In order to minimize the electrical loss of millimeter waveguides, their surfaces have to be covered with silver with a surface roughness of less than 0.1μm (Rmax) and a dimensional accuracy of within 10μm. Present developments, employing advanced cold hobbing with simultaneous silver cladding, have focused on establishing economical fabrication techniques for the waveguides.Ω and U-shaped hobbs were indented into copper blanks covered with silver plates. Metal flow of the blanks was investigated to define the conditions necessary for precise shaping, such as the shape of the hob and the work hardening characteristics of the copper blanks. It has been found that precise shaping can be accomplished using a hob with a shoulder. The initial distortion of the waveguide is corrected by pressing the upper free surface around the guide with the shoulder followed by penetration of an auxiliary hob around the center of the sharpest curve. The newly-developed techniques, facilitating the production of waveguides, decrease the surface roughness to 1/10 and the electrical loss to 2/3 of conventional ones.