A spindle with quick coupling, particularly for machines for winding electric coils, which comprises: - a fixed part, which extends around a main axis and can be actuated with a rotary motion about said main axis; - a movable part, which can be mated detachably with a main seat defined in said fixed part, said main seat extending around said main axis and having an access opening, which is defined at an axial end of said fixed part and can be passed through by a shank-like portion of said moveable part; - means for connecting in rotation about said main axis said moveable part to said fixed part; - axial locking means, which are arranged in said fixed part and can be engaged detachably with said shank-like portion of the moveable part which is inserted into said main seat of the fixed part; and - means for eliminating the axial play between said moveable part and said fixed part with said axial locking means engaged with said shank-like portion of said moveable part inserted into said main seat, said axial locking means comprising an axial shoulder defined on said shank-like portion and at least one coupling element which is accommodated in said fixed part and can move from a release position, in which it does not interfere with said axial shoulder of the shank-like portion, to a coupling position, in which it protrudes radially from the lateral surface of said main seat and engages with said axial shoulder of the shank-like portion for the retention thereof in said main seat, and vice versa, said means for eliminating the axial play comprising first elastic means arranged in said fixed part and acting on said shank-like portion in the opposite axial direction with respect to the axial direction of insertion of said shank-like portion into said main seat, said main seat having a frustum-shaped portion, which tapers in the opposite direction with respect to said access opening; said shank-like portion having a frustum-shaped segment that mates with said frustum-shaped portion of the main seat upon the insertion of said shank-like portion into said main seat, said frustum-shaped portion of said main seat being defined in a mating sleeve, the axis of which coincides with said main axis; said mating sleeve being supported, so that it can slide along said main axis, by a main body of said fixed part which extends around said main axis; said first elastic means being interposed between said mating sleeve and said main body, characterized in that said at least one coupling element comprises at least one ball that is susceptible of protruding radially toward the inside of said main seat through a corresponding hole, defined in said main body, in order to interfere with said axial shoulder; a locking sleeve being provided which is fitted over said main body and can move parallel to said main axis with respect to said main body from a locking position, in which it locks radially said at least one ball in the coupling position in engagement with said axial shoulder, to an unlocking position, in which it allows the radial movement of said at least one ball with respect to said main body for its passage from the coupling position to the release position and vice versa. - a fixed part, which extends around a main axis and can be actuated with a rotary motion about said main axis; - a movable part, which can be mated detachably with a main seat defined in said fixed part, said main seat extending around said main axis and having an access opening, which is defined at an axial end of said fixed part and can be passed through by a shank-like portion of said moveable part; - means for connecting in rotation about said main axis said moveable part to said fixed part; - axial locking means, which are arranged in said fixed part and can be engaged detachably with said shank-like portion of the moveable part which is inserted into said main seat of the fixed part; and - means for eliminating the axial play between said moveable part and said fixed part with said axial locking means engaged with said shank-like portion of said moveable part inserted into said main seat,