Abstract: A workpiece holder assembly for aligning a turbine with a turbine shaft without the requirement of an aligning pin received by the workpieces. The workpiece holder assembly receives the turbine shaft and the turbine. Upon depression of the top of the assembly, as by moving the assembly upward so as to engage an abutment, the interface between an end of the turbine shaft and one face of the turbine is exposed. The assembly is rotated over a full circle while the interface receives a welding beam of electrons. The assembly and abutment may be employed with existing electron beam welding apparatus.