What is the sheet metal thickness? There are no definite answers. The thickness of sheet metal can be from 0.006 inches (0.15mm) to 0.25 inches (6.35mm).
Two things can affect the exact thickness. These two things are the gauge number and the metal type. This knowledge is the initial step to understanding any project.
Material thinner than this range is commonly referred to as foil. Material that is thicker is often classified as metal plate. This guide will walk you through everything you need to know about how thick is sheet metal.
Gauge System to Understand Sheet Metal: Why a Higher Number Refers to a Thinner Metal
If you don’t know it, the gauge system can prove to be a little bit tricky. It is a standard for measuring the material thickness. But it is a bit reversed from what you would think. Understanding it is essential for the success of your project.
What is Sheet Metal Gauge?
A sheet metal gauge, or “gage,” is a number that indicates the thickness of the material. The most crucial rule to remember is that the system is backwards.
This means that as the gauge number goes up, the material gets thinner. For instance, a 22 gauge steel sheet is way less thick than a 10 gauge steel sheet.
Why Shouldn’t the Gauge System be the Same for All Metals?
One of the mistakes people make is to believe that a gauge number is the same for all metals. Well, this is a false statement. There are different gauge standards for different materials, including steel, aluminum, and stainless steel.
An 18 gauge steel sheet does not have the same thickness as an 18 gauge aluminum sheet. It is very important to refer to the right chart for your material. You can read more by Understanding Sheet Metal Types, Gauges and Thicknesses.
In the old days, steel gauge standards were based on the weight of the material and were measured in pounds per square foot. Since different metals weigh differently, their thickness for a certain gauge number will be different. This is why determining how thick is sheet metal may involve knowing the material type.
Sheet vs. Plate: Where’s the Dividing Line?
There is a general industry guideline to follow when distinguishing between “sheet” and “plate.” The change usually happens around 7 gauge, which is about 3/16 inch to 1/4 inch thick.
Once the material is thicker than this, it is considered a plate. Plate thickness is measured directly in inches or millimeters, without the use of a gauge number.
Understand Sheet Metal Thickness Charts: Gauge to Inches & Millimeters
To find the exact thickness of sheet metal, the easiest way is to consult a chart. Below are charts for the most common materials used in manufacturing. They convert gauge numbers to both inches and millimeters.
Standard Steel Sheet Metal Gauge Chart
This particular chart applies to common carbon steel. It is one of the most used standards for manufacturing.
| Gauge | Thickness (Inches) | Thickness (mm) |
|---|---|---|
| 30 | 0.0120 | 0.30 |
| 28 | 0.0149 | 0.38 |
| 26 | 0.0179 | 0.45 |
| 24 | 0.0239 | 0.61 |
| 22 | 0.0299 | 0.76 |
| 20 | 0.0359 | 0.91 |
| 18 | 0.0478 | 1.21 |
| 16 | 0.0598 | 1.52 |
| 14 | 0.0747 | 1.90 |
| 12 | 0.1046 | 2.66 |
| 10 | 0.1345 | 3.42 |
| 7 | 0.1793 | 4.55 |
Stainless Steel Sheet Metal Gauge Chart
Stainless steel uses a slightly different gauge scale than regular steel. The differences are small but can be crucial for precision work.
| Gauge | Thickness (Inches) | Thickness (mm) |
|---|---|---|
| 30 | 0.0125 | 0.32 |
| 28 | 0.0156 | 0.40 |
| 26 | 0.0187 | 0.47 |
| 24 | 0.0250 | 0.64 |
| 22 | 0.0312 | 0.79 |
| 20 | 0.0375 | 0.95 |
| 18 | 0.0500 | 1.27 |
| 16 | 0.0625 | 1.59 |
| 14 | 0.0781 | 1.98 |
| 12 | 0.1094 | 2.78 |
| 10 | 0.1406 | 3.57 |
| 7 | 0.1875 | 4.76 |
Aluminum Sheet Metal Gauge Chart
Aluminum thickness is very different from steel for the same gauge number. Therefore, you should always ensure that you use the correct chart when working with aluminum projects.
| Gauge | Thickness (Inches) | Thickness (mm) |
|---|---|---|
| 30 | 0.0100 | 0.25 |
| 28 | 0.0126 | 0.32 |
| 26 | 0.0159 | 0.40 |
| 24 | 0.0201 | 0.51 |
| 22 | 0.0253 | 0.64 |
| 20 | 0.0320 | 0.81 |
| 18 | 0.0403 | 1.02 |
| 16 | 0.0508 | 1.29 |
| 14 | 0.0641 | 1.63 |
| 12 | 0.0808 | 2.05 |
| 10 | 0.1019 | 2.59 |
| 7 | 0.1443 | 3.67 |
Moreover, other metals like copper and brass also have their own gauge systems. It is of utmost importance to use the right standard for your specific material.
How to Choose an Appropriate Sheet Metal Thickness for Your Job
Theoretical knowledge about the metal thickness is one thing, while the selection of the appropriate thickness is another matter. Your decision governs everything, including the strength, weight, and the final price.
