... ,Plain Steel,Brass plate 1/32" Diameter 1/16" Straight Centers 28.28% Open Are Round Staggered Perforated Metal ... sifting of grains, decorations and designs of buildings.Perforation patterns Round perforations, square perforations, slotted perforations, fish scale perforations, ... cross perforations as well as some other special patterns. Round Staggered The specification only for reference, it can be ...