A jointing member for limbs of a frame is in the form of a hollow tapered unit open at its wider end, comprising more than two flat wall surfaces each inclined to each neighboring flat wall surface by an angle differing substantially from 90*, and some of said wall surfaces being apertured to receive bolting means. The member may be shaped as a truncated pyramid. In setting up a frame a flattened end of a frame limb is held between facing wall surfaces of two of said jointing members, by bolting means passing through the jointing members and the frame limb.