Key Considerations
When you are looking for material thickness, consider these key points:
- Strength & Load-Bearing: Should the part be able to hold weight or withstand bending? Thicker material provides more strength.
- Weight: Does the weight of the final product matter? For parts in airplanes or cars, it is often better to use lighter, thinner materials.
- Formability: Does the part need to be bent or formed into a complex shape? Thinner material is much simpler to work with.
- Robustness & Lifespan: Will the part be impacted, scraped, or exposed to weather? A thicker sheet gives better protection against damage in the long run.
- Cost: Thicker material is more expensive per sheet. It might also require more time to work with, adding to the overall project cost.
Real-World Examples by Thickness Range
As an industry leader in manufacturing, we help clients every day by suggesting thicknesses that are just right. Here are some common examples based on gauge range:
- Thin Gauge (22-30 ga): Ideal for lightweight jobs that require forming, this range is great. You see it in computer cases, electronic boxes, signs, and air ducts. Additionally, car panels that do not hold weight also use this thin material.
- Medium Gauge (16-20 ga): This is the go-to range for many general projects. It offers an excellent combination of strength, formability, and cost. Common uses include appliance housings, strong brackets, equipment frames, and durable boxes. It is also one of the most common choices for sheet metal fabrication of all types.
- Heavy Gauge (7-14 ga): When strength is the first priority, you move into this category. These thick sheets are used for supports, heavy-duty equipment frames, mounting plates, and parts for farm machinery.
Beyond Gauge: Why Sheet Metal Thickness Tolerance Should be Considered
For professionals, knowledge of the gauge alone is not enough. You must also be aware of thickness tolerance. This small detail can determine the success or failure of a high-precision project.
What is Thickness Tolerance?
Thickness tolerance is the small amount of change allowed in a sheet’s thickness. When a mill manufactures a sheet of 16 gauge steel (0.0598″), it will not be exactly that thick all over.
The tolerance could be +/- 0.005 inches. This means the actual thickness could be anywhere from 0.0548″ to 0.0648″. You can find this information on the material’s spec sheet.
Why is Tolerance Important for Making Things?
This little adjustment can drastically change the final product.
First, it can affect bending. A press brake is set for a specific thickness. If the material is thicker or thinner than expected, the bend angle will be wrong. This can ruin the part’s final size.
Second, it can lead to welding problems. A large variation in thickness can affect how the material heats and melts, which can lead to poor weld quality.
Finally, tolerance is key for assembly. When many parts are joined together, their small variations can add up. This “tolerance stack-up” can prevent parts from fitting correctly. This is especially critical when combining fabricated sheets with precision parts from China CNC machining services, where every dimension must be exact.
A Look at a Tolerance Chart
Tolerance values are determined by industry standards, and they can differ depending on the material, thickness, and width of the sheet. Be sure to check the standard thickness tolerance charts for your specific material. Here is a simple example for steel:
| Nominal Thickness (in) | Tolerance (+/- in) for 48″ Wide Sheet |
|---|---|
| 0.0359 (20 ga) | 0.004 |
| 0.0598 (16 ga) | 0.005 |
| 0.1046 (12 ga) | 0.007 |
How to Measure Sheet Metal Thickness the Right Way
You can’t always trust that a sheet is the gauge it’s supposed to be. Checking the thickness yourself is a good practice to ensure quality and avoid mistakes. Knowing how to measure sheet metal thickness correctly is a basic skill.
The Correct Tools for the Job
You will need a proper tool to get a precise measurement.
A digital caliper is great for quick checks. It is user-friendly and gives a fast reading. However, be careful with rough edges, which can give a false reading.
A micrometer is the professional’s choice. It is more accurate than a caliper because it uses a special system to apply even pressure. This gives a more reliable measurement of the true sheet metal thickness.
A sheet metal gauge tool, often a wheel with slots, is used for quick identification. You find the slot the metal fits into to identify the gauge. It is less for exact measurement and more for a fast check.
Step-by-Step Measurement Process
Adhere to these steps for an accurate measurement:
- Clean the surface of the metal. Remove any dirt, oil, or coatings that could alter the reading.
- Measure away from the edges. The cutting process often leaves a small rough spot on the edge that will make the sheet seem thicker than it is.
- Take measurements at several different locations. This helps you check for consistency and understand the material’s tolerance.
- Compare your average measurement to a gauge chart. This will help you verify the gauge of the material you are working with.
Your Partner for Precision Sheet Metal Projects
Knowing how thick sheet metal is, how the gauge system works, and how to choose the right material are the basic foundations for any successful project. These details are what separate a good part from a great one.
Whether it’s a simple bracket or a complex assembly, getting the thickness right is the first step. This guarantees that your product will have the desired strength, weight, and performance.
For projects that require expert guidance and precision from start to finish, we can help. The team at Mekalite provides comprehensive solutions based on years of experience. Contact us to discuss your next project’s needs.
Frequently Asked Questions (FAQ)
What is the most common sheet metal thickness?
While it varies by industry, 16 gauge (about 0.06 inches or 1.5mm) is very common, as it offers an excellent balance of strength, formability, and weight. This makes it suitable for a wide range of applications, from boxes to brackets.
