Intro
In the world of engineering, starting with the right material can dramatically change how well your final part works. For sheet metal projects, not only do you need to pick the right material option, but you also need to pick the right sheet metal thickness, or “gauge”.
In this guide, our manufacturing experts at Rapid Axis will walk you through everything you need to know about sheet metal gauges. We’ll explain what it is, how to measure it, and why it’s important for your manufacturing projects.
What Is a Sheet Metal Gauge?
A sheet metal gauge is a standard unit of measure used to determine the thickness of a metal sheet. The gauge number and thickness have an inverse relationship – the higher the gauge number, the thinner the sheet. For instance, 10-gauge aluminum is 0.1019” thick, while 18-gauge aluminum is 0.040”.
This system helps standardize measurements across different types of metal, ensuring consistency in manufacturing and construction.
It’s also worth noting that the same gauge can vary in thickness depending on the material. For example, 10-gauge stainless steel, galvanized steel, mild steel, aluminum, and copper are all different thicknesses.
Gauge Thickness vs Measured Thickness
While gauge thickness provides a convenient shorthand, it isn’t a direct physical measurement. Gauge thickness is based on a legacy numbering system that originated from the number of times a piece of metal was passed through a rolling mill.
This is why 16-gauge steel and 16-gauge aluminum have different physical thicknesses. The number refers to the manufacturing process, not an exact dimension.
In contrast, measured thickness refers to the actual thickness of the physical material, typically expressed in decimal inches (e.g., 0.063″) or millimeters (e.g., 1.60 mm). Measured thickness is much more precise and consistent across materials.
How to Quickly Measure Sheet Metal’s Thickness
When it comes to measuring sheet metal thickness, there are several methods at your disposal. However, some techniques are more accurate and reliable than others.
Option 1: Using Calipers
Calipers are an accurate measuring tool used to measure the thickness of a sheet of metal. They can provide precise measurements down to the thousandth of an inch, making them an ideal choice for measuring sheet metal.
To use a caliper, simply open the jaws, place the metal between them, close the jaws, and then read the measurement on the scale or digital display.
Option 2: Using a Tape Measure (Not Recommended)
While a tape measure can give you a rough estimate of the thickness of your sheet metal, it’s not the most accurate method — some sheet metal gauge thicknesses vary by as little as 0.01”.
Due to its lack of precision, we don’t generally recommend using a tape measure for measuring sheet metal thickness, especially in professional settings where exact measurements are required.
Option 3: Using a Gauge Wheel
A gauge wheel is a specialized tool designed specifically for measuring the gauge of sheet metal. It’s easy to use – just match the sheet metal with the corresponding slot on the wheel to find out its gauge. While not as precise as calipers, gauge wheels are portable and convenient, making them a useful tool for quick, on-the-go measurements.
Sheet Metal Gauge Charts
A gauge number means different things for different materials. That’s why engineers and fabricators rely on material-specific sheet metal gauge charts to make sure they’re working with the correct thickness.
Below are gauge charts for some of the most common materials used across industries.
