Precision and accuracy are paramount in metalworking. Whether fabricating automotive parts, constructing industrial machinery, or crafting delicate art pieces, understanding the nuances of sheet metal gauge is essential. Sheet metal gauge serves as a universal language, guiding engineers, artisans, and manufacturers in selecting the appropriate thickness for their projects.
What Do Sheet Metal Gauges Mean?
Sheet metal gauge refers to a standardized method used to measure and categorize the thickness of sheet metal. This system, which has its roots in the British iron wire industry in the 19th century, provides a series of numerical gauge values to represent different thicknesses. Interestingly, as the gauge number increases, the material thickness decreases for most metals, a counterintuitive aspect that often surprises newcomers.
Gauge charts are crucial because they guide the selection process, ensuring that the material chosen meets a project’s structural and aesthetic needs. Whether you’re constructing a robust architectural framework or crafting delicate jewelry, understanding gauge numbers can significantly impact the outcome of your work.
Importance of Understanding Metal Sheet Gauge
Understanding sheet metal gauge, or thickness, is crucial before purchasing. Here’s why:
Durability
The gauge of metal significantly influences the durability of your project or design. Thicker metal can withstand more wear and tear, making it essential for longevity and resilience applications.
Cost Efficiency
Choosing the right thickness is also a matter of cost. Opting for metal that’s too thick for your needs can unnecessarily increase your expenses, affecting production and shipping costs. Conversely, using metal that is too thin might reduce initial costs but could lead to higher expenses due to repairs or replacements.
Structural Integrity
The integrity of any structure or item made from metal heavily depends on choosing the appropriate thickness. Metal that’s too thin may not support the intended load, leading to structural failures or bending under pressure. Ensuring you have the right gauge for your application is pivotal to avoiding such issues.
How Do Sheet Metal Gauges Work?
Unlike standard or metric measurements, which rely on units like inches or millimeters, gauging follows its own set of rules. To find out the actual thickness of sheet metal, you can refer to a gauge conversion chart. This chart helps translate gauge numbers, such as 18 gauge, into familiar measurements—0.0478 inches or 1.214 millimeters for steel, for example. However, the gauge number, like “18” in this case, doesn’t directly relate to the actual thickness measurements.
It’s important to note that various gauge systems are in use today and differ based on the type of metal. For instance, while 18 gauge steel is 0.0478 inches thick according to one system, 18 gauge aluminum might be slightly thinner at 0.0403 inches. This difference underscores the importance of using a gauge chart to accurately determine the necessary thickness for your metal, ensuring that it meets the specific requirements of your project.
Sheet Metal Gauge Charts
Mild Steel Gauge Chart
| Gauge Number | Inches | Millimeters |
| 7 | 0.1793 | 4.554 |
| 8 | 0.1644 | 4.175 |
| 9 | 0.1495 | 3.797 |
| 10 | 0.1345 | 3.416 |
| 11 | 0.1196 | 3.038 |
| 12 | 0.1046 | 2.656 |
| 14 | 0.0747 | 1.897 |
| 16 | 0.0598 | 1.518 |
| 18 | 0.0478 | 1.214 |
| 20 | 0.0359 | 0.911 |
| 22 | 0.0299 | 0.759 |
| 24 | 0.0239 | 0.607 |
| 26 | 0.0179 | 0.454 |
