How to Measure an Aluminum Gauge

Standard calipers quickly measure aluminum sheets without damaging them.

Contractors and suppliers buy and sell sheet metal using a numbered gauge system. The gauge of aluminum sheet metal is based on two related measurements: the thickness of the metal and its poundage per square foot. Since these numbers are set values for a particular gauge of aluminum sheet metal, a person inspecting a new shipment or determining the gauge of older aluminum stock can measure the thickness of the metal and reference it against a conversion list of aluminum gauge information.

Things You'll Need

• Caliper
• Aluminum gauge conversion list

Instructions

1. Open the jaws of the caliper until they are opened wider than the thickness of the aluminum sheet metal.

2. Close the tips of the jaws gently around the aluminum. Align the caliper jaws so their flat edges sit flush against the metal. Record the thickness.

3. Repeat the procedure for each edge of the sheet metal. Add the four values together. Divide the sum by four to determine an average thickness for the aluminum.

4. Consult an aluminum gauge conversion sheet (see Resources) and look for the thickness measurement closest to the average thickness of your aluminum sheet. Check the corresponding gauge number to determine the measurement of your aluminum gauge.

Tips & Warnings

• The thickness of your sheet may be slightly different than an exact gauge measurement due to variations in the manufacturing process and thickness tolerances on the metal.

References

• Tresna Instruments: How Does a Dial Caliper Work?

Resources

• Engineering Tool Box: Gauge and Weight Conversions
• Engineer's Edge: Sheet Metal Gauge Size
• Corrugated Metals Inc.: Gauge in Decimals of an Inch