Abstract: A building kit for the production of three-dimensional frameworks comprising ball-shaped joints having threaded joint bores and integral formed tube-shaped rods, the end regions of which are formed with a substantially reduced diameter relative to the thickness of the rod by means of a bottleneck-shaped construction thereof having an internal thread, the pitch of which has the same sense as that of the joint bores and deviates from the pitch of the threads of the joint bores. Coupling means are provided at the rod end regions for threaded connection of the rods with the bores of the joints, the coupling means each comprising a bolt provided at both ends with bolt threads of a same sense and of a different pitch and a box spanner sleeve axially displaceable yet not rotatably disposed thereon.