There are other measurement units used to categorise metals by thickness though.
Common stainless steel sheet thickness.
Foils sheets and plates are pretty much the same with the only difference being in thickness.
For plates up to 10 inches excl in thickness the tolerance under the specified thickness is 0 010.
1300 thru 2100.
Inches mm inches mm 26.
Sheet metal is one of the shapes and forms metal can be bought in.
1000 thru 1300.
0 025 0 64 mm.
Sheet metal is any metal that has a thickness in between 0 5 6 millimetres.
0 0187 0 452 0 0217 0 55 0 0179 0 45 0 0159 40 25.
Thickness is measured along the longitudinal edges of the plate at least 3 8inches but not more than 3 inches from the edge.
A gauge conversion chart can be used to determine the actual thickness of sheet metal in inches or millimeters.
The gauge number 18 holds no relevance to the actual measurements.