Commonly used steel sheet metal ranges from 30 gauge to about 7 gauge.
Car sheet metal 20 gauge.
In most of the world sheet metal thickness is consistently specified in millimeters.
This is not a fancy finish sheet but perfect for patches or fabricating brackets or boxes.
The larger the gauge number the thinner the metal.
20 gauge became common in more recent times and this meant 0 0359 inch thick metal still a lot to work with in bumping and metal finishing.
In the u s the thickness of sheet metal is commonly specified by a traditional non linear measure known as its gauge.
For example 18 gauge steel according to a gauge conversion chart is 0 0478 inch or 1 214 millimeter.
20ga is bit tough to crease well with a crappy bender but if you have a decent press brake it should bend nicely.
A gauge conversion chart can be used to determine the actual thickness of sheet metal in inches or millimeters.
No rust no fingerprints from handling no bends or dings.
Automotive sheet metal once ran in the range of 18 gauge which was 48 thousandths of an inch thick actually 0 0478 inch.