... bar centers15-30, 40, 60, 80, 90 mm etc. with 30, 40 mm recommended.Cross bar centersany greater than 30mm is ... covers which require high security.Notes: common welding standard: single-side full welding every 6 bearing bars.Bearing bar centers at ... Attic panel, trestle, guardrail, sunshade gate, etc. common welding standard: single-side full welding every 4 bearing bars.Bearing bar centers at ...