| 28 | 0.0149 | 0.378 |
Aluminum Gauge Chart
| Gauge Number | Inches | Millimeters |
| 7 | 0.1443 | 3.665 |
| 8 | 0.1285 | 3.264 |
| 9 | 0.1144 | 2.906 |
| 10 | 0.1019 | 2.588 |
| 11 | 0.09074 | 2.305 |
| 12 | 0.08081 | 2.053 |
| 14 | 0.06408 | 1.628 |
| 16 | 0.05082 | 1.291 |
| 18 | 0.04030 | 1.024 |
| 20 | 0.03196 | 0.812 |
| 22 | 0.02535 | 0.644 |
| 24 | 0.02010 | 0.511 |
| 26 | 0.01594 | 0.405 |
| 28 | 0.01264 | 0.321 |
| 30 | 0.01003 | 0.255 |
Stainless Steel Gauge Chart
| Stainless Steel Gauge Number | Inches | Millimeters |
| 8 | 0.17187 | 4.365 |
| 9 | 0.15625 | 3.968 |
| 10 | 0.14062 | 3.571 |
| 11 | 0.125 | 3.175 |
| 12 | 0.10937 | 2.778 |
| 14 | 0.07812 | 1.984 |
| 16 | 0.0625 | 1.587 |
| 18 | 0.05 | 1.27 |
| 20 | 0.0375 | 0.9525 |
| 22 | 0.03125 | 0.7937 |
| 24 | 0.025 | 0.635 |
| 26 | 0.01875 | 0.476 |
| 28 | 0.01562 | 0.396 |
| 30 | 0.0125 | 0.3175 |
Galvanized Steel Gauge Chart
| Galvanized Steel Gauge Number | Inches | Millimeters |
| 8 | 0.1681 | 4.269 |
| 9 | 0.1532 | 3.891 |
| 10 | 0.1382 | 3.510 |
| 11 | 0.1233 | 3.1318 |
| 12 | 0.1084 | 2.753 |
| 14 | 0.0785 | 1.9939 |
| 16 | 0.0635 | 1.6129 |
| 18 | 0.0516 | 1.310 |
| 20 | 0.0396 | 1.005 |
| 22 | 0.0336 | 0.853 |
| 24 | 0.0276 | 0.701 |
| 26 | 0.0217 | 0.551 |
| 28 | 0.0187 | 0.474 |
| 30 | 0.0157 | 0.398 |
Brass Gauge Chart
| Brass Gauge Number | Inches | Millimeters |
| 7 | 0.1443 | 3.665 |
| 8 | 0.1285 | 3.264 |
| 9 | 0.1144 | 2.906 |
| 10 | 0.1019 | 2.588 |
| 11 | 0.09074 | 2.305 |
| 12 | 0.08081 | 2.053 |
| 14 | 0.06408 | 1.628 |
| 16 | 0.05082 | 1.291 |
| 18 | 0.04030 | 1.024 |
| 20 | 0.03196 | 0.812 |
| 22 | 0.02535 | 0.644 |
| 24 | 0.02010 | 0.511 |
| 26 | 0.01594 | 0.405 |
| 28 | 0.01264 | 0.321 |
| 30 | 0.01003 | 0.255 |
Copper Gauge Chart
| Copper Gauge Number | Inches | Millimeters |
| 7 | 0.180 | 4.572 |
| 8 | 0.165 | 4.191 |
| 9 | 0.148 | 3.759 |
| 10 | 0.134 | 3.404 |
| 11 | 0.120 | 3.048 |
| 12 | 0.109 | 2.769 |
| 14 | 0.083 | 2.108 |
| 16 | 0.065 | 1.651 |
| 18 | 0.049 | 1.245 |
| 20 | 0.035 | 0.889 |
| 22 | 0.028 | 0.711 |
| 24 | 0.022 | 0.559 |
| 26 | 0.018 | 0.457 |
| 28 | 0.014 | 0.356 |
| 30 | 0.012 | 0.305 |
Where Did Sheet Metal Gauges Originate?
The history of sheet metal gauges can be traced back to the wire drawing industry before the industrial revolution. Initially, wire was sold by weight, which led to inconsistencies as wires of varying thicknesses could have the same weight. To address this issue, wire drawers began quoting wire based on the number of draws required to create it, with the number of draws becoming the gauge.
This measurement method evolved from drawing wires through progressively thinner dies, assigning each size a numerical gauge. When steelmakers began rolling sheets of steel, they adopted a similar approach. Since measuring sheet thickness directly was challenging, they used the gauge system to specify sheet metal thickness by weight per square foot.
Unlock Precision and Quality: Explore FastMetals’ Sheet Metal Selection Today
The sheet metal gauge chart is more than just a list of numbers; it’s the foundation for successful projects. By understanding and utilizing these charts you can ensure precision and quality in their work. Remember, whether you’re in a professional machine shop or your garage, the key to achieving excellence lies in the details.
For those looking to purchase quality materials, FastMetals offers a wide range of sheet metals suitable for various projects and the expertise to help you select the right gauge for your needs.