Weiler Roughneck Max 4″ stringer bead wheels deliver unmatched weld cleaning performance by maximizing life, efficiency and consistency. This brush is recommended for cleaning root pass welds, surface prep and other cleaning applications. 5/8″-11 nut for use on right angle grinders. deliver unmatched weld cleaning performance by maximizing life, efficiency and consistency. The 4″ brushes are recommended for cleaning root pass welds, surface prep and other cleaning applications. Narrow Face Brushes are Suitable for Cleaning Root and Hot Passes and Reaching Into Corners. . .