Abstract: An adjustable clamping assembly is disclosed that includes first and second blocks each having a passageway through which support rods are inserted. The blocks may be rotated relative to each other. In one embodiment, each block has a slot extending from one face of each block to the passageway housing the support rod. The second block includes a frusto-conical seat for receiving a frusto-conical bearing member of the first block. A partially threaded stem extends from the first block coaxial with the bearing member and is inserted through an aperture in the second block. The stem is inserted within the tapped portion of a handle for adjusting the tightness of the assembly. As the handle is tightened the slots compress thereby securing the support rods in a fixed position within the passageways. In another embodiment, the first block includes a set screw instead of the slot for securing the support rod in a fixed position.