A universal clamp assembly includes an elongate tubular base, a clamp arm adjustably secured to the tubular base at a threaded connection and an adjustment screw that adjusts the angle of the clamp arm relative to an upper surface of the base. Various workpieces can be secured between the clamping arm and the base. An optional clamping block is provided for cooperating with the clamping arm to secure cylindrical workpieces therebetween. In addition, workpieces can be inserted through the tubular base and secured.