tool-holder spindle. The mechanism uses a first member for driving the spindle in rotation about its axis and a second member for driving the spindle in translation along its axis. The second drive member is screwed onto a threaded portion of the spindle so that the spindle advances or returns as a function of the relative rate of rotation of the drive members. The second drive member is displaced along the axis between an advanced position and a returned position.