The invention relates to a polygonal spindle arrangement (8) for a
handle set for opening and closing a door or window, comprising a first outer spindle (14.1), a second outer spindle (14.2), and an inner spindle (15) which extends coaxially through one of the two outer spindles (14) and is rotatable therein about a pivot axis (12) and axially adjustable between a
coupling position (KS), in which the two outer spindles (14) are rotationally fixed to each other, and a decoupling position (ES), in which the two outer spindles (14) are rotatable relative to each other. A compact design is achieved by the fact that the first outer spindle (14.1) has a radially outwardly projecting first
coupling structure (18), and that the second outer spindle (14.2) has a radially outwardly projecting second
coupling structure (19), and that the inner pin (15) has a radially outwardly projecting driver (20) which, in the coupling position (KS), engages axially with the first coupling structure (18) and with the second coupling structure (19), such that the driver (20) couples the first coupling structure (18) with the second coupling structure (19) in a rotationally fixed manner, and which, in the decoupling position (ES), does not engage axially with the first coupling structure (18), such that the first coupling structure (18) and the second coupling structure (19) are rotatable relative to each other about the axis of rotation (12).