Mild/Carbon Steel Sheet Metal Gauge Chart
Mild or carbon steel is one of the most commonly used materials in manufacturing. It’s durable, weldable, and cost-effective. Below is the standard gauge chart for carbon steel:
| Gauge | Thickness (inches) |
Thickness (mm) |
|---|---|---|
| 10 | 0.135 | 3.42 |
| 12 | 0.105 | 2.66 |
| 14 | 0.075 | 1.90 |
| 16 | 0.060 | 1.52 |
| 18 | 0.048 | 1.21 |
| 20 | 0.036 | 0.91 |
| 22 | 0.030 | 0.76 |
| 24 | 0.024 | 0.61 |
| 26 | 0.018 | 0.45 |
Galvanized Steel Sheet Metal Gauge Chart
Galvanized steel is coated with zinc to improve corrosion resistance. Because the coating adds some thickness, the values here differ slightly from regular steel:
| Gauge | Thickness (inches) |
Thickness (mm) |
|---|---|---|
| 10 | 0.138 | 3.51 |
| 12 | 0.108 | 2.75 |
| 14 | 0.079 | 1.99 |
| 16 | 0.064 | 1.61 |
| 18 | 0.052 | 1.31 |
| 20 | 0.040 | 1.01 |
| 22 | 0.034 | 0.85 |
| 24 | 0.028 | 0.71 |
| 26 | 0.022 | 0.55 |
Stainless Steel Sheet Metal Gauge Chart
Stainless steel has a higher density and strength than mild steel, which affects its thickness-to-gauge ratio. This chart helps maintain precise metal fabrication:
| Gauge | Thickness (inches) |
Thickness (mm) |
|---|---|---|
| 10 | 0.141 | 3.57 |
| 12 | 0.109 | 2.78 |
| 14 | 0.078 | 1.98 |
| 16 | 0.063 | 1.59 |
| 18 | 0.050 | 1.27 |
| 20 | 0.038 | 0.95 |
| 22 | 0.031 | 0.79 |
| 24 | 0.025 | 0.64 |
| 26 | 0.019 | 0.48 |
Aluminum Sheet Metal Gauge Chart
Aluminum is lighter and more malleable, so the thickness per gauge is different from steel.
| Gauge | Thickness (inches) |
Thickness (mm) |
|---|---|---|
| 10 | 0.102 | 2.59 |
| 12 | 0.081 | 2.05 |
| 14 | 0.064 | 1.63 |
| 16 | 0.051 | 1.29 |
| 18 | 0.040 | 1.02 |
| 20 | 0.032 | 0.81 |
| 22 | 0.025 | 0.64 |
| 24 | 0.020 | 0.51 |
| 26 | 0.017 | 0.43 |
Using the wrong gauge chart can cause major design and fit issues. For example, 10-gauge stainless steel is 0.141″ thick, while 10-gauge aluminum is just 0.102″ thick — a difference of nearly 0.04″. That’s enough to cause tolerance failures, misaligned joints, or even compromised structural integrity.
To avoid these mistakes:
- Always use a material-specific gauge chart.
- Confirm physical measurements using calipers or a gauge wheel.
- When in doubt, refer to decimal thickness instead of gauge numbers.
The Benefits of Sheet Metal Gauge in Fabrication
Why should you care about the gauge of sheet metal you’re using? There are a few major benefits that can change how well your sheet metal design works in application:
- Strength of Parts: Different gauges of sheet metal have different strengths. As an engineer, understanding this allows you to choose the right gauge for your design, ensuring the final part can withstand the intended forces and stresses, helping the reliability of your parts.
- Cost Control: Thinner gauges are generally less expensive, and knowing when it’s appropriate to use them can lead to significant cost savings. On the other hand, understanding when a thicker, potentially more costly gauge is necessary for structural integrity is equally important.
- Overall Durability: Selecting the right gauge is crucial to the overall durability of your part. Thicker gauges tend to be more robust and less prone to denting or warping, contributing to the longevity of your components. Understanding the balance between gauge, durability, and cost can lead to more efficient and effective designs.
- Size and Weight Constraints: The gauge of sheet metal you choose can also affect the size and weight of your final part. Thicker gauges result in heavier parts, which might be a consideration for designs with weight or size constraints. Understanding sheet metal gauges can help you make informed decisions, enabling you to optimize your design for its intended application.
Which Sheet Metal Gauge Is the Best?
The “best” sheet metal gauge depends entirely on your specific project requirements. Thicker gauges are typically stronger and heavier, making them suitable for projects requiring durable, sturdy components. On the other hand, thinner gauges are less expensive and lighter, which can be advantageous for projects where cost and weight are major considerations.
When choosing a gauge, it’s essential to consider the trade-offs between cost, strength, and weight.
Conclusion
Understanding sheet metal gauges is crucial in the world of fabrication. It ensures consistency, facilitates quality control, and allows you to make informed decisions about the best material for your project. At Rapid Axis, we take these factors into account to deliver high-quality, tailored fabrication services for your specific needs. Whether you’re seeking a cost-effective solution or need a durable, heavy-duty component, we’re here to help. Get a free quote today.