Abstract: The inside, outside and opposite side surfaces of elongate, helical shaped, rectangular cross-section metal work pieces are individually close tolerance machined to produce finished conductor segments. These segments are connected end to end to form a helical coil which encircles a toroidal conducting shell of a fusion reactor. An apparatus is provided which may be fitted with corresponding tooling for separately machining the inside and outside surfaces of a work piece. The work piece is supported by the apparatus with the surface to be machined unobstructed. The unobstructed surface is cut in the poloidal direction as the work piece is moved in the toroidal direction. The side surfaces of the work piece are machined with a programmable, numerically controlled milling machine.