Abstract: Machine for cold butt welding of metal blanks, wherein one of the blank clamping devices mounts on its housing a carriage with blades for cutting off the ends of the blanks, adapted for possible displacement in the direction of the force upsetting the blanks to position these blades at such distances from the device housings that assure the upsetting of an amount of metal as needed for the welding. The machine is provided with guide members carrying blank clamping devices, single-endedly fixed, that is in a cantilever fashion, in a power drive housing installed on a bed of the machine and adapted for set turning in at least one vertical plane in relation of the upsetting force. The blanks may be in different relationships in space. The invention can be successfully employed in welding aluminum and copper blanks of any cross-sectional shapes: circular, square, rectangular, rhombic, etc.