Abstract: In the continuous manufacture of gratings in which transverse bars (8) are welded at intervals to continuous longitudinal bars (15) which are subsequently cut to obtain the required length gratings, the positioning of the transverse bars (8) at the welding station (3) by a transverse bar holder (4) and the advancement of the longitudinal bars after each welding step by an advancing mechanism (5) is controlled by a computer so as to control the spacing between the transverse bars as necessary to produce gratings of the required length and in which, after cutting, the ends of the longitudinal bars will project by predetermined amounts (preferably equal) at opposite ends of the gratings, and the transverse bars are evenly spaced at a pitch which is within a predetermined tolerance of a predetermined basic pitch.