To read a metal gauge thickness chart, determine the type of metal and the metal's gauge. Locate the gauge in the first column. Follow that row to the right to the column that indicates the metal's type. That column also features the pounds per square feet of the particular metal. The gauge decimal in inches is located to the left of that column, except in the case of the metal found in column one; there, it is to the right.
The header row of a metal gauge thickness chart indicates, from left to right, the gauge number, non-ferrous metals (both brown and sharp), steel sheets, and strip and tubing including Birmingham and stubs. The latter three categories are broken down to indicate specific types of metal and the gauge of decimals in inches. The non-ferrous category includes a column for 1100 and 6061 aluminum, as well as a column for alloy 260 brass. The steel sheets and strip and tubing categories both include a column for steel strips.
Other charts break down the type of materials even further. The Specific Engineering Materials chart includes the gauges in millimeters for steel, galvanized steel, stainless steel, aluminum and zinc. The chart for Sheet Metal Gauge Tolerances indicates the minimum and maximum tolerance levels for steel, aluminum and stainless steel sheet metal.