Sheet Metal Gauge Chart

by AMC

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Posted on july 01, 2023 at 01:19 AM

When working with sheet metal, the term "gauge" is commonly used to describe the thickness or thickness range of the material. However, those unfamiliar with the gauge system may find it confusing to understand what is meant by a specific gauge, such as 18 gauge steel. To provide clarity, this blog will explain the gauge system and include a helpful sheet metal gauge chart.

The gauge system is a standardized method used to measure and categorize the thickness of sheet metal. It assigns a numerical value to different thicknesses, where a higher gauge number indicates a thinner sheet. For example, a lower gauge like 18 gauge steel is thicker than a higher gauge like 22 gauge steel.

To help you visualize and understand the various gauges and corresponding thicknesses, a sheet metal gauge chart will be featured in the blog. This chart will display the gauge numbers along with the corresponding thickness in inches or millimeters, making it easier to comprehend the dimensions of different gauges.

By providing an explanation of the gauge system and presenting a sheet metal gauge chart, readers will gain a better understanding of how to interpret and work with sheet metal of varying thicknesses. This knowledge will be particularly useful for individuals involved in industries such as manufacturing, construction or metal fabrication where working with sheet metal is common.

How are Sheet Metal Gauges Used?

Gauges are used to specify the thickness of sheet metal and they are not standardized or based on the standard or metric measurement systems. The gauge values are independent and do not directly correlate to specific measurements.

To determine the actual thickness of sheet metal in inches or millimeters, a gauge conversion chart is used. This chart provides the corresponding thickness values for each gauge. For instance, according to a gauge conversion chart, 18 gauge steel measures approximately 0.0478 inch or 1.214 millimeters. It's important to note that the gauge number itself does not hold any relevance to the actual measurements.

Different gauge systems are employed for different metal types. For example, in one gauge system, 18 gauge steel measures 0.0478 inches thick, while 18 gauge aluminum is 0.0403 inches thick. These variations highlight the importance of referring to a gauge chart to ensure the metal meets the required dimensions.

Using a gauge conversion chart allows individuals to accurately determine the thickness of sheet metal, irrespective of the specific gauge system or metal type being used. This information is valuable for various industries, including manufacturing, construction and metal fabrication, where precise measurements are necessary for successful projects.

History of the Gauge System

The gauge system has a long history in metal fabrication. It is believed to have originated from the British wire industry before the standard and metric measurement systems became widely adopted.

Initially, the gauge system was used to describe the diameter of metal wires being drawn. Over time, it evolved and extended to include the thickness of sheet metal as well. Despite the introduction of standard and metric measurement systems, the gauge system has persisted as a prevalent method of designating the thickness of both wire and sheet metal.

The gauge system is deeply ingrained in the metal fabrication industry, and it is still widely used today. It provides a convenient and established way to communicate the thickness of sheet metal, especially in industries where historical practices and conventions remain prevalent.

While the gauge system may not align directly with standard or metric measurements, it continues to be employed due to its historical significance, widespread acceptance and practicality within the metal fabrication field.

Sheet Metal Gauge Charts

Mild Steel Gauge Chart
Gauge Number	Inches	MM
7	.1793	4.554
8	.1644	4.175
9	.1495	3.797
10	.1345	3.416
11	.1196	3.038
12	.1046	2.656
14	.0747	1.897
16	.0598	1.518
18	.0478	1.214
20	.0359	.911
22	.0299	.759
24	.0239	.607
26	.0179	.454
28	.0149	.378

Aluminum Gauge Chart*
Gauge Number	Inches	MM
7	.1443	3.665
8	.1285	3.264
9	.1144	2.906
10	.1019	2.588
11	.09074	2.305
12	.08081	2.053
14	.06408	1.628
16	.05082	1.291
18	.04030	1.024
20	.03196	.812
22	.02535	.644
24	.02010	.511
26	.01594	.405
28	.01264	.321
30	.01003	.255

Stainless Steel Gauge Chart*
Gauge Number	Inches	MM
8	.17187	4.365
9	.15625	3.968
10	.14062	3.571
11	.125	3.175
12	.10937	2.778
14	.07812	1.984
16	.0625	1.587
18	.050	1.270
20	.0375	.9525
22	.03125	.7937
24	.025	.635
26	.01875	.476
28	.01562	.396
30	.0125	.3175

Galvanized Steel Gauge Chart*
Gauge Number	Inches	MM
8	.1681	4.269
9	.1532	3.891
10	.1382	3.510
11	.1233	3.1318
12	.1084	2.753
14	.0785	1.9939
16	.0635	1.6129
18	.0516	1.310
20	.0396	1.005
22	.0336	.853
24	.0276	.701
26	.0217	.551
28	.0187	.474
30	.0157	.398

Brass Gauge Chart*
Gauge Number	Inches	MM
7	.1443	3.665
8	.1285	3.264
9	.1144	2.906
10	.1019	2.588
11	.09074	2.305
12	.08081	2.053
14	.06408	1.628
16	.05082	1.291
18	.04030	1.024
20	.03196	.812
22	.02535	.644
24	.02010	.511
26	.01594	.405
28	.01264	.321
30	.01003	.255

Copper Gauge Chart*
Gauge Number	Inches	MM
7	.180	4.572
8	.165	4.191
9	.148	3.759
10	.134	3.404
11	.120	3.048
12	.109	2.769
14	.083	2.108
16	.065	1.651
18	.049	1.245
20	.035	.889
22	.028	.711
24	.022	.559
26	.018	.457
28	.014	.356
30	.012	.305

Common Types of Sheet Metal to Consider

Picking the right sheet metal type is the first step in finding the right gauge and ensuring project success. Below are some of the more common sheet metals used in the industry, architecture and manufactured goods:

• Zinc-plated steel: Steel that is coated with zinc, providing it corrosion protection. Perfect for outdoor and/or moist environments (agriculture, solar mounting, automobile components, construction frames). 
• Stainless Steel: Stainless Steel is alloyed with at least 10.5% chromium to resist corrosion. Perfect for sanitary applications, medical devices, architectural uses, and food-grade applications.
• Aluminum: A lightweight, corrosion-resistant metal. Commonly used in aerospace, automotive, facades, food packaging and other manufactured goods.
• Brass: An alloy of copper and zinc, known for its attractive appearance and acoustic properties. Commonly used in musical instruments, architecture, plumbing, and electrical connectors.
• Copper: A pliable metal, with high conductive properties. Commonly used in electrical systems, plumbing, roofing and siding, industrial machinery and electronics.

Conclusion

In conclusion, the gauge system has a long-standing history in the metal fabrication industry. Originating from the British wire industry, it was initially used to describe the diameter of metal wires being drawn. Over time, it expanded to include the thickness of sheet metal.

The gauge system remains prevalent today, even in the presence of standard and metric measurement systems. It provides a convenient and widely accepted method of designating the thickness of sheet metal, allowing for effective communication in the industry.

Although gauge values are independent of standard or metric measurements, conversion charts are available to determine the actual thickness in inches or millimeters. This ensures accuracy and consistency when working with sheet metal of varying gauges.

Overall, the gauge system's historical significance, widespread acceptance, and practicality have contributed to its continued use in metal fabrication. It serves as a valuable tool for professionals in industries such as manufacturing, construction, and metal fabrication, enabling effective communication and precise measurements for successful projects.