When ordering steel sheet or plate for any project, you will inevitably come across thickness measurements that can confuse you. Even if you understand how manufacturers rate the thickness, it can still come as a surprise when you run into different groups using different measurement types as a standard.
For example, some manufacturers measure in gauges. Some use fractions or decimals. Some indicate sheet with gauge but switch to fractions for plate. Then there are those manufacturers that stick strictly to the metric system.
The Many Different Gauge Standards
The thing that separates steel plate from sheet metal is thickness as measured by gauge. Measuring steel by gauge is confusing to the uninitiated. There are multiple standards, and while it's considered an archaic form of measurement, it's so ubiquitous that it still gets a lot of usage.
Gauge is based on an average weight amount per square inch of steel thickness. The gauge number indicates how thick the piece is in comparison to that average weight. The higher the gauge number, the thicker the material.
To make matters worse, there's not real agreement on the gauge standard. They vary widely and you can never be absolutely sure which standard a manufacturer is using. To put that in perspective, these standards include:
- Standard Decimal Gauge
- U.S. Standard Gauge
- American Standard Gauge (Brown and Sharpe)
- Manufacturer's Standard Gauge
- British Standard Gauge
There are other standards besides such as the Washburn and Moen, Music Wire, and others. Over time, some of them joined and became the standards they are today.
So that means you will see gauge measurements that can come from any one of these, but also from older forms of these as well as split off from these. That's why, if you look, you can find numerous charts and calculators for figuring out the equivalent of one standard as another measurement.
How to Navigate the Different Sizes
Given the confusion that can come of ordering steel plate or sheet for your project, the best thing you can do is make sure you order by specification. That means that you should know precisely the size and weight of the steel you need. When you order it, you can specifically state that size. It will be on the manufacturer or distributor to figure out which of their gauges fit your requirements.
By going with specifications rather than gauges, fractions, fractions of gauges, or anything that's not exact, you risk receiving steel plate or sheets that are not right for your project. One more thing about gauge that you should know is that it varies not just by thickness, but by the base materials used in its particular type. It becomes a bit much. Just make sure that you know what you want, and ask for that specifically.
To learn more, contact a company like Steel Plate Products Inc. with any questions you have.