A dead-end termination clamp including a cast body, a clamping end, and a connection end. The dead-end clamp may be scaled to support various size wires or cables. The dead-end clamp may be able to provide a support strength less than, equal to, or exceeding the breaking strength of a supported cable. A collet with a length, two ends, a central cavity and at least one helical slot running along the length of the collet. The at least one helical slot may have a varying width or pitch along the length. The at least one helical slot may terminate before reaching one or both ends. The collet may have one helical slots which runs the entire length of the collet. The collet may be substantially cylindrical or another shape. The center cavity may be substantially cylindrical or another shape.