The following information covers the strength of materials perforated with round holes in a standard staggered 60” 

Round holes arranged in a standard 60” triangular pattern ranging from .020” to 3/4” account for more than half of the perforating industry’ s production. They produce the strongest pattern and are the most versatile in their application. The standard 60” staggered formation is the most popular hole arrangement because of its inherent strength and the wide range of open areas it provides. In perforating this pattern, the direction of the stagger is the short dimension or width of the sheet as illustrated. The straight row of closely- spaced holes is parallel to the long dimension or length of the sheet. This is the so-called “closed pattern.” Under special order, the holes may be punched in the “open pattern.”