How to use a gauge chart? A metal gauge chart will contain the gauge number and the corresponding thickness of certain metal, in inches or millimeters. You can use the chart to confirm the metal thickness for the CNC machining process or material selection. The sheet metal gauges are neither standard nor metric, the numbers are independent of measurement systems and do not mean actually measured value. In addition, the same gauge number for different materials presents different thickness, for example, 37 gauge stainless steel is 0.0066 inches thick, while 37 gauge aluminum is 0.0045 inches thick.
There are different gauge size standards, the equivalent thickness for each gauge is different, the standard is developed according to the weight of the sheet for a given material. The Manufacturers’ Standard Gage provides the thicknesses for standard steel, galvanized steel, and stainless steel. The Brown and Sharpe Gage, also known as the American Wire Gage (AWG), is used for most non-ferrous metals, such as Aluminum and Brass. In the UK, the Birmingham Gauge (BG) is used for metals in strip & tubing and a standard exists for Zinc in which a higher gauge number indicates a thicker sheet.